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| author | Tony Luck <tony.luck@intel.com> | 2016-09-01 11:39:33 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-09-05 11:47:31 +0200 |
| commit | 9a6fb28a355d2609ace4dab4e6425442c647894d (patch) | |
| tree | 7c66135ce9e31daa18d5486e17c2f44ab3cfefd5 /arch/x86/include/asm/string_64.h | |
| parent | 3637efb00864f465baebd49464e58319fd295b65 (diff) | |
| download | linux-0-day-9a6fb28a355d2609ace4dab4e6425442c647894d.tar.gz linux-0-day-9a6fb28a355d2609ace4dab4e6425442c647894d.tar.xz | |
x86/mce: Improve memcpy_mcsafe()
Use the mcsafe_key defined in the previous patch to make decisions on which
copy function to use. We can't use the FEATURE bit any more because PCI
quirks run too late to affect the patching of code. So we use a static key.
Turn memcpy_mcsafe() into an inline function to make life easier for
callers. The assembly code that actually does the copy is now named
memcpy_mcsafe_unrolled()
Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Boris Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/bfde2fc774e94f53d91b70a4321c85a0d33e7118.1472754712.git.tony.luck@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/include/asm/string_64.h')
| -rw-r--r-- | arch/x86/include/asm/string_64.h | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h index 877a1dfbf7707..a164862d77e3b 100644 --- a/arch/x86/include/asm/string_64.h +++ b/arch/x86/include/asm/string_64.h @@ -79,6 +79,7 @@ int strcmp(const char *cs, const char *ct); #define memset(s, c, n) __memset(s, c, n) #endif +__must_check int memcpy_mcsafe_unrolled(void *dst, const void *src, size_t cnt); DECLARE_STATIC_KEY_FALSE(mcsafe_key); /** @@ -89,10 +90,23 @@ DECLARE_STATIC_KEY_FALSE(mcsafe_key); * @cnt: number of bytes to copy * * Low level memory copy function that catches machine checks + * We only call into the "safe" function on systems that can + * actually do machine check recovery. Everyone else can just + * use memcpy(). * * Return 0 for success, -EFAULT for fail */ -int memcpy_mcsafe(void *dst, const void *src, size_t cnt); +static __always_inline __must_check int +memcpy_mcsafe(void *dst, const void *src, size_t cnt) +{ +#ifdef CONFIG_X86_MCE + if (static_branch_unlikely(&mcsafe_key)) + return memcpy_mcsafe_unrolled(dst, src, cnt); + else +#endif + memcpy(dst, src, cnt); + return 0; +} #endif /* __KERNEL__ */ |