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-rw-r--r--arch/x86/lib/memset_64.S61
1 files changed, 24 insertions, 37 deletions
diff --git a/arch/x86/lib/memset_64.S b/arch/x86/lib/memset_64.S
index f6153c1cdddc..93118fb23976 100644
--- a/arch/x86/lib/memset_64.S
+++ b/arch/x86/lib/memset_64.S
@@ -5,19 +5,30 @@
#include <asm/cpufeature.h>
#include <asm/alternative-asm.h>
+.weak memset
+
/*
* ISO C memset - set a memory block to a byte value. This function uses fast
* string to get better performance than the original function. The code is
* simpler and shorter than the orignal function as well.
- *
+ *
* rdi destination
- * rsi value (char)
- * rdx count (bytes)
- *
+ * rsi value (char)
+ * rdx count (bytes)
+ *
* rax original destination
- */
- .section .altinstr_replacement, "ax", @progbits
-.Lmemset_c:
+ */
+ENTRY(memset)
+ENTRY(__memset)
+ /*
+ * Some CPUs support enhanced REP MOVSB/STOSB feature. It is recommended
+ * to use it when possible. If not available, use fast string instructions.
+ *
+ * Otherwise, use original memset function.
+ */
+ ALTERNATIVE_2 "jmp memset_orig", "", X86_FEATURE_REP_GOOD, \
+ "jmp memset_erms", X86_FEATURE_ERMS
+
movq %rdi,%r9
movq %rdx,%rcx
andl $7,%edx
@@ -31,8 +42,8 @@
rep stosb
movq %r9,%rax
ret
-.Lmemset_e:
- .previous
+ENDPROC(memset)
+ENDPROC(__memset)
/*
* ISO C memset - set a memory block to a byte value. This function uses
@@ -45,21 +56,16 @@
*
* rax original destination
*/
- .section .altinstr_replacement, "ax", @progbits
-.Lmemset_c_e:
+ENTRY(memset_erms)
movq %rdi,%r9
movb %sil,%al
movq %rdx,%rcx
rep stosb
movq %r9,%rax
ret
-.Lmemset_e_e:
- .previous
-
-.weak memset
+ENDPROC(memset_erms)
-ENTRY(memset)
-ENTRY(__memset)
+ENTRY(memset_orig)
CFI_STARTPROC
movq %rdi,%r10
@@ -134,23 +140,4 @@ ENTRY(__memset)
jmp .Lafter_bad_alignment
.Lfinal:
CFI_ENDPROC
-ENDPROC(memset)
-ENDPROC(__memset)
-
- /* Some CPUs support enhanced REP MOVSB/STOSB feature.
- * It is recommended to use this when possible.
- *
- * If enhanced REP MOVSB/STOSB feature is not available, use fast string
- * instructions.
- *
- * Otherwise, use original memset function.
- *
- * In .altinstructions section, ERMS feature is placed after REG_GOOD
- * feature to implement the right patch order.
- */
- .section .altinstructions,"a"
- altinstruction_entry __memset,.Lmemset_c,X86_FEATURE_REP_GOOD,\
- .Lfinal-__memset,.Lmemset_e-.Lmemset_c,0
- altinstruction_entry __memset,.Lmemset_c_e,X86_FEATURE_ERMS, \
- .Lfinal-__memset,.Lmemset_e_e-.Lmemset_c_e,0
- .previous
+ENDPROC(memset_orig)