diff options
| author | Ma Ling <ling.ma@intel.com> | 2012-10-18 03:52:45 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-10-24 12:42:47 +0200 |
| commit | 269833bd5a0f4443873da358b71675a890b47c3c (patch) | |
| tree | 40d476ea896ded8c0957f20c77e583673f8d1d0b /arch/x86/lib | |
| parent | 0e9e3e306c7e472bdcffa34c4c4584301eda03b3 (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.S | 120 |
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 6b34d04d096..176cca67212 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" |