diff options
Diffstat (limited to 'arch/x86/lib/memmove_64.S')
| -rw-r--r-- | arch/x86/lib/memmove_64.S | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/arch/x86/lib/memmove_64.S b/arch/x86/lib/memmove_64.S index 0ecb8433e5a..d0ec9c2936d 100644 --- a/arch/x86/lib/memmove_64.S +++ b/arch/x86/lib/memmove_64.S @@ -8,6 +8,7 @@ #define _STRING_C #include <linux/linkage.h> #include <asm/dwarf2.h> +#include <asm/cpufeature.h> #undef memmove @@ -24,6 +25,7 @@ */ ENTRY(memmove) CFI_STARTPROC + /* Handle more 32bytes in loop */ mov %rdi, %rax cmp $0x20, %rdx @@ -31,8 +33,13 @@ ENTRY(memmove) /* Decide forward/backward copy mode */ cmp %rdi, %rsi - jb 2f + jge .Lmemmove_begin_forward + mov %rsi, %r8 + add %rdx, %r8 + cmp %rdi, %r8 + jg 2f +.Lmemmove_begin_forward: /* * movsq instruction have many startup latency * so we handle small size by general register. @@ -78,6 +85,8 @@ ENTRY(memmove) rep movsq movq %r11, (%r10) jmp 13f +.Lmemmove_end_forward: + /* * Handle data backward by movsq. */ @@ -194,4 +203,22 @@ ENTRY(memmove) 13: retq CFI_ENDPROC + + .section .altinstr_replacement,"ax" +.Lmemmove_begin_forward_efs: + /* Forward moving data. */ + movq %rdx, %rcx + rep movsb + retq +.Lmemmove_end_forward_efs: + .previous + + .section .altinstructions,"a" + .align 8 + .quad .Lmemmove_begin_forward + .quad .Lmemmove_begin_forward_efs + .word X86_FEATURE_ERMS + .byte .Lmemmove_end_forward-.Lmemmove_begin_forward + .byte .Lmemmove_end_forward_efs-.Lmemmove_begin_forward_efs + .previous ENDPROC(memmove) |