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/linux-master/scripts/ | ||
H A D | Makefile.host | diff 9f3f1fd2 Wed Jun 21 17:28:03 MDT 2017 Matthias Kaehlcke <mka@chromium.org> kbuild: Add __cc-option macro cc-option uses KBUILD_CFLAGS and KBUILD_CPPFLAGS when it determines whether an option is supported or not. This is fine for options used to build the kernel itself, however some components like the x86 boot code use a different set of flags. Add the new macro __cc-option which is a more generic version of cc-option with additional parameters. One parameter is the compiler with which the check should be performed, the other the compiler options to be used instead KBUILD_C*FLAGS. Refactor cc-option and hostcc-option to use __cc-option and move hostcc-option to scripts/Kbuild.include. Suggested-by: Arnd Bergmann <arnd@arndb.de> Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Michal Marek <mmarek@suse.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 9f3f1fd2 Wed Jun 21 17:28:03 MDT 2017 Matthias Kaehlcke <mka@chromium.org> kbuild: Add __cc-option macro cc-option uses KBUILD_CFLAGS and KBUILD_CPPFLAGS when it determines whether an option is supported or not. This is fine for options used to build the kernel itself, however some components like the x86 boot code use a different set of flags. Add the new macro __cc-option which is a more generic version of cc-option with additional parameters. One parameter is the compiler with which the check should be performed, the other the compiler options to be used instead KBUILD_C*FLAGS. Refactor cc-option and hostcc-option to use __cc-option and move hostcc-option to scripts/Kbuild.include. Suggested-by: Arnd Bergmann <arnd@arndb.de> Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Michal Marek <mmarek@suse.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> |
H A D | Kbuild.include | diff 875ef1a5 Sat Dec 10 08:10:59 MST 2022 Masahiro Yamada <masahiroy@kernel.org> kbuild: use .NOTINTERMEDIATE for future GNU Make versions In Kbuild, some files are generated by chains of pattern/implicit rules. For example, *.dtb.o files in drivers/of/unittest-data/Makefile are generated by the chain of 3 pattern rules, like this: %.dts -> %.dtb -> %.dtb.S -> %.dtb.o Here, %.dts is the real source, %.dtb.o is the final target. %.dtb and %.dtb.S are called "intermediate files". As GNU Make manual [1] says, intermediate files are treated differently in two ways: (a) The first difference is what happens if the intermediate file does not exist. If an ordinary file 'b' does not exist, and make considers a target that depends on 'b', it invariably creates 'b' and then updates the target from 'b'. But if 'b' is an intermediate file, then make can leave well enough alone: it won't create 'b' unless one of its prerequisites is out of date. This means the target depending on 'b' won't be rebuilt either, unless there is some other reason to update that target: for example the target doesn't exist or a different prerequisite is newer than the target. (b) The second difference is that if make does create 'b' in order to update something else, it deletes 'b' later on after it is no longer needed. Therefore, an intermediate file which did not exist before make also does not exist after make. make reports the deletion to you by printing a 'rm' command showing which file it is deleting. The combination of these is problematic for Kbuild because most of the build rules depend on FORCE and the if_changed* macros really determine if the target should be updated. So, all missing files, whether they are intermediate or not, are always rebuilt. To see the problem, delete ".SECONDARY:" from scripts/Kbuild.include, and repeat this command: $ make allmodconfig drivers/of/unittest-data/ The intermediate files will be deleted, which results in rebuilding intermediate and final objects in the next run of make. In the old days, people suppressed (b) in inconsistent ways. As commit 54a702f70589 ("kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers") noted, you should not use .PRECIOUS because .PRECIOUS has the following behavior (c), which is not likely what you want. (c) If make is killed or interrupted during the execution of their recipes, the target is not deleted. Also, the target is not deleted on error even if .DELETE_ON_ERROR is specified. .SECONDARY is a much better way to disable (b), but a small problem is that .SECONDARY enables (a), which gives a side-effect to $?; prerequisites marked as .SECONDARY do not appear in $?. This is a drawback for Kbuild. I thought it was a bug and opened a bug report. As Paul, the GNU Make maintainer, concluded in [2], this is not a bug. A good news is that, GNU Make 4.4 added the perfect solution, .NOTINTERMEDIATE, which cancels both (a) and (b). For clarificaton, my understanding of .INTERMEDIATE, .SECONDARY, .PRECIOUS and .NOTINTERMEDIATE are as follows: (a) (b) (c) .INTERMEDIATE enable enable disable .SECONDARY enable disable disable .PRECIOUS disable disable enable .NOTINTERMEDIATE disable disable disable However, GNU Make 4.4 has a bug for the global .NOTINTERMEDIATE. [3] It was fixed by commit 6164608900ad ("[SV 63417] Ensure global .NOTINTERMEDIATE disables all intermediates"), and will be available in the next release of GNU Make. The following is the gain for .NOTINTERMEDIATE: [Current Make] $ make allnoconfig vmlinux [ full build ] $ rm include/linux/device.h $ make vmlinux CALL scripts/checksyscalls.sh Make does not notice the removal of <linux/device.h>. [Future Make] $ make-latest allnoconfig vmlinux [ full build ] $ rm include/linux/device.h $ make-latest vmlinux CC arch/x86/kernel/asm-offsets.s In file included from ./include/linux/writeback.h:13, from ./include/linux/memcontrol.h:22, from ./include/linux/swap.h:9, from ./include/linux/suspend.h:5, from arch/x86/kernel/asm-offsets.c:13: ./include/linux/blk_types.h:11:10: fatal error: linux/device.h: No such file or directory 11 | #include <linux/device.h> | ^~~~~~~~~~~~~~~~ compilation terminated. make-latest[1]: *** [scripts/Makefile.build:114: arch/x86/kernel/asm-offsets.s] Error 1 make-latest: *** [Makefile:1282: prepare0] Error 2 Make notices the removal of <linux/device.h>, and rebuilds objects that depended on <linux/device.h>. There exists a source file that includes <linux/device.h>, and it raises an error. To see detailed background information, refer to commit 2d3b1b8f0da7 ("kbuild: drop $(wildcard $^) check in if_changed* for faster rebuild"). [1]: https://www.gnu.org/software/make/manual/make.html#Chained-Rules [2]: https://savannah.gnu.org/bugs/?55532 [3]: https://savannah.gnu.org/bugs/?63417 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> diff 392885ee Thu Nov 29 18:05:22 MST 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> diff 77b0bf55 Wed Oct 03 15:30:52 MDT 2018 Nadav Amit <namit@vmware.com> kbuild/Makefile: Prepare for using macros in inline assembly code to work around asm() related GCC inlining bugs Using macros in inline assembly allows us to work around bugs in GCC's inlining decisions. Compile macros.S and use it to assemble all C files. Currently only x86 will use it. Background: The inlining pass of GCC doesn't include an assembler, so it's not aware of basic properties of the generated code, such as its size in bytes, or that there are such things as discontiuous blocks of code and data due to the newfangled linker feature called 'sections' ... Instead GCC uses a lazy and fragile heuristic: it does a linear count of certain syntactic and whitespace elements in inlined assembly block source code, such as a count of new-lines and semicolons (!), as a poor substitute for "code size and complexity". Unsurprisingly this heuristic falls over and breaks its neck whith certain common types of kernel code that use inline assembly, such as the frequent practice of putting useful information into alternative sections. As a result of this fresh, 20+ years old GCC bug, GCC's inlining decisions are effectively disabled for inlined functions that make use of such asm() blocks, because GCC thinks those sections of code are "large" - when in reality they are often result in just a very low number of machine instructions. This absolute lack of inlining provess when GCC comes across such asm() blocks both increases generated kernel code size and causes performance overhead, which is particularly noticeable on paravirt kernels, which make frequent use of these inlining facilities in attempt to stay out of the way when running on baremetal hardware. Instead of fixing the compiler we use a workaround: we set an assembly macro and call it from the inlined assembly block. As a result GCC considers the inline assembly block as a single instruction. (Which it often isn't but I digress.) This uglifies and bloats the source code - for example just the refcount related changes have this impact: Makefile | 9 +++++++-- arch/x86/Makefile | 7 +++++++ arch/x86/kernel/macros.S | 7 +++++++ scripts/Kbuild.include | 4 +++- scripts/mod/Makefile | 2 ++ 5 files changed, 26 insertions(+), 3 deletions(-) Yay readability and maintainability, it's not like assembly code is hard to read and maintain ... We also hope that GCC will eventually get fixed, but we are not holding our breath for that. Yet we are optimistic, it might still happen, any decade now. [ mingo: Wrote new changelog describing the background. ] Tested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Nadav Amit <namit@vmware.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@amacapital.net> 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: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kbuild@vger.kernel.org Link: http://lkml.kernel.org/r/20181003213100.189959-3-namit@vmware.com Signed-off-by: Ingo Molnar <mingo@kernel.org> diff 9c2af1c7 Fri Jul 20 01:46:33 MDT 2018 Masahiro Yamada <yamada.masahiro@socionext.com> kbuild: add .DELETE_ON_ERROR special target If Make gets a fatal signal while a shell is executing, it may delete the target file that the recipe was supposed to update. This is needed to make sure that it is remade from scratch when Make is next run; if Make is interrupted after the recipe has begun to write the target file, it results in an incomplete file whose time stamp is newer than that of the prerequisites files. Make automatically deletes the incomplete file on interrupt unless the target is marked .PRECIOUS. The situation is just the same as when the shell fails for some reasons. Usually when a recipe line fails, if it has changed the target file at all, the file is corrupted, or at least it is not completely updated. Yet the file’s time stamp says that it is now up to date, so the next time Make runs, it will not try to update that file. However, Make does not cater to delete the incomplete target file in this case. We need to add .DELETE_ON_ERROR somewhere in the Makefile to request it. scripts/Kbuild.include seems a suitable place to add it because it is included from almost all sub-makes. Please note .DELETE_ON_ERROR is not effective for phony targets. The external module building should never ever touch the kernel tree. The following recipe fails if include/generated/autoconf.h is missing. However, include/config/auto.conf is not deleted since it is a phony target. PHONY += include/config/auto.conf include/config/auto.conf: $(Q)test -e include/generated/autoconf.h -a -e $@ || ( \ echo >&2; \ echo >&2 " ERROR: Kernel configuration is invalid."; \ echo >&2 " include/generated/autoconf.h or $@ are missing.";\ echo >&2 " Run 'make oldconfig && make prepare' on kernel src to fix it."; \ echo >&2 ; \ /bin/false) Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff e08d6de4 Mon May 28 03:21:38 MDT 2018 Masahiro Yamada <yamada.masahiro@socionext.com> kbuild: remove kbuild cache The kbuild cache was introduced to remember the result of shell commands, some of which are expensive to compute, such as $(call cc-option,...). However, this turned out not so clever as I had first expected. Actually, it is problematic. For example, "$(CC) -print-file-name" is cached. If the compiler is updated, the stale search path causes build error, which is difficult to figure out. Another problem scenario is cache files could be touched while install targets are running under the root permission. We can patch them if desired, but the build infrastructure is getting uglier and uglier. Now, we are going to move compiler flag tests to the configuration phase. If this is completed, the result of compiler tests will be naturally cached in the .config file. We will not have performance issues of incremental building since this testing only happens at Kconfig time. To start this work with a cleaner code base, remove the kbuild cache first. Revert the following commits: Commit 9a234a2e3843 ("kbuild: create directory for make cache only when necessary") Commit e17c400ae194 ("kbuild: shrink .cache.mk when it exceeds 1000 lines") Commit 4e56207130ed ("kbuild: Cache a few more calls to the compiler") Commit 3298b690b21c ("kbuild: Add a cache for generated variables") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Kees Cook <keescook@chromium.org> diff 9a234a2e Mon Nov 13 03:29:34 MST 2017 Masahiro Yamada <yamada.masahiro@socionext.com> kbuild: create directory for make cache only when necessary Currently, the existence of $(dir $(make-cache)) is always checked, and created if it is missing. We can avoid unnecessary system calls by some tricks. [1] If KBUILD_SRC is unset, we are building in the source tree. The output directory checks can be entirely skipped. [2] If at least one cache data is found, it means the cache file was included. Obviously its directory exists. Skip "mkdir -p". [3] If Makefile does not contain any call of __run-and-store, it will not create a cache file. No need to create its directory. [4] The "mkdir -p" should be only invoked by the first call of __run-and-store Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> diff 9f3f1fd2 Wed Jun 21 17:28:03 MDT 2017 Matthias Kaehlcke <mka@chromium.org> kbuild: Add __cc-option macro cc-option uses KBUILD_CFLAGS and KBUILD_CPPFLAGS when it determines whether an option is supported or not. This is fine for options used to build the kernel itself, however some components like the x86 boot code use a different set of flags. Add the new macro __cc-option which is a more generic version of cc-option with additional parameters. One parameter is the compiler with which the check should be performed, the other the compiler options to be used instead KBUILD_C*FLAGS. Refactor cc-option and hostcc-option to use __cc-option and move hostcc-option to scripts/Kbuild.include. Suggested-by: Arnd Bergmann <arnd@arndb.de> Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Michal Marek <mmarek@suse.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 9f3f1fd2 Wed Jun 21 17:28:03 MDT 2017 Matthias Kaehlcke <mka@chromium.org> kbuild: Add __cc-option macro cc-option uses KBUILD_CFLAGS and KBUILD_CPPFLAGS when it determines whether an option is supported or not. This is fine for options used to build the kernel itself, however some components like the x86 boot code use a different set of flags. Add the new macro __cc-option which is a more generic version of cc-option with additional parameters. One parameter is the compiler with which the check should be performed, the other the compiler options to be used instead KBUILD_C*FLAGS. Refactor cc-option and hostcc-option to use __cc-option and move hostcc-option to scripts/Kbuild.include. Suggested-by: Arnd Bergmann <arnd@arndb.de> Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Michal Marek <mmarek@suse.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 9c8fa9bc Sat May 07 00:48:26 MDT 2016 Masahiro Yamada <yamada.masahiro@socionext.com> kbuild: fix if_change and friends to consider argument order Currently, arg-check is implemented as follows: arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ $(filter-out $(cmd_$@), $(cmd_$(1))) ) This does not care about the order of arguments that appear in $(cmd_$(1)) and $(cmd_$@). So, if_changed and friends never rebuild the target if only the argument order is changed. This is a problem when the link order is changed. Apparently, obj-y += foo.o obj-y += bar.o and obj-y += bar.o obj-y += foo.o should be distinguished because the link order determines the probe order of drivers. So, built-in.o should be rebuilt when the order of objects is changed. This commit fixes arg-check to compare the old/current commands including the argument order. Of course, this change has a side effect; Kbuild will react to the change of compile option order. For example, "-DFOO -DBAR" and "-DBAR -DFOO" should give no difference to the build result, but false positive should be better than false negative. I am moving space_escape to the top of Kbuild.include just for a matter of preference. In practical terms, space_escape can be defined after arg-check because arg-check uses "=" flavor, not ":=". Having said that, collecting convenient variables in one place makes sense from the point of readability. Chaining "%%%SPACE%%%" to "_-_SPACE_-_" is also a matter of taste at this point. Actually, it can be arbitrary as long as it is an unlikely used string. The only problem I see in "%%%SPACE%%%" is that "%" is a special character in "$(patsubst ...)" context. This commit just uses "$(subst ...)" for arg-check, but I am fixing it now in case we might want to use it in $(patsubst ...) context in the future. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Michal Marek <mmarek@suse.com> diff 9fb5e537 Wed Sep 03 07:29:24 MDT 2014 Robert Richter <rrichter@cavium.com> dts, kbuild: Factor out dtbs install rules to Makefile.dtbinst Move dtbs install rules to Makefile.dtbinst. This change is needed to implement support for dts vendor subdirs. The change makes Makefiles easier and smaller as no longer the dtbs_install rule needs to be defined. Another advantage is that install goals are not encoded in targets anymore (%.dtb_dtbinst_). Signed-off-by: Robert Richter <rrichter@cavium.com> |
/linux-master/ | ||
H A D | Makefile | diff 9d361173 Sat Oct 14 04:54:36 MDT 2023 Masahiro Yamada <masahiroy@kernel.org> kbuild: unify no-compiler-targets and no-sync-config-targets Now that vdso_install does not depend on any in-tree build artifact, it no longer needs a compiler, making no-compiler-targets the same as no-sync-config-targets. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> diff 5fc10e76 Mon Jun 26 17:30:13 MDT 2023 Masahiro Yamada <masahiroy@kernel.org> kbuild: revive "Entering directory" for Make >= 4.4.1 With commit 9da0763bdd82 ("kbuild: Use relative path when building in a subdir of the source tree"), compiler messages in out-of-tree builds include relative paths, which are relative to the build directory, not the directory where make was started. To help IDEs/editors find the source files, Kbuild lets GNU Make print "Entering directory ..." when it changes the working directory. It has been working fine for a long time, but David reported it is broken with the latest GNU Make. The behavior was changed by GNU Make commit 8f9e7722ff0f ("[SV 63537] Fix setting -w in makefiles"). Previously, setting --no-print-directory to MAKEFLAGS only affected child makes, but it is now interpreted in the current make as soon as it is set. [test code] $ cat /tmp/Makefile ifneq ($(SUBMAKE),1) MAKEFLAGS += --no-print-directory all: ; $(MAKE) SUBMAKE=1 else all: ; : endif [before 8f9e7722ff0f] $ make -C /tmp make: Entering directory '/tmp' make SUBMAKE=1 : make: Leaving directory '/tmp' [after 8f9e7722ff0f] $ make -C /tmp make SUBMAKE=1 : Previously, the effect of --no-print-directory was delayed until Kbuild started the directory descending, but it is no longer true with GNU Make 4.4.1. This commit adds one more recursion to cater to GNU Make >= 4.4.1. When Kbuild needs to change the working directory, __submake will be executed twice. __submake without --no-print-directory --> show "Entering directory ..." __submake with --no-print-directory --> parse the rest of Makefile We end up with one more recursion than needed for GNU Make < 4.4.1, but I do not want to complicate the version check. Reported-by: David Howells <dhowells@redhat.com> Closes: https://lore.kernel.org/all/2427604.1686237298@warthog.procyon.org.uk/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nicolas Schier <n.schier@avm.de> diff 9c73bcfa Tue Jan 17 22:05:34 MST 2023 Thomas Weißschuh <linux@weissschuh.net> kbuild: also delete temporary directories Reuse the standard naming schema for temporary files also for temporary directories. Such a directory will be used by the kheaders generation. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nicolas Schier <nicolas@fjasle.eu> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> diff 9beccca0 Thu Oct 27 09:59:07 MDT 2022 Ard Biesheuvel <ardb@kernel.org> scs: add support for dynamic shadow call stacks In order to allow arches to use code patching to conditionally emit the shadow stack pushes and pops, rather than always taking the performance hit even on CPUs that implement alternatives such as stack pointer authentication on arm64, add a Kconfig symbol that can be set by the arch to omit the SCS codegen itself, without otherwise affecting how support code for SCS and compiler options (for register reservation, for instance) are emitted. Also, add a static key and some plumbing to omit the allocation of shadow call stack for dynamic SCS configurations if SCS is disabled at runtime. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Tested-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lore.kernel.org/r/20221027155908.1940624-3-ardb@kernel.org Signed-off-by: Will Deacon <will@kernel.org> diff 9abf2313 Sun Oct 16 16:36:24 MDT 2022 Linus Torvalds <torvalds@linux-foundation.org> Linux 6.1-rc1 diff 9c5a0ac3 Sat Sep 24 12:19:12 MDT 2022 Masahiro Yamada <masahiroy@kernel.org> kbuild: move vmlinux.o rule to the top Makefile Move the build rules of vmlinux.o out of scripts/link-vmlinux.sh to clearly separate 1) pre-modpost, 2) modpost, 3) post-modpost stages. This will make further refactoring possible. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> diff 9a68fd7f Wed Jul 13 23:02:42 MDT 2022 Masahiro Yamada <masahiroy@kernel.org> kbuild: error out if $(KBUILD_EXTMOD) contains % or : If the directory path given to KBUILD_EXTMOD (or M=) contains % or :, the module fails to build. % is used in pattern rules, and : as the separator of dependencies. Bail out with a clearer error message. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <n.schier@avm.de> diff dee2b702 Sat Nov 13 17:57:25 MST 2021 Gustavo A. R. Silva <gustavoars@kernel.org> kconfig: Add support for -Wimplicit-fallthrough Add Kconfig support for -Wimplicit-fallthrough for both GCC and Clang. The compiler option is under configuration CC_IMPLICIT_FALLTHROUGH, which is enabled by default. Special thanks to Nathan Chancellor who fixed the Clang bug[1][2]. This bugfix only appears in Clang 14.0.0, so older versions still contain the bug and -Wimplicit-fallthrough won't be enabled for them, for now. This concludes a long journey and now we are finally getting rid of the unintentional fallthrough bug-class in the kernel, entirely. :) Link: https://github.com/llvm/llvm-project/commit/9ed4a94d6451046a51ef393cd62f00710820a7e8 [1] Link: https://bugs.llvm.org/show_bug.cgi?id=51094 [2] Link: https://github.com/KSPP/linux/issues/115 Link: https://github.com/ClangBuiltLinux/linux/issues/236 Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> diff 86cffecd Fri Nov 05 14:36:19 MDT 2021 Kees Cook <keescook@chromium.org> Compiler Attributes: add __alloc_size() for better bounds checking GCC and Clang can use the "alloc_size" attribute to better inform the results of __builtin_object_size() (for compile-time constant values). Clang can additionally use alloc_size to inform the results of __builtin_dynamic_object_size() (for run-time values). Because GCC sees the frequent use of struct_size() as an allocator size argument, and notices it can return SIZE_MAX (the overflow indication), it complains about these call sites overflowing (since SIZE_MAX is greater than the default -Walloc-size-larger-than=PTRDIFF_MAX). This isn't helpful since we already know a SIZE_MAX will be caught at run-time (this was an intentional design). To deal with this, we must disable this check as it is both a false positive and redundant. (Clang does not have this warning option.) Unfortunately, just checking the -Wno-alloc-size-larger-than is not sufficient to make the __alloc_size attribute behave correctly under older GCC versions. The attribute itself must be disabled in those situations too, as there appears to be no way to reliably silence the SIZE_MAX constant expression cases for GCC versions less than 9.1: In file included from ./include/linux/resource_ext.h:11, from ./include/linux/pci.h:40, from drivers/net/ethernet/intel/ixgbe/ixgbe.h:9, from drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c:4: In function 'kmalloc_node', inlined from 'ixgbe_alloc_q_vector' at ./include/linux/slab.h:743:9: ./include/linux/slab.h:618:9: error: argument 1 value '18446744073709551615' exceeds maximum object size 9223372036854775807 [-Werror=alloc-size-larger-than=] return __kmalloc_node(size, flags, node); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ./include/linux/slab.h: In function 'ixgbe_alloc_q_vector': ./include/linux/slab.h:455:7: note: in a call to allocation function '__kmalloc_node' declared here void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_slab_alignment __malloc; ^~~~~~~~~~~~~~ Specifically: '-Wno-alloc-size-larger-than' is not correctly handled by GCC < 9.1 https://godbolt.org/z/hqsfG7q84 (doesn't disable) https://godbolt.org/z/P9jdrPTYh (doesn't admit to not knowing about option) https://godbolt.org/z/465TPMWKb (only warns when other warnings appear) '-Walloc-size-larger-than=18446744073709551615' is not handled by GCC < 8.2 https://godbolt.org/z/73hh1EPxz (ignores numeric value) Since anything marked with __alloc_size would also qualify for marking with __malloc, just include __malloc along with it to avoid redundant markings. (Suggested by Linus Torvalds.) Finally, make sure checkpatch.pl doesn't get confused about finding the __alloc_size attribute on functions. (Thanks to Joe Perches.) Link: https://lkml.kernel.org/r/20210930222704.2631604-3-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Cc: Andy Whitcroft <apw@canonical.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Micay <danielmicay@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Dwaipayan Ray <dwaipayanray1@gmail.com> Cc: Joe Perches <joe@perches.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Alexandre Bounine <alex.bou9@gmail.com> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jing Xiangfeng <jingxiangfeng@huawei.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: kernel test robot <lkp@intel.com> Cc: Matt Porter <mporter@kernel.crashing.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> diff 86cffecd Fri Nov 05 14:36:19 MDT 2021 Kees Cook <keescook@chromium.org> Compiler Attributes: add __alloc_size() for better bounds checking GCC and Clang can use the "alloc_size" attribute to better inform the results of __builtin_object_size() (for compile-time constant values). Clang can additionally use alloc_size to inform the results of __builtin_dynamic_object_size() (for run-time values). Because GCC sees the frequent use of struct_size() as an allocator size argument, and notices it can return SIZE_MAX (the overflow indication), it complains about these call sites overflowing (since SIZE_MAX is greater than the default -Walloc-size-larger-than=PTRDIFF_MAX). This isn't helpful since we already know a SIZE_MAX will be caught at run-time (this was an intentional design). To deal with this, we must disable this check as it is both a false positive and redundant. (Clang does not have this warning option.) Unfortunately, just checking the -Wno-alloc-size-larger-than is not sufficient to make the __alloc_size attribute behave correctly under older GCC versions. The attribute itself must be disabled in those situations too, as there appears to be no way to reliably silence the SIZE_MAX constant expression cases for GCC versions less than 9.1: In file included from ./include/linux/resource_ext.h:11, from ./include/linux/pci.h:40, from drivers/net/ethernet/intel/ixgbe/ixgbe.h:9, from drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c:4: In function 'kmalloc_node', inlined from 'ixgbe_alloc_q_vector' at ./include/linux/slab.h:743:9: ./include/linux/slab.h:618:9: error: argument 1 value '18446744073709551615' exceeds maximum object size 9223372036854775807 [-Werror=alloc-size-larger-than=] return __kmalloc_node(size, flags, node); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ./include/linux/slab.h: In function 'ixgbe_alloc_q_vector': ./include/linux/slab.h:455:7: note: in a call to allocation function '__kmalloc_node' declared here void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_slab_alignment __malloc; ^~~~~~~~~~~~~~ Specifically: '-Wno-alloc-size-larger-than' is not correctly handled by GCC < 9.1 https://godbolt.org/z/hqsfG7q84 (doesn't disable) https://godbolt.org/z/P9jdrPTYh (doesn't admit to not knowing about option) https://godbolt.org/z/465TPMWKb (only warns when other warnings appear) '-Walloc-size-larger-than=18446744073709551615' is not handled by GCC < 8.2 https://godbolt.org/z/73hh1EPxz (ignores numeric value) Since anything marked with __alloc_size would also qualify for marking with __malloc, just include __malloc along with it to avoid redundant markings. (Suggested by Linus Torvalds.) Finally, make sure checkpatch.pl doesn't get confused about finding the __alloc_size attribute on functions. (Thanks to Joe Perches.) Link: https://lkml.kernel.org/r/20210930222704.2631604-3-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Cc: Andy Whitcroft <apw@canonical.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Micay <danielmicay@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Dwaipayan Ray <dwaipayanray1@gmail.com> Cc: Joe Perches <joe@perches.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Alexandre Bounine <alex.bou9@gmail.com> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jing Xiangfeng <jingxiangfeng@huawei.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: kernel test robot <lkp@intel.com> Cc: Matt Porter <mporter@kernel.crashing.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> diff 86cffecd Fri Nov 05 14:36:19 MDT 2021 Kees Cook <keescook@chromium.org> Compiler Attributes: add __alloc_size() for better bounds checking GCC and Clang can use the "alloc_size" attribute to better inform the results of __builtin_object_size() (for compile-time constant values). Clang can additionally use alloc_size to inform the results of __builtin_dynamic_object_size() (for run-time values). Because GCC sees the frequent use of struct_size() as an allocator size argument, and notices it can return SIZE_MAX (the overflow indication), it complains about these call sites overflowing (since SIZE_MAX is greater than the default -Walloc-size-larger-than=PTRDIFF_MAX). This isn't helpful since we already know a SIZE_MAX will be caught at run-time (this was an intentional design). To deal with this, we must disable this check as it is both a false positive and redundant. (Clang does not have this warning option.) Unfortunately, just checking the -Wno-alloc-size-larger-than is not sufficient to make the __alloc_size attribute behave correctly under older GCC versions. The attribute itself must be disabled in those situations too, as there appears to be no way to reliably silence the SIZE_MAX constant expression cases for GCC versions less than 9.1: In file included from ./include/linux/resource_ext.h:11, from ./include/linux/pci.h:40, from drivers/net/ethernet/intel/ixgbe/ixgbe.h:9, from drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c:4: In function 'kmalloc_node', inlined from 'ixgbe_alloc_q_vector' at ./include/linux/slab.h:743:9: ./include/linux/slab.h:618:9: error: argument 1 value '18446744073709551615' exceeds maximum object size 9223372036854775807 [-Werror=alloc-size-larger-than=] return __kmalloc_node(size, flags, node); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ./include/linux/slab.h: In function 'ixgbe_alloc_q_vector': ./include/linux/slab.h:455:7: note: in a call to allocation function '__kmalloc_node' declared here void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_slab_alignment __malloc; ^~~~~~~~~~~~~~ Specifically: '-Wno-alloc-size-larger-than' is not correctly handled by GCC < 9.1 https://godbolt.org/z/hqsfG7q84 (doesn't disable) https://godbolt.org/z/P9jdrPTYh (doesn't admit to not knowing about option) https://godbolt.org/z/465TPMWKb (only warns when other warnings appear) '-Walloc-size-larger-than=18446744073709551615' is not handled by GCC < 8.2 https://godbolt.org/z/73hh1EPxz (ignores numeric value) Since anything marked with __alloc_size would also qualify for marking with __malloc, just include __malloc along with it to avoid redundant markings. (Suggested by Linus Torvalds.) Finally, make sure checkpatch.pl doesn't get confused about finding the __alloc_size attribute on functions. (Thanks to Joe Perches.) Link: https://lkml.kernel.org/r/20210930222704.2631604-3-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Cc: Andy Whitcroft <apw@canonical.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Micay <danielmicay@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Dwaipayan Ray <dwaipayanray1@gmail.com> Cc: Joe Perches <joe@perches.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Alexandre Bounine <alex.bou9@gmail.com> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jing Xiangfeng <jingxiangfeng@huawei.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: kernel test robot <lkp@intel.com> Cc: Matt Porter <mporter@kernel.crashing.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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