diff options
Diffstat (limited to 'arch/x86/include/asm/uaccess_64.h')
| -rw-r--r-- | arch/x86/include/asm/uaccess_64.h | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h index 8e796fbbf9c6..d8def8b3dba0 100644 --- a/arch/x86/include/asm/uaccess_64.h +++ b/arch/x86/include/asm/uaccess_64.h @@ -17,6 +17,8 @@ /* Handles exceptions in both to and from, but doesn't do access_ok */ __must_check unsigned long +copy_user_enhanced_fast_string(void *to, const void *from, unsigned len); +__must_check unsigned long copy_user_generic_string(void *to, const void *from, unsigned len); __must_check unsigned long copy_user_generic_unrolled(void *to, const void *from, unsigned len); @@ -26,9 +28,16 @@ copy_user_generic(void *to, const void *from, unsigned len) { unsigned ret; - alternative_call(copy_user_generic_unrolled, + /* + * If CPU has ERMS feature, use copy_user_enhanced_fast_string. + * Otherwise, if CPU has rep_good feature, use copy_user_generic_string. + * Otherwise, use copy_user_generic_unrolled. + */ + alternative_call_2(copy_user_generic_unrolled, copy_user_generic_string, X86_FEATURE_REP_GOOD, + copy_user_enhanced_fast_string, + X86_FEATURE_ERMS, ASM_OUTPUT2("=a" (ret), "=D" (to), "=S" (from), "=d" (len)), "1" (to), "2" (from), "3" (len) |