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authorDave Airlie <airlied@redhat.com>2015-04-20 04:32:26 +0300
committerDave Airlie <airlied@redhat.com>2015-04-20 06:05:20 +0300
commit2c33ce009ca2389dbf0535d0672214d09738e35e (patch)
tree6186a6458c3c160385d794a23eaf07c786a9e61b /arch/x86/lib/memcpy_64.S
parentcec32a47010647e8b0603726ebb75b990a4057a4 (diff)
parent09d51602cf84a1264946711dd4ea0dddbac599a1 (diff)
downloadlinux-2c33ce009ca2389dbf0535d0672214d09738e35e.tar.xz
Merge Linus master into drm-next
The merge is clean, but the arm build fails afterwards, due to API changes in the regulator tree. I've included the patch into the merge to fix the build. Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'arch/x86/lib/memcpy_64.S')
-rw-r--r--arch/x86/lib/memcpy_64.S68
1 files changed, 21 insertions, 47 deletions
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index 89b53c9968e7..b046664f5a1c 100644
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -1,12 +1,20 @@
/* Copyright 2002 Andi Kleen */
#include <linux/linkage.h>
-
#include <asm/cpufeature.h>
#include <asm/dwarf2.h>
#include <asm/alternative-asm.h>
/*
+ * We build a jump to memcpy_orig by default which gets NOPped out on
+ * the majority of x86 CPUs which set REP_GOOD. In addition, CPUs which
+ * have the enhanced REP MOVSB/STOSB feature (ERMS), change those NOPs
+ * to a jmp to memcpy_erms which does the REP; MOVSB mem copy.
+ */
+
+.weak memcpy
+
+/*
* memcpy - Copy a memory block.
*
* Input:
@@ -17,15 +25,11 @@
* Output:
* rax original destination
*/
+ENTRY(__memcpy)
+ENTRY(memcpy)
+ ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \
+ "jmp memcpy_erms", X86_FEATURE_ERMS
-/*
- * memcpy_c() - fast string ops (REP MOVSQ) based variant.
- *
- * This gets patched over the unrolled variant (below) via the
- * alternative instructions framework:
- */
- .section .altinstr_replacement, "ax", @progbits
-.Lmemcpy_c:
movq %rdi, %rax
movq %rdx, %rcx
shrq $3, %rcx
@@ -34,29 +38,21 @@
movl %edx, %ecx
rep movsb
ret
-.Lmemcpy_e:
- .previous
+ENDPROC(memcpy)
+ENDPROC(__memcpy)
/*
- * memcpy_c_e() - enhanced fast string memcpy. This is faster and simpler than
- * memcpy_c. Use memcpy_c_e when possible.
- *
- * This gets patched over the unrolled variant (below) via the
- * alternative instructions framework:
+ * memcpy_erms() - enhanced fast string memcpy. This is faster and
+ * simpler than memcpy. Use memcpy_erms when possible.
*/
- .section .altinstr_replacement, "ax", @progbits
-.Lmemcpy_c_e:
+ENTRY(memcpy_erms)
movq %rdi, %rax
movq %rdx, %rcx
rep movsb
ret
-.Lmemcpy_e_e:
- .previous
-
-.weak memcpy
+ENDPROC(memcpy_erms)
-ENTRY(__memcpy)
-ENTRY(memcpy)
+ENTRY(memcpy_orig)
CFI_STARTPROC
movq %rdi, %rax
@@ -183,26 +179,4 @@ ENTRY(memcpy)
.Lend:
retq
CFI_ENDPROC
-ENDPROC(memcpy)
-ENDPROC(__memcpy)
-
- /*
- * Some CPUs are adding enhanced REP MOVSB/STOSB feature
- * If the feature is supported, memcpy_c_e() is the first choice.
- * If enhanced rep movsb copy is not available, use fast string copy
- * memcpy_c() when possible. This is faster and code is simpler than
- * original memcpy().
- * Otherwise, original memcpy() is used.
- * In .altinstructions section, ERMS feature is placed after REG_GOOD
- * feature to implement the right patch order.
- *
- * Replace only beginning, memcpy is used to apply alternatives,
- * so it is silly to overwrite itself with nops - reboot is the
- * only outcome...
- */
- .section .altinstructions, "a"
- altinstruction_entry __memcpy,.Lmemcpy_c,X86_FEATURE_REP_GOOD,\
- .Lmemcpy_e-.Lmemcpy_c,.Lmemcpy_e-.Lmemcpy_c
- altinstruction_entry __memcpy,.Lmemcpy_c_e,X86_FEATURE_ERMS, \
- .Lmemcpy_e_e-.Lmemcpy_c_e,.Lmemcpy_e_e-.Lmemcpy_c_e
- .previous
+ENDPROC(memcpy_orig)