diff options
Diffstat (limited to 'arch/x86/include/asm/string_64.h')
| -rw-r--r-- | arch/x86/include/asm/string_64.h | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h index 90dbbd9666d4..a164862d77e3 100644 --- a/arch/x86/include/asm/string_64.h +++ b/arch/x86/include/asm/string_64.h @@ -2,6 +2,7 @@ #define _ASM_X86_STRING_64_H #ifdef __KERNEL__ +#include <linux/jump_label.h> /* Written 2002 by Andi Kleen */ @@ -78,6 +79,9 @@ 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); + /** * memcpy_mcsafe - copy memory with indication if a machine check happened * @@ -86,10 +90,23 @@ int strcmp(const char *cs, const char *ct); * @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__ */ |