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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>
111 lines
2.1 KiB
ArmAsm
111 lines
2.1 KiB
ArmAsm
/* Written 2003 by Andi Kleen, based on a kernel by Evandro Menezes */
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#include <linux/linkage.h>
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#include <asm/dwarf2.h>
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#include <asm/alternative-asm.h>
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ALIGN
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copy_page_rep:
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CFI_STARTPROC
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movl $4096/8, %ecx
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rep movsq
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ret
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CFI_ENDPROC
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ENDPROC(copy_page_rep)
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/*
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* Don't use streaming copy unless the CPU indicates X86_FEATURE_REP_GOOD.
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* Could vary the prefetch distance based on SMP/UP.
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*/
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ENTRY(copy_page)
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CFI_STARTPROC
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subq $2*8, %rsp
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CFI_ADJUST_CFA_OFFSET 2*8
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movq %rbx, (%rsp)
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CFI_REL_OFFSET rbx, 0
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movq %r12, 1*8(%rsp)
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CFI_REL_OFFSET r12, 1*8
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movl $(4096/64)-5, %ecx
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.p2align 4
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.Loop64:
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dec %rcx
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movq 0x8*0(%rsi), %rax
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movq 0x8*1(%rsi), %rbx
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movq 0x8*2(%rsi), %rdx
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movq 0x8*3(%rsi), %r8
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movq 0x8*4(%rsi), %r9
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movq 0x8*5(%rsi), %r10
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movq 0x8*6(%rsi), %r11
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movq 0x8*7(%rsi), %r12
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prefetcht0 5*64(%rsi)
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movq %rax, 0x8*0(%rdi)
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movq %rbx, 0x8*1(%rdi)
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movq %rdx, 0x8*2(%rdi)
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movq %r8, 0x8*3(%rdi)
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movq %r9, 0x8*4(%rdi)
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movq %r10, 0x8*5(%rdi)
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movq %r11, 0x8*6(%rdi)
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movq %r12, 0x8*7(%rdi)
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leaq 64 (%rsi), %rsi
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leaq 64 (%rdi), %rdi
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jnz .Loop64
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movl $5, %ecx
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.p2align 4
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.Loop2:
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decl %ecx
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movq 0x8*0(%rsi), %rax
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movq 0x8*1(%rsi), %rbx
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movq 0x8*2(%rsi), %rdx
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movq 0x8*3(%rsi), %r8
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movq 0x8*4(%rsi), %r9
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movq 0x8*5(%rsi), %r10
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movq 0x8*6(%rsi), %r11
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movq 0x8*7(%rsi), %r12
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movq %rax, 0x8*0(%rdi)
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movq %rbx, 0x8*1(%rdi)
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movq %rdx, 0x8*2(%rdi)
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movq %r8, 0x8*3(%rdi)
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movq %r9, 0x8*4(%rdi)
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movq %r10, 0x8*5(%rdi)
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movq %r11, 0x8*6(%rdi)
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movq %r12, 0x8*7(%rdi)
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leaq 64(%rdi), %rdi
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leaq 64(%rsi), %rsi
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jnz .Loop2
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movq (%rsp), %rbx
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CFI_RESTORE rbx
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movq 1*8(%rsp), %r12
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CFI_RESTORE r12
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addq $2*8, %rsp
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CFI_ADJUST_CFA_OFFSET -2*8
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ret
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.Lcopy_page_end:
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CFI_ENDPROC
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ENDPROC(copy_page)
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/* Some CPUs run faster using the string copy instructions.
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It is also a lot simpler. Use this when possible */
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#include <asm/cpufeature.h>
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.section .altinstr_replacement,"ax"
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1: .byte 0xeb /* jmp <disp8> */
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.byte (copy_page_rep - copy_page) - (2f - 1b) /* offset */
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2:
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.previous
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.section .altinstructions,"a"
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altinstruction_entry copy_page, 1b, X86_FEATURE_REP_GOOD, \
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.Lcopy_page_end-copy_page, 2b-1b
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.previous
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