diff options
| author | Nathan Chancellor <[email protected]> | 2022-03-09 12:16:34 -0700 |
|---|---|---|
| committer | Catalin Marinas <[email protected]> | 2022-03-09 21:56:50 +0000 |
| commit | 52c9f93a9c482251cb0d224faa602ba26d462be8 (patch) | |
| tree | a1bf7457ca27f1593fbaf68b3b7caa9b63fc619c | |
| parent | 58c9a5060cb7cd529d49c93954cdafe81c1d642a (diff) | |
arm64: Do not include __READ_ONCE() block in assembly files
When building arm64 defconfig + CONFIG_LTO_CLANG_{FULL,THIN}=y after
commit 558c303c9734 ("arm64: Mitigate spectre style branch history side
channels"), the following error occurs:
<instantiation>:4:2: error: invalid fixup for movz/movk instruction
mov w0, #ARM_SMCCC_ARCH_WORKAROUND_3
^
Marc figured out that moving "#include <linux/init.h>" in
include/linux/arm-smccc.h into a !__ASSEMBLY__ block resolves it. The
full include chain with CONFIG_LTO=y from include/linux/arm-smccc.h:
include/linux/init.h
include/linux/compiler.h
arch/arm64/include/asm/rwonce.h
arch/arm64/include/asm/alternative-macros.h
arch/arm64/include/asm/assembler.h
The asm/alternative-macros.h include in asm/rwonce.h only happens when
CONFIG_LTO is set, which ultimately casues asm/assembler.h to be
included before the definition of ARM_SMCCC_ARCH_WORKAROUND_3. As a
result, the preprocessor does not expand ARM_SMCCC_ARCH_WORKAROUND_3 in
__mitigate_spectre_bhb_fw, which results in the error above.
Avoid this problem by just avoiding the CONFIG_LTO=y __READ_ONCE() block
in asm/rwonce.h with assembly files, as nothing in that block is useful
to assembly files, which allows ARM_SMCCC_ARCH_WORKAROUND_3 to be
properly expanded with CONFIG_LTO=y builds.
Fixes: e35123d83ee3 ("arm64: lto: Strengthen READ_ONCE() to acquire when CONFIG_LTO=y")
Cc: <[email protected]> # 5.11.x
Link: https://lore.kernel.org/r/[email protected]/
Reported-by: Marc Zyngier <[email protected]>
Acked-by: James Morse <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>
| -rw-r--r-- | arch/arm64/include/asm/rwonce.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/rwonce.h b/arch/arm64/include/asm/rwonce.h index 1bce62fa908a..56f7b1d4d54b 100644 --- a/arch/arm64/include/asm/rwonce.h +++ b/arch/arm64/include/asm/rwonce.h @@ -5,7 +5,7 @@ #ifndef __ASM_RWONCE_H #define __ASM_RWONCE_H -#ifdef CONFIG_LTO +#if defined(CONFIG_LTO) && !defined(__ASSEMBLY__) #include <linux/compiler_types.h> #include <asm/alternative-macros.h> @@ -66,7 +66,7 @@ }) #endif /* !BUILD_VDSO */ -#endif /* CONFIG_LTO */ +#endif /* CONFIG_LTO && !__ASSEMBLY__ */ #include <asm-generic/rwonce.h> |