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bf48d9b7 |
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16-Feb-2024 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: change tool coverage variables to take the path relative to $(obj) Commit 54b8ae66ae1a ("kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)") changed the syntax of per-file compiler flags. The situation is the same for the following variables: OBJECT_FILES_NON_STANDARD_<basetarget>.o GCOV_PROFILE_<basetarget>.o KASAN_SANITIZE_<basetarget>.o KMSAN_SANITIZE_<basetarget>.o KMSAN_ENABLE_CHECKS_<basetarget>.o UBSAN_SANITIZE_<basetarget>.o KCOV_INSTRUMENT_<basetarget>.o KCSAN_SANITIZE_<basetarget>.o KCSAN_INSTRUMENT_BARRIERS_<basetarget>.o The <basetarget> is the filename of the target with its directory and suffix stripped. This syntax comes into a trouble when two files with the same basename appear in one Makefile, for example: obj-y += dir1/foo.o obj-y += dir2/foo.o OBJECT_FILES_NON_STANDARD_foo.o := y OBJECT_FILES_NON_STANDARD_foo.o is applied to both dir1/foo.o and dir2/foo.o. This syntax is not flexbile enough to handle cases where one of them is a standard object, but the other is not. It is more sensible to use the relative path to the Makefile, like this: obj-y += dir1/foo.o OBJECT_FILES_NON_STANDARD_dir1/foo.o := y obj-y += dir2/foo.o OBJECT_FILES_NON_STANDARD_dir2/foo.o := y To maintain the current behavior, I made adjustments to the following two Makefiles: - arch/x86/entry/vdso/Makefile, which compiles vclock_gettime.o, vgetcpu.o, and their vdso32 variants. - arch/x86/kvm/Makefile, which compiles vmx/vmenter.o and svm/vmenter.o Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Acked-by: Sean Christopherson <seanjc@google.com>
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24507871 |
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09-Jan-2024 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: create a list of all built DTB files It is useful to have a list of all *.dtb and *.dtbo files generated from the current build. With this commit, 'make dtbs' creates arch/*/boot/dts/dtbs-list, which lists the dtb(o) files created in the current build. It maintains the order of the dtb-y additions in Makefiles although the order is not important for DTBs. It is a (good) side effect through the reuse of the modules.order rule. Please note this list only includes the files directly added to dtb-y. For example, consider this case: foo-dtbs := foo_base.dtb foo_overlay.dtbo dtb-y := foo.dtb In this example, the list will include foo.dtb, but not foo_base.dtb or foo_overlay.dtbo. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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ecab4115 |
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16-Feb-2024 |
Miguel Ojeda <ojeda@kernel.org> |
kbuild: mark `rustc` (and others) invocations as recursive `rustc` (like Cargo) may take advantage of the jobserver at any time (e.g. for backend parallelism, or eventually frontend too). In the kernel, we call `rustc` with `-Ccodegen-units=1` (and `-Zthreads` is 1 so far), so we do not expect parallelism. However, in the upcoming Rust 1.76.0, a warning is emitted by `rustc` [1] when it cannot connect to the jobserver it was passed (in many cases, but not all: compiling and `--print sysroot` do, but `--version` does not). And given GNU Make always passes the jobserver in the environment variable (even when a line is deemed non-recursive), `rustc` will end up complaining about it (in particular in Make 4.3 where there is only the simple pipe jobserver style). One solution is to remove the jobserver from `MAKEFLAGS`. However, we can mark the lines with calls to `rustc` (and Cargo) as recursive, which looks simpler. This is being documented as a recommendation in `rustc` [2] and allows us to be ready for the time we may use parallelism inside `rustc` (potentially now, if a user passes `-Zthreads`). Thus do so. Similarly, do the same for `rustdoc` and `cargo` calls. Finally, there is one case that the solution does not cover, which is the `$(shell ...)` call we have. Thus, for that one, set an empty `MAKEFLAGS` environment variable. Link: https://github.com/rust-lang/rust/issues/120515 [1] Acked-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://github.com/rust-lang/rust/pull/121564 [2] Link: https://lore.kernel.org/r/20240217002638.57373-1-ojeda@kernel.org [ Reworded to add link to PR documenting the recommendation. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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71479eee |
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31-Oct-2023 |
Matthew Maurer <mmaurer@google.com> |
rust: Suppress searching builtin sysroot By default, if Rust is passed `--target=foo` rather than a target.json file, it will infer a default sysroot if that component is installed. As the proposed aarch64 support [1] uses `aarch64-unknown-none` rather than a target.json file, this is needed [2] to prevent rustc from being confused between the custom kernel sysroot and the pre-installed one. [ Miguel: Applied Boqun's extra case (for `rusttest`) and reworded to add links to the arm64 patch series discussion. In addition, fixed the `rustdoc` target too (which requires a conditional since `cmd_rustdoc` is also used for host crates like `macros`). ] Signed-off-by: Matthew Maurer <mmaurer@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/rust-for-linux/20231020155056.3495121-1-Jamie.Cunliffe@arm.com/ [1] Link: https://lore.kernel.org/rust-for-linux/CAGSQo01pOixiPXkW867h4vPUaAjtKtHGKhkV-rpifJvKxAf4Ww@mail.gmail.com/ [2] Link: https://lore.kernel.org/r/20231031201752.1189213-1-mmaurer@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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1b1595cd |
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22-Oct-2023 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: simplify cmd_ld_multi_m $(patsubst %.o,%.mod,$@) can be replaced with $<. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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7324b889 |
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28-Aug-2023 |
Alice Ryhl <aliceryhl@google.com> |
rust: workqueue: add helper for defining work_struct fields The main challenge with defining `work_struct` fields is making sure that the function pointer stored in the `work_struct` is appropriate for the work item type it is embedded in. It needs to know the offset of the `work_struct` field being used (even if there are several!) so that it can do a `container_of`, and it needs to know the type of the work item so that it can call into the right user-provided code. All of this needs to happen in a way that provides a safe API to the user, so that users of the workqueue cannot mix up the function pointers. There are three important pieces that are relevant when doing this: * The pointer type. * The work item struct. This is what the pointer points at. * The `work_struct` field. This is a field of the work item struct. This patch introduces a separate trait for each piece. The pointer type is given a `WorkItemPointer` trait, which pointer types need to implement to be usable with the workqueue. This trait will be implemented for `Arc` and `Box` in a later patch in this patchset. Implementing this trait is unsafe because this is where the `container_of` operation happens, but user-code will not need to implement it themselves. The work item struct should then implement the `WorkItem` trait. This trait is where user-code specifies what they want to happen when a work item is executed. It also specifies what the correct pointer type is. Finally, to make the work item struct know the offset of its `work_struct` field, we use a trait called `HasWork<T, ID>`. If a type implements this trait, then the type declares that, at the given offset, there is a field of type `Work<T, ID>`. The trait is marked unsafe because the OFFSET constant must be correct, but we provide an `impl_has_work!` macro that can safely implement `HasWork<T>` on a type. The macro expands to something that only compiles if the specified field really has the type `Work<T>`. It is used like this: ``` struct MyWorkItem { work_field: Work<MyWorkItem, 1>, } impl_has_work! { impl HasWork<MyWorkItem, 1> for MyWorkItem { self.work_field } } ``` Note that since the `Work` type is annotated with an id, you can have several `work_struct` fields by using a different id for each one. Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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df01b7cf |
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23-Jul-2023 |
Miguel Ojeda <ojeda@kernel.org> |
kbuild: rust: avoid creating temporary files `rustc` outputs by default the temporary files (i.e. the ones saved by `-Csave-temps`, such as `*.rcgu*` files) in the current working directory when `-o` and `--out-dir` are not given (even if `--emit=x=path` is given, i.e. it does not use those for temporaries). Since out-of-tree modules are compiled from the `linux` tree, `rustc` then tries to create them there, which may not be accessible. Thus pass `--out-dir` explicitly, even if it is just for the temporary files. Similarly, do so for Rust host programs too. Reported-by: Raphael Nestler <raphael.nestler@gmail.com> Closes: https://github.com/Rust-for-Linux/linux/issues/1015 Reported-by: Andrea Righi <andrea.righi@canonical.com> Tested-by: Raphael Nestler <raphael.nestler@gmail.com> # non-hostprogs Tested-by: Andrea Righi <andrea.righi@canonical.com> # non-hostprogs Fixes: 295d8398c67e ("kbuild: specify output names separately for each emission type from rustc") Cc: stable@vger.kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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5e9e95cc9 |
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11-Jun-2023 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. Linus stated negative opinions about this slowness in commits: - 5cf0fd591f2e ("Kbuild: disable TRIM_UNUSED_KSYMS option") - a555bdd0c58c ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding") We can do this better now. The final data structures of EXPORT_SYMBOL are generated by the modpost stage, so modpost can selectively emit KSYMTAB entries that are really used by modules. Commit f73edc8951b2 ("kbuild: unify two modpost invocations") is another ground-work to do this in a one-pass algorithm. With the list of modules, modpost sets sym->used if it is used by a module. modpost emits KSYMTAB only for symbols with sym->used==true. BTW, Nicolas explained why the trimming was implemented with recursion: https://lore.kernel.org/all/2o2rpn97-79nq-p7s2-nq5-8p83391473r@syhkavp.arg/ Actually, we never achieved that level of optimization where the chain reaction of trimming comes into play because: - CONFIG_LTO_CLANG cannot remove any unused symbols - CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled only for vmlinux, but not modules If deeper trimming is required, we need to revisit this, but I guess that is unlikely to happen. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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6d62b1c4 |
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11-Jun-2023 |
Masahiro Yamada <masahiroy@kernel.org> |
modpost: check static EXPORT_SYMBOL* by modpost again Commit 31cb50b5590f ("kbuild: check static EXPORT_SYMBOL* by script instead of modpost") moved the static EXPORT_SYMBOL* check from the mostpost to a shell script because I thought it must be checked per compilation unit to avoid false negatives. I came up with an idea to do this in modpost, against combined ELF files. The relocation entries in ELF will find the correct exported symbol even if there exist symbols with the same name in different compilation units. Again, the same sample code. Makefile: obj-y += foo1.o foo2.o foo1.c: #include <linux/export.h> static void foo(void) {} EXPORT_SYMBOL(foo); foo2.c: void foo(void) {} Then, modpost can catch it correctly. MODPOST Module.symvers ERROR: modpost: vmlinux: local symbol 'foo' was exported Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
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ddb5cdba |
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11-Jun-2023 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: generate KSYMTAB entries by modpost Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way whether the EXPORT_SYMBOL() is placed in *.c or *.S. For further cleanups, this commit applies a similar approach to the entire data structure of EXPORT_SYMBOL(). The EXPORT_SYMBOL() compilation is split into two stages. When a source file is compiled, EXPORT_SYMBOL() will be converted into a dummy symbol in the .export_symbol section. For example, EXPORT_SYMBOL(foo); EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE); will be encoded into the following assembly code: .section ".export_symbol","a" __export_symbol_foo: .asciz "" /* license */ .asciz "" /* name space */ .balign 8 .quad foo /* symbol reference */ .previous .section ".export_symbol","a" __export_symbol_bar: .asciz "GPL" /* license */ .asciz "BAR_NAMESPACE" /* name space */ .balign 8 .quad bar /* symbol reference */ .previous They are mere markers to tell modpost the name, license, and namespace of the symbols. They will be dropped from the final vmlinux and modules because the *(.export_symbol) will go into /DISCARD/ in the linker script. Then, modpost extracts all the information about EXPORT_SYMBOL() from the .export_symbol section, and generates the final C code: KSYMTAB_FUNC(foo, "", ""); KSYMTAB_FUNC(bar, "_gpl", "BAR_NAMESPACE"); KSYMTAB_FUNC() (or KSYMTAB_DATA() if it is data) is expanded to struct kernel_symbol that will be linked to the vmlinux or a module. With this change, EXPORT_SYMBOL() works in the same way for *.c and *.S files, providing the following benefits. [1] Deprecate EXPORT_DATA_SYMBOL() In the old days, EXPORT_SYMBOL() was only available in C files. To export a symbol in *.S, EXPORT_SYMBOL() was placed in a separate *.c file. arch/arm/kernel/armksyms.c is one example written in the classic manner. Commit 22823ab419d8 ("EXPORT_SYMBOL() for asm") removed this limitation. Since then, EXPORT_SYMBOL() can be placed close to the symbol definition in *.S files. It was a nice improvement. However, as that commit mentioned, you need to use EXPORT_DATA_SYMBOL() for data objects on some architectures. In the new approach, modpost checks symbol's type (STT_FUNC or not), and outputs KSYMTAB_FUNC() or KSYMTAB_DATA() accordingly. There are only two users of EXPORT_DATA_SYMBOL: EXPORT_DATA_SYMBOL_GPL(empty_zero_page) (arch/ia64/kernel/head.S) EXPORT_DATA_SYMBOL(ia64_ivt) (arch/ia64/kernel/ivt.S) They are transformed as follows and output into .vmlinux.export.c KSYMTAB_DATA(empty_zero_page, "_gpl", ""); KSYMTAB_DATA(ia64_ivt, "", ""); The other EXPORT_SYMBOL users in ia64 assembly are output as KSYMTAB_FUNC(). EXPORT_DATA_SYMBOL() is now deprecated. [2] merge <linux/export.h> and <asm-generic/export.h> There are two similar header implementations: include/linux/export.h for .c files include/asm-generic/export.h for .S files Ideally, the functionality should be consistent between them, but they tend to diverge. Commit 8651ec01daed ("module: add support for symbol namespaces.") did not support the namespace for *.S files. This commit shifts the essential implementation part to C, which supports EXPORT_SYMBOL_NS() for *.S files. <asm/export.h> and <asm-generic/export.h> will remain as a wrapper of <linux/export.h> for a while. They will be removed after #include <asm/export.h> directives are all replaced with #include <linux/export.h>. [3] Implement CONFIG_TRIM_UNUSED_KSYMS in one-pass algorithm (by a later commit) When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. We can do this better now; modpost can selectively emit KSYMTAB entries that are really used by modules. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
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dd203fef |
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09-Jun-2023 |
Johannes Berg <johannes.berg@intel.com> |
kbuild: enable kernel-doc -Wall for W=2 For W=2, we can enable more kernel-doc warnings, such as missing return value descriptions etc. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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56b0f453 |
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09-Jun-2023 |
Johannes Berg <johannes.berg@intel.com> |
kernel-doc: don't let V=1 change outcome The kernel-doc script currently reports a number of issues only in "verbose" mode, but that's initialized from V=1 (via KBUILD_VERBOSE), so if you use KDOC_WERROR=1 then adding V=1 might actually break the build. This is rather unexpected. Change kernel-doc to not change its behaviour wrt. errors (or warnings) when verbose mode is enabled, but rather add separate warning flags (and -Wall) for it. Allow enabling those flags via environment/make variables in the kernel's build system for easier user use, but to not have to parse them in the script itself. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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3ed03f4d |
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18-Apr-2023 |
Miguel Ojeda <ojeda@kernel.org> |
rust: upgrade to Rust 1.68.2 This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d6e08e ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: https://github.com/Rust-for-Linux/linux/issues/2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: https://github.com/rust-lang/rust/issues/106142 [4] Link: https://github.com/rust-lang/rust/pull/89891 [5] Link: https://github.com/rust-lang/rust/pull/98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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90e53c5e7 |
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07-Apr-2023 |
Benno Lossin <benno.lossin@proton.me> |
rust: add pin-init API core This API is used to facilitate safe pinned initialization of structs. It replaces cumbersome `unsafe` manual initialization with elegant safe macro invocations. Due to the size of this change it has been split into six commits: 1. This commit introducing the basic public interface: traits and functions to represent and create initializers. 2. Adds the `#[pin_data]`, `pin_init!`, `try_pin_init!`, `init!` and `try_init!` macros along with their internal types. 3. Adds the `InPlaceInit` trait that allows using an initializer to create an object inside of a `Box<T>` and other smart pointers. 4. Adds the `PinnedDrop` trait and adds macro support for it in the `#[pin_data]` macro. 5. Adds the `stack_pin_init!` macro allowing to pin-initialize a struct on the stack. 6. Adds the `Zeroable` trait and `init::zeroed` function to initialize types that have `0x00` in all bytes as a valid bit pattern. -- In this section the problem that the new pin-init API solves is outlined. This message describes the entirety of the API, not just the parts introduced in this commit. For a more granular explanation and additional information on pinning and this issue, view [1]. Pinning is Rust's way of enforcing the address stability of a value. When a value gets pinned it will be impossible for safe code to move it to another location. This is done by wrapping pointers to said object with `Pin<P>`. This wrapper prevents safe code from creating mutable references to the object, preventing mutable access, which is needed to move the value. `Pin<P>` provides `unsafe` functions to circumvent this and allow modifications regardless. It is then the programmer's responsibility to uphold the pinning guarantee. Many kernel data structures require a stable address, because there are foreign pointers to them which would get invalidated by moving the structure. Since these data structures are usually embedded in structs to use them, this pinning property propagates to the container struct. Resulting in most structs in both Rust and C code needing to be pinned. So if we want to have a `mutex` field in a Rust struct, this struct also needs to be pinned, because a `mutex` contains a `list_head`. Additionally initializing a `list_head` requires already having the final memory location available, because it is initialized by pointing it to itself. But this presents another challenge in Rust: values have to be initialized at all times. There is the `MaybeUninit<T>` wrapper type, which allows handling uninitialized memory, but this requires using the `unsafe` raw pointers and a casting the type to the initialized variant. This problem gets exacerbated when considering encapsulation and the normal safety requirements of Rust code. The fields of the Rust `Mutex<T>` should not be accessible to normal driver code. After all if anyone can modify the fields, there is no way to ensure the invariants of the `Mutex<T>` are upheld. But if the fields are inaccessible, then initialization of a `Mutex<T>` needs to be somehow achieved via a function or a macro. Because the `Mutex<T>` must be pinned in memory, the function cannot return it by value. It also cannot allocate a `Box` to put the `Mutex<T>` into, because that is an unnecessary allocation and indirection which would hurt performance. The solution in the rust tree (e.g. this commit: [2]) that is replaced by this API is to split this function into two parts: 1. A `new` function that returns a partially initialized `Mutex<T>`, 2. An `init` function that requires the `Mutex<T>` to be pinned and that fully initializes the `Mutex<T>`. Both of these functions have to be marked `unsafe`, since a call to `new` needs to be accompanied with a call to `init`, otherwise using the `Mutex<T>` could result in UB. And because calling `init` twice also is not safe. While `Mutex<T>` initialization cannot fail, other structs might also have to allocate memory, which would result in conditional successful initialization requiring even more manual accommodation work. Combine this with the problem of pin-projections -- the way of accessing fields of a pinned struct -- which also have an `unsafe` API, pinned initialization is riddled with `unsafe` resulting in very poor ergonomics. Not only that, but also having to call two functions possibly multiple lines apart makes it very easy to forget it outright or during refactoring. Here is an example of the current way of initializing a struct with two synchronization primitives (see [3] for the full example): struct SharedState { state_changed: CondVar, inner: Mutex<SharedStateInner>, } impl SharedState { fn try_new() -> Result<Arc<Self>> { let mut state = Pin::from(UniqueArc::try_new(Self { // SAFETY: `condvar_init!` is called below. state_changed: unsafe { CondVar::new() }, // SAFETY: `mutex_init!` is called below. inner: unsafe { Mutex::new(SharedStateInner { token_count: 0 }) }, })?); // SAFETY: `state_changed` is pinned when `state` is. let pinned = unsafe { state.as_mut().map_unchecked_mut(|s| &mut s.state_changed) }; kernel::condvar_init!(pinned, "SharedState::state_changed"); // SAFETY: `inner` is pinned when `state` is. let pinned = unsafe { state.as_mut().map_unchecked_mut(|s| &mut s.inner) }; kernel::mutex_init!(pinned, "SharedState::inner"); Ok(state.into()) } } The pin-init API of this patch solves this issue by providing a comprehensive solution comprised of macros and traits. Here is the example from above using the pin-init API: #[pin_data] struct SharedState { #[pin] state_changed: CondVar, #[pin] inner: Mutex<SharedStateInner>, } impl SharedState { fn new() -> impl PinInit<Self> { pin_init!(Self { state_changed <- new_condvar!("SharedState::state_changed"), inner <- new_mutex!( SharedStateInner { token_count: 0 }, "SharedState::inner", ), }) } } Notably the way the macro is used here requires no `unsafe` and thus comes with the usual Rust promise of safe code not introducing any memory violations. Additionally it is now up to the caller of `new()` to decide the memory location of the `SharedState`. They can choose at the moment `Arc<T>`, `Box<T>` or the stack. -- The API has the following architecture: 1. Initializer traits `PinInit<T, E>` and `Init<T, E>` that act like closures. 2. Macros to create these initializer traits safely. 3. Functions to allow manually writing initializers. The initializers (an `impl PinInit<T, E>`) receive a raw pointer pointing to uninitialized memory and their job is to fully initialize a `T` at that location. If initialization fails, they return an error (`E`) by value. This way of initializing cannot be safely exposed to the user, since it relies upon these properties outside of the control of the trait: - the memory location (slot) needs to be valid memory, - if initialization fails, the slot should not be read from, - the value in the slot should be pinned, so it cannot move and the memory cannot be deallocated until the value is dropped. This is why using an initializer is facilitated by another trait that ensures these requirements. These initializers can be created manually by just supplying a closure that fulfills the same safety requirements as `PinInit<T, E>`. But this is an `unsafe` operation. To allow safe initializer creation, the `pin_init!` is provided along with three other variants: `try_pin_init!`, `try_init!` and `init!`. These take a modified struct initializer as a parameter and generate a closure that initializes the fields in sequence. The macros take great care in upholding the safety requirements: - A shadowed struct type is used as the return type of the closure instead of `()`. This is to prevent early returns, as these would prevent full initialization. - To ensure every field is only initialized once, a normal struct initializer is placed in unreachable code. The type checker will emit errors if a field is missing or specified multiple times. - When initializing a field fails, the whole initializer will fail and automatically drop fields that have been initialized earlier. - Only the correct initializer type is allowed for unpinned fields. You cannot use a `impl PinInit<T, E>` to initialize a structurally not pinned field. To ensure the last point, an additional macro `#[pin_data]` is needed. This macro annotates the struct itself and the user specifies structurally pinned and not pinned fields. Because dropping a pinned struct is also not allowed to break the pinning invariants, another macro attribute `#[pinned_drop]` is needed. This macro is introduced in a following commit. These two macros also have mechanisms to ensure the overall safety of the API. Additionally, they utilize a combined proc-macro, declarative macro design: first a proc-macro enables the outer attribute syntax `#[...]` and does some important pre-parsing. Notably this prepares the generics such that the declarative macro can handle them using token trees. Then the actual parsing of the structure and the emission of code is handled by a declarative macro. For pin-projections the crates `pin-project` [4] and `pin-project-lite` [5] had been considered, but were ultimately rejected: - `pin-project` depends on `syn` [6] which is a very big dependency, around 50k lines of code. - `pin-project-lite` is a more reasonable 5k lines of code, but contains a very complex declarative macro to parse generics. On top of that it would require modification that would need to be maintained independently. Link: https://rust-for-linux.com/the-safe-pinned-initialization-problem [1] Link: https://github.com/Rust-for-Linux/linux/tree/0a04dc4ddd671efb87eef54dde0fb38e9074f4be [2] Link: https://github.com/Rust-for-Linux/linux/blob/f509ede33fc10a07eba3da14aa00302bd4b5dddd/samples/rust/rust_miscdev.rs [3] Link: https://crates.io/crates/pin-project [4] Link: https://crates.io/crates/pin-project-lite [5] Link: https://crates.io/crates/syn [6] Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Link: https://lore.kernel.org/r/20230408122429.1103522-7-y86-dev@protonmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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2d19d369 |
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07-Apr-2023 |
Benno Lossin <benno.lossin@proton.me> |
rust: enable the `pin_macro` feature This feature enables the use of the `pin!` macro for the `stack_pin_init!` macro. This feature is already stabilized in Rust version 1.68. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230408122429.1103522-2-y86-dev@protonmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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3c01a424 |
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24-Feb-2023 |
Asahi Lina <lina@asahilina.net> |
rust: Enable the new_uninit feature for kernel and driver crates The unstable new_uninit feature enables various library APIs to create uninitialized containers, such as `Box::assume_init()`. This is necessary to build abstractions that directly initialize memory at the target location, instead of doing copies through the stack. Will be used by the DRM scheduler abstraction in the kernel crate, and by field-wise initialization (e.g. using `place!()` or a future replacement macro which may itself live in `kernel`) in driver crates. Link: https://github.com/Rust-for-Linux/linux/issues/879 Link: https://github.com/Rust-for-Linux/linux/issues/2 Link: https://github.com/rust-lang/rust/issues/63291 Signed-off-by: Asahi Lina <lina@asahilina.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Link: https://lore.kernel.org/r/20230224-rust-new_uninit-v1-1-c951443d9e26@asahilina.net [ Reworded to use `Link` tags. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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2185242f |
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07-Jan-2023 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: remove sed commands after rustc rules rustc may put comments in dep-info, so sed is used to drop them before passing it to fixdep. Now that fixdep can remove comments, Makefiles do not need to run sed. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Tested-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
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295d8398 |
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07-Jan-2023 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: specify output names separately for each emission type from rustc In Kbuild, two different rules must not write to the same file, but it happens when compiling rust source files. For example, set CONFIG_SAMPLE_RUST_MINIMAL=m and run the following: $ make -j$(nproc) samples/rust/rust_minimal.o samples/rust/rust_minimal.rsi \ samples/rust/rust_minimal.s samples/rust/rust_minimal.ll [snip] RUSTC [M] samples/rust/rust_minimal.o RUSTC [M] samples/rust/rust_minimal.rsi RUSTC [M] samples/rust/rust_minimal.s RUSTC [M] samples/rust/rust_minimal.ll mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory make[3]: *** [scripts/Makefile.build:334: samples/rust/rust_minimal.ll] Error 1 make[3]: *** Waiting for unfinished jobs.... mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory make[3]: *** [scripts/Makefile.build:309: samples/rust/rust_minimal.o] Error 1 mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory make[3]: *** [scripts/Makefile.build:326: samples/rust/rust_minimal.s] Error 1 make[2]: *** [scripts/Makefile.build:504: samples/rust] Error 2 make[1]: *** [scripts/Makefile.build:504: samples] Error 2 make: *** [Makefile:2008: .] Error 2 The reason for the error is that 4 threads running in parallel renames the same file, samples/rust/rust_minimal.d. This does not happen when compiling C or assembly files because -Wp,-MMD,$(depfile) explicitly specifies the dependency filepath. $(depfile) is a unique path for each target. Currently, rustc is only given --out-dir and --emit=<list-of-types> So, all the rust build rules output the dep-info into the default <CRATE_NAME>.d, which causes the path conflict. Fortunately, the --emit option is able to specify the output path individually, with the form --emit=<type>=<path>. Add --emit=dep-info=$(depfile) to the common part. Also, remove the redundant --out-dir because the output path is specified for each type. The code gets much cleaner because we do not need to rename *.d files. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Tested-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
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f65a4868 |
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11-Dec-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: change module.order to list *.o instead of *.ko scripts/Makefile.build replaces the suffix .o with .ko, then scripts/Makefile.modpost calls the sed command to change .ko back to the original .o suffix. Instead of converting the suffixes back-and-forth, store the .o paths in modules.order, and replace it with .ko in 'make modules_install'. This avoids the unneeded sed command. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
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598afa05 |
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18-Nov-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: warn objects shared among multiple modules If an object is shared among multiple modules, and some of them are configured as 'm', but the others as 'y', the shared object is built as modular, then linked to the modules and vmlinux. This is a potential issue because the expected CFLAGS are different between modules and builtins. Commit 637a642f5ca5 ("zstd: Fixing mixed module-builtin objects") reported that this could be even more fatal in some cases such as Clang LTO. That commit fixed lib/zlib/zstd_{compress,decompress}, but there are still more instances of breakage. This commit adds a W=1 warning for shared objects, so that the kbuild test robot, which provides build tests with W=1, will avoid a new breakage slipping in. Quick compile tests on v6.1-rc4 detected the following: scripts/Makefile.build:252: ./drivers/block/rnbd/Makefile: rnbd-common.o is added to multiple modules: rnbd-client rnbd-server scripts/Makefile.build:252: ./drivers/crypto/marvell/octeontx2/Makefile: cn10k_cpt.o is added to multiple modules: rvu_cptpf rvu_cptvf scripts/Makefile.build:252: ./drivers/crypto/marvell/octeontx2/Makefile: otx2_cptlf.o is added to multiple modules: rvu_cptpf rvu_cptvf scripts/Makefile.build:252: ./drivers/crypto/marvell/octeontx2/Makefile: otx2_cpt_mbox_common.o is added to multiple modules: rvu_cptpf rvu_cptvf scripts/Makefile.build:252: ./drivers/edac/Makefile: skx_common.o is added to multiple modules: i10nm_edac skx_edac scripts/Makefile.build:252: ./drivers/gpu/drm/bridge/imx/Makefile: imx-ldb-helper.o is added to multiple modules: imx8qm-ldb imx8qxp-ldb scripts/Makefile.build:252: ./drivers/mfd/Makefile: rsmu_core.o is added to multiple modules: rsmu-i2c rsmu-spi scripts/Makefile.build:252: ./drivers/mtd/tests/Makefile: mtd_test.o is added to multiple modules: mtd_nandbiterrs mtd_oobtest mtd_pagetest mtd_readtest mtd_speedtest mtd_stresstest mtd_subpagetest mtd_torturetest scripts/Makefile.build:252: ./drivers/net/dsa/ocelot/Makefile: felix.o is added to multiple modules: mscc_felix mscc_seville scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: cn23xx_pf_device.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: cn23xx_vf_device.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: cn66xx_device.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: cn68xx_device.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: lio_core.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: lio_ethtool.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: octeon_device.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: octeon_droq.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: octeon_mailbox.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: octeon_mem_ops.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: octeon_nic.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: request_manager.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: response_manager.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/freescale/dpaa2/Makefile: dpaa2-mac.o is added to multiple modules: fsl-dpaa2-eth fsl-dpaa2-switch scripts/Makefile.build:252: ./drivers/net/ethernet/freescale/dpaa2/Makefile: dpmac.o is added to multiple modules: fsl-dpaa2-eth fsl-dpaa2-switch scripts/Makefile.build:252: ./drivers/net/ethernet/freescale/enetc/Makefile: enetc_cbdr.o is added to multiple modules: fsl-enetc fsl-enetc-vf scripts/Makefile.build:252: ./drivers/net/ethernet/freescale/enetc/Makefile: enetc_ethtool.o is added to multiple modules: fsl-enetc fsl-enetc-vf scripts/Makefile.build:252: ./drivers/net/ethernet/freescale/enetc/Makefile: enetc.o is added to multiple modules: fsl-enetc fsl-enetc-vf scripts/Makefile.build:252: ./drivers/net/ethernet/hisilicon/hns3/Makefile: hns3_common/hclge_comm_cmd.o is added to multiple modules: hclge hclgevf scripts/Makefile.build:252: ./drivers/net/ethernet/hisilicon/hns3/Makefile: hns3_common/hclge_comm_rss.o is added to multiple modules: hclge hclgevf scripts/Makefile.build:252: ./drivers/net/ethernet/hisilicon/hns3/Makefile: hns3_common/hclge_comm_tqp_stats.o is added to multiple modules: hclge hclgevf scripts/Makefile.build:252: ./drivers/net/ethernet/marvell/octeontx2/nic/Makefile: otx2_dcbnl.o is added to multiple modules: rvu_nicpf rvu_nicvf scripts/Makefile.build:252: ./drivers/net/ethernet/marvell/octeontx2/nic/Makefile: otx2_devlink.o is added to multiple modules: rvu_nicpf rvu_nicvf scripts/Makefile.build:252: ./drivers/net/ethernet/ti/Makefile: cpsw_ale.o is added to multiple modules: keystone_netcp keystone_netcp_ethss ti_cpsw ti_cpsw_new scripts/Makefile.build:252: ./drivers/net/ethernet/ti/Makefile: cpsw_ethtool.o is added to multiple modules: ti_cpsw ti_cpsw_new scripts/Makefile.build:252: ./drivers/net/ethernet/ti/Makefile: cpsw_priv.o is added to multiple modules: ti_cpsw ti_cpsw_new scripts/Makefile.build:252: ./drivers/net/ethernet/ti/Makefile: cpsw_sl.o is added to multiple modules: ti_cpsw ti_cpsw_new scripts/Makefile.build:252: ./drivers/net/ethernet/ti/Makefile: davinci_cpdma.o is added to multiple modules: ti_cpsw ti_cpsw_new ti_davinci_emac scripts/Makefile.build:252: ./drivers/platform/x86/intel/int3472/Makefile: common.o is added to multiple modules: intel_skl_int3472_discrete intel_skl_int3472_tps68470 scripts/Makefile.build:252: ./sound/soc/codecs/Makefile: wcd-clsh-v2.o is added to multiple modules: snd-soc-wcd9335 snd-soc-wcd934x snd-soc-wcd938x Once all the warnings are fixed, it can become an error without the W= option. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Tested-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
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a2430b25 |
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18-Nov-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: add kbuild-file macro While building, installing, cleaning, Kbuild visits sub-directories and includes 'Kbuild' or 'Makefile' that exists there. Add 'kbuild-file' macro, and reuse it from scripts/Makefie.* Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Tested-by: Alexander Lobakin <alobakin@pm.me>
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dcad240c |
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14-Nov-2022 |
Andrew Davis <afd@ti.com> |
kbuild: Cleanup DT Overlay intermediate files as appropriate %.dtbo.o and %.dtbo.S files are used to build-in DT Overlay. They should should not be removed by Make or the kernel will be needlessly rebuilt. These should be removed by "clean" and ignored by git like other intermediate files. Reported-by: Andy Shevchenko <andriy.shevchenko@intel.com> Signed-off-by: Andrew Davis <afd@ti.com> Fixes: 941214a512d8 ("kbuild: Allow DTB overlays to built into .dtbo.S files") Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://lore.kernel.org/r/20221114205939.27994-1-afd@ti.com Signed-off-by: Rob Herring <robh@kernel.org>
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c67a85be |
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14-Oct-2022 |
Nick Desaulniers <ndesaulniers@google.com> |
kbuild: add -fno-discard-value-names to cmd_cc_ll_c When debugging LLVM IR, it can be handy for clang to not discard value names used for local variables and parameters. Compare the generated IR. -fdiscard-value-names: define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) { %6 = alloca i64 %7 = alloca %struct.poll_wqueues %8 = alloca [64 x i32] -fno-discard-value-names: define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp, ptr %end_time) { %expire.i = alloca i64 %table.i = alloca %struct.poll_wqueues %stack_fds = alloca [64 x i32] The rule for generating human readable LLVM IR (.ll) is only useful as a debugging feature: $ make LLVM=1 fs/select.ll As Fangrui notes: A LLVM_ENABLE_ASSERTIONS=off build of Clang defaults to -fdiscard-value-names. A LLVM_ENABLE_ASSERTIONS=on build of Clang defaults to -fno-discard-value-names. Explicitly enable -fno-discard-value-names so that the IR always contains value names regardless of whether assertions were enabled or not. Assertions generally are not enabled in releases of clang packaged by distributions. Link: https://github.com/ClangBuiltLinux/linux/issues/1467 Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Fangrui Song <maskray@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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cc306abd |
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06-Sep-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: fix and refactor single target build The single target build has a subtle bug for the combination for an individual file and a subdirectory. [1] 'make kernel/fork.i' builds only kernel/fork.i $ make kernel/fork.i CALL scripts/checksyscalls.sh DESCEND objtool CPP kernel/fork.i [2] 'make kernel/' builds only under the kernel/ directory. $ make kernel/ CALL scripts/checksyscalls.sh DESCEND objtool CC kernel/fork.o CC kernel/exec_domain.o [snip] CC kernel/rseq.o AR kernel/built-in.a But, if you try to do [1] and [2] in a single command, you will get only [1] with a weird log: $ make kernel/fork.i kernel/ CALL scripts/checksyscalls.sh DESCEND objtool CPP kernel/fork.i make[2]: Nothing to be done for 'kernel/'. With 'make kernel/fork.i kernel/', you should get both [1] and [2]. Rewrite the single target build. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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d724b578 |
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20-Aug-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: do not deduplicate modules.order The AWK code was added to deduplicate modules.order in case $(obj-m) contains the same module multiple times, but it is actually unneeded since commit b2c885549122 ("kbuild: update modules.order only when contained modules are updated"). The list is already deduplicated before being processed by AWK because $^ is the deduplicated list of prerequisites. (Please note the real-prereqs macro uses $^) Yet, modules.order will contain duplication if two different Makefiles build the same module: foo/Makefile: obj-m += bar/baz.o foo/bar/Makefile: obj-m += baz.o However, the parallel builds cannot properly handle this case in the first place. So, it is better to let it fail (as already done by scripts/modules-check.sh). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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2f7ab126 |
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03-Jul-2021 |
Miguel Ojeda <ojeda@kernel.org> |
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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5439d4d4 |
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13-Jun-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: remove sed command from cmd_ar_builtin Replace a pipeline of echo and sed with printf to decrease process forks. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
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7bf179de |
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06-Jun-2022 |
Kevin Locke <kevin@kevinlocke.name> |
kbuild: avoid regex RS for POSIX awk In 22f26f21774f8 awk was added to deduplicate *.mod files. The awk invocation passes -v RS='( |\n)' to match a space or newline character as the record separator. Unfortunately, POSIX states[1] > If RS contains more than one character, the results are unspecified. Some implementations (such as the One True Awk[2] used by the BSDs) do not treat RS as a regular expression. When awk does not support regex RS, build failures such as the following are produced (first error using allmodconfig): CC [M] arch/x86/events/intel/uncore.o CC [M] arch/x86/events/intel/uncore_nhmex.o CC [M] arch/x86/events/intel/uncore_snb.o CC [M] arch/x86/events/intel/uncore_snbep.o CC [M] arch/x86/events/intel/uncore_discovery.o LD [M] arch/x86/events/intel/intel-uncore.o ld: cannot find uncore_nhmex.o: No such file or directory ld: cannot find uncore_snb.o: No such file or directory ld: cannot find uncore_snbep.o: No such file or directory ld: cannot find uncore_discovery.o: No such file or directory make[3]: *** [scripts/Makefile.build:422: arch/x86/events/intel/intel-uncore.o] Error 1 make[2]: *** [scripts/Makefile.build:487: arch/x86/events/intel] Error 2 make[1]: *** [scripts/Makefile.build:487: arch/x86/events] Error 2 make: *** [Makefile:1839: arch/x86] Error 2 To avoid this, use printf(1) to produce a newline between each object path, instead of the space produced by echo(1), so that the default RS can be used by awk. [1]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/awk.html [2]: https://github.com/onetrueawk/awk Fixes: 22f26f21774f ("kbuild: get rid of duplication in *.mod files") Signed-off-by: Kevin Locke <kevin@kevinlocke.name> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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b42d2306 |
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28-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: factor out the common objtool arguments scripts/Makefile.build and scripts/link-vmlinux.sh have similar setups for the objtool arguments. It was difficult to factor out them because all the vmlinux build rules were written in a shell script. It is somewhat tedious to touch the two files every time a new objtool option is supported. To reduce the code duplication, move the objtool for vmlinux.o into scripts/Makefile.vmlinux_o. Then, move the common macros to Makefile.lib so they are shared between Makefile.build and Makefile.vmlinux_o. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
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f6b66ca4 |
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27-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: rebuild multi-object modules when objtool is updated When CONFIG_LTO_CLANG or CONFIG_X86_KERNEL_IBT is enabled, objtool for multi-object modules is postponed until the objects are linked together. Make sure to re-run objtool and re-link multi-object modules when objtool is updated. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nicolas Schier <n.schier@avm.de> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
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c6031b1d |
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27-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: make *.mod rule robust against too long argument error Like built-in.a, the command length of the *.mod rule scales with the depth of the directory times the number of objects in the Makefile. Add $(obj)/ by the shell command (awk) instead of by Make's builtin function. In-tree modules still have some room to the limit (ARG_MAX=2097152), but this is more future-proof for big modules in a deep directory. For example, you can build i915 as a module (CONFIG_DRM_I915=m) and compare drivers/gpu/drm/i915/.i915.mod.cmd with/without this commit. The issue is more critical for external modules because the M= path can be very long as Jeff Johnson reported before [1]. [1] https://lore.kernel.org/linux-kbuild/4c02050c4e95e4cb8cc04282695f8404@codeaurora.org/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
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cd968b97 |
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27-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: make built-in.a rule robust against too long argument error Kbuild runs at the top of objtree instead of changing the working directory to subdirectories. I think this design is nice overall but some commands have a scalability issue. The build command of built-in.a is one of them whose length scales with: O(D * N) Here, D is the length of the directory path (i.e. $(obj)/ prefix), N is the number of objects in the Makefile, O() is the big O notation. The deeper directory the Makefile directory is located, the more easily it will hit the too long argument error. We can make it better. Trim the $(obj)/ by Make's builtin function, and restore it by a shell command (sed). With this, the command length scales with: O(D + N) In-tree modules still have some room to the limit (ARG_MAX=2097152), but this is more future-proof for big modules in a deep directory. For example, you can build i915 as builtin (CONFIG_DRM_I915=y) and compare drivers/gpu/drm/i915/.built-in.a.cmd with/without this commit. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
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31cb50b5 |
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27-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: check static EXPORT_SYMBOL* by script instead of modpost The 'static' specifier and EXPORT_SYMBOL() are an odd combination. Commit 15bfc2348d54 ("modpost: check for static EXPORT_SYMBOL* functions") tried to detect it, but this check has false negatives. Here is the sample code. Makefile: obj-y += foo1.o foo2.o foo1.c: #include <linux/export.h> static void foo(void) {} EXPORT_SYMBOL(foo); foo2.c: void foo(void) {} foo1.c exports the static symbol 'foo', but modpost cannot catch it because it is fooled by foo2.c, which has a global symbol with the same name. s->is_static is cleared if a global symbol with the same name is found somewhere, but EXPORT_SYMBOL() and the global symbol do not necessarily belong to the same compilation unit. This check should be done per compilation unit, but I do not know how to do it in modpost. modpost runs against vmlinux.o or modules, which merges multiple objects, then forgets their origin. modpost cannot parse individual objects because they may not be ELF but LLVM IR when CONFIG_LTO_CLANG=y. Add a simple bash script to parse the output from ${NM}. This works for CONFIG_LTO_CLANG=y because llvm-nm can dump symbols of LLVM IR files. Revert 15bfc2348d54. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
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c25e1c55 |
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27-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: do not create *.prelink.o for Clang LTO or IBT When CONFIG_LTO_CLANG=y, additional intermediate *.prelink.o is created for each module. Also, objtool is postponed until LLVM IR is converted to ELF. CONFIG_X86_KERNEL_IBT works in a similar way to postpone objtool until objects are merged together. This commit stops generating *.prelink.o, so the build flow will look similar with/without LTO. The following figures show how the LTO build currently works, and how this commit is changing it. Current build flow ================== [1] single-object module $(LD) $(CC) +objtool $(LD) foo.c --------------------> foo.o -----> foo.prelink.o -----> foo.ko (LLVM IR) (ELF) | (ELF) | foo.mod.o --/ (LLVM IR) [2] multi-object module $(LD) $(CC) $(AR) +objtool $(LD) foo1.c -----> foo1.o -----> foo.o -----> foo.prelink.o -----> foo.ko | (archive) (ELF) | (ELF) foo2.c -----> foo2.o --/ | (LLVM IR) foo.mod.o --/ (LLVM IR) One confusion is that foo.o in multi-object module is an archive despite of its suffix. New build flow ============== [1] single-object module Since there is only one object, there is no need to keep the LLVM IR. Use $(CC)+$(LD) to generate an ELF object in one build rule. When LTO is disabled, $(LD) is unneeded because $(CC) produces an ELF object. $(CC)+$(LD)+objtool $(LD) foo.c ----------------------------> foo.o ---------> foo.ko (ELF) | (ELF) | foo.mod.o --/ (LLVM IR) [2] multi-object module Previously, $(AR) was used to combine LLVM IR files into an archive, but there was no technical reason to do so. Use $(LD) to merge them into a single ELF object. $(LD) $(CC) +objtool $(LD) foo1.c ---------> foo1.o ---------> foo.o ---------> foo.ko | (ELF) | (ELF) foo2.c ---------> foo2.o ----/ | (LLVM IR) foo.mod.o --/ (LLVM IR) Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64) Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
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0cfd9006 |
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27-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: replace $(linked-object) with CONFIG options *.prelink.o is created when CONFIG_LTO_CLANG or CONFIG_X86_KERNEL_IBT is enabled. Replace $(linked-object) with $(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT) so you will get a quick idea of when the --link option is passed. No functional change is intended. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14
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5f3da8c0 |
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19-Apr-2022 |
Josh Poimboeuf <jpoimboe@kernel.org> |
objtool: Add CONFIG_HAVE_UACCESS_VALIDATION Allow an arch specify that it has objtool uaccess validation with CONFIG_HAVE_UACCESS_VALIDATION. For now, doing so unconditionally selects CONFIG_OBJTOOL. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/d393d5e2fe73aec6e8e41d5c24f4b6fe8583f2d8.1650384225.git.jpoimboe@redhat.com
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5ce2176b |
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13-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
genksyms: adjust the output format to modpost Make genksyms output symbol versions in the format modpost expects, so the 'sed' is unneeded. This commit makes *.symversions completely unneeded. I will keep *.symversions in .gitignore and 'make clean' for a while. Otherwise, 'git status' might be surprising. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
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7375cbcf |
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13-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: stop merging *.symversions Now modpost reads symbol versions from .*.cmd files. The merged *.symversions are no longer needed. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
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7b453719 |
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13-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS include/{linux,asm-generic}/export.h defines a weak symbol, __crc_* as a placeholder. Genksyms writes the version CRCs into the linker script, which will be used for filling the __crc_* symbols. The linker script format depends on CONFIG_MODULE_REL_CRCS. If it is enabled, __crc_* holds the offset to the reference of CRC. It is time to get rid of this complexity. Now that modpost parses text files (.*.cmd) to collect all the CRCs, it can generate C code that will be linked to the vmlinux or modules. Generate a new C file, .vmlinux.export.c, which contains the CRCs of symbols exported by vmlinux. It is compiled and linked to vmlinux in scripts/link-vmlinux.sh. Put the CRCs of symbols exported by modules into the existing *.mod.c files. No additional build step is needed for modules. As before, *.mod.c are compiled and linked to *.ko in scripts/Makefile.modfinal. No linker magic is used here. The new C implementation works in the same way, whether CONFIG_RELOCATABLE is enabled or not. CONFIG_MODULE_REL_CRCS is no longer needed. Previously, Kbuild invoked additional $(LD) to update the CRCs in objects, but this step is unneeded too. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
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78e9e56a |
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05-May-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: record symbol versions in *.cmd files When CONFIG_MODVERSIONS=y, the output from genksyms is saved in separate *.symversions files, and will be used much later when CONFIG_LTO_CLANG=y because it is impossible to update LLVM bit code here. This approach is not robust because: - *.symversions may or may not exist. If *.symversions does not exist, we never know if it is missing for legitimate reason (i.e. no EXPORT_SYMBOL) or something bad has happened (for example, the user accidentally deleted it). Once it occurs, it is not self-healing because *.symversions is generated as a side effect. - stale (i.e. invalid) *.symversions might be picked up if an object is generated in a non-ordinary way, and corresponding *.symversions (, which was generated by old builds) just happen to exist. A more robust approach is to save symbol versions in *.cmd files because: - *.cmd always exists (if the object is generated by if_changed rule or friends). Even if the user accidentally deletes it, it will be regenerated in the next build. - *.cmd is always re-generated when the object is updated. This avoid stale version information being picked up. I will remove *.symversions later. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org>
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feb7d79f |
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06-Apr-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: read *.mod to get objects passed to $(LD) or $(AR) ld and ar support @file, which command-line options are read from. Now that *.mod lists the member objects in the correct order, without duplication, it is ready to be passed to ld and ar. By using the @file syntax, people will not be worried about the pitfall described in the NOTE. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
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fc93a4cd |
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06-Apr-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: make *.mod not depend on *.o The dependency $(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o ... exists because *.mod files previously contained undefined symbols, which are computed from *.o files when CONFIG_TRIM_UNUSED_KSYMS=y. Now that the undefined symbols are put into separate *.usyms files, there is no reason to make *.mod depend on *.o files. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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22f26f21 |
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06-Apr-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: get rid of duplication in *.mod files It is allowed to add the same objects multiple times to obj-y / obj-m: obj-y += foo.o foo.o foo.o obj-m += bar.o bar.o bar.o It is also allowed to add the same objects multiple times to a composite module: obj-m += foo.o foo-y := foo1.o foo2.o foo2.o foo1.o This flexibility is useful because the same object might be selected by different CONFIG options, like this: obj-m += foo.o foo-y := foo1.o foo-$(CONFIG_FOO_X) += foo2.o foo-$(CONFIG_FOO_Y) += foo2.o The duplicated objects are omitted at link time. It works naturally in Makefiles because GNU Make removes duplication in $^ without changing the order. It is working well, almost... A small flaw I notice is, *.mod contains duplication in such a case. This is probably not a big deal. As far as I know, the only small problem is scripts/mod/sumversion.c parses the same file multiple times. I am fixing this because I plan to reuse *.mod for other purposes, where the duplication can be problematic. The code change is quite simple. We already use awk to drop duplicated lines in modules.order (see cmd_modules_order in the same file). I copied the code, but changed RS to use spaces as record separators. I also changed the file format to list one object per line. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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9413e764 |
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06-Apr-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: split the second line of *.mod into *.usyms The *.mod files have two lines; the first line lists the member objects of the module, and the second line, if CONFIG_TRIM_UNUSED_KSYMS=y, lists the undefined symbols. Currently, we generate *.mod after constructing composite modules, otherwise, we cannot compute the second line. No prerequisite is required to print the first line. They are orthogonal. Splitting them into separate commands will ease further cleanups. This commit splits the list of undefined symbols out to *.usyms files. Previously, the list of undefined symbols ended up with a very long line, but now it has one symbol per line. Use sed like we did before commit 7d32358be8ac ("kbuild: avoid split lines in .mod files"). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
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b3591e06 |
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06-Apr-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: reuse real-search to simplify cmd_mod The first command in cmd_mod is similar to the real-search macro. Reuse it. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
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7cfa2fcb |
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05-Apr-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: refactor cmd_modversions_S Split the code into two macros, cmd_gen_symversions_S for running genksyms, and cmd_modversions for running $(LD) to update the object with CRCs. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
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8017ce50 |
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05-Apr-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: refactor cmd_modversions_c cmd_modversions_c implements two parts; run genksyms to calculate CRCs of exported symbols, run $(LD) to update the object with the CRCs. The latter is not executed for CONFIG_LTO_CLANG=y since the object is not ELF but LLVM bit code at this point. The first part can be unified because we can always use $(NM) instead of "$(OBJDUMP) -h" to dump the symbols. Split the code into the two macros, cmd_gen_symversions_c and cmd_modversions. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
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dc6dc3e7 |
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05-Apr-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: do not remove empty *.symtypes explicitly Presumably, 'test -s $@ || rm -f $@' intends to remove the output when the genksyms command fails. It is unneeded because .DELETE_ON_ERROR automatically removes the output on failure. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
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f43e31d5 |
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05-Apr-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: factor out genksyms command from cmd_gensymtypes_{c,S} The genksyms command part in cmd_gensymtypes_{c,S} is duplicated. Factor it out into the 'genksyms' macro. For the readability, I slightly refactor the arguments to genksyms. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
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753da417 |
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18-Apr-2022 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Remove --lto and --vmlinux in favor of --link The '--lto' option is a confusing way of telling objtool to do stack validation despite it being a linked object. It's no longer needed now that an explicit '--stackval' option exists. The '--vmlinux' option is also redundant. Remove both options in favor of a straightforward '--link' option which identifies a linked object. Also, implicitly set '--link' with a warning if the user forgets to do so and we can tell that it's a linked object. This makes it easier for manual vmlinux runs. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/dcd3ceffd15a54822c6183e5766d21ad06082b45.1650300597.git.jpoimboe@redhat.com
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22102f45 |
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18-Apr-2022 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Make noinstr hacks optional Objtool has some hacks in place to workaround toolchain limitations which otherwise would break no-instrumentation rules. Make the hacks explicit (and optional for other arches) by turning it into a cmdline option and kernel config option. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/b326eeb9c33231b9dfbb925f194ed7ee40edcd7c.1650300597.git.jpoimboe@redhat.com
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4ab7674f |
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18-Apr-2022 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Make jump label hack optional Objtool secretly does a jump label hack to overcome the limitations of the toolchain. Make the hack explicit (and optional for other arches) by turning it into a cmdline option and kernel config option. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/3bdcbfdd27ecb01ddec13c04bdf756a583b13d24.1650300597.git.jpoimboe@redhat.com
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26e17689 |
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18-Apr-2022 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Make static call annotation optional As part of making objtool more modular, put the existing static call code behind a new '--static-call' option. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/d59ac57ef3d6d8380cdce20322314c9e2e556750.1650300597.git.jpoimboe@redhat.com
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72064474 |
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18-Apr-2022 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Make stack validation frame-pointer-specific Now that CONFIG_STACK_VALIDATION is frame-pointer specific, do the same for the '--stackval' option. Now the '--no-fp' option is redundant and can be removed. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/f563fa064b3b63d528de250c72012d49e14742a3.1650300597.git.jpoimboe@redhat.com
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03f16cd0 |
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18-Apr-2022 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Add CONFIG_OBJTOOL Now that stack validation is an optional feature of objtool, add CONFIG_OBJTOOL and replace most usages of CONFIG_STACK_VALIDATION with it. CONFIG_STACK_VALIDATION can now be considered to be frame-pointer specific. CONFIG_UNWINDER_ORC is already inherently valid for live patching, so no need to "validate" it. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/939bf3d85604b2a126412bf11af6e3bd3b872bcb.1650300597.git.jpoimboe@redhat.com
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7dce6204 |
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18-Apr-2022 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Make stack validation optional Make stack validation an explicit cmdline option so that individual objtool features can be enabled individually by other arches. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/52da143699574d756e65ca4c9d4acaffe9b0fe5f.1650300597.git.jpoimboe@redhat.com
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b51277eb |
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18-Apr-2022 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Ditch subcommands Objtool has a fairly singular focus. It runs on object files and does validations and transformations which can be combined in various ways. The subcommand model has never been a good fit, making it awkward to combine and remove options. Remove the "check" and "orc" subcommands in favor of a more traditional cmdline option model. This makes it much more flexible to use, and easier to port individual features to other arches. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/5c61ebf805e90aefc5fa62bc63468ffae53b9df6.1650300597.git.jpoimboe@redhat.com
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2daf7fab |
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18-Apr-2022 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Reorganize cmdline options Split the existing options into two groups: actions, which actually do something; and options, which modify the actions in some way. Also there's no need to have short flags for all the non-action options. Reserve short flags for the more important actions. While at it: - change a few of the short flags to be more intuitive - make option descriptions more consistently descriptive - sort options in the source like they are when printed - move options to a global struct Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/9dcaa752f83aca24b1b21f0b0eeb28a0c181c0b0.1650300597.git.jpoimboe@redhat.com
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dbae0a93 |
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26-Jan-2022 |
Borislav Petkov <bp@suse.de> |
x86/cpu: Remove CONFIG_X86_SMAP and "nosmap" Those were added as part of the SMAP enablement but SMAP is currently an integral part of kernel proper and there's no need to disable it anymore. Rip out that functionality. Leave --uaccess default on for objtool as this is what objtool should do by default anyway. If still needed - clearcpuid=smap. Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220127115626.14179-4-bp@alien8.de
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4a5de9b7 |
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18-Apr-2022 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Enable unreachable warnings for CLANG LTO With IBT support in, objtool is now fully capable of following vmlinux code flow in LTO mode. Start reporting unreachable warnings for Clang LTO as well. Fixes: ed53a0d97192 ("x86/alternative: Use .ibt_endbr_seal to seal indirect calls") Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/7b12df54bceeb0761fe9fc8269ea0c00501214a9.1650300597.git.jpoimboe@redhat.com
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5c816641 |
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10-Feb-2022 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: replace $(if A,A,B) with $(or A,B) $(or ...) is available since GNU Make 3.81, and useful to shorten the code in some places. Covert as follows: $(if A,A,B) --> $(or A,B) This patch also converts: $(if A, A, B) --> $(or A, B) Strictly speaking, the latter is not an equivalent conversion because GNU Make keeps spaces after commas; if A is not empty, $(if A, A, B) expands to " A", while $(or A, B) expands to "A". Anyway, preceding spaces are not significant in the code hunks I touched. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
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d31ed5d7 |
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17-Mar-2022 |
Peter Zijlstra <peterz@infradead.org> |
kbuild: Fixup the IBT kbuild changes Masahiro-san deemed my kbuild changes to support whole module objtool runs too terrible to live and gracefully provided an alternative. Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/CAK7LNAQ2mYMnOKMQheVi+6byUFE3KEkjm1zcndNUfe0tORGvug@mail.gmail.com
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ed53a0d9 |
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08-Mar-2022 |
Peter Zijlstra <peterz@infradead.org> |
x86/alternative: Use .ibt_endbr_seal to seal indirect calls Objtool's --ibt option generates .ibt_endbr_seal which lists superfluous ENDBR instructions. That is those instructions for which the function is never indirectly called. Overwrite these ENDBR instructions with a NOP4 such that these function can never be indirect called, reducing the number of viable ENDBR targets in the kernel. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220308154319.822545231@infradead.org
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e463a09a |
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04-Dec-2021 |
Peter Zijlstra <peterz@infradead.org> |
x86: Add straight-line-speculation mitigation Make use of an upcoming GCC feature to mitigate straight-line-speculation for x86: https://gcc.gnu.org/g:53a643f8568067d7700a9f2facc8ba39974973d3 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952 https://bugs.llvm.org/show_bug.cgi?id=52323 It's built tested on x86_64-allyesconfig using GCC-12 and GCC-11. Maintenance overhead of this should be fairly low due to objtool validation. Size overhead of all these additional int3 instructions comes to: text data bss dec hex filename 22267751 6933356 2011368 31212475 1dc43bb defconfig-build/vmlinux 22804126 6933356 1470696 31208178 1dc32f2 defconfig-build/vmlinux.sls Or roughly 2.4% additional text. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20211204134908.140103474@infradead.org
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90a35349 |
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31-Aug-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: reuse $(cmd_objtool) for cmd_cc_lto_link_modules For CONFIG_LTO_CLANG=y, the objtool processing is not possible at the compilation, hence postponed by the link time. Reuse $(cmd_objtool) for CONFIG_LTO_CLANG=y by defining objtool-enabled properly. For CONFIG_LTO_CLANG=y: objtool-enabled is off for %.o compilation objtool-enabled is on for %.lto link For CONFIG_LTO_CLANG=n: objtool-enabled is on for %.o compilation (but, it depends on OBJECT_FILE_NON_STANDARD) Set part-of-module := y for %.lto.o to avoid repeating --module. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
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ef62588c |
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31-Aug-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: detect objtool update without using .SECONDEXPANSION Redo commit 8852c5524029 ("kbuild: Fix objtool dependency for 'OBJECT_FILES_NON_STANDARD_<obj> := n'") to add the objtool dependency in a cleaner way. Using .SECONDEXPANSION ends up with unreadable code due to escaped dollars. Also, it is not efficient because the second half of Makefile.build is parsed twice every time. Append the objtool dependency to the *.cmd files at the build time. This is what fixdep and gen_ksymdeps.sh already do. So, following the same pattern seems a natural solution. This allows us to drop $$(objtool_dep) entirely. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
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918a6b7f |
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31-Aug-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: factor out OBJECT_FILES_NON_STANDARD check into a macro The OBJECT_FILES_NON_STANDARD check is quite long. Factor it out into a new macro, objtool-enabled, to not repeat it. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
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92594d56 |
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31-Aug-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: store the objtool command in *.cmd files objtool_dep includes include/config/{ORC_UNWINDER,STACK_VALIDATION} so that all the objects are rebuilt when CONFIG_ORC_UNWINDER or CONFIG_STACK_VALIDATION is toggled. BTW, the correct option name is not CONFIG_ORC_UNWINDER, but CONFIG_UNWINDER_ORC. Commit 11af847446ed ("x86/unwind: Rename unwinder config options to 'CONFIG_UNWINDER_*'") missed to adjust this part. So, this dependency has been broken for a long time. As you can see in 'objtool_args', there are more CONFIG options that affect the objtool command line. Adding more and more include/config/* is ugly and unmaintainable. Another issue is that non-standard objects are needlessly rebuilt. Objects specified as OBJECT_FILES_NON_STANDARD is not processed by objtool, but they are rebuilt anyway when CONFIG_STACK_VALIDATION is toggled. This is not a big deal, but better to fix. A cleaner and more precise fix is to include the objtool command in *.cmd files so any command change is naturally detected by if_change. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
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5c4859e7 |
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31-Aug-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: rename __objtool_obj and reuse it for cmd_cc_lto_link_modules Rename __objtool_obj to objtool, and move it out of the 'ifndef CONFIG_LTO_CLANG' conditional, so it can be used for cmd_cc_lto_link_modules as well. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
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8f0c32c7 |
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31-Aug-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: move objtool_args back to scripts/Makefile.build Commit b1a1a1a09b46 ("kbuild: lto: postpone objtool") moved objtool_args to Makefile.lib, so the arguments can be used in Makefile.modfinal as well as Makefile.build. With commit 850ded46c642 ("kbuild: Fix TRIM_UNUSED_KSYMS with LTO_CLANG"), module LTO linking came back to scripts/Makefile.build again. So, there is no more reason to keep objtool_args in a separate file. Get it back to the original place, close to the objtool command. Remove the stale comment too. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
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a8390ba9 |
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18-Aug-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: remove stale *.symversions cmd_update_lto_symversions merges all the existing *.symversions, but some of them might be stale. If the last EXPORT_SYMBOL is removed from a C file, the *.symversions file is not deleted or updated. It contains stale CRCs, but still they will be used for linking the vmlinux or modules. It is not a big deal when the EXPORT_SYMBOL is really removed. However, when the EXPORT_SYMBOL is moved to another file, the same __crc_<symbol> will appear twice in the merged *.symversions, possibly with different CRCs if the function argument is changed at the same time. It would confuse module versioning. If no EXPORT_SYMBOL is found, let's remove *.symversions explicitly. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org>
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f01ac2a1 |
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18-Aug-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: remove unused quiet_cmd_update_lto_symversions This is not used anywhere because the short log is displayed when it is used through a $(call cmd,...) invocation. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org>
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850ded46 |
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16-Aug-2021 |
Sami Tolvanen <samitolvanen@google.com> |
kbuild: Fix TRIM_UNUSED_KSYMS with LTO_CLANG With CONFIG_LTO_CLANG, we currently link modules into native code just before modpost, which means with TRIM_UNUSED_KSYMS enabled, we still look at the LLVM bitcode in the .o files when generating the list of used symbols. As the bitcode doesn't yet have calls to compiler intrinsics and llvm-nm doesn't see function references that only exist in function-level inline assembly, we currently need a whitelist for TRIM_UNUSED_KSYMS to work with LTO. This change moves module LTO linking to happen earlier, and thus avoids the issue with LLVM bitcode and TRIM_UNUSED_KSYMS entirely, allowing us to also drop the whitelist from gen_autoksyms.sh. Link: https://github.com/ClangBuiltLinux/linux/issues/1369 Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Tested-by: Alexander Lobakin <alobakin@pm.me> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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1d11053d |
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15-Jul-2021 |
Lecopzer Chen <lecopzer.chen@mediatek.com> |
Kbuild: lto: fix module versionings mismatch in GNU make 3.X When building modules(CONFIG_...=m), I found some of module versions are incorrect and set to 0. This can be found in build log for first clean build which shows WARNING: EXPORT symbol "XXXX" [drivers/XXX/XXX.ko] version generation failed, symbol will not be versioned. But in second build(incremental build), the WARNING disappeared and the module version becomes valid CRC and make someone who want to change modules without updating kernel image can't insert their modules. The problematic code is + $(foreach n, $(filter-out FORCE,$^), \ + $(if $(wildcard $(n).symversions), \ + ; cat $(n).symversions >> $@.symversions)) For example: rm -f fs/notify/built-in.a.symversions ; rm -f fs/notify/built-in.a; \ llvm-ar cDPrST fs/notify/built-in.a fs/notify/fsnotify.o \ fs/notify/notification.o fs/notify/group.o ... `foreach n` shows nothing to `cat` into $(n).symversions because `if $(wildcard $(n).symversions)` return nothing, but actually they do exist during this line was executed. -rw-r--r-- 1 root root 168580 Jun 13 19:10 fs/notify/fsnotify.o -rw-r--r-- 1 root root 111 Jun 13 19:10 fs/notify/fsnotify.o.symversions The reason is the $(n).symversions are generated at runtime, but Makefile wildcard function expends and checks the file exist or not during parsing the Makefile. Thus fix this by use `test` shell command to check the file existence in runtime. Rebase from both: 1. [https://lore.kernel.org/lkml/20210616080252.32046-1-lecopzer.chen@mediatek.com/] 2. [https://lore.kernel.org/lkml/20210702032943.7865-1-lecopzer.chen@mediatek.com/] Fixes: 38e891849003 ("kbuild: lto: fix module versioning") Co-developed-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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0d989ac2 |
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12-May-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: remove libelf checks from top Makefile I do not see a good reason why only the libelf development package must be so carefully checked. Kbuild generally does not check host tools or libraries. For example, x86_64 defconfig fails to build with no libssl development package installed. scripts/extract-cert.c:21:10: fatal error: openssl/bio.h: No such file or directory 21 | #include <openssl/bio.h> | ^~~~~~~~~~~~~~~ To solve the build error, you need to install libssl-dev or openssl-devel package, depending on your distribution. 'apt-file search', 'dnf provides', etc. is your frined to find a proper package to install. This commit removes all the libelf checks from the top Makefile. If libelf is missing, objtool will fail to build in a similar pattern: .../linux/tools/objtool/include/objtool/elf.h:10:10: fatal error: gelf.h: No such file or directory 10 | #include <gelf.h> You need to install libelf-dev, libelf-devel, or elfutils-libelf-devel to proceed. Another remarkable change is, CONFIG_STACK_VALIDATION (without CONFIG_UNWINDER_ORC) previously continued to build with a warning, but now it will treat missing libelf as an error. This is just a one-time installation, so it should not hurt to break a build and make a user install the package. BTW, the traditional way to handle such checks is autotool, but according to [1], I do not expect the kernel build would have similar scripting like './configure' does. [1]: https://lore.kernel.org/lkml/CA+55aFzr2HTZVOuzpHYDwmtRJLsVzE-yqg2DHpHi_9ePsYp5ug@mail.gmail.com/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org>
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8852c552 |
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18-May-2021 |
Josh Poimboeuf <jpoimboe@redhat.com> |
kbuild: Fix objtool dependency for 'OBJECT_FILES_NON_STANDARD_<obj> := n' "OBJECT_FILES_NON_STANDARD_vma.o := n" has a dependency bug. When objtool source is updated, the affected object doesn't get re-analyzed by objtool. Peter's new variable-sized jump label feature relies on objtool rewriting the object file. Otherwise the system can fail to boot. That effectively upgrades this minor dependency issue to a major bug. The problem is that variables in prerequisites are expanded early, during the read-in phase. The '$(objtool_dep)' variable indirectly uses '$@', which isn't yet available when the target prerequisites are evaluated. Use '.SECONDEXPANSION:' which causes '$(objtool_dep)' to be expanded in a later phase, after the target-specific '$@' variable has been defined. Fixes: b9ab5ebb14ec ("objtool: Add CONFIG_STACK_VALIDATION option") Fixes: ab3257042c26 ("jump_label, x86: Allow short NOPs") Reported-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
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bcf0c664 |
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02-May-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: refactor fdtoverlay rule Rename overlay-y to multi-dtb-y, which is a consistent name with multi-obj-y. Also, use multi-search to avoid code duplication. Introduce real-dtb-y, which is a consistent name with real-obj-y, to contain primitive blobs compiled from *.dts. This is used to calculate the list of *.dt.yaml files. Set -@ to base DTB without using $(eval ). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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0e0345b7 |
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15-Apr-2021 |
Alexey Dobriyan <adobriyan@gmail.com> |
kbuild: redo fake deps at include/config/*.h Make include/config/foo/bar.h fake deps files generation simpler. * delete .h suffix those aren't header files, shorten filenames, * delete tolower() Linux filesystems can deal with both upper and lowercase filenames very well, * put everything in 1 directory Presumably 'mkdir -p' split is from dark times when filesystems handled huge directories badly, disks were round adding to seek times. x86_64 allmodconfig lists 12364 files in include/config. ../obj/include/config/ ├── 104_QUAD_8 ├── 60XX_WDT ├── 64BIT ... ├── ZSWAP_DEFAULT_ON ├── ZSWAP_ZPOOL_DEFAULT └── ZSWAP_ZPOOL_DEFAULT_ZBUD 0 directories, 12364 files Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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a6601e01 |
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05-Mar-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: rename multi-used-* to multi-obj-* I think multi-obj-* is clearer, and more consistent with real-obj-*. Rename as follows: multi-used-y -> multi-obj-y multi-used-m -> multi-obj-m multi-used -> multi-obj-ym Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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57fd251c |
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27-Feb-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: split cc-option and friends to scripts/Makefile.compiler scripts/Kbuild.include is included everywhere, but macros such as cc-option are needed by build targets only. For example, when 'make clean' traverses the tree, it does not need to evaluate $(call cc-option,). Split cc-option, ld-option, etc. to scripts/Makefile.compiler, which is only included from the top Makefile and scripts/Makefile.build. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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3204a7fb |
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27-Feb-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: prefix $(srctree)/ to some included Makefiles VPATH is used in Kbuild to make pattern rules search for prerequisites in both $(objtree) and $(srctree). Some of *.c, *.S files are not real sources, but generated by tools such as flex, bison, perl. In contrast, I doubt the benefit of --include-dir=$(abs_srctree) because it is always clear which Makefiles are real sources, and which are not. So, my hope is to add $(srctree)/ prefix to all check-in Makefiles, then remove --include-dir=$(abs_srctree) flag in the future. I am touching only some Kbuild core parts for now. Treewide fixes will be needed to achieve this goal. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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b97652bf |
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21-Feb-2021 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: remove deprecated 'always' and 'hostprogs-y/m' These have no more user in the upstream code. The use of them has been warned for a while for external modules. The migration is finished. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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b1a1a1a0 |
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13-Apr-2020 |
Sami Tolvanen <samitolvanen@google.com> |
kbuild: lto: postpone objtool With LTO, LLVM bitcode won't be compiled into native code until modpost_link, or modfinal for modules. This change postpones calls to objtool until after these steps, and moves objtool_args to Makefile.lib, so the arguments can be reused in Makefile.modfinal. As we didn't have objects to process earlier, we use --duplicate when processing vmlinux.o. This change also disables unreachable instruction warnings with LTO to avoid warnings about the int3 padding between functions. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org>
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22c8542d |
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25-Sep-2020 |
Sami Tolvanen <samitolvanen@google.com> |
tracing: add support for objtool mcount This change adds build support for using objtool to generate __mcount_loc sections. Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
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38e89184 |
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11-Dec-2020 |
Sami Tolvanen <samitolvanen@google.com> |
kbuild: lto: fix module versioning With CONFIG_MODVERSIONS, version information is linked into each compilation unit that exports symbols. With LTO, we cannot use this method as all C code is compiled into LLVM bitcode instead. This change collects symbol versions into .symversions files and merges them in link-vmlinux.sh where they are all linked into vmlinux.o at the same time. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201211184633.3213045-4-samitolvanen@google.com
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dc5723b0 |
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11-Dec-2020 |
Sami Tolvanen <samitolvanen@google.com> |
kbuild: add support for Clang LTO This change adds build system support for Clang's Link Time Optimization (LTO). With -flto, instead of ELF object files, Clang produces LLVM bitcode, which is compiled into native code at link time, allowing the final binary to be optimized globally. For more details, see: https://llvm.org/docs/LinkTimeOptimization.html The Kconfig option CONFIG_LTO_CLANG is implemented as a choice, which defaults to LTO being disabled. To use LTO, the architecture must select ARCH_SUPPORTS_LTO_CLANG and support: - compiling with Clang, - compiling all assembly code with Clang's integrated assembler, - and linking with LLD. While using CONFIG_LTO_CLANG_FULL results in the best runtime performance, the compilation is not scalable in time or memory. CONFIG_LTO_CLANG_THIN enables ThinLTO, which allows parallel optimization and faster incremental builds. ThinLTO is used by default if the architecture also selects ARCH_SUPPORTS_LTO_CLANG_THIN: https://clang.llvm.org/docs/ThinLTO.html To enable LTO, LLVM tools must be used to handle bitcode files, by passing LLVM=1 and LLVM_IAS=1 options to make: $ make LLVM=1 LLVM_IAS=1 defconfig $ scripts/config -e LTO_CLANG_THIN $ make LLVM=1 LLVM_IAS=1 To prepare for LTO support with other compilers, common parts are gated behind the CONFIG_LTO option, and LTO can be disabled for specific files by filtering out CC_FLAGS_LTO. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201211184633.3213045-3-samitolvanen@google.com
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3b15cdc1 |
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11-Dec-2020 |
Sami Tolvanen <samitolvanen@google.com> |
tracing: move function tracer options to Kconfig Move function tracer options to Kconfig to make it easier to add new methods for generating __mcount_loc, and to make the options available also when building kernel modules. Note that FTRACE_MCOUNT_USE_* options are updated on rebuild and therefore, work even if the .config was generated in a different environment. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201211184633.3213045-2-samitolvanen@google.com
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7d32358b |
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03-Dec-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: avoid split lines in .mod files "xargs echo" is not a safe way to remove line breaks because the input may exceed the command line limit and xargs may break it up into multiple invocations of echo. This should never happen because scripts/gen_autoksyms.sh expects all undefined symbols are placed in the second line of .mod files. One possible way is to replace "xargs echo" with "sed ':x;N;$!bx;s/\n/ /g'" or something, but I rewrote the code by using awk because it is more readable. This issue was reported by Sami Tolvanen; in his Clang LTO patch set, $(multi-used-m) is no longer an ELF object, but a thin archive that contains LLVM bitcode files. llvm-nm prints out symbols for each archive member separately, which results a lot of dupications, in some places, beyond the system-defined limit. This problem must be fixed irrespective of LTO, and we must ensure zero possibility of having this issue. Link: https://lkml.org/lkml/2020/12/1/1658 Reported-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
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0f6372e5 |
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12-Oct-2020 |
Sami Tolvanen <samitolvanen@google.com> |
treewide: remove DISABLE_LTO This change removes all instances of DISABLE_LTO from Makefiles, as they are currently unused, and the preferred method of disabling LTO is to filter out the flags instead. Note added by Masahiro Yamada: DISABLE_LTO was added as preparation for GCC LTO, but GCC LTO was not pulled into the mainline. (https://lkml.org/lkml/2014/4/8/272) Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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85569d19 |
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28-Jul-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: sort hostprogs before passing it to ifneq The conditional: ifneq ($(hostprogs),) ... is evaluated to true if $(hostprogs) does not contain any word but whitespace characters. ifneq ($(strip $(hostprogs)),) ... is a safe way to avoid interpreting whitespace as a non-empty value, but I'd rather want to use the side-effect of $(sort ...) to do the equivalent. $(sort ...) is used in scripts/Makefile.host in order to drop duplication in $(hostprogs). It is also useful to strip excessive spaces. Move $(sort ...) before evaluating the ifneq. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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42640b13 |
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28-Jul-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: move host .so build rules to scripts/gcc-plugins/Makefile The host shared library rules are currently implemented in scripts/Makefile.host, but actually GCC-plugin is the only user of them. (The VDSO .so files are built for the target by different build rules) Hence, they do not need to be treewide available. Move all the relevant build rules to scripts/gcc-plugins/Makefile. I also optimized the build steps so *.so is directly built from .c because every upstream plugin is compiled from a single source file. I am still keeping the multi-file plugin support, which Kees Cook mentioned might be needed by out-of-tree plugins. (https://lkml.org/lkml/2019/1/11/1107) If the plugin, foo.so, is compiled from two files foo.c and foo2.c, then you can do like follows: foo-objs := foo.o foo2.o Single-file plugins do not need the *-objs notation. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
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cc8a51ca |
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30-Jun-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: always create directories of targets Currently, the directories of objects are automatically created only for O= builds. It should not hurt to cater to this for in-tree builds too. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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0c33f125 |
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22-Jun-2020 |
Luc Van Oostenryck <luc.vanoostenryck@gmail.com> |
kbuild: run the checker after the compiler Since the pre-git time the checker is run first, before the compiler. But if the source file contains some syntax error, the warnings from the compiler are more useful than those from sparse (and other checker most probably too). So move the 'check' command to run after the compiler. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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b2c88554 |
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31-May-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: update modules.order only when contained modules are updated Make modules.order depend on $(obj-m), and use if_changed to build it. This will avoid unneeded update of modules.order, which will be useful to optimize the modpost stage. Currently, the second pass of modpost is always invoked. By checking the timestamp of modules.order, we can avoid the unneeded modpost. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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f3908ab3 |
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31-May-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: refactor tagets caluculation for KBUILD_{BUILTIN,KBUILD_MODULES} Remove lib-target, builtin-target, modorder-target, and modtargets. Instead, add targets-for-builtin and targets-for-modules. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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454753d9 |
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21-May-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: make modules.order rule consistent with built-in.a built-in.a contains the built-in object paths from the current and sub directories. module.order collects the module paths from the current and sub directories. Make their build rules look more symmetrical. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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aaa385ba |
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21-May-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: rename subdir-obj-y to subdir-builtin I think subdir-builtin is clearer. While I was here, I made its build rule explicit. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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6ba3bcb0 |
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21-May-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: move subdir-obj-y to scripts/Makefile.build Save $(addprefix ...) for subdir-obj-y. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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b480fec9 |
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21-May-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: clear KBUILD_MODULES in top Makefile if CONFIG_MODULES=n Do not try to build any module-related artifacts when CONFIG_MODULES is disabled. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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e578edc7 |
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21-May-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: remove ifdef builtin-target / lib-target I do not see a good reason to add ifdef here. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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7f3a59db |
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28-Apr-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: add infrastructure to build userspace programs Kbuild supports the infrastructure to build host programs, but there was no support to build userspace programs for the target architecture (i.e. the same architecture as the kernel). Sam Ravnborg worked on this in 2014 (https://lkml.org/lkml/2014/7/13/154), but it was not merged. One problem at that time was, there was no good way to know whether $(CC) can link standalone programs. In fact, pre-built kernel.org toolchains [1] are often used for building the kernel, but they do not provide libc. Now, we can handle this cleanly because the compiler capability is evaluated at the Kconfig time. If $(CC) cannot link standalone programs, the relevant options are hidden by 'depends on CC_CAN_LINK'. The implementation just mimics scripts/Makefile.host The userspace programs are compiled with the same flags as the host programs. In addition, it uses -m32 or -m64 if it is found in $(KBUILD_CFLAGS). This new syntax has two usecases. - Sample programs Several userspace programs under samples/ include UAPI headers installed in usr/include. Most of them were previously built for the host architecture just to use the 'hostprogs' syntax. However, 'make headers' always works for the target architecture. This caused the arch mismatch in cross-compiling. To fix this distortion, sample code should be built for the target architecture. - Bpfilter net/bpfilter/Makefile compiles bpfilter_umh as the user mode helper, and embeds it into the kernel. Currently, it overrides HOSTCC with CC to use the 'hostprogs' syntax. This hack should go away. [1]: https://mirrors.edge.kernel.org/pub/tools/crosstool/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Sam Ravnborg <sam@ravnborg.org>
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7273ad2b |
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11-Mar-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: link lib-y objects to vmlinux forcibly when CONFIG_MODULES=y Kbuild supports not only obj-y but also lib-y to list objects linked to vmlinux. The difference between them is that all the objects from obj-y are forcibly linked to vmlinux, whereas the objects from lib-y are linked as needed; if there is no user of a lib-y object, it is not linked. lib-y is intended to list utility functions that may be called from all over the place (and may be unused at all), but it is a problem for EXPORT_SYMBOL(). Even if there is no call-site in the vmlinux, we need to keep exported symbols for the use from loadable modules. Commit 7f2084fa55e6 ("[kbuild] handle exports in lib-y objects reliably") worked around it by linking a dummy object, lib-ksyms.o, which contains references to all the symbols exported from lib.a in that directory. It uses the linker script command, EXTERN. Unfortunately, the meaning of EXTERN of ld.lld is different from that of ld.bfd. Therefore, this does not work with LD=ld.lld (CBL issue #515). Anyway, the build rule of lib-ksyms.o is somewhat tricky. So, I want to get rid of it. At first, I was thinking of accumulating lib-y objects into obj-y (or even replacing lib-y with obj-y entirely), but the lib-y syntax is used beyond the ordinary use in lib/ and arch/*/lib/. Examples: - drivers/firmware/efi/libstub/Makefile builds lib.a, which is linked into vmlinux in the own way (arm64), or linked to the decompressor (arm, x86). - arch/alpha/lib/Makefile builds lib.a which is linked not only to vmlinux, but also to bootloaders in arch/alpha/boot/Makefile. - arch/xtensa/boot/lib/Makefile builds lib.a for use from arch/xtensa/boot/boot-redboot/Makefile. One more thing, adding everything to obj-y would increase the vmlinux size of allnoconfig (or tinyconfig). For less impact, I tweaked the destination of lib.a at the top Makefile; when CONFIG_MODULES=y, lib.a goes to KBUILD_VMLINUX_OBJS, which is forcibly linked to vmlinux, otherwise lib.a goes to KBUILD_VMLINUX_LIBS as before. The size impact for normal usecases is quite small since at lease one symbol in every lib-y object is eventually called by someone. In case you are intrested, here are the figures. x86_64_defconfig: text data bss dec hex filename 19566602 5422072 1589328 26578002 1958c52 vmlinux.before 19566932 5422104 1589328 26578364 1958dbc vmlinux.after The case with the biggest impact is allnoconfig + CONFIG_MODULES=y. ARCH=x86 allnoconfig + CONFIG_MODULES=y: text data bss dec hex filename 1175162 254740 1220608 2650510 28718e vmlinux.before 1177974 254836 1220608 2653418 287cea vmlinux.after Hopefully this is still not a big deal. The per-file trimming with the static library is not so effective after all. If fine-grained optimization is desired, some architectures support CONFIG_LD_DEAD_CODE_DATA_ELIMINATION, which trims dead code per-symbol basis. When LTO is supported in mainline, even better optimization will be possible. Link: https://github.com/ClangBuiltLinux/linux/issues/515 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reported-by: kbuild test robot <lkp@intel.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
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77342a02 |
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29-Mar-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
gcc-plugins: drop support for GCC <= 4.7 Nobody was opposed to raising minimum GCC version to 4.8 [1] So, we will drop GCC <= 4.7 support sooner or later. We always use C++ compiler for building plugins for GCC >= 4.8. This commit drops the plugin support for GCC <= 4.7 a bit earlier, which allows us to dump lots of code. [1] https://lkml.org/lkml/2020/1/23/545 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
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5f2fb52f |
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01-Feb-2020 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: rename hostprogs-y/always to hostprogs/always-y In old days, the "host-progs" syntax was used for specifying host programs. It was renamed to the current "hostprogs-y" in 2004. It is typically useful in scripts/Makefile because it allows Kbuild to selectively compile host programs based on the kernel configuration. This commit renames like follows: always -> always-y hostprogs-y -> hostprogs So, scripts/Makefile will look like this: always-$(CONFIG_BUILD_BIN2C) += ... always-$(CONFIG_KALLSYMS) += ... ... hostprogs := $(always-y) $(always-m) I think this makes more sense because a host program is always a host program, irrespective of the kernel configuration. We want to specify which ones to compile by CONFIG options, so always-y will be handier. The "always", "hostprogs-y", "hostprogs-m" will be kept for backward compatibility for a while. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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a7499267 |
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18-Dec-2019 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: use pattern rule for building built-in.a in sub-directories The built-in.a in a sub-directory is created by descending into that directory. It does not depend on the other sub-directories. Loosen the dependency. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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56d58936 |
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18-Dec-2019 |
Masahiro Yamada <masahiroy@kernel.org> |
kbuild: do not create orphan built-in.a or obj-y objects Both 'obj-y += foo/' and 'obj-m += foo/' request Kbuild to visit the sub-directory foo/, but the difference is that only the former combines foo/built-in.a into the built-in.a of the current directory because everything in sub-directories visited by obj-m is supposed to be modular. So, it makes sense to create built-in.a only if that sub-directory is reachable by the chain of obj-y. Otherwise, built-in.a will not be linked into vmlinux anyway. For the same reason, it is pointless to compile obj-y objects in the directory visited by obj-m. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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fcbb8461 |
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07-Nov-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove header compile test There are both positive and negative options about this feature. At first, I thought it was a good idea, but actually Linus stated a negative opinion (https://lkml.org/lkml/2019/9/29/227). I admit it is ugly and annoying. The baseline I'd like to keep is the compile-test of uapi headers. (Otherwise, kernel developers have no way to ensure the correctness of the exported headers.) I will maintain a small build rule in usr/include/Makefile. Remove the other header test functionality. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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2dffd23f |
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15-Oct-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: make single target builds much faster Since commit 394053f4a4b3 ("kbuild: make single targets work more correctly"), building single targets is really slow. Speed it up by not descending into unrelated directories. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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20312629 |
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15-Oct-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: reduce KBUILD_SINGLE_TARGETS as descending into subdirectories KBUILD_SINGLE_TARGETS does not need to contain all the targets. Change it to keep track the targets only from the current directory and its subdirectories. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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13dc8c02 |
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21-Sep-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove ar-option and KBUILD_ARFLAGS Commit 40df759e2b9e ("kbuild: Fix build with binutils <= 2.19") introduced ar-option and KBUILD_ARFLAGS to deal with old binutils. According to Documentation/process/changes.rst, the current minimal supported version of binutils is 2.21 so you can assume the 'D' option is always supported. Not only GNU ar but also llvm-ar supports it. With the 'D' option hard-coded, there is no more user of ar-option or KBUILD_ARFLAGS. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com>
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e27128db |
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31-Aug-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to KBUILD_EXTRA_WARN KBUILD_ENABLE_EXTRA_GCC_CHECKS started as a switch to add extra warning options for GCC, but now it is a historical misnomer since we use it also for Clang, DTC, and even kernel-doc. Rename it to more sensible, shorter KBUILD_EXTRA_WARN. For the backward compatibility, KBUILD_ENABLE_EXTRA_GCC_CHECKS is still supported (but not advertised in the documentation). I also fixed up 'make help', and updated the documentation. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
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eb27ea5c |
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19-Aug-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: move modkern_{c,a}flags to Makefile.lib from Makefile.build Makefile.lib is included by Makefile.modfinal as well as Makefile.build. Move modkern_cflags to Makefile.lib in order to simplify cmd_cc_o_c in Makefile.modfinal. Move modkern_cflags as well for consistency. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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2ff2b7ec |
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18-Aug-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: add CONFIG_ASM_MODVERSIONS Add CONFIG_ASM_MODVERSIONS. This allows to remove one if-conditional nesting in scripts/Makefile.build. scripts/Makefile.build is run every time Kbuild descends into a sub-directory. So, I want to avoid $(wildcard ...) evaluation where possible although computing $(wildcard ...) is so cheap that it may not make measurable performance difference. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
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394053f4 |
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14-Aug-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: make single targets work more correctly Currently, the single target build directly descends into the directory of the target. For example, $ make foo/bar/baz.o ... directly descends into foo/bar/. On the other hand, the normal build usually descends one directory at a time, i.e. descends into foo/, and then foo/bar/. This difference causes some problems. [1] miss subdir-asflags-y, subdir-ccflags-y in upper Makefiles The options in subdir-{as,cc}flags-y take effect in the current and its sub-directories. In other words, they are inherited downward. In the example above, the single target will miss subdir-{as,cc}flags-y if they are defined in foo/Makefile. [2] could be built in a different directory As Documentation/kbuild/modules.rst section 4.3 says, Kbuild can handle files that are spread over several sub-directories. The build rule of foo/bar/baz.o may not necessarily be specified in foo/bar/Makefile. It might be specifies in foo/Makefile as follows: [foo/Makefile] obj-y := bar/baz.o This often happens when a module is so big that its source files are divided into sub-directories. In this case, there is no Makefile in the foo/bar/ directory, yet the single target descends into foo/bar/, then fails due to the missing Makefile. You can still do 'make foo/bar/' for partial building, but cannot do 'make foo/bar/baz.s'. I believe the single target '%.s' is a useful feature for inspecting the compiler output. Some modules work around this issue by putting an empty Makefile in every sub-directory. This commit fixes those problems by making the single target build descend in the same way as the normal build does. Another change is the single target build will observe the CONFIG options. Previously, it allowed users to build the foo.o even when the corresponding CONFIG_FOO is disabled: obj-$(CONFIG_FOO) += foo.o In the new behavior, the single target build will just fail and show "No rule to make target ..." (or "Nothing to be done for ..." if the stale object already exists, but cannot be updated). The disadvantage of this commit is the build speed. Now that the single target build visits every directory and parses lots of Makefiles, it is slower than before. (But, I hope it will not be too slow.) Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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c2290f32 |
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10-Aug-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: fix modkern_aflags implementation For the single target building %.symtypes from %.S, $(a_flags) is expanded into the _KERNEL flags even if the object is a part of a module. $(real-obj-m:.o=.symtypes): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) ... would fix the issue, but it is not nice to duplicate similar code for every suffix. Implement modkern_aflags in the same way as modkern_cflags. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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986662b9 |
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10-Aug-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: refactor part-of-module more Make it even shorter. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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49d5089d |
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20-Jul-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: use $(basename ...) for cmd_asn1_compiler $(basename ...) trims the last suffix. Using it is more intuitive in my opinion. This pattern rule makes %.asn1.c and %.asn1.h at the same time. Previously, the short log showed only either of them, depending on the target file in question. To clarify that two files are being generated by the single recipe, I changed the log as follows: Before: ASN.1 crypto/asymmetric_keys/x509.asn1.c After: ASN.1 crypto/asymmetric_keys/x509.asn1.[ch] Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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c07d8d47 |
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08-Aug-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: show hint if subdir-y/m is used to visit module Makefile Since commit ff9b45c55b26 ("kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod"), a module is no longer built in the following pattern: [Makefile] subdir-y := some-module [some-module/Makefile] obj-m := some-module.o You cannot write Makefile this way in upstream because modules.order is not correctly generated. subdir-y is used to descend to a sub-directory that builds tools, device trees, etc. For external modules, the modules order does not matter. So, the Makefile above was known to work. I believe the Makefile should be re-written as follows: [Makefile] obj-m := some-module/ [some-module/Makefile] obj-m := some-module.o However, people will have no idea if their Makefile suddenly stops working. In fact, I received questions from multiple people. Show a warning for a while if obj-m is specified in a Makefile visited by subdir-y or subdir-m. I touched the %/ rule to avoid false-positive warnings for the single target. Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Tom Stonecypher <thomas.edwardx.stonecypher@intel.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Jan Kiszka <jan.kiszka@siemens.com>
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4f2c8f30 |
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06-Aug-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: generate modules.order only in directories visited by obj-y/m The modules.order files in directories visited by the chain of obj-y or obj-m are merged to the upper-level ones, and become parts of the top-level modules.order. On the other hand, there is no need to generate modules.order in directories visited by subdir-y or subdir-m since they would become orphan anyway. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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d9f78edf |
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06-Aug-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: fix false-positive need-builtin calculation The current implementation of need-builtin is false-positive, for example, in the following Makefile: obj-m := foo/ obj-y := foo/bar/ ..., where foo/built-in.a is not required. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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9f69a496 |
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17-Jul-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: split out *.mod out of {single,multi}-used-m rules Currently, *.mod is created as a side-effect of obj-m. Split out *.mod as a dedicated build rule, which allows to unify the %.c -> %.o rule, and remove the single-used-m rule. This also makes the incremental build of allmodconfig faster because it saves $(NM) invocation when there is no change in the module. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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60ae1b19 |
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17-Jul-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove the first line of *.mod files The current format of *.mod is like this: line 1: directory path to the .ko file line 2: a list of objects linked into this module line 3: unresolved symbols (only when CONFIG_TRIM_UNUSED_KSYMS=y) Now that *.mod and *.ko are created in the same directory, the line 1 provides no valuable information. It can be derived by replacing the extension .mod with .ko. In fact, nobody uses the first line any more. Cut down the first line. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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b7dca6dd |
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17-Jul-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: create *.mod with full directory path and remove MODVERDIR While descending directories, Kbuild produces objects for modules, but do not link final *.ko files; it is done in the modpost. To keep track of modules, Kbuild creates a *.mod file in $(MODVERDIR) for every module it is building. Some post-processing steps read the necessary information from *.mod files. This avoids descending into directories again. This mechanism was introduced in 2003 or so. Later, commit 551559e13af1 ("kbuild: implement modules.order") added modules.order. So, we can simply read it out to know all the modules with directory paths. This is easier than parsing the first line of *.mod files. $(MODVERDIR) has a flat directory structure, that is, *.mod files are named only with base names. This is based on the assumption that the module name is unique across the tree. This assumption is really fragile. Stephen Rothwell reported a race condition caused by a module name conflict: https://lkml.org/lkml/2019/5/13/991 In parallel building, two different threads could write to the same $(MODVERDIR)/*.mod simultaneously. Non-unique module names are the source of all kind of troubles, hence commit 3a48a91901c5 ("kbuild: check uniqueness of module names") introduced a new checker script. However, it is still fragile in the build system point of view because this race happens before scripts/modules-check.sh is invoked. If it happens again, the modpost will emit unclear error messages. To fix this issue completely, create *.mod with full directory path so that two threads never attempt to write to the same file. $(MODVERDIR) is no longer needed. Since modules with directory paths are listed in modules.order, Kbuild is still able to find *.mod files without additional descending. I also killed cmd_secanalysis; scripts/mod/sumversion.c computes MD4 hash for modules with MODULE_VERSION(). When CONFIG_DEBUG_SECTION_MISMATCH=y, it occurs not only in the modpost stage, but also during directory descending, where sumversion.c may parse stale *.mod files. It would emit 'No such file or directory' warning when an object consisting a module is renamed, or when a single-obj module is turned into a multi-obj module or vice versa. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Nicolas Pitre <nico@fluxnic.net>
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e0e1b1ec |
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17-Jul-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove duplication from modules.order in sub-directories Currently, only the top-level modules.order drops duplicated entries. The modules.order files in sub-directories potentially contain duplication. To list out the paths of all modules, I want to use modules.order instead of parsing *.mod files in $(MODVERDIR). To achieve this, I want to rip off duplication from modules.order of external modules too. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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1bd9a468 |
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17-Jul-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: get rid of kernel/ prefix from in-tree modules.{order,builtin} Removing the 'kernel/' prefix will make our life easier because we can simply do 'cat modules.order' to get all built modules with full paths. Currently, we parse the first line of '*.mod' files in $(MODVERDIR). Since we have duplicated functionality here, I plan to remove MODVERDIR entirely. In fact, modules.order is generated also for external modules in a broken format. It adds the 'kernel/' prefix to the absolute path of the module, like this: kernel//path/to/your/external/module/foo.ko This is fine for now since modules.order is not used for external modules. However, I want to sanitize the format everywhere towards the goal of removing MODVERDIR. We cannot change the format of installed module.{order,builtin}. So, 'make modules_install' will add the 'kernel/' prefix while copying them to $(MODLIB)/. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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7e131918 |
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17-Jul-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: do not create empty modules.order in the prepare stage Currently, $(objtree)/modules.order is touched in two places. In the 'prepare0' rule, scripts/Makefile.build creates an empty modules.order while processing 'obj=.' In the 'modules' rule, the top-level Makefile overwrites it with the correct list of modules. While this might be a good side-effect that modules.order is made empty every time (probably this is not intended functionality), I personally do not like this behavior. Create modules.order only when it is sensible to do so. This avoids creating the following pointless files: scripts/basic/modules.order scripts/dtc/modules.order scripts/gcc-plugins/modules.order scripts/genksyms/modules.order scripts/mod/modules.order scripts/modules.order scripts/selinux/genheaders/modules.order scripts/selinux/mdp/modules.order scripts/selinux/modules.order Going forward, $(objtree)/modules.order lists the modules that was built in the last successful build. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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4bd01de8 |
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16-Jul-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: compile-test headers listed in header-test-m as well It will be useful to control the header-test by a tristate option. If CONFIG_FOO is a tristate option, you can write like this: header-test-$(CONFIG_FOO) += foo.h Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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051f278e |
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05-Jul-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctree Commit 25b146c5b8ce ("kbuild: allow Kbuild to start from any directory") deprecated KBUILD_SRCTREE. It is only used in tools/testing/selftest/ to distinguish out-of-tree build. Replace it with a new boolean flag, building_out_of_srctree. I also replaced the conditional ($(srctree),.) because the next commit will allow an absolute path to be used for $(srctree) even when building in the source tree. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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c93a0368 |
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30-Jun-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: do not create wrappers for header-test-y header-test-y does not work with headers in sub-directories. For example, you may want to write a Makefile, like this: include/linux/Kbuild: header-test-y += mtd/nand.h This entry will create a wrapper include/linux/mtd/nand.hdrtest.c with the following content: #include "mtd/nand.h" To make this work, we need to add $(srctree)/include/linux to the header search path. It would be tedious to add ccflags-y. Instead, we could change the *.hdrtest.c rule to wrap: #include "nand.h" This works for in-tree build since #include "..." searches in the relative path from the header with this directive. For O=... build, we need to add $(srctree)/include/linux/mtd to the header search path, which will be even more tedious. After all, I thought it would be handier to compile headers directly without creating wrappers. I added a new build rule to compile %.h into %.h.s The target is %.h.s instead of %.h.o because it is slightly faster. Also, as for GCC, an empty assembly is smaller than an empty object. I wrote the build rule: $(CC) $(c_flags) -S -o $@ -x c /dev/null -include $< instead of: $(CC) $(c_flags) -S -o $@ -x c $< Both work fine with GCC, but the latter is bad for Clang. This comes down to the difference in the -Wunused-function policy. GCC does not warn about unused 'static inline' functions at all. Clang does not warn about the ones in included headers, but does about the ones in the source. So, we should handle headers as headers, not as source files. In fact, this has been hidden since commit abb2ea7dfd82 ("compiler, clang: suppress warning for unused static inline functions"), but we should not rely on that. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Jani Nikula <jani.nikula@intel.com> Tested-by: Jani Nikula <jani.nikula@intel.com>
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e846f0dc |
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04-Jun-2019 |
Jani Nikula <jani.nikula@intel.com> |
kbuild: add support for ensuring headers are self-contained Sometimes it's useful to be able to explicitly ensure certain headers remain self-contained, i.e. that they are compilable as standalone units, by including and/or forward declaring everything they depend on. Add special target header-test-y where individual Makefiles can add headers to be tested if CONFIG_HEADER_TEST is enabled. This will generate a dummy C file per header that gets built as part of extra-y. Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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ea24213d |
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24-Feb-2019 |
Peter Zijlstra <peterz@infradead.org> |
objtool: Add UACCESS validation It is important that UACCESS regions are as small as possible; furthermore the UACCESS state is not scheduled, so doing anything that might directly call into the scheduler will cause random code to be ran with UACCESS enabled. Teach objtool too track UACCESS state and warn about any CALL made while UACCESS is enabled. This very much includes the __fentry__() and __preempt_schedule() calls. Note that exceptions _do_ save/restore the UACCESS state, and therefore they can drive preemption. This also means that all exception handlers must have an otherwise redundant UACCESS disable instruction; therefore ignore this warning for !STT_FUNC code (exception handlers are not normal functions). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
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a9a49c2a |
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30-Mar-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: use $(srctree) instead of KBUILD_SRC to check out-of-tree build KBUILD_SRC was conventionally used for some different purposes: [1] To remember the source tree path [2] As a flag to check if sub-make is already done [3] As a flag to check if Kbuild runs out of tree For [1], we do not need to remember it because the top Makefile can compute it by $(realpath $(dir $(lastword $(MAKEFILE_LIST)))) [2] has been replaced with self-commenting 'sub_make_done'. For [3], we can distinguish in-tree/out-of-tree by comparing $(srctree) and '.' This commit converts [3] to prepare for the KBUILD_SRC removal. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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1a49b2fd |
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26-Mar-2019 |
Joe Lawrence <joe.lawrence@redhat.com> |
kbuild: strip whitespace in cmd_record_mcount findstring CC_FLAGS_FTRACE may contain trailing whitespace that interferes with findstring. For example, commit 6977f95e63b9 ("powerpc: avoid -mno-sched-epilog on GCC 4.9 and newer") introduced a change such that on my ppc64le box, CC_FLAGS_FTRACE="-pg -mprofile-kernel ". (Note the trailing space.) When cmd_record_mcount is now invoked, findstring fails as the ftrace flags were found at very end of _c_flags, without the trailing space. _c_flags=" ... -pg -mprofile-kernel" CC_FLAGS_FTRACE="-pg -mprofile-kernel " ^ findstring is looking for this extra space Remove the redundant whitespaces from CC_FLAGS_FTRACE in cmd_record_mcount to avoid this problem. [masahiro.yamada: This issue only happens in the released versions of GNU Make. CC_FLAGS_FTRACE will not contain the trailing space if you use the latest GNU Make, which contains commit b90fabc8d6f3 ("* NEWS: Do not insert a space during '+=' if the value is empty.") ] Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> (refactoring) Fixes: 6977f95e63b9 ("powerpc: avoid -mno-sched-epilog on GCC 4.9 and newer"). Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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898f5a00 |
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05-Feb-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: move archive command to scripts/Makefile.lib scripts/Makefile.build and arch/s390/boot/Makefile use the same command (thin archiving with symbol table creation). Avoid the code duplication, and move it to scripts/Makefile.lib. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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88110713 |
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19-Feb-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: hardcode genksyms path and remove GENKSYMS variable The genksyms source was integrated into the kernel tree in 2003. I do not expect anybody still using the external /sbin/genksyms. Kbuild does not need to provide the ability to override GENKSYMS. Let's remove the GENKSYMS variable, and use the hardcoded path. Since it occurred in the pre-git era, I attached the commit message in case somebody is interested in the historical background. | Author: Kai Germaschewski <kai@tp1.ruhr-uni-bochum.de> | Date: Wed Feb 19 04:17:28 2003 -0600 | | kbuild: [PATCH] put genksyms in scripts dir | | This puts genksyms into scripts/genksyms/. | | genksyms used to be maintained externally, though the only possible user | was the kernel build. Moving it into the kernel sources makes it easier to | keep it uptodate, like for example updating it to generate linker scripts | directly instead of postprocessing the generated header file fragments | with sed, as we do currently. | | Also, genksyms does not handle __typeof__, which needs to be fixed since | some of the exported symbol in the kernel are defined using __typeof__. | | (Rusty Russell/me) Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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1d8001ef |
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13-Feb-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: generate modules.order only when CONFIG_MODULES=y Do not generate pointless modules.order when the module support is disabled. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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1e88e415 |
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09-Feb-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: Disable extra debugging info in .s output Modern gcc adds view assignments, reset assertion checking in .loc directives and a couple more additional debug markers, which clutters the asm output unnecessarily: For example: bsp_resume: .LFB3466: .loc 1 1868 1 is_stmt 1 view -0 .cfi_startproc .loc 1 1869 2 view .LVU73 # arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume) .loc 1 1869 14 is_stmt 0 view .LVU74 movq this_cpu(%rip), %rax # this_cpu, this_cpu movq 64(%rax), %rax # this_cpu.94_1->c_bsp_resume, _2 # arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume) .loc 1 1869 5 view .LVU75 testq %rax, %rax # _2 je .L8 #, .loc 1 1870 3 is_stmt 1 view .LVU76 movq $boot_cpu_data, %rdi #, jmp __x86_indirect_thunk_rax or .loc 2 57 9 view .LVU478 .loc 2 57 9 view .LVU479 .loc 2 57 9 view .LVU480 .loc 2 57 9 view .LVU481 .LBB1385: .LBB1383: .LBB1379: .LBB1377: .LBB1375: .loc 2 57 9 view .LVU482 .loc 2 57 9 view .LVU483 movl %edi, %edx # cpu, cpu .LVL87: .loc 2 57 9 is_stmt 0 view .LVU484 That MOV in there is drowned in debugging information and latter makes it hard to follow the asm. And that DWARF info is not really needed for asm output staring. Disable the debug information generation which clutters the asm output unnecessarily: bsp_resume: # arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume) movq this_cpu(%rip), %rax # this_cpu, this_cpu movq 64(%rax), %rax # this_cpu.94_1->c_bsp_resume, _2 # arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume) testq %rax, %rax # _2 je .L8 #, # arch/x86/kernel/cpu/common.c:1870: this_cpu->c_bsp_resume(&boot_cpu_data); movq $boot_cpu_data, %rdi #, jmp __x86_indirect_thunk_rax .L8: # arch/x86/kernel/cpu/common.c:1871: } rep ret .size bsp_resume, .-bsp_resume [ bp: write commit message. ] Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Borislav Petkov <bp@suse.de>
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b79c6aa6 |
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17-Jan-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove unnecessary in-subshell execution The commands surrounded by ( ) are executed in a subshell, but in most cases, we do not need to spawn an extra subshell. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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afa974b7 |
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17-Jan-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: add real-prereqs shorthand for $(filter-out FORCE,$^) In Kbuild, if_changed and friends must have FORCE as a prerequisite. Hence, $(filter-out FORCE,$^) or $(filter-out $(PHONY),$^) is a common idiom to get the names of all the prerequisites except phony targets. Add real-prereqs as a shorthand. Note: We cannot replace $(filter %.o,$^) in cmd_link_multi-m because $^ may include auto-generated dependencies from the .*.cmd file when a single object module is changed into a multi object module. Refer to commit 69ea912fda74 ("kbuild: remove unneeded link_multi_deps"). I added some comment to avoid accidental breakage. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Rob Herring <robh@kernel.org>
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dee94953 |
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16-Jan-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove top-level built-in.a The symbol table in the final archive is unneeded; the linker does not require the symbol table after the --whole-archive option. Every object file in the archive is included in the link anyway. Pass thin archives from subdirectories directly to the linker, and remove the final archiving step. Fix up the document and comments as well. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Nicholas Piggin <npiggin@gmail.com>
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1d467bb8 |
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11-Dec-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: handle part-of-module correctly for *.ll and *.symtypes The single targets *.ll and *.symtypes have never been treated as a module. Fix it. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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96c0a918 |
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11-Dec-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: refactor part-of-module Use $(foreach ...) to make it shorter. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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45c4372d |
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11-Dec-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: refactor quiet_modtag part-of-module and quiet_modtag are set for the same targets. Define quiet_modtag based on part-of-module. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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b39a6916 |
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11-Dec-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove redundant quiet_modtag for $(obj-m) All objects in $(obj-m) are contained in $(real-obj-m) as well. It is true composite objects are only contained in $(obj-m), but [M] is hard-coded in quiet_cmd_link_multi-m. This line is redundant. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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8e9b61b2 |
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30-Nov-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: move .SECONDARY special target to Kbuild.include In commit 54a702f70589 ("kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers"), I missed one important feature of the .SECONDARY target: .SECONDARY with no prerequisites causes all targets to be treated as secondary. ... which agrees with the policy of Kbuild. Let's move it to scripts/Kbuild.include, with no prerequisites. Note: If an intermediate file is generated by $(call if_changed,...), you still need to add it to "targets" so its .*.cmd file is included. The arm/arm64 crypto files are generated by $(call cmd,shipped), so they do not need to be added to "targets", but need to be added to "clean-files" so "make clean" can properly clean them away. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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5439f09f |
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29-Nov-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove redundant 'set -e' from cmd_* defines These three cmd_* are invoked in the $(call cmd,*) form. Now that 'set -e' moved to the 'cmd' macro, they do not need to explicitly give 'set -e'. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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e5d28910 |
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29-Nov-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove trailing semicolon from cmd_* passed to if_changed_rule With the change of rule_cc_o_c / rule_as_o_S in the last commit, each command is executed in a separate subshell. Rip off unneeded semicolons. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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3a2429e1 |
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29-Nov-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: change if_changed_rule for multi-line recipe The 'define' ... 'endef' directive is useful to confine a series of shell commands into a single macro: define foo [action1] [action2] [action3] endif Each action is executed in a separate subshell. However, rule_cc_o_c and rule_as_o_S in scripts/Makefile.build are written as follows (with a trailing semicolon in each cmd_*): define rule_cc_o_c [action1] ; \ [action2] ; \ [action3] ; endef All shell commands are concatenated with '; \' so that it looks like a single command from the Makefile point of view. This does not exploit the benefits of 'define' ... 'endef' form because a single shell command can be more simply written, like this: rule_cc_o_c = \ [action1] ; \ [action2] ; \ [action3] ; I guess the intention for the command concatenation was to let the '@set -e' in if_changed_rule cover all the commands. We can improve the readability by moving '@set -e' to the 'cmd' macro. The combo of $(call echo-cmd,*) $(cmd_*) in rule_cc_o_c and rule_as_o_S have been replaced with $(call cmd,*). The trailing back-slashes have been removed. Here is a note about the performance: the commands in rule_cc_o_c and rule_as_o_S were previously executed all together in a single subshell, but now each line in a separate subshell. This means Make will spawn extra subshells [1]. I measured the build performance for x86_64_defconfig + CONFIG_MODVERSIONS + CONFIG_TRIM_UNUSED_KSYMS and I saw slight performance regression, but I believe code readability and maintainability wins. [1] Precisely, GNU Make may optimize this by executing the command directly instead of forking a subshell, if no shell special characters are found in the command line and omitting the subshell will not change the behavior. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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bbda5ec6 |
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29-Nov-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS My main motivation of this commit is to clean up scripts/Kbuild.include and scripts/Makefile.build. Currently, CONFIG_TRIM_UNUSED_KSYMS works with a tricky gimmick; possibly exported symbols are detected by letting $(CPP) replace EXPORT_SYMBOL* with a special string '=== __KSYM_*===', which is post-processed by sed, and passed to fixdep. The extra preprocessing is costly, and hacking cmd_and_fixdep is ugly. I came up with a new way to find exported symbols; insert a dummy symbol __ksym_marker_* to each potentially exported symbol. Those dummy symbols are picked up by $(NM), post-processed by sed, then appended to .*.cmd files. I collected the post-process part to a new shell script scripts/gen_ksymdeps.sh for readability. The dummy symbols are put into the .discard.* section so that the linker script rips them off the final vmlinux or modules. A nice side-effect is building with CONFIG_TRIM_UNUSED_KSYMS will be much faster. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nicolas Pitre <nico@linaro.org>
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ee3e46b7 |
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29-Nov-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: refactor modversions build rules Let $(CC) compile objects into normal files *.o instead of .tmp_*.o whether CONFIG_MODVERSIONS is enabled or not. With this, the input file for objtool is always *.o so objtool_o can go away. I guess the reason of using .tmp_*.o for intermediate objects was to avoid leaving incomplete *.o file (, whose timestamp says it is up-to-date) when the genksyms tool failed for some reasons. It no longer matters because any targets are deleted on errors since commit 9c2af1c7377a ("kbuild: add .DELETE_ON_ERROR special target"). Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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4317ee3b |
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29-Nov-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove redundant 'set -e' from sub_cmd_record_mcount This is executed inside the if_changed_rule, which already sets 'set -e'. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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392885ee |
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29-Nov-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: let fixdep directly write to .*.cmd files Currently, fixdep writes dependencies to .*.tmp, which is renamed to .*.cmd after everything succeeds. This is a very safe way to avoid corrupted .*.cmd files. The if_changed_dep has carried this safety mechanism since it was added in 2002. If fixdep fails for some reasons or a user terminates the build while fixdep is running, the incomplete output from the fixdep could be troublesome. This is my insight about some bad scenarios: [1] If the compiler succeeds to generate *.o file, but fixdep fails to write necessary dependencies to .*.cmd file, Make will miss to rebuild the object when headers or CONFIG options are changed. In this case, fixdep should not generate .*.cmd file at all so that 'arg-check' will surely trigger the rebuild of the object. [2] A partially constructed .*.cmd file may not be a syntactically correct makefile. The next time Make runs, it would include it, then fail to parse it. Once this happens, 'make clean' is be the only way to fix it. In fact, [1] is no longer a problem since commit 9c2af1c7377a ("kbuild: add .DELETE_ON_ERROR special target"). Make deletes a target file on any failure in its recipe. Because fixdep is a part of the recipe of *.o target, if it fails, the *.o is deleted anyway. However, I am a bit worried about the slight possibility of [2]. So, here is a solution. Let fixdep directly write to a .*.cmd file, but allow makefiles to include it only when its corresponding target exists. This effectively reverts commit 2982c953570b ("kbuild: remove redundant $(wildcard ...) for cmd_files calculation"), and commit 00d78ab2ba75 ("kbuild: remove dead code in cmd_files calculation in top Makefile") because now we must check the presence of targets. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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4cd24de3 |
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02-Nov-2018 |
Zhenzhong Duan <zhenzhong.duan@oracle.com> |
x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support Since retpoline capable compilers are widely available, make CONFIG_RETPOLINE hard depend on the compiler capability. Break the build when CONFIG_RETPOLINE is enabled and the compiler does not support it. Emit an error message in that case: "arch/x86/Makefile:226: *** You are building kernel with non-retpoline compiler, please update your compiler.. Stop." [dwmw: Fail the build with non-retpoline compiler] Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Borislav Petkov <bp@suse.de> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: <srinivas.eeda@oracle.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/cca0cb20-f9e2-4094-840b-fb0f8810cd34@default
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7d0ea252 |
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09-Oct-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: use 'else ifeq' for checksrc to improve readability 'ifeq ... else ifeq ... endif' notation is supported by GNU Make 3.81 or later, which is the requirement for building the kernel since commit 37d69ee30808 ("docs: bump minimal GNU Make version to 3.81"). Use it to improve the readability. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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69ea912f |
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03-Oct-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove unneeded link_multi_deps Since commit c8589d1e9e01 ("kbuild: handle multi-objs dependency appropriately"), $^ really represents all the prerequisite of the composite object being built. Hence, $(filter %.o,$^) contains all the objects to link together, which is much simpler than link_multi_deps calculation. Please note $(filter-out FORCE,$^) does not work here. When a single object module is turned into a multi object module, $^ will contain header files that were previously included for building the single object, and recorded in the .*.cmd file. To filter out such headers, $(filter %.o,$^) should be used here. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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5a4630aa |
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17-Sep-2018 |
Joel Stanley <joel@jms.id.au> |
ftrace: Build with CPPFLAGS to get -Qunused-arguments When building to record the mcount locations the kernel uses KBUILD_CFLAGS but not KBUILD_CPPFLAGS. This means it lacks -Qunused-arguments when building with clang, resulting in a lot of noisy warnings. Signed-off-by: Joel Stanley <joel@jms.id.au> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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0d91bf58 |
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12-Sep-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove old check for CFLAGS use This check has been here for more than a decade since commit 0c53c8e6eb45 ("kbuild: check for wrong use of CFLAGS"). Enough time for migration has passed. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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113fc083 |
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26-Aug-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
objtool: Remove workaround for unreachable warnings from old GCC Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6") bumped the minimum GCC version to 4.6 for all architectures. This effectively reverts commit da541b20021c ("objtool: Skip unreachable warnings for GCC 4.4 and older"), which was a workaround for GCC 4.4 or older. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: linux-kbuild@vger.kernel.org Link: https://lkml.kernel.org/r/1535341183-19994-1-git-send-email-yamada.masahiro@socionext.com
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d503ac53 |
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23-Aug-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: rename LDFLAGS to KBUILD_LDFLAGS Commit a0f97e06a43c ("kbuild: enable 'make CFLAGS=...' to add additional options to CC") renamed CFLAGS to KBUILD_CFLAGS. Commit 222d394d30e7 ("kbuild: enable 'make AFLAGS=...' to add additional options to AS") renamed AFLAGS to KBUILD_AFLAGS. Commit 06c5040cdb13 ("kbuild: enable 'make CPPFLAGS=...' to add additional options to CPP") renamed CPPFLAGS to KBUILD_CPPFLAGS. For some reason, LDFLAGS was not renamed. Using a well-known variable like LDFLAGS may result in accidental override of the variable. Kbuild generally uses KBUILD_ prefixed variables for the internally appended options, so here is one more conversion to sanitize the naming convention. I did not touch Makefiles under tools/ since the tools build system is a different world. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
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87a32e62 |
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23-Aug-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: pass LDFLAGS to recordmcount.pl Since commit 0fbe9a245c60 ("microblaze: add endianness options to LDFLAGS instead of LD"), you cannot build the kernel for microblaze with CONFIG_DYNAMIC_FTRACE. Fixes: 0fbe9a245c60 ("microblaze: add endianness options to LDFLAGS instead of LD") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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07d04081 |
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06-Aug-2018 |
Vasily Gorbik <gor@linux.ibm.com> |
tracing: Avoid calling cc-option -mrecord-mcount for every Makefile Currently if CONFIG_FTRACE_MCOUNT_RECORD is enabled -mrecord-mcount compiler flag support is tested for every Makefile. Top 4 cc-option usages: 511 -mrecord-mcount 11 -fno-stack-protector 9 -Wno-override-init 2 -fsched-pressure To address that move cc-option from scripts/Makefile.build to top Makefile and export CC_USING_RECORD_MCOUNT to be used in original place. While doing that also add -mrecord-mcount to CC_FLAGS_FTRACE (if gcc actually supports it). Link: http://lkml.kernel.org/r/patch-2.thread-aa7b8d.git-de935bace15a.your-ad-here.call-01533557518-ext-9465@work.hours Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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d6c6ab93 |
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08-Aug-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove deprecated host-progs variable The host-progs has been kept as an alias of hostprogs-y for a long time (at least since the beginning of Git era), with the clear prompt: Usage of host-progs is deprecated. Please replace with hostprogs-y! Enough time for the migration has passed. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Max Filippov <jcmvbkbc@gmail.com>
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6916162c |
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04-Jul-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove duplicated comments about PHONY The comment is the same as in the top-level Makefile. Also, the comments contain typos: - the .PHONY variable -> the PHONY variable - se we can ... -> so we can ... Instead of fixing the typos, just remove the duplicated comments. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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ed7d40bc |
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08-Jun-2018 |
Greg Thelen <gthelen@google.com> |
tracing: Fix SKIP_STACK_VALIDATION=1 build due to bad merge with -mrecord-mcount Non gcc-5 builds with CONFIG_STACK_VALIDATION=y and SKIP_STACK_VALIDATION=1 fail. Example output: /bin/sh: init/.tmp_main.o: Permission denied commit 96f60dfa5819 ("trace: Use -mcount-record for dynamic ftrace"), added a mismatched endif. This causes cmd_objtool to get mistakenly set. Relocate endif to balance the newly added -record-mcount check. Link: http://lkml.kernel.org/r/20180608214746.136554-1-gthelen@google.com Fixes: 96f60dfa5819 ("trace: Use -mcount-record for dynamic ftrace") Acked-by: Andi Kleen <ak@linux.intel.com> Tested-by: David Rientjes <rientjes@google.com> Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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96f60dfa |
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27-Nov-2017 |
Andi Kleen <ak@linux.intel.com> |
trace: Use -mcount-record for dynamic ftrace gcc 5 supports a new -mcount-record option to generate ftrace tables directly. This avoids the need to run record_mcount manually. Use this option when available. So far doesn't use -mcount-nop, which also exists now. This is needed to make ftrace work with LTO because the normal record-mcount script doesn't run over the link time output. It should also improve build times slightly in the general case. Link: http://lkml.kernel.org/r/20171127213423.27218-12-andi@firstfloor.org Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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704db5433 |
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09-May-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX was selected by BLACKFIN, METAG. They were removed by commit 4ba66a976072 ("arch: remove blackfin port"), commit bb6fb6dfcc17 ("metag: Remove arch/metag/"), respectively. No more architecture enables CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX. Clean up the rest of scripts, and remove the Kconfig entry. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
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74d93171 |
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09-May-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
genksyms: remove symbol prefix support CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX was selected by BLACKFIN, METAG. They were removed by commit 4ba66a976072 ("arch: remove blackfin port"), commit bb6fb6dfcc17 ("metag: Remove arch/metag/"), respectively. No more architecture enables CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX, hence the -s (--symbol-prefix) option is unnecessary. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
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54a702f7 |
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23-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers GNU Make automatically deletes intermediate files that are updated in a chain of pattern rules. Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts Example 2) %.o <- %.c <- %.c_shipped A couple of makefiles mark such targets as .PRECIOUS to prevent Make from deleting them, but the correct way is to use .SECONDARY. .SECONDARY Prerequisites of this special target are treated as intermediate files but are never automatically deleted. .PRECIOUS When make is interrupted during execution, it may delete the target file it is updating if the file was modified since make started. If you mark the file as precious, make will never delete the file if interrupted. Both can avoid deletion of intermediate files, but the difference is the behavior when Make is interrupted; .SECONDARY deletes the target, but .PRECIOUS does not. The use of .PRECIOUS is relatively rare since we do not want to keep partially constructed (possibly corrupted) targets. Another difference is that .PRECIOUS works with pattern rules whereas .SECONDARY does not. .PRECIOUS: $(obj)/%.lex.c works, but .SECONDARY: $(obj)/%.lex.c has no effect. However, for the reason above, I do not want to use .PRECIOUS which could cause obscure build breakage. The targets specified as .SECONDARY must be explicit. $(targets) contains all targets that need to include .*.cmd files. So, the intermediates you want to keep are mostly in there. Therefore, mark $(targets) as .SECONDARY. It means primary targets are also marked as .SECONDARY, but I do not see any drawback for this. I replaced some .SECONDARY / .PRECIOUS markers with 'targets'. This will make Kbuild search for non-existing .*.cmd files, but this is not a noticeable performance issue. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Frank Rowand <frowand.list@gmail.com> Acked-by: Ingo Molnar <mingo@kernel.org>
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4fa8bc94 |
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23-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: rename *-asn1.[ch] to *.asn1.[ch] Our convention is to distinguish file types by suffixes with a period as a separator. *-asn1.[ch] is a different pattern from other generated sources such as *.lex.c, *.tab.[ch], *.dtb.S, etc. More confusing, files with '-asn1.[ch]' are generated files, but '_asn1.[ch]' are checked-in files: net/netfilter/nf_conntrack_h323_asn1.c include/linux/netfilter/nf_conntrack_h323_asn1.h include/linux/sunrpc/gss_asn1.h Rename generated files to *.asn1.[ch] for consistency. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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a7f92419 |
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23-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: add %.dtb.S and %.dtb to 'targets' automatically Another common pattern that consists of chained commands is to compile a DTB as binary data into the kernel image or a module. It is used in several places in the source tree. Support it in the core Makefile. $(call if_changed,dt_S_dtb) is more suitable than $(call cmd,dt_S_dtb) in case cmd_dt_S_dtb is changed in the future. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Frank Rowand <frowand.list@gmail.com>
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b23d1a24 |
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23-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: add %.lex.c and %.tab.[ch] to 'targets' automatically Files generated by if_changed* must be added to 'targets' to include *.cmd files. Otherwise, they would be regenerated every time. The build system automatically adds objects to 'targets' where appropriate, such as obj-y, extra-y, etc. but does nothing for intermediate files. So, each Makefile needs to add them by itself. There are some common cases where objects are generated by chained rules. Lexers and parsers are compiled like follows: %.lex.o <- %.lex.c <- %.l %.tab.o <- %.tab.c <- %.y They are common patterns, so it is reasonable to take care of them in the core Makefile instead of requiring each Makefile to do so. At this moment, you cannot delete 'target += zconf.lex.c' in the Kconfig Makefile because zconf.lex.c is included from zconf.tab.c instead of being compiled separately. It should be deleted after Kconfig is more refactored. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Frank Rowand <frowand.list@gmail.com>
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127668cf |
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19-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: clean up link rule of composite modules cmd_link_multi-link is used only for cmd_link_multi-m. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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5e18f029 |
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19-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: clean up archive rule of built-in.a With the incremental linking entirely dropped, we can simplify the Makefile. While I am here, I renamed cmd_link_o_target to cmd_ar_builtin. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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7657f60e |
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19-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove partial section mismatch detection for built-in.a When built-in.o was incrementally linked with 'ld -r', the section mismatch analysis for the individual built-in.o was possible when CONFIG_DEBUG_SECTION_MISMATCH was enabled. With the migration to the thin archive, built-in.a (former, built-in.o) is no longer an ELF file. So, the modpost does nothing useful. scripts/mod/modpost.c just checks the header to bail out, as follows: /* Is this a valid ELF file? */ if ((hdr->e_ident[EI_MAG0] != ELFMAG0) || (hdr->e_ident[EI_MAG1] != ELFMAG1) || (hdr->e_ident[EI_MAG2] != ELFMAG2) || (hdr->e_ident[EI_MAG3] != ELFMAG3)) { /* Not an ELF file - silently ignore it */ return 0; } We have the full analysis in the final link stage anyway, so we would not miss the section mismatching. I do not see a good reason to require extra linking only for the purpose of the per-directory analysis. Just get rid of this part. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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f98fe47c |
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19-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: link $(real-obj-y) instead of $(obj-y) into built-in.a In Kbuild, Makefiles can add the same object to obj-y multiple times. So, obj-y += foo.o obj-y += foo.o is fine. However, this is not true when the same object is added multiple times via composite objects. For example, obj-y += foo.o bar.o foo-objs := foo-bar-common.o foo-only.o bar-objs := foo-bar-common.o bar-only.o causes build error because two instances of foo-bar-common.o are linked into the vmlinux. Makefiles tend to invent ugly work-around, for example - lib/zstd/Makefile - drivers/net/ethernet/cavium/liquidio/Makefile The technique used in Kbuild to avoid the multiple definition error is to use $(filter $(obj-y), $^). Here, $^ lists the names of all the prerequisites with duplicated names removed. By replacing it with $(filter $(real-obj-y), $^) we can do likewise for composite objects. For built-in objects, we do not need to keep the composite object structure. We can simply expand them, and link $(real-obj-y) to built-in.a. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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f5f33681 |
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19-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: rename real-objs-y/m to real-obj-y/m When I was refactoring Makefiles, I stupidly mistook 'real-obj-y' for 'real-objs-y' over and over again. Finally, I decide to rename it to 'real-obj-y'. This is consistent with 'obj-y', 'subdir-obj-y'. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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c0152e9a |
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19-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: move modname and modname-multi close to modname_flags Just a cosmetic change to put related code close together. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Cao jin <caoj.fnst@cn.fujitsu.com>
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fe852ac2 |
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19-Mar-2018 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: simplify modname calculation modname can be calculated much more simply. If modname-multi is empty, it is a single-used object. So, modname = $(basetarget). Otherwise, modname = $(modname-multi). Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Cao jin <caoj.fnst@cn.fujitsu.com>
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f49821ee |
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10-Feb-2018 |
Nicholas Piggin <npiggin@gmail.com> |
kbuild: rename built-in.o to built-in.a Incremental linking is gone, so rename built-in.o to built-in.a, which is the usual extension for archive files. This patch does two things, first is a simple search/replace: git grep -l 'built-in\.o' | xargs sed -i 's/built-in\.o/built-in\.a/g' The second is to invert nesting of nested text manipulations to avoid filtering built-in.a out from libs-y2: -libs-y2 := $(filter-out %.a, $(patsubst %/, %/built-in.a, $(libs-y))) +libs-y2 := $(patsubst %/, %/built-in.a, $(filter-out %.a, $(libs-y))) Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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6358d6e8 |
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10-Feb-2018 |
Nicholas Piggin <npiggin@gmail.com> |
kbuild: remove incremental linking option This removes the old `ld -r` incremental link option, which has not been selected by any architecture since June 2017. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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1fe7d2bb |
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06-Feb-2018 |
Michael Forney <forney@google.com> |
kbuild: Improve portability of some sed invocations * Use BREs where EREs aren't necessary. * Pass -E instead of -r to use EREs. This will be standardized in the next POSIX revision[0]. GNU sed supports this since 4.2 (May 2009), and busybox since 1.22.0 (Jan 2014). * Use the [:space:] character class instead of ` \t` in bracket expressions. In bracket expressions, POSIX says that <backslash> loses its special meaning, so a conforming implementation cannot expand \t to <tab>[1]. * In BREs, use interval expressions (\{n,m\}) instead of non-standard features like \+ and \?. * Use a loop instead of -s flag. There are still plenty of other cases of non-standard sed invocations (use of ERE features in BREs, in-place editing), but this fixes some core ones. [0] http://austingroupbugs.net/view.php?id=528 [1] http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_03_05 Signed-off-by: Michael Forney <forney@google.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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d5028ba8 |
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06-Feb-2018 |
Peter Zijlstra <peterz@infradead.org> |
objtool, retpolines: Integrate objtool with retpoline support more closely Disable retpoline validation in objtool if your compiler sucks, and otherwise select the validation stuff for CONFIG_RETPOLINE=y (most builds would already have it set due to ORC). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
ca41b97e |
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31-Jan-2018 |
Peter Zijlstra <peterz@infradead.org> |
objtool: Add module specific retpoline rules David allowed retpolines in .init.text, except for modules, which will trip up objtool retpoline validation, fix that. Requested-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
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b5bc2231 |
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16-Jan-2018 |
Peter Zijlstra <peterz@infradead.org> |
objtool: Add retpoline validation David requested a objtool validation pass for CONFIG_RETPOLINE=y enabled builds, where it validates no unannotated indirect jumps or calls are left. Add an additional .discard.retpoline_safe section to allow annotating the few indirect sites that are required and safe. Requested-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: David Woodhouse <dwmw@amazon.co.uk> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
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2a0098d7 |
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15-Jan-2018 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Fix seg fault with gold linker Objtool segfaults when the gold linker is used with CONFIG_MODVERSIONS=y and CONFIG_UNWINDER_ORC=y. With CONFIG_MODVERSIONS=y, the .o file gets passed to the linker before being passed to objtool. The gold linker seems to strip unused ELF symbols by default, which confuses objtool and causes the seg fault when it's trying to generate ORC metadata. Objtool should really be running immediately after GCC anyway, without a linker call in between. Change the makefile ordering so that objtool is called before the linker. Reported-and-tested-by: Markus <M4rkusXXL@web.de> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder") Link: http://lkml.kernel.org/r/355f04da33581f4a3bf82e5b512973624a1e23a2.1516025651.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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3a025e1d |
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20-Nov-2017 |
Matthew Wilcox <willy@infradead.org> |
Add optional check for bad kernel-doc comments Implement a '-none' output mode for kernel-doc which will only output warning messages, and suppresses the warning message about there being no kernel-doc in the file. If the build has requested additional warnings, automatically check all .c files. This patch does not check .h files. Enabling the warning by default would add about 1300 warnings, so it's default off for now. People who care can use this to check they didn't break the docs and maybe we'll get all the warnings fixed and be able to enable this check by default in the future. Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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f7adc312 |
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07-Nov-2017 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: create built-in.o automatically if parent directory wants it "obj-y += foo/" syntax requires Kbuild to visit the "foo" subdirectory and link built-in.o from that directory. This means foo/Makefile is responsible for creating built-in.o even if there is no object to link (in this case, built-in.o is an empty archive). We have had several fixups like commit 4b024242e8a4 ("kbuild: Fix linking error built-in.o no such file or directory"), then ended up with a complex condition as follows: ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),) builtin-target := $(obj)/built-in.o endif We still have more cases not covered by the above, so we need to add obj- := dummy.o in several places just for creating empty built-in.o. A key point is, the parent Makefile knows whether built-in.o is needed or not. If a subdirectory needs to create built-in.o, its parent can tell the fact when descending. If non-empty $(need-builtin) flag is passed from the parent, built-in.o should be created. $(obj-y) should be still checked to support the single target "%/". All of ugly tricks will go away. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
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c4da7ed0 |
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13-Nov-2017 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: optimize object directory creation for incremental build The previous commit largely optimized the object directory creation. We can optimize it more for incremental build. There are already *.cmd files in the output directory. The existing *.cmd files have been picked up by $(wildcard ...). Obviously, directories containing them exist too, so we can skip "mkdir -p". With this, Kbuild runs almost zero "mkdir -p" in incremental building. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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8a78756e |
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13-Nov-2017 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: create object directories simpler and faster For the out-of-tree build, scripts/Makefile.build creates output directories, but this operation is not efficient. scripts/Makefile.lib calculates obj-dirs as follows: obj-dirs := $(dir $(multi-objs) $(obj-y)) Please notice $(sort ...) is not used here. Usually the result is as many "./" as objects here. For a lot of duplicated paths, the following command is invoked. _dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d))) Then, the costly shell command is run over and over again. I see many points for optimization: [1] Use $(sort ...) to cut down duplicated paths before passing them to system call [2] Use single $(shell ...) instead of repeating it with $(foreach ...) This will reduce forking. [3] We can calculate obj-dirs more simply. Most of objects are already accumulated in $(targets). So, $(dir $(targets)) is fine and more comprehensive. I also removed ugly code in arch/x86/entry/vdso/Makefile. This is now really unnecessary. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Ingo Molnar <mingo@kernel.org> Tested-by: Douglas Anderson <dianders@chromium.org>
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591f6689 |
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13-Nov-2017 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: filter-out PHONY targets from "targets" The variable "targets" contains object paths for which existing .*.cmd files should be included. scripts/Makefile.build automatically adds $(MAKECMDGOALS) to "targets" as follows: targets += $(extra-y) $(MAKECMDGOALS) $(always) The $(MAKECMDGOALS) is a PHONY target in several places. PHONY targets never create .*.cmd files. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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2982c953 |
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13-Nov-2017 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: remove redundant $(wildcard ...) for cmd_files calculation I do not see any reason why $(wildcard ...) needs to be called twice for computing cmd_files. Remove the first one. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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5cb0512c |
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02-Nov-2017 |
Linus Torvalds <torvalds@linux-foundation.org> |
Kbuild: don't pass "-C" to preprocessor when processing linker scripts For some odd historical reason, we preprocessed the linker scripts with "-C", which keeps comments around. That makes no sense, since the comments are not meaningful for the build anyway. And it actually breaks things, since linker scripts can't have C++ style "//" comments in them, so keeping comments after preprocessing now limits us in odd and surprising ways in our header files for no good reason. The -C option goes back to pre-git and pre-bitkeeper times, but seems to have been historically used (along with "-traditional") for some odd-ball architectures (ia64, MIPS and SH). It probably didn't matter back then either, but might possibly have been used to minimize the difference between the original file and the pre-processed result. The reason for this may be lost in time, but let's not perpetuate it only because we can't remember why we did this crazy thing. This was triggered by the recent addition of SPDX lines to the source tree, where people apparently were confused about why header files couldn't use the C++ comment format. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Greg KH <gregkh@linuxfoundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b2441318 |
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01-Nov-2017 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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11af8474 |
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13-Oct-2017 |
Josh Poimboeuf <jpoimboe@redhat.com> |
x86/unwind: Rename unwinder config options to 'CONFIG_UNWINDER_*' Rename the unwinder config options from: CONFIG_ORC_UNWINDER CONFIG_FRAME_POINTER_UNWINDER CONFIG_GUESS_UNWINDER to: CONFIG_UNWINDER_ORC CONFIG_UNWINDER_FRAME_POINTER CONFIG_UNWINDER_GUESS ... in order to give them a more logical config namespace. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/73972fc7e2762e91912c6b9584582703d6f1b8cc.1507924831.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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da541b20 |
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27-Sep-2017 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Skip unreachable warnings for GCC 4.4 and older The kbuild bot occasionally reports warnings like: drivers/scsi/pcmcia/aha152x_core.o: warning: objtool: seldo_run()+0x130: unreachable instruction These warnings are always with GCC 4.4. That version of GCC sometimes places unreachable instructions after calls to noreturn functions. The unreachable warnings aren't very important anyway. Just ignore them for old versions of GCC. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/bc89b807d965b98ec18a0bb94f96a594bd58f2f2.1506551639.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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312a3d09 |
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01-Aug-2017 |
Cao jin <caoj.fnst@cn.fujitsu.com> |
kbuild: trivial cleanups on the comments This is a bunch of trivial fixes and cleanups. Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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#
ee9f8fce |
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24-Jul-2017 |
Josh Poimboeuf <jpoimboe@redhat.com> |
x86/unwind: Add the ORC unwinder Add the new ORC unwinder which is enabled by CONFIG_ORC_UNWINDER=y. It plugs into the existing x86 unwinder framework. It relies on objtool to generate the needed .orc_unwind and .orc_unwind_ip sections. For more details on why ORC is used instead of DWARF, see Documentation/x86/orc-unwinder.txt - but the short version is that it's a simplified, fundamentally more robust debugninfo data structure, which also allows up to two orders of magnitude faster lookups than the DWARF unwinder - which matters to profiling workloads like perf. Thanks to Andy Lutomirski for the performance improvement ideas: splitting the ORC unwind table into two parallel arrays and creating a fast lookup table to search a subset of the unwind table. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/0a6cbfb40f8da99b7a45a1a8302dc6aef16ec812.1500938583.git.jpoimboe@redhat.com [ Extended the changelog. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
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867ac9d7 |
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24-Jul-2017 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Fix gcov check for older versions of GCC Objtool tries to silence 'unreachable instruction' warnings when it detects gcov is enabled, because gcov produces a lot of unreachable instructions and they don't really matter. However, the 0-day bot is still reporting some unreachable instruction warnings with CONFIG_GCOV_KERNEL=y on GCC 4.6.4. As it turns out, objtool's gcov detection doesn't work with older versions of GCC because they don't create a bunch of symbols with the 'gcov.' prefix like newer versions of GCC do. Move the gcov check out of objtool and instead just create a new '--no-unreachable' flag which can be passed in by the kernel Makefile when CONFIG_GCOV_KERNEL is defined. Also rename the 'nofp' variable to 'no_fp' for consistency with the new 'no_unreachable' variable. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 9cfffb116887 ("objtool: Skip all "unreachable instruction" warnings for gcov kernels") Link: http://lkml.kernel.org/r/c243dc78eb2ffdabb6e927844dea39b6033cd395.1500939244.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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9a6cfca4 |
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08-Jun-2017 |
Nicholas Piggin <npiggin@gmail.com> |
kbuild: thin archives use P option to ar The P option makes ar do full path name matching and can prevent ar from discarding files with duplicate names in some cases of creating thin archives from thin archives. The sh architecture in particular loses some object files from its kernel/cpu/sh*/ directories without this option. This could be a bug in binutils ar, but the P option should not cause any negative effects so it is safe to use to work around this with. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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e8a3118e |
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21-Apr-2017 |
Jiri Slaby <jirislaby@kernel.org> |
objtool: make it visible in make V=1 output It is currently impossible to see what is going on with objtool when building, so call echo-cmd to see the actions: gcc -Wp,-MD,arch/x86/entry/.entry_64.o.d -nostdinc -isystem ... ./tools/objtool/objtool check "arch/x86/entry/entry_64.o"; Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Michal Marek <mmarek@suse.com> Cc: linux-kbuild@vger.kernel.org Cc: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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433db3e2 |
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24-Apr-2017 |
Vinícius Tinti <viniciustinti@gmail.com> |
kbuild: Add support to generate LLVM assembly files Add rules to kbuild in order to generate LLVM assembly files with the .ll extension when using clang. # from c code make CC=clang kernel/pid.ll Signed-off-by: Vinícius Tinti <viniciustinti@gmail.com> Signed-off-by: Behan Webster <behanw@converseincode.com> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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56067812 |
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03-Feb-2017 |
Ard Biesheuvel <ardb@kernel.org> |
kbuild: modversions: add infrastructure for emitting relative CRCs This add the kbuild infrastructure that will allow architectures to emit vmlinux symbol CRCs as 32-bit offsets to another location in the kernel where the actual value is stored. This works around problems with CRCs being mistaken for relocatable symbols on kernels that self relocate at runtime (i.e., powerpc with CONFIG_RELOCATABLE=y) For the kbuild side of things, this comes down to the following: - introducing a Kconfig symbol MODULE_REL_CRCS - adding a -R switch to genksyms to instruct it to emit the CRC symbols as references into the .rodata section - making modpost distinguish such references from absolute CRC symbols by the section index (SHN_ABS) - making kallsyms disregard non-absolute symbols with a __crc_ prefix Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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76bee234 |
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16-Nov-2016 |
Nicolas Pitre <nico@fluxnic.net> |
kbuild: cmd_export_list: tighten the sed script When LTO is used, some ___ksymtab_string sections are seen by this sed script, creating lines containing a single ) such as: EXPORT(foo) ) ) EXPORT(bar) Let's make it so the + character is also required for any line to be printed. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Michal Marek <mmarek@suse.com>
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9da2f584 |
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23-Nov-2016 |
Nicholas Piggin <npiggin@gmail.com> |
kbuild: improve linker compatibility with lib-ksyms.o build lib-ksyms.o is created by linking an empty input file with a linker script containing the interesting bits. Currently the empty input file is an archive containing nothing, however this causes the gold linker to segfault. I have opened a bug against gold https://sourceware.org/bugzilla/show_bug.cgi?id=20767 However this can be worked around by assembling an empty file to link with instead. The resulting lib-ksyms.o is slightly larger (seemingly due to empty .text, .data, .bss setions added), but final linked output should not be changed. Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.com>
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fe026a85 |
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23-Nov-2016 |
Nicholas Piggin <npiggin@gmail.com> |
kbuild: thin archives for multi-y targets THIN_ARCHIVES builds archives for built-in.o targets, have it build multi-y targets as archives as well. This saves another ~15% of the size of intermediate artifacts in the build tree. After this patch, the linker is only used in final link, and special cases like vdsos. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.com>
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cc6acc11 |
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08-Nov-2016 |
Nicholas Piggin <npiggin@gmail.com> |
kbuild: be more careful about matching preprocessed asm ___EXPORT_SYMBOL The CRC code for asm exports grabs the preprocessed asm, finds the ___EXPORT_SYMBOL and turns those into EXPORT_SYMBOL in a C program that can be preprocessed and parsed to create the CRC signatures from the type. The existing regex matching and replacement is too strict, and doesn't deal well with whitespace among other things. The line " EXPORT_SYMBOL(sym)" in a .S file would not match due to initial whitespace, for example, which resulted in x86's ___preempt_schedule failing to get CRCs. Reported-by: Philip Müller <philm@manjaro.org> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.com>
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4efca4ed |
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31-Oct-2016 |
Nicholas Piggin <npiggin@gmail.com> |
kbuild: modversions for EXPORT_SYMBOL() for asm Allow architectures to create asm/asm-prototypes.h file that provides C prototypes for exported asm functions, which enables proper CRC versions to be generated for them. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.com>
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989cea5c |
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20-Oct-2016 |
Nicholas Piggin <npiggin@gmail.com> |
kbuild: prevent lib-ksyms.o rebuilds Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reported-by: Russell King <rmk+kernel@armlinux.org.uk> Tested-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Michal Marek <mmarek@suse.com>
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a5967db9 |
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24-Aug-2016 |
Stephen Rothwell <sfr@canb.auug.org.au> |
kbuild: allow architectures to use thin archives instead of ld -r ld -r is an incremental link used to create built-in.o files in build subdirectories. It produces relocatable object files containing all its input files, and these are are then pulled together and relocated in the final link. Aside from the bloat, this constrains the final link relocations, which has bitten large powerpc builds with unresolvable relocations in the final link. Alan Modra has recommended the kernel use thin archives for linking. This is an alternative and means that the linker has more information available to it when it links the kernel. This patch enables a config option architectures can select, which causes all built-in.o files to be built as thin archives. built-in.o files in subdirectories do not get symbol table or index attached, which improves speed and size. The final link pass creates a built-in.o archive in the root output directory which includes the symbol table and index. The linker then uses takes this file to link. The --whole-archive linker option is required, because the linker now has visibility to every individual object file, and it will otherwise just completely avoid including those without external references (consider a file with EXPORT_SYMBOL or initcall or hardware exceptions as its only entry points). The traditional built works "by luck" as built-in.o files are large enough that they're going to get external references. However this optimisation is unpredictable for the kernel (due to above external references), ineffective at culling unused, and costly because the .o files have to be searched for references. Superior alternatives for link-time culling should be used instead. Build characteristics for inclink vs thinarc, on a small powerpc64le pseries VM with a modest .config: inclink thinarc sizes vmlinux 15 618 680 15 625 028 sum of all built-in.o 56 091 808 1 054 334 sum excluding root built-in.o 151 430 find -name built-in.o | xargs rm ; time make vmlinux real 22.772s 21.143s user 13.280s 13.430s sys 4.310s 2.750s - Final kernel pulled in only about 6K more, which shows how ineffective the object file culling is. - Build performance looks improved due to less pagecache activity. On IO constrained systems it could be a bigger win. - Build size saving is significant. Side note, the toochain understands archives, so there's some tricks, $ ar t built-in.o # list all files you linked with $ size built-in.o # and their sizes $ objdump -d built-in.o # disassembly (unrelocated) with filenames Implementation by sfr, minor tweaks by npiggin. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.com>
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7f2084fa |
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15-Jan-2016 |
Al Viro <viro@zeniv.linux.org.uk> |
[kbuild] handle exports in lib-y objects reliably Collect the symbols exported by anything that goes into lib.a and add an empty object (lib-exports.o) with explicit undefs for each of those to obj-y. That allows to relax the rules regarding the use of exports in lib-* objects - right now an object with export can be in lib-* only if we are guaranteed that there always will be users in built-in parts of the tree, otherwise it needs to be in obj-*. As the result, we have an unholy mix of lib- and obj- in lib/Makefile and (especially) in arch/*/lib/Makefile. Moreover, a change in generic part of the kernel can lead to mysteriously missing exports on some configs. With this change we don't have to worry about that anymore. One side effect is that built-in.o now pulls everything with exports from the corresponding lib.a (if such exists). That's exactly what we want for linking vmlinux and fortunately it's almost the only thing built-in.o is used in. arch/ia64/hp/sim/boot/bootloader is the only exception and it's easy to get rid of now - just turn everything in arch/ia64/lib into lib-* and don't bother with arch/ia64/lib/built-in.o anymore. [AV: stylistic fix from Michal folded in] Acked-by: Michal Marek <mmarek@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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24403874 |
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23-May-2016 |
Emese Revfy <re.emese@gmail.com> |
Shared library support Infrastructure for building independent shared library targets. Based on work created by the PaX Team. Signed-off-by: Emese Revfy <re.emese@gmail.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Michal Marek <mmarek@suse.com>
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e0f41e52 |
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07-Apr-2016 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: rename cmd_as_s_S to cmd_cpp_s_S This command just preprocesses .S files into .s files, so cmd_cpp_s_S seems more suitable. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Michal Marek <mmarek@suse.com>
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23d43848 |
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07-Apr-2016 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: rename cmd_cc_i_c to cmd_cpp_i_c This command just preprocesses .c files into .i files, so cmd_cpp_i_c seems more suitable. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Michal Marek <mmarek@suse.com>
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e4aca459 |
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17-Feb-2016 |
Nicolas Pitre <nico@fluxnic.net> |
kbuild: de-duplicate fixdep usage The generation and postprocessing of automatic dependency rules is duplicated in rule_cc_o_c, rule_as_o_S and if_changed_dep. Since this is not a trivial one-liner action, it is now abstracted under cmd_and_fixdep to simplify things and make future changes in this area easier. In the rule_cc_o_c and rule_as_o_S cases that means the order of some commands has been altered, namely fixdep and related file manipulations are executed earlier, but they didn't depend on those commands that now execute later. Signed-off-by: Nicolas Pitre <nico@linaro.org>
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9895c03d |
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21-Jan-2016 |
Nicolas Pitre <nico@fluxnic.net> |
kbuild: record needed exported symbols for modules Kernel modules are partially linked object files with some undefined symbols that are expected to be matched with EXPORT_SYMBOL() entries from elsewhere. Each .tmp_versions/*.mod file currently contains two line of text separated by a newline character. The first line has the actual module file name while the second line has a list of object files constituting that module. Those files are parsed by modpost (scripts/mod/sumversion.c), scripts/Makefile.modpost, scripts/Makefile.modsign, etc. Only the modpost utility cares about the second line while the others retrieve only the first line. Therefore we can add a third line to record the list of undefined symbols aka required EXPORT_SYMBOL() entries for each module into that file without breaking anything. Like for the second line, symbols are separated by a blank and the list is terminated with a newline character. To avoid needless build overhead, the undefined symbols extraction is performed only when CONFIG_TRIM_UNUSED_KSYMS is selected. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au>
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3b27a0c8 |
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03-Mar-2016 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Detect and warn if libelf is missing and don't break the build With CONFIG_STACK_VALIDATION enabled, if the host system doesn't have a development version of libelf installed, the build fails with errors like: elf.h:22:18: fatal error: gelf.h: No such file or directory compilation terminated. Instead of failing to build, instead just print a warning and disable stack validation. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-next@vger.kernel.org Cc: linux@roeck-us.net Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/8c27fe00face60f42e888ddb3142c97e45223165.1457026550.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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b9ab5ebb |
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28-Feb-2016 |
Josh Poimboeuf <jpoimboe@redhat.com> |
objtool: Add CONFIG_STACK_VALIDATION option Add a CONFIG_STACK_VALIDATION option which will run "objtool check" for each .o file to ensure the validity of its stack metadata. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris J Arges <chris.j.arges@canonical.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Pedro Alves <palves@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/92baab69a6bf9bc7043af0bfca9fb964a1d45546.1456719558.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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cf4f2193 |
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27-Oct-2015 |
Michal Marek <mmarek@suse.com> |
kbuild: Allow to specify composite modules with modname-m This allows to write drm-$(CONFIG_AGP) += drm_agpsupport.o without having to handle CONFIG_AGP=y vs. CONFIG_AGP=m. Only support this syntax for modules, since built-in code depending on something modular cannot work and init/Makefile actually relies on the current semantics. There are a few drivers which adapted to the current semantics out of necessity; these are fixed to also work when the respective subsystem is modular. Acked-by: Peter Chen <peter.chen@freescale.com> [chipidea] Signed-off-by: Michal Marek <mmarek@suse.com>
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c0a80c0c |
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09-Jan-2015 |
Heiko Carstens <hca@linux.ibm.com> |
ftrace: allow architectures to specify ftrace compile options If the kernel is compiled with function tracer support the -pg compile option is passed to gcc to generate extra code into the prologue of each function. This patch replaces the "open-coded" -pg compile flag with a CC_FLAGS_FTRACE makefile variable which architectures can override if a different option should be used for code generation. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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a4954fd7 |
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09-Sep-2014 |
Masahiro Yamada <yamada.m@jp.panasonic.com> |
kbuild: remove obj-n and lib-n handling Kconfig never defines CONFIG_* as 'n'. Now obj-n is only used in firmware/Makefile and it can be replaced with obj-. No makefile uses lib-n. Let's rip off obj-n and lib-n. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Acked-by: Peter Foley <pefoley2@pefoley.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
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c8589d1e |
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19-Aug-2014 |
Masahiro Yamada <yamada.m@jp.panasonic.com> |
kbuild: handle multi-objs dependency appropriately The comment in scripts/Makefile.build says as follows: We would rather have a list of rules like foo.o: $(foo-objs) but that's not so easy, so we rather make all composite objects depend on the set of all their parts This commit makes it possible! For example, assume a Makefile like this obj-m = foo.o bar.o foo-objs := foo1.o foo2.o bar-objs := bar1.o bar2.o Without this patch, foo.o depends on all of foo1.o foo2.o bar1.o bar2.o. It looks funny that foo.o is regenerated when bar1.c is updated. Now we can handle the dependency of foo.o and bar.o separately. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
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38385f8f |
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28-Apr-2014 |
Masahiro Yamada <yamada.m@jp.panasonic.com> |
kbuild: trivial - remove trailing spaces Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
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a86fe353 |
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14-Apr-2014 |
Masahiro Yamada <yamada.m@jp.panasonic.com> |
kbuild: move extra gcc checks to scripts/Makefile.extrawarn W=... provides extra gcc checks. Having such code in scripts/Makefile.build results in the same flags being added to KBUILD_CFLAGS multiple times becuase scripts/Makefile.build is invoked every time Kbuild descends into the subdirectories. Since the top Makefile is already too cluttered, this commit moves all of extra gcc check stuff to a new file scripts/Makefile.extrawarn, which is included from the top Makefile. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> CC: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
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3d3d6b84 |
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14-Nov-2012 |
Jan-Simon Möller <dl9pf@gmx.de> |
kbuild: LLVMLinux: Adapt warnings for compilation with clang When compiling kernel with clang, disable warnings which are too noisy, and add the clang flag catch-undefined-behavior. Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de> Signed-off-by: Behan Webster <behanw@converseincode.com> Signed-off-by: Mark Charlebois <mcharleb@gmail.com> Cc: PaX Team <pageexec@freemail.hu>
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1e64ff42 |
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08-Feb-2014 |
Andi Kleen <ak@linux.intel.com> |
Kbuild, lto: Disable LTO for asm-offsets.c The asm-offset.c technique to fish data out of the assembler file does not work with LTO. Just disable for the asm-offset.c build. Signed-off-by: Andi Kleen <ak@linux.intel.com> Link: http://lkml.kernel.org/r/1391846481-31491-11-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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d70f82ac |
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18-Mar-2013 |
James Hogan <jhogan@kernel.org> |
genksyms: pass symbol-prefix instead of arch Pass symbol-prefix to genksyms instead of arch, so that the decision what symbol prefix to use is kept in one place. Basically genksyms used to take a -a $ARCH argument and it used that to determine whether to add an underscore symbol prefix. It's now changed to take a -s $SYMBOL_PREFIX argument so that the caller decides whether a symbol prefix is required. The build system then uses CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX to determine whether to pass the argument. Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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4520c6a4 |
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21-Sep-2012 |
David Howells <dhowells@redhat.com> |
X.509: Add simple ASN.1 grammar compiler Add a simple ASN.1 grammar compiler. This produces a bytecode output that can be fed to a decoder to inform the decoder how to interpret the ASN.1 stream it is trying to parse. Action functions can be specified in the grammar by interpolating: ({ foo }) after a type, for example: SubjectPublicKeyInfo ::= SEQUENCE { algorithm AlgorithmIdentifier, subjectPublicKey BIT STRING ({ do_key_data }) } The decoder is expected to call these after matching this type and parsing the contents if it is a constructed type. The grammar compiler does not currently support the SET type (though it does support SET OF) as I can't see a good way of tracking which members have been encountered yet without using up extra stack space. Currently, the grammar compiler will fail if more than 256 bytes of bytecode would be produced or more than 256 actions have been specified as it uses 8-bit jump values and action indices to keep space usage down. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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f858ee8b |
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23-Jan-2012 |
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
kbuild: disable -Wmissing-field-initializers for W=1 -Wmissing-field-initializers is too noisy to be useful on W=1. Let's move it to W=2. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
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49c57d25 |
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14-Aug-2011 |
Arnaud Lacombe <lacombar@gmail.com> |
scripts/Makefile.build: do not reference EXTRA_CFLAGS as CFLAGS replacement Usage of these flags has been deprecated for nearly 4 years by: commit f77bf01425b11947eeb3b5b54685212c302741b8 Author: Sam Ravnborg <sam@neptun.(none)> Date: Mon Oct 15 22:25:06 2007 +0200 kbuild: introduce ccflags-y, asflags-y and ldflags-y Moreover, these flags (at least EXTRA_CFLAGS) have been documented for command line use. By default, gmake(1) do not override command line setting, so this is likely to result in build failure or unexpected behavior. Do not advertise for its usage. Cc: Sam Ravnborg <sam@ravnborg.org> Cc: linux-kbuild@vger.kernel.org Signed-off-by: Arnaud Lacombe <lacombar@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
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d6971822 |
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17-May-2011 |
Michal Marek <mmarek@suse.cz> |
ftrace/kbuild: Add recordmcount files to force full build Modifications to recordmcount must be performed on all object files to stay consistent with what the kernel code may expect. Add the recordmcount files to the main dependencies to make sure any change to them causes a full recompile. Signed-off-by: Michal Marek <mmarek@suse.cz> Link: http://lkml.kernel.org/r/20110517133646.GP13293@sepie.suse.cz Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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a3a8350a |
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12-Apr-2011 |
Steven Rostedt <srostedt@redhat.com> |
kbuild/recordmcount: Add RECORDMCOUNT_WARN to warn about mcount callers When mcount is called in a section that ftrace will not modify it into a nop, we want to warn about this. But not warn about this always. Now if the user builds the kernel with the option RECORDMCOUNT_WARN=1 then the build will warn about mcount callers that are ignored and will just waste execution time. Acked-by: Michal Marek <mmarek@suse.cz> Cc: linux-kbuild@vger.kernel.org Link: http://lkml.kernel.org/r/20110421023738.714956282@goodmis.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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44e6a206 |
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17-May-2011 |
Michal Marek <mmarek@suse.cz> |
ftrace/kbuild: Add recordmcount files to force full build Modifications to recordmcount must be performed on all object files to stay consistent with what the kernel code may expect. Add the recordmcount files to the main dependencies to make sure any change to them causes a full recompile. Signed-off-by: Michal Marek <mmarek@suse.cz> Link: http://lkml.kernel.org/r/20110517133646.GP13293@sepie.suse.cz Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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85356f80 |
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12-Apr-2011 |
Steven Rostedt <srostedt@redhat.com> |
kbuild/recordmcount: Add RECORDMCOUNT_WARN to warn about mcount callers When mcount is called in a section that ftrace will not modify it into a nop, we want to warn about this. But not warn about this always. Now if the user builds the kernel with the option RECORDMCOUNT_WARN=1 then the build will warn about mcount callers that are ignored and will just waste execution time. Acked-by: Michal Marek <mmarek@suse.cz> Cc: linux-kbuild@vger.kernel.org Link: http://lkml.kernel.org/r/20110421023738.714956282@goodmis.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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a6de553d |
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29-Apr-2011 |
Michal Marek <mmarek@suse.cz> |
kbuild: Allow to combine multiple W= levels Add support for make W=12, make W=123 and so on, to enable warnings from multiple W= levels. Normally, make W=<level> does not include warnings from the previous level. Signed-off-by: Michal Marek <mmarek@suse.cz> Acked-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-By: Valdis Kletnieks <valdis.kletnieks@vt.edu>
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af0e5d56 |
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21-Apr-2011 |
Dave Jones <davej@redhat.com> |
kbuild: Disable -Wunused-but-set-variable for gcc 4.6.0 Disable the new -Wunused-but-set-variable that was added in gcc 4.6.0 It produces more false positives than useful warnings. This can still be enabled using W=1 Signed-off-by: Dave Jones <davej@redhat.com> Acked-by: Sam Ravnborg <sam@ravnborg.org> Tested-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
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28bc20dc |
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27-Apr-2011 |
Sam Ravnborg <sam@ravnborg.org> |
kbuild: implement several W= levels Building a kernel with "make W=1" produces far too much noise to be useful. Divide the warning options in three groups: W=1 - warnings that may be relevant and does not occur too often W=2 - warnings that occur quite often but may still be relevant W=3 - the more obscure warnings, can most likely be ignored When building the whole kernel, those levels produce: W=1 - 4859 warnings W=2 - 1394 warnings W=3 - 86666 warnings respectively. Warnings have been counted with Geert's script at http://www.kernel.org/pub/linux/kernel/people/geert/linux-log/linux-log-summary.pl Many warnings occur from .h files so fixing one file may have a nice effect on the total number of warnings. With these changes I am actually tempted to try W=1 now and then. Previously there was just too much noise. Borislav: - make the W= levels exclusive - move very noisy and making little sense for the kernel warnings to W=3 - drop -Woverlength-strings due to useless warning message - copy explanatory text for the different warning levels to 'make help' - recount warnings per level Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Borislav Petkov <bp@alien8.de> Cc: Dave Jones <davej@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
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40df759e |
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20-Apr-2011 |
Michal Marek <mmarek@suse.cz> |
kbuild: Fix build with binutils <= 2.19 The D option of ar is only available in newer versions. Signed-off-by: Michal Marek <mmarek@suse.cz>
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09ff9fec |
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31-Mar-2011 |
Michal Marek <mmarek@suse.cz> |
kbuild: Use the deterministic mode of ar Signed-off-by: Michal Marek <mmarek@suse.cz>
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4a5838ad |
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01-Mar-2011 |
Borislav Petkov <bp@alien8.de> |
kbuild: Add extra gcc checks Add a 'W=1' Makefile switch which adds additional checking per build object. The idea behind this option is targeted at developers who, in the process of writing their code, want to do the occasional make W=1 [target.o] and let gcc do more extensive code checking for them. Then, they could eyeball the output for valid gcc warnings about various bugs/discrepancies which are not reported during the normal build process. For more background information and a use case, read through this thread: http://marc.info/?l=kernel-janitors&m=129802065918147&w=2 Cc: Michal Marek <mmarek@suse.cz> Cc: linux-kbuild@vger.kernel.org Acked-by: Sam Ravnborg <sam@ravnborg.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Michal Marek <mmarek@suse.cz>
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45677454 |
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27-Oct-2010 |
Wu Zhangjin <wuzhangjin@gmail.com> |
ftrace: Speed up recordmcount cmd_record_mcount is used to locate the _mcount symbols in the object files, only the files compiled with -pg has the _mcount symbol, so, it is only needed for such files, but the current cmd_record_mcount is used for all of the object files, so, we need to fix it and speed it up. Since -pg may be removed by the method used in kernel/trace/Makefile: ORIG_CFLAGS := $(KBUILD_CFLAGS) KBUILD_CFLAGS = $(subst -pg,,$(ORIG_CFLAGS)) Or may be removed by the method used in arch/x86/kernel/Makefile: CFLAGS_REMOVE_file.o = -pg So, we must check the last variable stores the compiling flags, that is c_flags(Please refer to cmd_cc_o_c and rule_cc_o_c defined in scripts/Makefile.build) and since the CFLAGS_REMOVE_file.o is already filtered in _c_flags(Please refer to scripts/Makefile.lib) and _c_flags has less symbols, therefore, we only need to check _c_flags. --------------- Changes from v1: o Don't touch Makefile for CONFIG_FTRACE_MCOUNT_RECORD is enough o Use _c_flags intead of KBUILD_CFLAGS to cover CONFIG_REMOVE_file.o = -pg (feedback from Steven Rostedt <rostedt@goodmis.org>) Acked-by: Michal Marek <mmarek@suse.cz> Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> LKML-Reference: <3dc8cddf022eb7024f9f2cf857529a15bee8999a.1288196498.git.wuzhangjin@gmail.com> [ changed if [ .. == .. ] to if [ .. = .. ] to handle dash environments ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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d7b4d6de |
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18-Oct-2010 |
Steven Rostedt <srostedt@redhat.com> |
ftrace: Remove recursion between recordmcount and scripts/mod/empty When DYNAMIC_FTRACE is enabled and we use the C version of recordmcount, all objects are run through the recordmcount program to create a separate section that stores all the callers of mcount. The build process has a special file: scripts/mod/empty.o. This is built from empty.c which is literally an empty file (except for a single comment). This file is used to find information about the target elf format, like endianness and word size. The problem comes up when we need to build recordmcount. The build process requires that empty.o is built first. The build rules for empty.o will try to execute recordmcount on the empty.o file. We get an error that recordmcount does not exist. To avoid this recursion, the build file will skip running recordmcount if the file that it is building is script/mod/empty.o. [ extra comment Suggested-by: Sam Ravnborg <sam@ravnborg.org> ] Reported-by: Ingo Molnar <mingo@elte.hu> Tested-by: Ingo Molnar <mingo@elte.hu> Cc: Michal Marek <mmarek@suse.cz> Cc: linux-kbuild@vger.kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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85caa993 |
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14-Oct-2010 |
Steven Rostedt <srostedt@redhat.com> |
ftrace: Use objtree for C version of recordmcount The C version of recordmcount is compiled to a binary, which will end up located in the objtree. If the kernel is built with O=path, the srctree will not include the binary recordmcount caller. Cc: Michal Marek <mmarek@suse.cz> Cc: linux-kbuild@vger.kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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72441cb1 |
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13-Oct-2010 |
Steven Rostedt <srostedt@redhat.com> |
ftrace/x86: Add support for C version of recordmcount This patch adds the support for the C version of recordmcount and compile times show ~ 12% improvement. After verifying this works, other archs can add: HAVE_C_MCOUNT_RECORD in its Kconfig and it will use the C version of recordmcount instead of the perl version. Cc: <linux-arch@vger.kernel.org> Cc: Michal Marek <mmarek@suse.cz> Cc: linux-kbuild@vger.kernel.org Cc: John Reiser <jreiser@bitwagon.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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f9810a82 |
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10-Aug-2010 |
Rabin Vincent <rabin@rab.in> |
ARM: 6317/1: ftrace: pass KBUILD_CFLAGS to record_mcount.pl On ARM, we have two ABIs, and the ABI used is controlled via a config option. Object files built with one ABI can't be merged with object files built with the other ABI. So, record_mcount.pl needs to use the same compiler flags as the kernel when generating the object file with the mcount locations. Ensure this by passing CFLAGS to the script. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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80c00ba9 |
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28-Jul-2010 |
Sam Ravnborg <sam@ravnborg.org> |
kbuild: allow assignment to {A,C}FLAGS_KERNEL on the command line It is now possible to assign options to AS and CC on the command line - which is only used for built-in code. {A,C}FLAGS_KERNEL was used both in the top-level Makefile in the arch makefiles, thus users had no way to specify additional options to AS, CC without overriding the original value. Introduce a new set of variables KBUILD_{A,C}FLAGS_KERNEL that is used by arch specific files and free up {A,C}FLAGS_KERNEL so they can be assigned on the command line. All arch Makefiles that used the old variables has been updated. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Michal Marek <mmarek@suse.cz>
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6588169d |
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28-Jul-2010 |
Sam Ravnborg <sam@ravnborg.org> |
kbuild: allow assignment to {A,C,LD}FLAGS_MODULE on the command line It is now possible to assign options to AS, CC and LD on the command line - which is only used when building modules. {A,C,LD}FLAGS_MODULE was all used both in the top-level Makefile in the arch makefiles, thus users had no way to specify additional options to AS, CC, LD when building modules without overriding the original value. Introduce a new set of variables KBUILD_{A,C,LD}FLAGS_MODULE that is used by arch specific files and free up {A,C,LD}FLAGS_MODULE so they can be assigned on the command line. All arch Makefiles that used the old variables has been updated. Note: Previously we had a MODFLAGS variable for both AS and CC. But in favour of consistency this was dropped. So in some cases arch Makefile has one assignmnet replaced by two assignmnets. Note2: MODFLAGS was not documented and is dropped without any notice. I do not expect much/any breakage from this. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Chen Liqin <liqin.chen@sunplusct.com> Acked-by: Mike Frysinger <vapier@gentoo.org> [blackfin] Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> [avr32] Signed-off-by: Michal Marek <mmarek@suse.cz>
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e26d6b83 |
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24-May-2010 |
Don Zickus <dzickus@redhat.com> |
Makefile.build: make KBUILD_SYMTYPES work again commit 37a8d9f67f18de1e2cbc7387311ce22d4dbff518 tried to combine some duplicate code and accidentally broke how KBUILD_SYMTYPES worked This fixes the code to match the original intention by the author who originally added the code I believe. The fixes include: - removing extra whitespaces in the if-statements - moving the if-statement from around the -r to the -T - adding a second arg to cmd_gensymtypes to simplify the options passed to genksyms. Tested by instrumenting genksyms and seeing what options were passed in during a make, KBUILD_SYMTYPES make, and when a foo.symref was created. Everything compiled and looked ok. Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
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4b024242 |
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17-Dec-2009 |
Jiafu He <jay@goldhive.com> |
kbuild: Fix linking error built-in.o no such file or directory This patch fixes the link error "built-in.o: no such file or directory". The problem happens if "dirx/Makefile" contains only "obj-m += diry/ dirz/" and the empty "dirx/built-in.o" is missing. Adding $(subdir-m) into check for builtin-target fixes this error. Signed-off-by: Jiafu He <jay@goldhive.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
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e6299d26 |
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20-Nov-2009 |
Wu Zhangjin <wuzhangjin@gmail.com> |
MIPS: Tracing: Add an endian argument to scripts/recordmcount.pl MIPS and some other architectures need this argument to handle big/little endian respectively. Signed-off-by: Wu Zhangjin <wuzj@lemote.com> Cc: Nicholas Mc Guire <der.herr@hofr.at> Cc: zhangfx@lemote.com Cc: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/674/ Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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42f29a25 |
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20-Sep-2009 |
Tim Abbott <tabbott@ksplice.com> |
kbuild: Don't define ALIGN and ENTRY when preprocessing linker scripts. Adding a reference to <linux/linkage.h> to x86's <asm/cache.h> causes the x86 linker script to have syntax errors, because the ALIGN and ENTRY keywords get redefined to the assembly implementations of those. One could fix this by adjusting the include structure, but I think any solution based on that approach would be fragile. Currently, it is impossible when writing a header to do something different for assembly files and linker scripts, even though there are clearly cases where one wants them to define macros differently for the two (ENTRY being an excellent example). So I think the right solution here is to introduce a new preprocessor definition, called LINKER_SCRIPT that is set along with __ASSEMBLY__ for linker scripts, and to use that to not define ALIGN and ENTRY in linker scripts. I suspect we'll find other uses for this mechanism in the future. Signed-off-by: Tim Abbott <tabbott@ksplice.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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51b563fc |
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19-Sep-2009 |
Sam Ravnborg <sam@ravnborg.org> |
arm, cris, mips, sparc, powerpc, um, xtensa: fix build with bash 4.0 Albin Tonnerre <albin.tonnerre@free-electrons.com> reported: Bash 4 filters out variables which contain a dot in them. This happends to be the case of CPPFLAGS_vmlinux.lds. This is rather unfortunate, as it now causes build failures when using SHELL=/bin/bash to compile, or when bash happens to be used by make (eg when it's /bin/sh) Remove the common definition of CPPFLAGS_vmlinux.lds by pushing relevant stuff to either Makefile.build or the arch specific kernel/Makefile where we build the linker script. This is also nice cleanup as we move the information out where it is used. Notes for the different architectures touched: arm - we use an already exported symbol cris - we use a config symbol aleady available [Not build tested] mips - the jiffies complexity has moved to vmlinux.lds.S where we need it. Added a few variables to CPPFLAGS - they are only used by the linker script. [Not build tested] powerpc - removed assignment that is not needed [not build tested] sparc - simplified it using $(BITS) um - introduced a few new exported variables to deal with this xtensa - added options to CPP invocation [not build tested] Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Chris Zankel <chris@zankel.net> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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66a57062 |
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18-Sep-2009 |
Andi Kleen <andi@firstfloor.org> |
kbuild: fail build if recordmcount.pl fails When this script fails the build should fail too. Otherwise there are mysterious build failures later. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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c3c63b6b |
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18-Sep-2009 |
Andi Kleen <andi@firstfloor.org> |
kbuild: echo the record_mcount command I had some problems with record_mcount in the Makefile and it was hard to track down. Echo it by default to make it easier to diagnose. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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720097d8 |
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19-Apr-2009 |
Sam Ravnborg <sam@ravnborg.org> |
kbuild: introduce subdir-ccflags-y Following patch introduce support for setting options to gcc that has effect for current directory and all subdirectories. The typical use case are an architecture or a subsystem that decide to cover all files with -Werror. Today alpha, mips and sparc uses -Werror in almost all their Makefile- with subdir-ccflag-y it is now simpler to do so as only the top-level directories needs to be covered. Likewise if we decide to cover a full subsystem such as net/ with -Werror this is done by adding a single line to net/Makefile. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de>
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2ea03891 |
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14-Jan-2009 |
Sam Ravnborg <sam@ravnborg.org> |
Revert "kbuild: strip generated symbols from *.ko" This reverts commit ad7a953c522ceb496611d127e51e278bfe0ff483. And commit: ("allow stripping of generated symbols under CONFIG_KALLSYMS_ALL") 9bb482476c6c9d1ae033306440c51ceac93ea80c These stripping patches has caused a set of issues: 1) People have reported compatibility issues with binutils due to lack of support for `--strip-unneeded-symbols' with objcopy 2.15.92.0.2 Reported by: Wenji 2) ccache and distcc no longer works as expeced Reported by: Ted, Roland, + others 3) The installed modules increased a lot in size Reported by: Ted, Davej + others Reported-by: Wenji Huang <wenji.huang@oracle.com> Reported-by: "Theodore Ts'o" <tytso@mit.edu> Reported-by: Dave Jones <davej@redhat.com> Reported-by: Roland McGrath <roland@redhat.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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18c167fd |
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11-Jan-2009 |
Shaohua Li <shaohua.li@intel.com> |
ftrace, ia64: make recordmcount distinct module compile In IA64, module build and kernel build use different option. Make recordmcount.pl differentiate the two cases. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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ad7a953c |
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16-Dec-2008 |
Jan Beulich <jbeulich@novell.com> |
kbuild: strip generated symbols from *.ko This patch changes the way __crc_ symbols are being resolved from using ld to do so to using the assembler, thus allowing these symbols to be marked local (the linker creates then as global ones) and hence allow stripping (for modules) or ignoring (for vmlinux) them. While at this, also strip other generated symbols during module installation. One potentially debatable point is the handling of the flags passeed to gcc when translating the intermediate assembly file into an object: passing $(c_flags) unchanged doesn't work as gcc passes --gdwarf2 to gas whenever is sees any -g* option, even for -g0, and despite the fact that the compiler would have already produced all necessary debug info in the C->assembly translation phase. I took the approach of just filtering out all -g* options, but an alternative to such negative filtering might be to have a positive filter which might, in the ideal case allow just all the -Wa,* options to pass through. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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37a8d9f6 |
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19-Dec-2008 |
Sam Ravnborg <sam@ravnborg.org> |
kbuild: simplify use of genksyms Avoid duplicating long list of options in two places Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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64e6c1e1 |
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01-Dec-2008 |
Andreas Gruenbacher <agruen@suse.de> |
genksyms: track symbol checksum changes Sometimes it is preferable to avoid changes of exported symbol checksums (to avoid breaking externally provided modules). When a checksum change occurs, it can be hard to figure out what caused this change: underlying types may have changed, or additional type information may simply have become available at the point where a symbol is exported. Add a new --reference option to genksyms which allows it to report why checksums change, based on the type information dumps it creates with the --dump-types flag. Genksyms will read in such a dump from a previous run, and report which symbols have changed (and why). The behavior can be controlled for an entire build as follows: If KBUILD_SYMTYPES is set, genksyms uses --dump-types to produce *.symtypes dump files. If any *.symref files exist, those will be used as the reference to check against. If KBUILD_PRESERVE is set, checksum changes will fail the build. Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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b3acf29a |
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29-Oct-2008 |
Steven Rostedt <rostedt@goodmis.org> |
ftrace, kbuild: condense recordmcount.pl parameter code Impact: cleanup Sam Ravnborg pointed out that I could condense the code for the parameters of recordmcount.pl by using an $(if ...) condition. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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dce9d18a |
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23-Oct-2008 |
Steven Rostedt <rostedt@goodmis.org> |
ftrace: handle generic arch calls The recordmcount script requires that the actual arch is passed in. This works well when ARCH=i386 or ARCH=x86_64 but does not handle the case of ARCH=x86. This patch adds a parameter to the function to pass in the number of bits of the architecture. So that it can determine if x86 should be run for x86_64 or i386 archs. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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b3a32041 |
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27-Aug-2008 |
Andrew Morton <akpm@linux-foundation.org> |
kbuild: ftrace: don't assume that scripts/recordmcount.pl is executable CHK include/linux/version.h CHK include/linux/utsrelease.h CC scripts/mod/empty.o /bin/sh: /usr/src/25/scripts/recordmcount.pl: Permission denied We shouldn't assume that files have their `x' bits set. There are various ways in which file permissions get lost, including use of patch(1). It might not be correct to assume that perl lives in $PATH? Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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6a4917e3 |
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18-Aug-2008 |
Jeremy Fitzhardinge <jeremy@goop.org> |
ftrace: fix build problem with CONFIG_FTRACE I'm seeing when I use separate src/build dirs: make[3]: *** [arch/x86/kernel/time_32.o] Error 1 /bin/sh: scripts/recordmcount.pl: No such file or directory make[3]: *** [arch/x86/kernel/irq_32.o] Error 1 /bin/sh: scripts/recordmcount.pl: No such file or directory make[3]: *** [arch/x86/kernel/ldt.o] Error 1 /bin/sh: scripts/recordmcount.pl: No such file or directory make[3]: *** [arch/x86/kernel/i8259.o] Error 1 /bin/sh: scripts/recordmcount.pl: No such file or directory This fixes it. Signed-off-by: Ingo Molnar <mingo@elte.hu>
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8da3821b |
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14-Aug-2008 |
Steven Rostedt <rostedt@goodmis.org> |
ftrace: create __mcount_loc section This patch creates a section in the kernel called "__mcount_loc". This will hold a list of pointers to the mcount relocation for each call site of mcount. For example: objdump -dr init/main.o [...] Disassembly of section .text: 0000000000000000 <do_one_initcall>: 0: 55 push %rbp [...] 000000000000017b <init_post>: 17b: 55 push %rbp 17c: 48 89 e5 mov %rsp,%rbp 17f: 53 push %rbx 180: 48 83 ec 08 sub $0x8,%rsp 184: e8 00 00 00 00 callq 189 <init_post+0xe> 185: R_X86_64_PC32 mcount+0xfffffffffffffffc [...] We will add a section to point to each function call. .section __mcount_loc,"a",@progbits [...] .quad .text + 0x185 [...] The offset to of the mcount call site in init_post is an offset from the start of the section, and not the start of the function init_post. The mcount relocation is at the call site 0x185 from the start of the .text section. .text + 0x185 == init_post + 0xa We need a way to add this __mcount_loc section in a way that we do not lose the relocations after final link. The .text section here will be attached to all other .text sections after final link and the offsets will be meaningless. We need to keep track of where these .text sections are. To do this, we use the start of the first function in the section. do_one_initcall. We can make a tmp.s file with this function as a reference to the start of the .text section. .section __mcount_loc,"a",@progbits [...] .quad do_one_initcall + 0x185 [...] Then we can compile the tmp.s into a tmp.o gcc -c tmp.s -o tmp.o And link it into back into main.o. ld -r main.o tmp.o -o tmp_main.o mv tmp_main.o main.o But we have a problem. What happens if the first function in a section is not exported, and is a static function. The linker will not let the tmp.o use it. This case exists in main.o as well. Disassembly of section .init.text: 0000000000000000 <set_reset_devices>: 0: 55 push %rbp 1: 48 89 e5 mov %rsp,%rbp 4: e8 00 00 00 00 callq 9 <set_reset_devices+0x9> 5: R_X86_64_PC32 mcount+0xfffffffffffffffc The first function in .init.text is a static function. 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices The lowercase 't' means that set_reset_devices is local and is not exported. If we simply try to link the tmp.o with the set_reset_devices we end up with two symbols: one local and one global. .section __mcount_loc,"a",@progbits .quad set_reset_devices + 0x10 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices U set_reset_devices We still have an undefined reference to set_reset_devices, and if we try to compile the kernel, we will end up with an undefined reference to set_reset_devices, or even worst, it could be exported someplace else, and then we will have a reference to the wrong location. To handle this case, we make an intermediate step using objcopy. We convert set_reset_devices into a global exported symbol before linking it with tmp.o and set it back afterwards. 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 T set_reset_devices 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 T set_reset_devices 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices Now we have a section in main.o called __mcount_loc that we can place somewhere in the kernel using vmlinux.ld.S and access it to convert all these locations that call mcount into nops before starting SMP and thus, eliminating the need to do this with kstop_machine. Note, A well documented perl script (scripts/recordmcount.pl) is used to do all this in one location. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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3156fd05 |
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18-Feb-2008 |
Robert P. J. Day <rpjday@crashcourse.ca> |
kbuild: fix some minor typoes Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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91341d4b |
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21-Jan-2008 |
Sam Ravnborg <sam@ravnborg.org> |
kbuild: introduce new option to enhance section mismatch analysis Setting the option DEBUG_SECTION_MISMATCH will report additional section mismatch'es but this should in the end makes it possible to get rid of all of them. See help text in lib/Kconfig.debug for details. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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551559e1 |
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07-Dec-2007 |
Tejun Heo <htejun@gmail.com> |
kbuild: implement modules.order When multiple built-in modules (especially drivers) provide the same capability, they're prioritized by link order specified by the order listed in Makefile. This implicit ordering is lost for loadable modules. When driver modules are loaded by udev, what comes first in modules.alias file is selected. However, the order in this file is indeterministic (depends on filesystem listing order of installed modules). This causes confusion. The solution is two-parted. This patch updates kbuild such that it generates and installs modules.order which contains the name of modules ordered according to Makefile. The second part is update to depmod such that it generates output files according to this file. Note that both obj-y and obj-m subdirs can contain modules and ordering information between those two are lost from beginning. Currently obj-y subdirs are put before obj-m subdirs. Sam Ravnborg cleaned up Makefile modifications and suggested using awk to remove duplicate lines from modules.order instead of using separate C program. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Bill Nottingham <notting@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Jon Masters <jonathan@jonmasters.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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f77bf014 |
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15-Oct-2007 |
Sam Ravnborg <sam@neptun.(none)> |
kbuild: introduce ccflags-y, asflags-y and ldflags-y Introduce ccflags-y, asflags-y and ldflags-y so we soon can deprecate use of EXTRA_CFLAGS, EXTRA_AFLAGS and EXTRA_LDFLAGS. This patch does not touch any in-tree users - thats next round. Lets get this committed first and then fix the users of the soon to be deprecated variants next. The rationale behind this change is to introduce support for makefile fragments like: ccflags-$(CONFIG_WHATEVER_DEBUG) := -DDEBUG As a replacement for the uglier: ifeq ($(CONFIG_WHATEVER_DEBUG),y) EXTRA_CFLAGS := -DDEBUG endif Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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0c53c8e6 |
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14-Oct-2007 |
Sam Ravnborg <sam@neptun.(none)> |
kbuild: check for wrong use of CFLAGS External modules have in a few cases modifed gcc option by modifying CFLAGS. This has never been documented and was a bad practice. With the check to use KBUILD_CFLAGS it will no longer work so we better error out and tell what was wrong as a service to the external module users. This check can be overruled if KBUILD_NOPEDANTIC is set to something. Addid this possibility may allow older external module to build without any code modifications but potentially only loosing some un-important gcc options. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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836caba7 |
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30-Sep-2007 |
Sam Ravnborg <sam@neptun.(none)> |
kbuild: kill backward compatibility checks These checks has been present for several kernel releases (> 5). So lets just get rid of them. With this we no longer check for use of: EXTRA_TARGETS, O_TARGET, L_TARGET, list-multi, export-objs There were three remaining in-tree users of O_TARGET in some unmaintained sh64 code - mail sent to the maintainer + list. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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5e54d5e5 |
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30-Sep-2007 |
Sam Ravnborg <sam@neptun.(none)> |
kbuild: kill EXTRA_ARFLAGS EXTRA_ARFLAGS have never been used so no need to carry around on this. A google search did not reveal any external module using this either. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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114f5157 |
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23-Jul-2007 |
Roland McGrath <roland@redhat.com> |
kbuild: use LDFLAGS_MODULE only for .ko links Sam Ravnborg pointed out that Documentation/kbuild/makefiles.txt already says this is what it's for. This patch makes the reality live up to the documentation. This fixes the problem of LDFLAGS_BUILD_ID getting into too many places. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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d72e5edb |
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28-May-2007 |
Sam Ravnborg <sam@ravnborg.org> |
kbuild: avoid environment to set variables used by kbuild A few of the variables used by kbuild has fixed naming. Make sure we do not pick up random values from the environment. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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767e581d |
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06-May-2007 |
Sam Ravnborg <sam@ravnborg.org> |
kbuild: enable use of code from a different dir To introduce support for source in one directory but output files in another directory during a non O= build prefix all paths with $(src) repsectively $(obj). Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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48f1f058 |
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23-Jul-2006 |
Sam Ravnborg <sam@mars.ravnborg.org> |
kbuild: consistently decide when to rebuild a target Consistently decide when to rebuild a target across all of if_changed, if_changed_dep, if_changed_rule. PHONY targets are now treated alike (ignored) for all targets While add it make Kbuild.include almost readable by factoring out a few bits to some common variables and reuse this in Makefile.build. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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5e8d780d |
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01-Jul-2006 |
Sam Ravnborg <sam@mars.ravnborg.org> |
kbuild: fix ia64 breakage after introducing make -rR kbuild used $¤(*F to get filename of target without extension. This was used in several places all over kbuild, but introducing make -rR broke his for all cases where we specified full path to target/prerequsite. It is assumed that make -rR disables old style suffix-rules which is why is suddenly failed. ia64 was impacted by this change because several div* routines in arch/ia64/lib are build using explicit paths and then kbuild failed. Thanks to David Mosberger-Tang <David.Mosberger@acm.org> for an explanation what was the root-cause and for testing on ia64. This patch also fixes two uses of $(*F) in arch/um Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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d38b6968 |
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26-Jun-2006 |
Linus Torvalds <torvalds@g5.osdl.org> |
Revert "kbuild: fix make -rR breakage" This reverts commit e5c44fd88c146755da6941d047de4d97651404a9. Thanks to Daniel Ritz and Michal Piotrowski for noticing the problem. Daniel says: "[The] reason is a recent change that made modules always shows as module.mod. it breaks modprobe and probably many scripts..besides lsmod looking horrible stuff like this in modprobe.conf: install pcmcia_core /sbin/modprobe --ignore-install pcmcia_core; /sbin/modprobe pcmcia makes modprobe fork/exec endlessly calling itself...until oom interrupts it" Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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15fde675 |
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09-May-2006 |
Andreas Gruenbacher <agruen@suse.de> |
kbuild: support for %.symtypes files Here is a patch that adds a new -T option to genksyms for generating dumps of the type definition that makes up the symbol version hashes. This allows to trace modversion changes back to what caused them. The dump format is the name of the type defined, followed by its definition (which is almost C): s#list_head struct list_head { s#list_head * next , * prev ; } The s#, u#, e#, and t# prefixes stand for struct, union, enum, and typedef. The exported symbols do not define types, and thus do not have an x# prefix: nfs4_acl_get_whotype int nfs4_acl_get_whotype ( char * , t#u32 ) The symbol type defintion of a single file can be generated with: make fs/jbd/journal.symtypes If KBUILD_SYMTYPES is defined, all the *.symtypes of all object files that export symbols are generated. The single *.symtypes files can be combined into a single file after a kernel build with a script like the following: for f in $(find -name '*.symtypes' | sort); do f=${f#./} echo "/* ${f%.symtypes}.o */" cat $f echo done \ | sed -e '\:UNKNOWN:d' \ -e 's:[,;] }:}:g' \ -e 's:\([[({]\) :\1:g' \ -e 's: \([])},;]\):\1:g' \ -e 's: $::' \ $f \ | awk ' /^.#/ { if (defined[$1] == $0) { print $1 next } defined[$1] = $0 } { print } ' When the kernel ABI changes, diffing individual *.symtype files, or the combined files, against each other will show which symbol changes caused the ABI changes. This can save a tremendous amount of time. Dump the types that make up modversions Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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e5c44fd8 |
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24-Jun-2006 |
Sam Ravnborg <sam@mars.ravnborg.org> |
kbuild: fix make -rR breakage make failed to supply the filename when using make -rR and using $(*F) to get target filename without extension. This bug was not reproduceable in small scale but using: $(basename $(notdir $@)) fixes it with same functionality. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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c955ccaf |
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08-Jun-2006 |
Roman Zippel <zippel@linux-m68k.org> |
kconfig: fix .config dependencies This fixes one of the worst kbuild warts left - the broken dependencies used to check and regenerate the .config file. This was done via an indirect dependency and the .config itself had an empty command, which can cause make not to reread the changed .config file. Instead of this we generate now a new file include/config/auto.conf from .config, which is used for kbuild and has the proper dependencies. It's also the main make target now for all files generated during this step (and thus replaces include/linux/autoconf.h). This also means we can now relax the syntax requirements for the .config file and we don't have to rewrite it all the time, i.e. silentoldconfig only writes .config now when it's necessary to keep it in sync with the Kconfig files and even this can be suppressed by setting the environment variable KCONFIG_NOSILENTUPDATE, so the update can (and must) be done manually. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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7d185983 |
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08-Mar-2006 |
Chuck Ebbert <76306.1226@compuserve.com> |
kbuild: add -fverbose-asm to i386 Makefile Add -fverbose-asm to i386 Makefile rule for building .s files. This makes the assembler output much more readable for humans. Suggested by Der Herr Hofrat <der.herr@hofr.at> Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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c79c7b09 |
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12-Mar-2006 |
Sam Ravnborg <sam@mars.ravnborg.org> |
kbuild: fix genksyms build error genksyms needs to know when a symbol must have a "_" prefex as is true for a few architectures. Pass $(ARCH) as commandline argument and hardcode what architectures that needs this info. Previous attemt to take it from elfconfig.h was br0ken since elfconfig.h is a generated file. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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4f193362 |
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05-Mar-2006 |
Paul Smith <psmith@gnu.org> |
kbuild: change kbuild to not rely on incorrect GNU make behavior The kbuild system takes advantage of an incorrect behavior in GNU make. Once this behavior is fixed, all files in the kernel rebuild every time, even if nothing has changed. This patch ensures kbuild works with both the incorrect and correct behaviors of GNU make. For more details on the incorrect behavior, see: http://lists.gnu.org/archive/html/bug-make/2006-03/msg00003.html Changes in this patch: - Keep all targets that are to be marked .PHONY in a variable, PHONY. - Add .PHONY: $(PHONY) to mark them properly. - Remove any $(PHONY) files from the $? list when determining whether targets are up-to-date or not. Signed-off-by: Paul Smith <psmith@gnu.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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6176aa9a |
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30-Jan-2006 |
Jan Beulich <jbeulich@novell.com> |
kbuild: consolidate command line escaping While the recent change to also escape # symbols when storing C-file compilation command lines was helpful, it should be in effect for all command lines, as much as the dollar escaping should be in effect for C-source compilation commands. Additionally, for better readability and maintenance, consolidating all the escaping (single quotes, dollars, and now sharps) was also desirable. Signed-Off-By: Jan Beulich <jbeulich@novell.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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20a468b5 |
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22-Jan-2006 |
Sam Ravnborg <sam@mars.ravnborg.org> |
kbuild: make cc-version available in kbuild files Move $(CC) support functions to Kbuild.include so they are available in the kbuild files. In addition the following was done: o as-option documented in Documentation/kbuild/makefiles.txt o Moved documentation to new section to match new scope of functions o added cc-ifversion used to conditionally select a text string dependent on actual $(CC) version o documented cc-ifversion o change so Kbuild.include is read before the kbuild file Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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d51bfb78 |
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06-Jan-2006 |
Sam Ravnborg <sam@mars.ravnborg.org> |
kbuild: introduce escsq to escapre single quotes This makes things a little bit more reader friendly and gvim is less confused. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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db8c1a7b |
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27-Jul-2005 |
Sam Ravnborg <sam@mars.(none)> |
kbuild: fix building external modules kbuild failed to locate Makefile for external modules. This brought to my attention how the variables for directories have different values in different usage scenarios. Different kbuild usage scenarios: make - plain make in same directory where kernel source lives make O= - kbuild is told to store output files in another directory make M= - building an external module make O= M= - building an external module with kernel output seperate from src Value assigned to the different variables: |$(src) |$(obj) |$(srctree) |$(objtree) make |reldir to k src |as src |abs path to k src |abs path to k src make O= |reldir to k src |as src |abs path to k src |abs path to output dir make M= |abs path to src |as src |abs path to k src |abs path to k src make O= M= |abs path to src |as src |abs path to k src |abs path to k output path to kbuild file: make | $(srctree)/$(src), $(src) make O= | $(srctree)/$(src) make M= | $(src) make O= M= | $(src) From the table above it can be seen that the only good way to find the home directory of the kbuild file is to locate the one of the two variants that is an absolute path. If $(src) is an absolute path (starts with /) then use it, otherwise prefix $(src) with $(srctree). Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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2a691470 |
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25-Jul-2005 |
Sam Ravnborg <sam@mars.(none)> |
kbuild: fix make O=... kbuild failed to locate Kbuild.include. Teach kbuild how to find Kbuild files when using make O=... Signed-off-by: Sam Ravnborg <sam@ravnborg.org> ---
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8ec4b4ff |
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25-Jul-2005 |
Sam Ravnborg <sam@mars.(none)> |
kbuild: introduce Kbuild.include Kbuild.include is a placeholder for definitions originally present in both the top-level Makefile and scripts/Makefile.build. There were a slight difference in the filechk definition, so the most videly used version was kept and usr/Makefile was adopted for this syntax. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> ---
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cfca82f2 |
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14-Jul-2005 |
Sam Ravnborg <sam@mars.(none)> |
kbuild: Fix build as root then user From: Matthew Wilcox <matthew@wil.cx> I inadvertently built a tree as root and then rebuilt it as a user. I got a lot of prompts ... mv: overwrite `drivers/char/drm/drm_auth.o', overriding mode 0644? Using mv -f fixes that. Signed-off-by: Matthew Wilcox <matthew@wil.cx> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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8476994a |
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23-Jun-2005 |
Jan Beulich <JBeulich@novell.com> |
[PATCH] apply quotation handling to Makefile.build Adding quotation handling to rule_cc_o_c in scripts/Makefile.build as used elsewhere. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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1da177e4 |
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16-Apr-2005 |
Linus Torvalds <torvalds@ppc970.osdl.org> |
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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