treewide: update LLVM Bugzilla links

LLVM moved their issue tracker from their own Bugzilla instance to GitHub
issues. While all of the links are still valid, they may not necessarily
show the most up to date information around the issues, as all updates
will occur on GitHub, not Bugzilla.

Another complication is that the Bugzilla issue number is not always the
same as the GitHub issue number. Thankfully, LLVM maintains this mapping
through two shortlinks:

https://llvm.org/bz<num> -> https://bugs.llvm.org/show_bug.cgi?id=<num>
https://llvm.org/pr<num> -> https://github.com/llvm/llvm-project/issues/<mapped_num>

Switch all "https://bugs.llvm.org/show_bug.cgi?id=<num>" links to the
"https://llvm.org/pr<num>" shortlink so that the links show the most up to
date information. Each migrated issue links back to the Bugzilla entry,
so there should be no loss of fidelity of information here.

Link: https://lkml.kernel.org/r/20240109-update-llvm-links-v1-3-eb09b59db071@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Fangrui Song <maskray@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Mykola Lysenko <mykolal@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

riscv/efistub: Tighten ELF relocation check

The EFI stub makefile contains logic to ensure that the objects that
make up the stub do not contain relocations that require runtime fixups
(typically to account for the runtime load address of the executable)

On RISC-V, we also avoid GP based relocations, as they require that GP
is assigned the correct base in the startup code, which is not
implemented in the EFI stub.

So add these relocation types to the grep expression that is used to
carry out this check.

Link: https://lkml.kernel.org/r/42c63cb9-87d0-49db-9af8-95771b186684%40siemens.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

riscv/efistub: Ensure GP-relative addressing is not used

The cflags for the RISC-V efistub were missing -mno-relax, thus were
under the risk that the compiler could use GP-relative addressing. That
happened for _edata with binutils-2.41 and kernel 6.1, causing the
relocation to fail due to an invalid kernel_size in handle_kernel_image.
It was not yet observed with newer versions, but that may just be luck.

Cc: <stable@vger.kernel.org>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

riscv: Optimize bitops with Zbb extension

This patch leverages the alternative mechanism to dynamically optimize
bitops (including __ffs, __fls, ffs, fls) with Zbb instructions. When
Zbb ext is not supported by the runtime CPU, legacy implementation is
used. If Zbb is supported, then the optimized variants will be selected
via alternative patching.

The legacy bitops support is taken from the generic C implementation as
fallback.

If the parameter is a build-time constant, we leverage compiler builtin to
calculate the result directly, this approach is inspired by x86 bitops
implementation.

EFI stub runs before the kernel, so alternative mechanism should not be
used there, this patch introduces a macro NO_ALTERNATIVE for this purpose.

Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20231031064553.2319688-3-xiao.w.wang@intel.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

x86/efi: Drop EFI stub .bss from .data section

Now that the EFI stub always zero inits its BSS section upon entry,
there is no longer a need to place the BSS symbols carried by the stub
into the .data section.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230912090051.4014114-18-ardb@google.com

riscv: libstub: Implement KASLR by using generic functions

We can now use arm64 functions to handle the move of the kernel physical
mapping: if KASLR is enabled, we will try to get a random seed from the
firmware, if not possible, the kernel will be moved to a location that
suits its alignment constraints.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Song Shuai <songshuaishuai@tinylab.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20230722123850.634544-6-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arm64: libstub: Move KASLR handling functions to kaslr.c

This prepares for riscv to use the same functions to handle the pĥysical
kernel move when KASLR is enabled.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Song Shuai <songshuaishuai@tinylab.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20230722123850.634544-4-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

x86/efistub: Perform 4/5 level paging switch from the stub

In preparation for updating the EFI stub boot flow to avoid the bare
metal decompressor code altogether, implement the support code for
switching between 4 and 5 levels of paging before jumping to the kernel
proper.

Reuse the newly refactored trampoline that the bare metal decompressor
uses, but relies on EFI APIs to allocate 32-bit addressable memory and
remap it with the appropriate permissions. Given that the bare metal
decompressor will no longer call into the trampoline if the number of
paging levels is already set correctly, it is no longer needed to remove
NX restrictions from the memory range where this trampoline may end up.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/20230807162720.545787-17-ardb@kernel.org

efi/riscv: libstub: Fix comment about absolute relocation

We don't want absolute symbols references in the stub, so fix the double
negation in the comment.

Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Implement support for unaccepted memory

UEFI Specification version 2.9 introduces the concept of memory
acceptance: Some Virtual Machine platforms, such as Intel TDX or AMD
SEV-SNP, requiring memory to be accepted before it can be used by the
guest. Accepting happens via a protocol specific for the Virtual
Machine platform.

Accepting memory is costly and it makes VMM allocate memory for the
accepted guest physical address range. It's better to postpone memory
acceptance until memory is needed. It lowers boot time and reduces
memory overhead.

The kernel needs to know what memory has been accepted. Firmware
communicates this information via memory map: a new memory type --
EFI_UNACCEPTED_MEMORY -- indicates such memory.

Range-based tracking works fine for firmware, but it gets bulky for
the kernel: e820 (or whatever the arch uses) has to be modified on every
page acceptance. It leads to table fragmentation and there's a limited
number of entries in the e820 table.

Another option is to mark such memory as usable in e820 and track if the
range has been accepted in a bitmap. One bit in the bitmap represents a
naturally aligned power-2-sized region of address space -- unit.

For x86, unit size is 2MiB: 4k of the bitmap is enough to track 64GiB or
physical address space.

In the worst-case scenario -- a huge hole in the middle of the
address space -- It needs 256MiB to handle 4PiB of the address
space.

Any unaccepted memory that is not aligned to unit_size gets accepted
upfront.

The bitmap is allocated and constructed in the EFI stub and passed down
to the kernel via EFI configuration table. allocate_e820() allocates the
bitmap if unaccepted memory is present, according to the size of
unaccepted region.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230606142637.5171-4-kirill.shutemov@linux.intel.com

arm64: efi: Enable BTI codegen and add PE/COFF annotation

UEFI heavily relies on so-called protocols, which are essentially
tables populated with pointers to executable code, and these are invoked
indirectly using BR or BLR instructions.

This makes the EFI execution context vulnerable to attacks on forward
edge control flow, and so it would help if we could enable hardware
enforcement (BTI) on CPUs that implement it.

So let's no longer disable BTI codegen for the EFI stub, and set the
newly introduced PE/COFF header flag when the kernel is built with BTI
landing pads.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>

efi: arm64: enter with MMU and caches enabled

Instead of cleaning the entire loaded kernel image to the PoC and
disabling the MMU and caches before branching to the kernel's bare metal
entry point, we can leave the MMU and caches enabled, and rely on EFI's
cacheable 1:1 mapping of all of system RAM (which is mandated by the
spec) to populate the initial page tables.

This removes the need for managing coherency in software, which is
tedious and error prone.

Note that we still need to clean the executable region of the image to
the PoU if this is required for I/D coherency, but only if we actually
decided to move the image in memory, as otherwise, this will have been
taken care of by the loader.

This change affects both the builtin EFI stub as well as the zboot
decompressor, which now carries the entire EFI stub along with the
decompression code and the compressed image.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230111102236.1430401-7-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: unwind: add asynchronous unwind tables to kernel and modules

Enable asynchronous unwind table generation for both the core kernel as
well as modules, and emit the resulting .eh_frame sections as init code
so we can use the unwind directives for code patching at boot or module
load time.

This will be used by dynamic shadow call stack support, which will rely
on code patching rather than compiler codegen to emit the shadow call
stack push and pop instructions.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20221027155908.1940624-2-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

efi/loongarch: libstub: Split off kernel image relocation for builtin stub

The LoongArch build of the EFI stub is part of the core kernel image, and
therefore accesses section markers directly when it needs to figure out
the size of the various section.

The zboot decompressor does not have access to those symbols, but
doesn't really need that either. So let's move handle_kernel_image()
into a separate file (or rather, move everything else into a separate
file) so that the zboot build does not pull in unused code that links to
symbols that it does not define.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/arm64: libstub: Split off kernel image relocation for builtin stub

The arm64 build of the EFI stub is part of the core kernel image, and
therefore accesses section markers directly when it needs to figure out
the size of the various section.

The zboot decompressor does not have access to those symbols, but
doesn't really need that either. So let's move handle_kernel_image()
into a separate file (or rather, move everything else into a separate
file) so that the zboot build does not pull in unused code that links to
symbols that it does not define.

While at it, introduce a helper routine that the generic zboot loader
will need to invoke after decompressing the image but before invoking
it, to ensure that the I-side view of memory is consistent.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/riscv: libstub: Split off kernel image relocation for builtin stub

The RISC-V build of the EFI stub is part of the core kernel image, and
therefore accesses section markers directly when it needs to figure out
the size of the various section.

The zboot decompressor does not have access to those symbols, but
doesn't really need that either. So let's move handle_kernel_image()
into a separate file (or rather, move everything else into a separate
file) so that the zboot build does not pull in unused code that links to
symbols that it does not define.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi: libstub: Factor out EFI stub entrypoint into separate file

In preparation for allowing the EFI zboot decompressor to reuse most of
the EFI stub machinery, factor out the actual EFI PE/COFF entrypoint
into a separate file.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi: libstub: Provide local implementations of strrchr() and memchr()

Clone the implementations of strrchr() and memchr() in lib/string.c so
we can use them in the standalone zboot decompressor app. These routines
are used by the FDT handling code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi: libstub: Move screen_info handling to common code

Currently, arm64, RISC-V and LoongArch rely on the fact that struct
screen_info can be accessed directly, due to the fact that the EFI stub
and the core kernel are part of the same image. This will change after a
future patch, so let's ensure that the screen_info handling is able to
deal with this, by adopting the arm32 approach of passing it as a
configuration table. While at it, switch to ACPI reclaim memory to hold
the screen_info data, which is more appropriate for this kind of
allocation.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi: libstub: Enable efi_printk() in zboot decompressor

Split the efi_printk() routine into its own source file, and provide
local implementations of strlen() and strnlen() so that the standalone
zboot app can efi_err and efi_info etc.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

arm64: efi: Move efi-entry.S into the libstub source directory

We will be sharing efi-entry.S with the zboot decompressor build, which
does not link against vmlinux directly. So move it into the libstub
source directory so we can include in the libstub static library.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>

efi: libstub: Deduplicate ftrace command line argument filtering

No need for the same pattern to be used four times for each architecture
individually if we can just apply it once later.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

arm64: efi: Force the use of SetVirtualAddressMap() on Altra machines

Ampere Altra machines are reported to misbehave when the SetTime() EFI
runtime service is called after ExitBootServices() but before calling
SetVirtualAddressMap(). Given that the latter is horrid, pointless and
explicitly documented as optional by the EFI spec, we no longer invoke
it at boot if the configured size of the VA space guarantees that the
EFI runtime memory regions can remain mapped 1:1 like they are at boot
time.

On Ampere Altra machines, this results in SetTime() calls issued by the
rtc-efi driver triggering synchronous exceptions during boot. We can
now recover from those without bringing down the system entirely, due to
commit 23715a26c8d81291 ("arm64: efi: Recover from synchronous
exceptions occurring in firmware"). However, it would be better to avoid
the issue entirely, given that the firmware appears to remain in a funny
state after this.

So attempt to identify these machines based on the 'family' field in the
type #1 SMBIOS record, and call SetVirtualAddressMap() unconditionally
in that case.

Tested-by: Alexandru Elisei <alexandru.elisei@gmail.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

kmsan: disable instrumentation of unsupported common kernel code

EFI stub cannot be linked with KMSAN runtime, so we disable
instrumentation for it.

Instrumenting kcov, stackdepot or lockdep leads to infinite recursion
caused by instrumentation hooks calling instrumented code again.

Link: https://lkml.kernel.org/r/20220915150417.722975-13-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

efi/loongarch: libstub: remove dependency on flattened DT

LoongArch does not use FDT or DT natively [yet], and the only reason it
currently uses it is so that it can reuse the existing EFI stub code.

Overloading the DT with data passed between the EFI stub and the core
kernel has been a source of problems: there is the overlap between
information provided by EFI which DT can also provide (initrd base/size,
command line, memory descriptions), requiring us to reason about which
is which and what to prioritize. It has also resulted in ABI leaks,
i.e., internal ABI being promoted to external ABI inadvertently because
the bootloader can set the EFI stub's DT properties as well (e.g.,
"kaslr-seed"). This has become especially problematic with boot
environments that want to pretend that EFI boot is being done (to access
ACPI and SMBIOS tables, for instance) but have no ability to execute the
EFI stub, and so the environment that the EFI stub creates is emulated
[poorly, in some cases].

Another downside of treating DT like this is that the DT binary that the
kernel receives is different from the one created by the firmware, which
is undesirable in the context of secure and measured boot.

Given that LoongArch support in Linux is brand new, we can avoid these
pitfalls, and treat the DT strictly as a hardware description, and use a
separate handover method between the EFI stub and the kernel. Now that
initrd loading and passing the EFI memory map have been refactored into
pure EFI routines that use EFI configuration tables, the only thing we
need to pass directly is the kernel command line (even if we could pass
this via a config table as well, it is used extremely early, so passing
it directly is preferred in this case.)

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Huacai Chen <chenhuacai@loongson.cn>

efi/libstub: implement generic EFI zboot

Implement a minimal EFI app that decompresses the real kernel image and
launches it using the firmware's LoadImage and StartImage boot services.
This removes the need for any arch-specific hacks.

Note that on systems that have UEFI secure boot policies enabled,
LoadImage/StartImage require images to be signed, or their hashes known
a priori, in order to be permitted to boot.

There are various possible strategies to work around this requirement,
but they all rely either on overriding internal PI/DXE protocols (which
are not part of the EFI spec) or omitting the firmware provided
LoadImage() and StartImage() boot services, which is also undesirable,
given that they encapsulate platform specific policies related to secure
boot and measured boot, but also related to memory permissions (whether
or not and which types of heap allocations have both write and execute
permissions.)

The only generic and truly portable way around this is to simply sign
both the inner and the outer image with the same key/cert pair, so this
is what is implemented here.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: move efi_system_table global var into separate object

To avoid pulling in the wrong object when using the libstub static
library to build the decompressor, define efi_system_table in a separate
compilation unit.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: use EFI provided memcpy/memset routines

The stub is used in different execution environments, but on arm64,
RISC-V and LoongArch, we still use the core kernel's implementation of
memcpy and memset, as they are just a branch instruction away, and can
generally be reused even from code such as the EFI stub that runs in a
completely different address space.

KAsan complicates this slightly, resulting in the need for some hacks to
expose the uninstrumented, __ prefixed versions as the normal ones, as
the latter are instrumented to include the KAsan checks, which only work
in the core kernel.

Unfortunately, #define'ing memcpy to __memcpy when building C code does
not guarantee that no explicit memcpy() calls will be emitted. And with
the upcoming zboot support, which consists of a separate binary which
therefore needs its own implementation of memcpy/memset anyway, it's
better to provide one explicitly instead of linking to the existing one.

Given that EFI exposes implementations of memmove() and memset() via the
boot services table, let's wire those up in the appropriate way, and
drop the references to the core kernel ones.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/loongarch: Add efistub booting support

This patch adds efistub booting support, which is the standard UEFI boot
protocol for LoongArch to use.

We use generic efistub, which means we can pass boot information (i.e.,
system table, memory map, kernel command line, initrd) via a light FDT
and drop a lot of non-standard code.

We use a flat mapping to map the efi runtime in the kernel's address
space. In efi, VA = PA; in kernel, VA = PA + PAGE_OFFSET. As a result,
flat mapping is not identity mapping, SetVirtualAddressMap() is still
needed for the efi runtime.

Tested-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
[ardb: change fpic to fpie as suggested by Xi Ruoyao]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

treewide: Filter out CC_FLAGS_CFI

In preparation for removing CC_FLAGS_CFI from CC_FLAGS_LTO, explicitly
filter out CC_FLAGS_CFI in all the makefiles where we currently filter
out CC_FLAGS_LTO.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-2-samitolvanen@google.com

efi: libstub: Disable struct randomization

The EFI stub is a wrapper around the core kernel that makes it look like
a EFI compatible PE/COFF application to the EFI firmware. EFI
applications run on top of the EFI runtime, which is heavily based on
so-called protocols, which are struct types consisting [mostly] of
function pointer members that are instantiated and recorded in a
protocol database.

These structs look like the ideal randomization candidates to the
randstruct plugin (as they only carry function pointers), but of course,
these protocols are contracts between the firmware that exposes them,
and the EFI applications (including our stubbed kernel) that invoke
them. This means that struct randomization for EFI protocols is not a
great idea, and given that the stub shares very little data with the
core kernel that is represented as a randomizable struct, we're better
off just disabling it completely here.

Cc: <stable@vger.kernel.org> # v4.14+
Reported-by: Daniel Marth <daniel.marth@inso.tuwien.ac.at>
Tested-by: Daniel Marth <daniel.marth@inso.tuwien.ac.at>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>

efi/libstub: Add $(CLANG_FLAGS) to x86 flags

When cross compiling x86 on an ARM machine with clang, there are several
errors along the lines of:

arch/x86/include/asm/page_64.h:52:7: error: invalid output constraint '=D' in asm

This happens because the x86 flags in the EFI stub are not derived from
KBUILD_CFLAGS like the other architectures are and the clang flags that
set the target architecture ('--target=') and the path to the GNU cross
tools ('--prefix=') are not present, meaning that the host architecture
is targeted.

These flags are available as $(CLANG_FLAGS) from the main Makefile so
add them to the cflags for x86 so that cross compiling works as expected.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lkml.kernel.org/r/20210326000435.4785-4-nathan@kernel.org

efi/libstub: disable LTO

With CONFIG_LTO_CLANG, we produce LLVM bitcode instead of ELF object
files. Since LTO is not really needed here and the Makefile assumes we
produce an object file, disable LTO for libstub.

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/20201211184633.3213045-13-samitolvanen@google.com

RISC-V: Add EFI stub support.

Add a RISC-V architecture specific stub code that actually copies the
actual kernel image to a valid address and jump to it after boot services
are terminated. Enable UEFI related kernel configs as well for RISC-V.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Link: https://lore.kernel.org/r/20200421033336.9663-4-atish.patra@wdc.com
[ardb: - move hartid fetch into check_platform_features()
- use image_size not reserve_size
- select ISA_C
- do not use dram_base]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

arm64: get rid of TEXT_OFFSET

TEXT_OFFSET serves no purpose, and for this reason, it was redefined
as 0x0 in the v5.8 timeframe. Since this does not appear to have caused
any issues that require us to revisit that decision, let's get rid of the
macro entirely, along with any references to it.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200825135440.11288-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

efi/libstub: Disable -mbranch-protection

In preparation for adding --orphan-handling=warn to more architectures,
disable -mbranch-protection, as EFI does not yet support it[1]. This was
noticed due to it producing unwanted .note.gnu.property sections (prefixed
with .init due to the objcopy build step).

However, we must also work around a bug in Clang where the section is
still emitted for code-less object files[2], so also remove the section
during the objcopy.

[1] https://lore.kernel.org/lkml/CAMj1kXHck12juGi=E=P4hWP_8vQhQ+-x3vBMc3TGeRWdQ-XkxQ@mail.gmail.com
[2] https://bugs.llvm.org/show_bug.cgi?id=46480

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200821194310.3089815-8-keescook@chromium.org

x86/boot/compressed: Force hidden visibility for all symbol references

Eliminate all GOT entries in the decompressor binary, by forcing hidden
visibility for all symbol references, which informs the compiler that
such references will be resolved at link time without the need for
allocating GOT entries.

To ensure that no GOT entries will creep back in, add an assertion to
the decompressor linker script that will fire if the .got section has
a non-zero size.

[Arvind: move hidden.h to include/linux instead of making a copy]

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200731230820.1742553-3-keescook@chromium.org

efi: Revert "efi/x86: Fix build with gcc 4"

This reverts commit 5435f73d5c4a1b75, which is no longer needed now
that the minimum GCC version has been bumped to v4.9

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

kbuild: remove cc-option test of -ffreestanding

Some Makefiles already pass -ffreestanding unconditionally.
For example, arch/arm64/lib/Makefile, arch/x86/purgatory/Makefile.

No problem report so far about hard-coding this option. So, we can
assume all supported compilers know -ffreestanding.

I confirmed GCC 4.8 and Clang manuals document this option.

Get rid of cc-option from -ffreestanding.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>

kbuild: remove cc-option test of -fno-stack-protector

Some Makefiles already pass -fno-stack-protector unconditionally.
For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile.

No problem report so far about hard-coding this option. So, we can
assume all supported compilers know -fno-stack-protector.

GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN)

Get rid of cc-option from -fno-stack-protector.

Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'.

Note:
arch/mips/vdso/Makefile adds -fno-stack-protector twice, first
unconditionally, and second conditionally. I removed the second one.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

efi/x86: Fix build with gcc 4

Commit

bbf8e8b0fe04 ("efi/libstub: Optimize for size instead of speed")

changed the optimization level for the EFI stub to -Os from -O2.

Andrey Ignatov reports that this breaks the build with gcc 4.8.5.

Testing on godbolt.org, the combination of -Os,
-fno-asynchronous-unwind-tables, and ms_abi functions doesn't work,
failing with the error:
sorry, unimplemented: ms_abi attribute requires
-maccumulate-outgoing-args or subtarget optimization implying it

This does appear to work with gcc 4.9 onwards.

Add -maccumulate-outgoing-args explicitly to unbreak the build with
pre-4.9 versions of gcc.

Reported-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200605150638.1011637-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Optimize for size instead of speed

Reclaim the bloat from the addition of printf by optimizing the stub for
size. With gcc 9, the text size of the stub is:

ARCH before +printf -Os
arm 35197 37889 34638
arm64 34883 38159 34479
i386 18571 21657 17025
x86_64 25677 29328 22144

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200518190716.751506-6-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Add a basic printf implementation

Copy vsprintf from arch/x86/boot/printf.c to get a simple printf
implementation.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200518190716.751506-5-nivedita@alum.mit.edu
[ardb: add some missing braces in if...else clauses]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Disable Shadow Call Stack

Shadow stacks are not available in the EFI stub, filter out SCS flags.

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

efi/libstub/x86: Work around LLVM ELF quirk build regression

When building the x86 EFI stub with Clang, the libstub Makefile rules
that manipulate the ELF object files may throw an error like:

STUBCPY drivers/firmware/efi/libstub/efi-stub-helper.stub.o
strip: drivers/firmware/efi/libstub/efi-stub-helper.stub.o: Failed to find link section for section 10
objcopy: drivers/firmware/efi/libstub/efi-stub-helper.stub.o: Failed to find link section for section 10

This is the result of a LLVM feature [0] where symbol references are
stored in a LLVM specific .llvm_addrsig section in a non-transparent way,
causing generic ELF tools such as strip or objcopy to choke on them.

So force the compiler not to emit these sections, by passing the
appropriate command line option.

[0] https://sourceware.org/bugzilla/show_bug.cgi?id=23817

Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/x86: Remove __efistub_global and add relocation check

Instead of using __efistub_global to force variables into the .data
section, leave them in the .bss but pull the EFI stub's .bss section
into .data in the linker script for the compressed kernel.

Add relocation checking for x86 as well to catch non-PC-relative
relocations that require runtime processing, since the EFI stub does not
do any runtime relocation processing.

This will catch, for example, data relocations created by static
initializers of pointers.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200416151227.3360778-3-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/arm: Remove __efistub_global annotation

Instead of using __efistub_global to force variables into the .data
section, leave them in the .bss but pull the EFI stub's .bss section
into .data in the linker script for the compressed kernel.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200416151227.3360778-2-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Move efi_relocate_kernel() into separate source file

Move efi_relocate_kernel() into a separate source file, so that it
only gets pulled into builds for architectures that use it. Since
efi_relocate_kernel() is the only user of efi_low_alloc(), let's
move that over as well.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Add API function to allocate aligned memory

Break out the code to create an aligned page allocation from mem.c
and move it into a function efi_allocate_pages_aligned() in alignedmem.c.
Update efi_allocate_pages() to invoke it unless the minimum alignment
equals the EFI page size (4 KB), in which case the ordinary page
allocator is sufficient. This way, efi_allocate_pages_aligned() will
only be pulled into the build if it is actually being used (which will
be on arm64 only in the immediate future)

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Move arm-stub to a common file

Most of the arm-stub code is written in an architecture independent manner.
As a result, RISC-V can reuse most of the arm-stub code.

Rename the arm-stub.c to efi-stub.c so that ARM, ARM64 and RISC-V can use it.
This patch doesn't introduce any functional changes.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Link: https://lore.kernel.org/r/20200415195422.19866-2-atish.patra@wdc.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

x86/*/Makefile: Use -fno-asynchronous-unwind-tables to suppress .eh_frame sections

While discussing a patch to discard .eh_frame from the compressed
vmlinux using the linker script, Fangrui Song pointed out [1] that these
sections shouldn't exist in the first place because arch/x86/Makefile
uses -fno-asynchronous-unwind-tables.

It turns out this is because the Makefiles used to build the compressed
kernel redefine KBUILD_CFLAGS, dropping this flag.

Add the flag to the Makefile for the compressed kernel, as well as the
EFI stub Makefile to fix this.

Also add the flag to boot/Makefile and realmode/rm/Makefile so that the
kernel's boot code (boot/setup.elf) and realmode trampoline
(realmode/rm/realmode.elf) won't be compiled with .eh_frame sections,
since their linker scripts also just discard them.

[1] https://lore.kernel.org/lkml/20200222185806.ywnqhfqmy67akfsa@google.com/

Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lkml.kernel.org/r/20200224232129.597160-2-nivedita@alum.mit.edu

efi/libstub: Clean up command line parsing routine

We currently parse the command non-destructively, to avoid having to
allocate memory for a copy before passing it to the standard parsing
routines that are used by the core kernel, and which modify the input
to delineate the parsed tokens with NUL characters.

Instead, we call strstr() and strncmp() to go over the input multiple
times, and match prefixes rather than tokens, which implies that we
would match, e.g., 'nokaslrfoo' in the stub and disable KASLR, while
the kernel would disregard the option and run with KASLR enabled.

In order to avoid having to reason about whether and how this behavior
may be abused, let's clean up the parsing routines, and rebuild them
on top of the existing helpers.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Move file I/O support code into separate file

Split off the file I/O support code into a separate source file so
it ends up in a separate object file in the static library, allowing
the linker to omit it if the routines are not used.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Move efi_random_alloc() into separate source file

efi_random_alloc() is only used on arm64, but as it shares a source
file with efi_random_get_seed(), the latter will pull in the former
on other architectures as well.

Let's take advantage of the fact that libstub is a static library,
and so the linker will only incorporate objects that are needed to
satisfy dependencies in other objects. This means we can move the
random alloc code to a separate source file that gets built
unconditionally, but only used when needed.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub/x86: Incorporate eboot.c into libstub

Most of the EFI stub source files of all architectures reside under
drivers/firmware/efi/libstub, where they share a Makefile with special
CFLAGS and an include file with declarations that are only relevant
for stub code.

Currently, we carry a lot of stub specific stuff in linux/efi.h only
because eboot.c in arch/x86 needs them as well. So let's move eboot.c
into libstub/, and move the contents of eboot.h that we still care
about into efistub.h

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Move memory map handling and allocation routines to mem.c

Create a new source file mem.c to keep the routines involved in memory
allocation and deallocation and manipulation of the EFI memory map.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub: Use hidden visibility for all source files

Instead of setting the visibility pragma for a small set of symbol
declarations that could result in absolute references that we cannot
support in the stub, declare hidden visibility for all code in the
EFI stub, which is more robust and future proof.

To ensure that the #pragma is taken into account before any other
includes are processed, put it in a header file of its own and
include it via the compiler command line using the -include option.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi/libstub/arm64: Use 1:1 mapping of RT services if property table exists

The UEFI spec defines (and deprecates) a misguided and shortlived
memory protection feature that is based on splitting memory regions
covering PE/COFF executables into separate code and data regions,
without annotating them as belonging to the same executable image.
When the OS assigns the virtual addresses of these regions, it may
move them around arbitrarily, without taking into account that the
PE/COFF code sections may contain relative references into the data
sections, which means the relative placement of these segments has
to be preserved or the executable image will be corrupted.

The original workaround on arm64 was to ensure that adjacent regions
of the same type were mapped adjacently in the virtual mapping, but
this requires sorting of the memory map, which we would prefer to
avoid.

Considering that the native physical mapping of the PE/COFF images
does not suffer from this issue, let's preserve it at runtime, and
install it as the virtual mapping as well.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi: Allow disabling PCI busmastering on bridges during boot

Add an option to disable the busmaster bit in the control register on
all PCI bridges before calling ExitBootServices() and passing control
to the runtime kernel. System firmware may configure the IOMMU to prevent
malicious PCI devices from being able to attack the OS via DMA. However,
since firmware can't guarantee that the OS is IOMMU-aware, it will tear
down IOMMU configuration when ExitBootServices() is called. This leaves
a window between where a hostile device could still cause damage before
Linux configures the IOMMU again.

If CONFIG_EFI_DISABLE_PCI_DMA is enabled or "efi=disable_early_pci_dma"
is passed on the command line, the EFI stub will clear the busmaster bit
on all PCI bridges before ExitBootServices() is called. This will
prevent any malicious PCI devices from being able to perform DMA until
the kernel reenables busmastering after configuring the IOMMU.

This option may cause failures with some poorly behaved hardware and
should not be enabled without testing. The kernel commandline options
"efi=disable_early_pci_dma" or "efi=no_disable_early_pci_dma" may be
used to override the default. Note that PCI devices downstream from PCI
bridges are disconnected from their drivers first, using the UEFI
driver model API, so that DMA can be disabled safely at the bridge
level.

[ardb: disconnect PCI I/O handles first, as suggested by Arvind]

Co-developed-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Matthew Garrett <matthewgarrett@google.com>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20200103113953.9571-18-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

build, kcsan: Add KCSAN build exceptions

This blacklists several compilation units from KCSAN. See the respective
inline comments for the reasoning.

Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

x86: efi/random: Invoke EFI_RNG_PROTOCOL to seed the UEFI RNG table

Invoke the EFI_RNG_PROTOCOL protocol in the context of the x86 EFI stub,
same as is done on arm/arm64 since commit 568bc4e87033 ("efi/arm*/libstub:
Invoke EFI_RNG_PROTOCOL to seed the UEFI RNG table"). Within the stub,
a Linux-specific RNG seed UEFI config table will be seeded. The EFI routines
in the core kernel will pick that up later, yet still early during boot,
to seed the kernel entropy pool. If CONFIG_RANDOM_TRUST_BOOTLOADER, entropy
is credited for this seed.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

efi: libstub/arm: Account for firmware reserved memory at the base of RAM

The EFI stubloader for ARM starts out by allocating a 32 MB window
at the base of RAM, in order to ensure that the decompressor (which
blindly copies the uncompressed kernel into that window) does not
overwrite other allocations that are made while running in the context
of the EFI firmware.

In some cases, (e.g., U-Boot running on the Raspberry Pi 2), this is
causing boot failures because this initial allocation conflicts with
a page of reserved memory at the base of RAM that contains the SMP spin
tables and other pieces of firmware data and which was put there by
the bootloader under the assumption that the TEXT_OFFSET window right
below the kernel is only used partially during early boot, and will be
left alone once the memory reservations are processed and taken into
account.

So let's permit reserved memory regions to exist in the region starting
at the base of RAM, and ending at TEXT_OFFSET - 5 * PAGE_SIZE, which is
the window below the kernel that is not touched by the early boot code.

Tested-by: Guillaume Gardet <Guillaume.Gardet@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Chester Lin <clin@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191029173755.27149-5-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi/arm/arm64: Makefile: Replace -pg with CC_FLAGS_FTRACE

In preparation for arm64 supporting ftrace built on other compiler
options, let's have Makefiles remove the $(CC_FLAGS_FTRACE) flags,
whatever these maybe, rather than assuming '-pg'.

While at it, fix arm32 as well. There should be no functional change as
a result of this patch.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>

efi/libstub/arm: Omit unneeded stripping of ksymtab/kcrctab sections

Commit f922c4abdf764 ("module: allow symbol exports to be disabled")
introduced a way to inhibit generation of kcrctab/ksymtab sections
when building ordinary kernel code to be used in a different execution
context (decompressor, EFI stub, etc)

That means we no longer have to strip those sections explicitly when
building the EFI libstub objects, so drop this from the Makefile.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20190328193429.21373-6-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi/libstub: Refactor the cmd_stubcopy Makefile command

It took me a while to understand what is going on in the nested
if-blocks.

Simplify it by removing unneeded code.

- if_changed automatically adds 'set -e', so any failure in the
series of commands makes it immediately fail as a whole.
So, the outer if block is entirely redundant.

- Since commit 9c2af1c7377a ("kbuild: add .DELETE_ON_ERROR special target"),
GNU Make automatically deletes the target on any failure
in its recipe. The explicit 'rm -f $@' is redundant.

- Surrounding commands with ( ) will spawn a subshell to execute them
in it, but it is rarely useful to do so.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20190328193429.21373-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi/fdt: Apply more cleanups

Apply a number of cleanups:

- Introduce fdt_setprop_*var() helper macros to simplify and shorten repetitive
sequences - this also makes it less likely that the wrong variable size is
passed in. This change makes a lot of the property-setting calls single-line
and easier to read.

- Harmonize comment style: capitalization, punctuation, whitespaces, etc.

- Fix some whitespace noise in the libstub Makefile which I happened to notice.

- Use the standard tabular initialization style:

- map.map = &runtime_map;
- map.map_size = &map_size;
- map.desc_size = &desc_size;
- map.desc_ver = &desc_ver;
- map.key_ptr = &mmap_key;
- map.buff_size = &buff_size;

+ map.map = &runtime_map;
+ map.map_size = &map_size;
+ map.desc_size = &desc_size;
+ map.desc_ver = &desc_ver;
+ map.key_ptr = &mmap_key;
+ map.buff_size = &buff_size;

- Use tabular structure definition for better readability.

- Make all pr*() lines single-line, even if they marginally exceed 80 cols - this
makes them visually less intrusive.

- Unbreak line breaks into single lines when the length exceeds 80 cols only
marginally, for better readability.

- Move assignment closer to the actual usage site.

- Plus some other smaller cleanups, spelling fixes, etc.

No change in functionality intended.

[ ardb: move changes to upstream libfdt into local header. ]

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Alexander Graf <agraf@suse.de>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20190202094119.13230-6-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi/libstub: Disable some warnings for x86{,_64}

When building the kernel with Clang, some disabled warnings appear
because this Makefile overrides KBUILD_CFLAGS for x86{,_64}. Add them to
this list so that the build is clean again.

-Wpointer-sign was disabled for the whole kernel before the beginning of Git history.

-Waddress-of-packed-member was disabled for the whole kernel and for
the early boot code in these commits:

bfb38988c51e ("kbuild: clang: Disable 'address-of-packed-member' warning")
20c6c1890455 ("x86/boot: Disable the address-of-packed-member compiler warning").

-Wgnu was disabled for the whole kernel and for the early boot code in
these commits:

61163efae020 ("kbuild: LLVMLinux: Add Kbuild support for building kernel with Clang")
6c3b56b19730 ("x86/boot: Disable Clang warnings about GNU extensions").

[ mingo: Made the changelog more readable. ]

Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arend van Spriel <arend.vanspriel@broadcom.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eric Snowberg <eric.snowberg@oracle.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jon Hunter <jonathanh@nvidia.com>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20181129171230.18699-8-ard.biesheuvel@linaro.org
Link: https://github.com/ClangBuiltLinux/linux/issues/112
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi/libstub: arm: support building with clang

When building with CONFIG_EFI and CONFIG_EFI_STUB on ARM, the libstub
Makefile would use -mno-single-pic-base without checking it was
supported by the compiler. As the ARM (32-bit) clang backend does not
support this flag, the build would fail.

This changes the Makefile to check the compiler's support for
-mno-single-pic-base before using it, similar to c1c386681bd7 ("ARM:
8767/1: add support for building ARM kernel with clang").

Signed-off-by: Alistair Strachan <astrachan@google.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

module: allow symbol exports to be disabled

To allow existing C code to be incorporated into the decompressor or the
UEFI stub, introduce a CPP macro that turns all EXPORT_SYMBOL_xxx
declarations into nops, and #define it in places where such exports are
undesirable. Note that this gets rid of a rather dodgy redefine of
linux/export.h's header guard.

Link: http://lkml.kernel.org/r/20180704083651.24360-3-ard.biesheuvel@linaro.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morris <james.morris@microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

efi/libstub: Only disable stackleak plugin for arm64

arm64 uses the full KBUILD_CFLAGS for building libstub as opposed
to x86 which doesn't. This means that x86 doesn't pick up
the gcc-plugins. We need to disable the stackleak plugin but
doing this unconditionally breaks x86 build since it doesn't
have any plugins. Switch to disabling the stackleak plugin for
arm64 only.

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm64: Add support for STACKLEAK gcc plugin

This adds support for the STACKLEAK gcc plugin to arm64 by implementing
stackleak_check_alloca(), based heavily on the x86 version, and adding the
two helpers used by the stackleak common code: current_top_of_stack() and
on_thread_stack(). The stack erasure calls are made at syscall returns.
Additionally, this disables the plugin in hypervisor and EFI stub code,
which are out of scope for the protection.

Acked-by: Alexander Popov <alex.popov@linux.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

efi: Use string literals for efi_char16_t variable initializers

Now that we unambiguously build the entire kernel with -fshort-wchar,
it is no longer necessary to open code efi_char16_t[] initializers as
arrays of characters, and we can move to the L"xxx" notation instead.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180312084500.10764-6-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi: call get_event_log before ExitBootServices

With TPM 2.0 specification, the event logs may only be accessible by
calling an EFI Boot Service. Modify the EFI stub to copy the log area to
a new Linux-specific EFI configuration table so it remains accessible
once booted.

When calling this service, it is possible to specify the expected format
of the logs: TPM 1.2 (SHA1) or TPM 2.0 ("Crypto Agile"). For now, only the
first format is retrieved.

Signed-off-by: Thiebaud Weksteen <tweek@google.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

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>

efi/libstub: arm: omit sorting of the UEFI memory map

ARM shares its EFI stub implementation with arm64, which has some
special handling in the virtual remapping code to
a) make sure that we can map everything even if the OS executes
with 64k page size, and
b) make sure that adjacent regions with the same attributes are not
reordered or moved apart in memory.

The latter is a workaround for a 'feature' that was shortly recommended
by UEFI spec v2.5, but deprecated shortly after, due to the fact that
it broke many OS installers, including non-Linux ones, and it was never
widely implemented for ARM systems. Before implementing b), the arm64
code simply rounded up all regions to 64 KB granularity, but given that
that results in moving adjacent regions apart, it had to be refined when
b) was implemented.

The adjacency check requires a sort() pass, due to the fact that the
UEFI spec does not mandate any ordering, and the inclusion of the
lib/sort.c code into the ARM EFI stub is causing some trouble with
the decompressor build due to the fact that its EXPORT_SYMBOL() call
triggers the creation of ksymtab/kcrctab sections.

So let's simply do away with the adjacency check for ARM, and simply put
all UEFI runtime regions together if they have the same memory attributes.
This is guaranteed to work, given that ARM only supports 4 KB pages,
and allows us to remove the sort() call entirely.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Tested-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

efi/libstub: Enable reset attack mitigation

If a machine is reset while secrets are present in RAM, it may be
possible for code executed after the reboot to extract those secrets
from untouched memory. The Trusted Computing Group specified a mechanism
for requesting that the firmware clear all RAM on reset before booting
another OS. This is done by setting the MemoryOverwriteRequestControl
variable at startup. If userspace can ensure that all secrets are
removed as part of a controlled shutdown, it can reset this variable to
0 before triggering a hardware reboot.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170825155019.6740-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi/libstub/arm64: Set -fpie when building the EFI stub

Clang may emit absolute symbol references when building in non-PIC mode,
even when using the default 'small' code model, which is already mostly
position independent to begin with, due to its use of adrp/add pairs
that have a relative range of +/- 4 GB. The remedy is to pass the -fpie
flag, which can be done safely now that the code has been updated to avoid
GOT indirections (which may be emitted due to the compiler assuming that
the PIC/PIE code may end up in a shared library that is subject to ELF
symbol preemption)

Passing -fpie when building code that needs to execute at an a priori
unknown offset is arguably an improvement in any case, and given that
the recent visibility changes allow the PIC build to pass with GCC as
well, let's add -fpie for all arm64 builds rather than only for Clang.

Tested-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170818194947.19347-5-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi: avoid fortify checks in EFI stub

This avoids CONFIG_FORTIFY_SOURCE from being enabled during the EFI stub
build, as adding a panic() implementation may not work well. This can
be adjusted in the future.

Link: http://lkml.kernel.org/r/1497903987-21002-2-git-send-email-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Suggested-by: Daniel Micay <danielmicay@gmail.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

efi: Get and store the secure boot status

Get the firmware's secure-boot status in the kernel boot wrapper and stash
it somewhere that the main kernel image can find.

The efi_get_secureboot() function is extracted from the ARM stub and (a)
generalised so that it can be called from x86 and (b) made to use
efi_call_runtime() so that it can be run in mixed-mode.

For x86, it is stored in boot_params and can be overridden by the boot
loader or kexec. This allows secure-boot mode to be passed on to a new
kernel.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1486380166-31868-5-git-send-email-ard.biesheuvel@linaro.org
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi/libstub: Preserve .debug sections after absolute relocation check

The build commands for the ARM and arm64 EFI stubs strip the .debug
sections and other sections that may legally contain absolute relocations,
in order to inspect the remaining sections for the presence of such
relocations.

This leaves us without debugging symbols in the stub for no good reason,
considering that these sections are omitted from the kernel binary anyway,
and that these relocations are thus only consumed by users of the ELF
binary, such as debuggers.

So move to 'strip' for performing the relocation check, and if it succeeds,
invoke objcopy as before, but leaving the .debug sections in place. Note
that these sections may refer to ksymtab/kcrctab contents, so leave those
in place as well.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1485868902-20401-11-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Remove references to dead make variable LINUX_INCLUDE

Commit 4fd06960f120 ("Use the new x86 setup code for i386") introduced a
reference to the make variable LINUX_INCLUDE. That reference got moved
around a bit and copied twice and now there are three references to it.

There has never been a definition of that variable. (Presumably that is
because it started out as a mistyped reference to LINUXINCLUDE.) So this
reference has always been an empty string. Let's remove it before it
spreads any further.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

efi/libstub: Add random.c to ARM build

Make random.c build for ARM by moving the fallback definition of
EFI_ALLOC_ALIGN to efistub.h, and replacing a division by a value
we know to be a power of 2 with a right shift (this is required since
ARM does not have any integer division helper routines in its decompressor)

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20161112213237.8804-5-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi/arm: Fix absolute relocation detection for older toolchains

When building the ARM kernel with CONFIG_EFI=y, the following build
error may occur when using a less recent version of binutils (2.23 or
older):

STUBCPY drivers/firmware/efi/libstub/lib-sort.stub.o
00000000 R_ARM_ABS32 sort
00000004 R_ARM_ABS32 __ksymtab_strings
drivers/firmware/efi/libstub/lib-sort.stub.o: absolute symbol references not allowed in the EFI stub

(and when building with debug symbols, the list above is much longer, and
contains all the internal references between the .debug sections and the
actual code)

This issue is caused by the fact that objcopy v2.23 or earlier does not
support wildcards in its -R and -j options, which means the following
line from the Makefile:

STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab* -R *kcrctab*

fails to take effect, leaving harmless absolute relocations in the binary
that are indistinguishable from relocations that may cause crashes at
runtime due to the fact that these relocations are resolved at link time
using the virtual address of the kernel, which is always different from
the address at which the EFI firmware loads and invokes the stub.

So, as a workaround, disable debug symbols explicitly when building the
stub for ARM, and strip the ksymtab and kcrctab symbols for the only
exported symbol we currently reuse in the stub, which is 'sort'.

Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1476805991-7160-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi/libstub: Move Graphics Output Protocol handling to generic code

The Graphics Output Protocol code executes in the stub, so create a generic
version based on the x86 version in libstub so that we can move other archs
to it in subsequent patches. The new source file gop.c is added to the
libstub build for all architectures, but only wired up for x86.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-18-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel: add kcov code coverage

kcov provides code coverage collection for coverage-guided fuzzing
(randomized testing). Coverage-guided fuzzing is a testing technique
that uses coverage feedback to determine new interesting inputs to a
system. A notable user-space example is AFL
(http://lcamtuf.coredump.cx/afl/). However, this technique is not
widely used for kernel testing due to missing compiler and kernel
support.

kcov does not aim to collect as much coverage as possible. It aims to
collect more or less stable coverage that is function of syscall inputs.
To achieve this goal it does not collect coverage in soft/hard
interrupts and instrumentation of some inherently non-deterministic or
non-interesting parts of kernel is disbled (e.g. scheduler, locking).

Currently there is a single coverage collection mode (tracing), but the
API anticipates additional collection modes. Initially I also
implemented a second mode which exposes coverage in a fixed-size hash
table of counters (what Quentin used in his original patch). I've
dropped the second mode for simplicity.

This patch adds the necessary support on kernel side. The complimentary
compiler support was added in gcc revision 231296.

We've used this support to build syzkaller system call fuzzer, which has
found 90 kernel bugs in just 2 months:

https://github.com/google/syzkaller/wiki/Found-Bugs

We've also found 30+ bugs in our internal systems with syzkaller.
Another (yet unexplored) direction where kcov coverage would greatly
help is more traditional "blob mutation". For example, mounting a
random blob as a filesystem, or receiving a random blob over wire.

Why not gcov. Typical fuzzing loop looks as follows: (1) reset
coverage, (2) execute a bit of code, (3) collect coverage, repeat. A
typical coverage can be just a dozen of basic blocks (e.g. an invalid
input). In such context gcov becomes prohibitively expensive as
reset/collect coverage steps depend on total number of basic
blocks/edges in program (in case of kernel it is about 2M). Cost of
kcov depends only on number of executed basic blocks/edges. On top of
that, kernel requires per-thread coverage because there are always
background threads and unrelated processes that also produce coverage.
With inlined gcov instrumentation per-thread coverage is not possible.

kcov exposes kernel PCs and control flow to user-space which is
insecure. But debugfs should not be mapped as user accessible.

Based on a patch by Quentin Casasnovas.

[akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
[akpm@linux-foundation.org: unbreak allmodconfig]
[akpm@linux-foundation.org: follow x86 Makefile layout standards]
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: David Drysdale <drysdale@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

objtool: Mark non-standard object files and directories

Code which runs outside the kernel's normal mode of operation often does
unusual things which can cause a static analysis tool like objtool to
emit false positive warnings:

- boot image
- vdso image
- relocation
- realmode
- efi
- head
- purgatory
- modpost

Set OBJECT_FILES_NON_STANDARD for their related files and directories,
which will tell objtool to skip checking them. It's ok to skip them
because they don't affect runtime stack traces.

Also skip the following code which does the right thing with respect to
frame pointers, but is too "special" to be validated by a tool:

- entry
- mcount

Also skip the test_nx module because it modifies its exception handling
table at runtime, which objtool can't understand. Fortunately it's
just a test module so it doesn't matter much.

Currently objtool is the only user of OBJECT_FILES_NON_STANDARD, but it
might eventually be useful for other tools.

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/366c080e3844e8a5b6a0327dc7e8c2b90ca3baeb.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

efi: stub: implement efi_get_random_bytes() based on EFI_RNG_PROTOCOL

This exposes the firmware's implementation of EFI_RNG_PROTOCOL via a new
function efi_get_random_bytes().

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

UBSAN: run-time undefined behavior sanity checker

UBSAN uses compile-time instrumentation to catch undefined behavior
(UB). Compiler inserts code that perform certain kinds of checks before
operations that could cause UB. If check fails (i.e. UB detected)
__ubsan_handle_* function called to print error message.

So the most of the work is done by compiler. This patch just implements
ubsan handlers printing errors.

GCC has this capability since 4.9.x [1] (see -fsanitize=undefined
option and its suboptions).
However GCC 5.x has more checkers implemented [2].
Article [3] has a bit more details about UBSAN in the GCC.

[1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
[2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
[3] - http://developerblog.redhat.com/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan/

Issues which UBSAN has found thus far are:

Found bugs:

* out-of-bounds access - 97840cb67ff5 ("netfilter: nfnetlink: fix
insufficient validation in nfnetlink_bind")

undefined shifts:

* d48458d4a768 ("jbd2: use a better hash function for the revoke
table")

* 10632008b9e1 ("clockevents: Prevent shift out of bounds")

* 'x << -1' shift in ext4 -
http://lkml.kernel.org/r/<5444EF21.8020501@samsung.com>

* undefined rol32(0) -
http://lkml.kernel.org/r/<1449198241-20654-1-git-send-email-sasha.levin@oracle.com>

* undefined dirty_ratelimit calculation -
http://lkml.kernel.org/r/<566594E2.3050306@odin.com>

* undefined roundown_pow_of_two(0) -
http://lkml.kernel.org/r/<1449156616-11474-1-git-send-email-sasha.levin@oracle.com>

* [WONTFIX] undefined shift in __bpf_prog_run -
http://lkml.kernel.org/r/<CACT4Y+ZxoR3UjLgcNdUm4fECLMx2VdtfrENMtRRCdgHB2n0bJA@mail.gmail.com>

WONTFIX here because it should be fixed in bpf program, not in kernel.

signed overflows:

* 32a8df4e0b33f ("sched: Fix odd values in effective_load()
calculations")

* mul overflow in ntp -
http://lkml.kernel.org/r/<1449175608-1146-1-git-send-email-sasha.levin@oracle.com>

* incorrect conversion into rtc_time in rtc_time64_to_tm() -
http://lkml.kernel.org/r/<1449187944-11730-1-git-send-email-sasha.levin@oracle.com>

* unvalidated timespec in io_getevents() -
http://lkml.kernel.org/r/<CACT4Y+bBxVYLQ6LtOKrKtnLthqLHcw-BMp3aqP3mjdAvr9FULQ@mail.gmail.com>

* [NOTABUG] signed overflow in ktime_add_safe() -
http://lkml.kernel.org/r/<CACT4Y+aJ4muRnWxsUe1CMnA6P8nooO33kwG-c8YZg=0Xc8rJqw@mail.gmail.com>

[akpm@linux-foundation.org: fix unused local warning]
[akpm@linux-foundation.org: fix __int128 build woes]
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yury Gribov <y.gribov@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

efi: stub: define DISABLE_BRANCH_PROFILING for all architectures

This moves the DISABLE_BRANCH_PROFILING define from the x86 specific
to the general CFLAGS definition for the stub. This fixes build errors
when building for arm64 with CONFIG_PROFILE_ALL_BRANCHES_ENABLED.

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

ARM: add UEFI stub support

This patch adds EFI stub support for the ARM Linux kernel.

The EFI stub operates similarly to the x86 and arm64 stubs: it is a
shim between the EFI firmware and the normal zImage entry point, and
sets up the environment that the zImage is expecting. This includes
optionally loading the initrd and device tree from the system partition
based on the kernel command line.

Signed-off-by: Roy Franz <roy.franz@linaro.org>
Tested-by: Ryan Harkin <ryan.harkin@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

arm64/efi: fix libstub build under CONFIG_MODVERSIONS

Now that we strictly forbid absolute relocations in libstub code,
make sure that we don't emit any when CONFIG_MODVERSIONS is enabled,
by stripping the kcrctab sections from the object file. This fixes
a build problem under CONFIG_MODVERSIONS=y.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64/efi: move arm64 specific stub C code to libstub

Now that we added special handling to the C files in libstub, move
the one remaining arm64 specific EFI stub C file to libstub as
well, so that it gets the same treatment. This should prevent future
changes from resulting in binaries that may execute incorrectly in
UEFI context.

With efi-entry.S the only remaining EFI stub source file under
arch/arm64, we can also simplify the Makefile logic somewhat.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64/efi: isolate EFI stub from the kernel proper

Since arm64 does not use a builtin decompressor, the EFI stub is built
into the kernel proper. So far, this has been working fine, but actually,
since the stub is in fact a PE/COFF relocatable binary that is executed
at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
should not be seamlessly sharing code with the kernel proper, which is a
position dependent executable linked at a high virtual offset.

So instead, separate the contents of libstub and its dependencies, by
putting them into their own namespace by prefixing all of its symbols
with __efistub. This way, we have tight control over what parts of the
kernel proper are referenced by the stub.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

of: clean-up unnecessary libfdt include paths

With the libfdt include fixups to use "" instead of <> in the
latest dtc import in commit 4760597 (scripts/dtc: Update to upstream
version 9d3649bd3be245c9), it is no longer necessary to add explicit
include paths to use libfdt. Remove these across the kernel.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Grant Likely <grant.likely@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linuxppc-dev@lists.ozlabs.org

kasan: add kernel address sanitizer infrastructure

Kernel Address sanitizer (KASan) is a dynamic memory error detector. It
provides fast and comprehensive solution for finding use-after-free and
out-of-bounds bugs.

KASAN uses compile-time instrumentation for checking every memory access,
therefore GCC > v4.9.2 required. v4.9.2 almost works, but has issues with
putting symbol aliases into the wrong section, which breaks kasan
instrumentation of globals.

This patch only adds infrastructure for kernel address sanitizer. It's
not available for use yet. The idea and some code was borrowed from [1].

Basic idea:

The main idea of KASAN is to use shadow memory to record whether each byte
of memory is safe to access or not, and use compiler's instrumentation to
check the shadow memory on each memory access.

Address sanitizer uses 1/8 of the memory addressable in kernel for shadow
memory and uses direct mapping with a scale and offset to translate a
memory address to its corresponding shadow address.

Here is function to translate address to corresponding shadow address:

unsigned long kasan_mem_to_shadow(unsigned long addr)
{
return (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET;
}

where KASAN_SHADOW_SCALE_SHIFT = 3.

So for every 8 bytes there is one corresponding byte of shadow memory.
The following encoding used for each shadow byte: 0 means that all 8 bytes
of the corresponding memory region are valid for access; k (1 <= k <= 7)
means that the first k bytes are valid for access, and other (8 - k) bytes
are not; Any negative value indicates that the entire 8-bytes are
inaccessible. Different negative values used to distinguish between
different kinds of inaccessible memory (redzones, freed memory) (see
mm/kasan/kasan.h).

To be able to detect accesses to bad memory we need a special compiler.
Such compiler inserts a specific function calls (__asan_load*(addr),
__asan_store*(addr)) before each memory access of size 1, 2, 4, 8 or 16.

These functions check whether memory region is valid to access or not by
checking corresponding shadow memory. If access is not valid an error
printed.

Historical background of the address sanitizer from Dmitry Vyukov:

"We've developed the set of tools, AddressSanitizer (Asan),
ThreadSanitizer and MemorySanitizer, for user space. We actively use
them for testing inside of Google (continuous testing, fuzzing,
running prod services). To date the tools have found more than 10'000
scary bugs in Chromium, Google internal codebase and various
open-source projects (Firefox, OpenSSL, gcc, clang, ffmpeg, MySQL and
lots of others): [2] [3] [4].
The tools are part of both gcc and clang compilers.

We have not yet done massive testing under the Kernel AddressSanitizer
(it's kind of chicken and egg problem, you need it to be upstream to
start applying it extensively). To date it has found about 50 bugs.
Bugs that we've found in upstream kernel are listed in [5].
We've also found ~20 bugs in out internal version of the kernel. Also
people from Samsung and Oracle have found some.

[...]

As others noted, the main feature of AddressSanitizer is its
performance due to inline compiler instrumentation and simple linear
shadow memory. User-space Asan has ~2x slowdown on computational
programs and ~2x memory consumption increase. Taking into account that
kernel usually consumes only small fraction of CPU and memory when
running real user-space programs, I would expect that kernel Asan will
have ~10-30% slowdown and similar memory consumption increase (when we
finish all tuning).

I agree that Asan can well replace kmemcheck. We have plans to start
working on Kernel MemorySanitizer that finds uses of unitialized
memory. Asan+Msan will provide feature-parity with kmemcheck. As
others noted, Asan will unlikely replace debug slab and pagealloc that
can be enabled at runtime. Asan uses compiler instrumentation, so even
if it is disabled, it still incurs visible overheads.

Asan technology is easily portable to other architectures. Compiler
instrumentation is fully portable. Runtime has some arch-dependent
parts like shadow mapping and atomic operation interception. They are
relatively easy to port."

Comparison with other debugging features:
========================================

KMEMCHECK:

- KASan can do almost everything that kmemcheck can. KASan uses
compile-time instrumentation, which makes it significantly faster than
kmemcheck. The only advantage of kmemcheck over KASan is detection of
uninitialized memory reads.

Some brief performance testing showed that kasan could be
x500-x600 times faster than kmemcheck:

$ netperf -l 30
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost (127.0.0.1) port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec

no debug: 87380 16384 16384 30.00 41624.72

kasan inline: 87380 16384 16384 30.00 12870.54

kasan outline: 87380 16384 16384 30.00 10586.39

kmemcheck: 87380 16384 16384 30.03 20.23

- Also kmemcheck couldn't work on several CPUs. It always sets
number of CPUs to 1. KASan doesn't have such limitation.

DEBUG_PAGEALLOC:
- KASan is slower than DEBUG_PAGEALLOC, but KASan works on sub-page
granularity level, so it able to find more bugs.

SLUB_DEBUG (poisoning, redzones):
- SLUB_DEBUG has lower overhead than KASan.

- SLUB_DEBUG in most cases are not able to detect bad reads,
KASan able to detect both reads and writes.

- In some cases (e.g. redzone overwritten) SLUB_DEBUG detect
bugs only on allocation/freeing of object. KASan catch
bugs right before it will happen, so we always know exact
place of first bad read/write.

[1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel
[2] https://code.google.com/p/address-sanitizer/wiki/FoundBugs
[3] https://code.google.com/p/thread-sanitizer/wiki/FoundBugs
[4] https://code.google.com/p/memory-sanitizer/wiki/FoundBugs
[5] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel#Trophies

Based on work by Andrey Konovalov.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arm64/efi: efistub: Apply __init annotation

This ensures all stub component are freed when the kernel proper is
done booting, by prefixing the names of all ELF sections that have
the SHF_ALLOC attribute with ".init". This approach ensures that even
implicitly emitted allocated data (like initializer values and string
literals) are covered.

At the same time, remove some __init annotations in the stub that have
now become redundant, and add the __init annotation to handle_kernel_image
which will now trigger a section mismatch warning without it.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

efi: efistub: Convert into static library

This patch changes both x86 and arm64 efistub implementations
from #including shared .c files under drivers/firmware/efi to
building shared code as a static library.

The x86 code uses a stub built into the boot executable which
uncompresses the kernel at boot time. In this case, the library is
linked into the decompressor.

In the arm64 case, the stub is part of the kernel proper so the library
is linked into the kernel proper as well.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>