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authorMa Ling <ling.ma@intel.com>2012-10-18 03:52:45 +0800
committerIngo Molnar <mingo@kernel.org>2012-10-24 12:42:47 +0200
commit269833bd5a0f4443873da358b71675a890b47c3c (patch)
tree40d476ea896ded8c0957f20c77e583673f8d1d0b /arch/x86/lib
parent0e9e3e306c7e472bdcffa34c4c4584301eda03b3 (diff)
x86/asm: Clean up copy_page_*() comments and code
Modern CPUs use fast-string instruction to accelerate copy performance, by combining data into 128 bit chunks. Modify comments and coding style to match it. Signed-off-by: Ma Ling <ling.ma@intel.com> Cc: iant@google.com Link: http://lkml.kernel.org/r/1350503565-19167-1-git-send-email-ling.ma@intel.com [ Cleaned up the clean up. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/lib')
-rw-r--r--arch/x86/lib/copy_page_64.S120
1 files changed, 59 insertions, 61 deletions
diff --git a/arch/x86/lib/copy_page_64.S b/arch/x86/lib/copy_page_64.S
index 6b34d04d096a..176cca67212b 100644
--- a/arch/x86/lib/copy_page_64.S
+++ b/arch/x86/lib/copy_page_64.S
@@ -5,91 +5,89 @@
#include <asm/alternative-asm.h>
ALIGN
-copy_page_c:
+copy_page_rep:
CFI_STARTPROC
- movl $4096/8,%ecx
- rep movsq
+ movl $4096/8, %ecx
+ rep movsq
ret
CFI_ENDPROC
-ENDPROC(copy_page_c)
+ENDPROC(copy_page_rep)
-/* Don't use streaming store because it's better when the target
- ends up in cache. */
-
-/* Could vary the prefetch distance based on SMP/UP */
+/*
+ * Don't use streaming copy unless the CPU indicates X86_FEATURE_REP_GOOD.
+ * Could vary the prefetch distance based on SMP/UP.
+*/
ENTRY(copy_page)
CFI_STARTPROC
- subq $2*8,%rsp
+ subq $2*8, %rsp
CFI_ADJUST_CFA_OFFSET 2*8
- movq %rbx,(%rsp)
+ movq %rbx, (%rsp)
CFI_REL_OFFSET rbx, 0
- movq %r12,1*8(%rsp)
+ movq %r12, 1*8(%rsp)
CFI_REL_OFFSET r12, 1*8
- movl $(4096/64)-5,%ecx
+ movl $(4096/64)-5, %ecx
.p2align 4
.Loop64:
- dec %rcx
-
- movq (%rsi), %rax
- movq 8 (%rsi), %rbx
- movq 16 (%rsi), %rdx
- movq 24 (%rsi), %r8
- movq 32 (%rsi), %r9
- movq 40 (%rsi), %r10
- movq 48 (%rsi), %r11
- movq 56 (%rsi), %r12
+ dec %rcx
+ movq 0x8*0(%rsi), %rax
+ movq 0x8*1(%rsi), %rbx
+ movq 0x8*2(%rsi), %rdx
+ movq 0x8*3(%rsi), %r8
+ movq 0x8*4(%rsi), %r9
+ movq 0x8*5(%rsi), %r10
+ movq 0x8*6(%rsi), %r11
+ movq 0x8*7(%rsi), %r12
prefetcht0 5*64(%rsi)
- movq %rax, (%rdi)
- movq %rbx, 8 (%rdi)
- movq %rdx, 16 (%rdi)
- movq %r8, 24 (%rdi)
- movq %r9, 32 (%rdi)
- movq %r10, 40 (%rdi)
- movq %r11, 48 (%rdi)
- movq %r12, 56 (%rdi)
+ movq %rax, 0x8*0(%rdi)
+ movq %rbx, 0x8*1(%rdi)
+ movq %rdx, 0x8*2(%rdi)
+ movq %r8, 0x8*3(%rdi)
+ movq %r9, 0x8*4(%rdi)
+ movq %r10, 0x8*5(%rdi)
+ movq %r11, 0x8*6(%rdi)
+ movq %r12, 0x8*7(%rdi)
- leaq 64 (%rsi), %rsi
- leaq 64 (%rdi), %rdi
+ leaq 64 (%rsi), %rsi
+ leaq 64 (%rdi), %rdi
- jnz .Loop64
+ jnz .Loop64
- movl $5,%ecx
+ movl $5, %ecx
.p2align 4
.Loop2:
- decl %ecx
-
- movq (%rsi), %rax
- movq 8 (%rsi), %rbx
- movq 16 (%rsi), %rdx
- movq 24 (%rsi), %r8
- movq 32 (%rsi), %r9
- movq 40 (%rsi), %r10
- movq 48 (%rsi), %r11
- movq 56 (%rsi), %r12
-
- movq %rax, (%rdi)
- movq %rbx, 8 (%rdi)
- movq %rdx, 16 (%rdi)
- movq %r8, 24 (%rdi)
- movq %r9, 32 (%rdi)
- movq %r10, 40 (%rdi)
- movq %r11, 48 (%rdi)
- movq %r12, 56 (%rdi)
-
- leaq 64(%rdi),%rdi
- leaq 64(%rsi),%rsi
-
+ decl %ecx
+
+ movq 0x8*0(%rsi), %rax
+ movq 0x8*1(%rsi), %rbx
+ movq 0x8*2(%rsi), %rdx
+ movq 0x8*3(%rsi), %r8
+ movq 0x8*4(%rsi), %r9
+ movq 0x8*5(%rsi), %r10
+ movq 0x8*6(%rsi), %r11
+ movq 0x8*7(%rsi), %r12
+
+ movq %rax, 0x8*0(%rdi)
+ movq %rbx, 0x8*1(%rdi)
+ movq %rdx, 0x8*2(%rdi)
+ movq %r8, 0x8*3(%rdi)
+ movq %r9, 0x8*4(%rdi)
+ movq %r10, 0x8*5(%rdi)
+ movq %r11, 0x8*6(%rdi)
+ movq %r12, 0x8*7(%rdi)
+
+ leaq 64(%rdi), %rdi
+ leaq 64(%rsi), %rsi
jnz .Loop2
- movq (%rsp),%rbx
+ movq (%rsp), %rbx
CFI_RESTORE rbx
- movq 1*8(%rsp),%r12
+ movq 1*8(%rsp), %r12
CFI_RESTORE r12
- addq $2*8,%rsp
+ addq $2*8, %rsp
CFI_ADJUST_CFA_OFFSET -2*8
ret
.Lcopy_page_end:
@@ -103,7 +101,7 @@ ENDPROC(copy_page)
.section .altinstr_replacement,"ax"
1: .byte 0xeb /* jmp <disp8> */
- .byte (copy_page_c - copy_page) - (2f - 1b) /* offset */
+ .byte (copy_page_rep - copy_page) - (2f - 1b) /* offset */
2:
.previous
.section .altinstructions,"a"