root/arch/x86/lib/copy_page_64.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* Written 2003 by Andi Kleen, based on a kernel by Evandro Menezes */
   3 
   4 #include <linux/linkage.h>
   5 #include <asm/cpufeatures.h>
   6 #include <asm/alternative-asm.h>
   7 #include <asm/export.h>
   8 
   9 /*
  10  * Some CPUs run faster using the string copy instructions (sane microcode).
  11  * It is also a lot simpler. Use this when possible. But, don't use streaming
  12  * copy unless the CPU indicates X86_FEATURE_REP_GOOD. Could vary the
  13  * prefetch distance based on SMP/UP.
  14  */
  15         ALIGN
  16 ENTRY(copy_page)
  17         ALTERNATIVE "jmp copy_page_regs", "", X86_FEATURE_REP_GOOD
  18         movl    $4096/8, %ecx
  19         rep     movsq
  20         ret
  21 ENDPROC(copy_page)
  22 EXPORT_SYMBOL(copy_page)
  23 
  24 ENTRY(copy_page_regs)
  25         subq    $2*8,   %rsp
  26         movq    %rbx,   (%rsp)
  27         movq    %r12,   1*8(%rsp)
  28 
  29         movl    $(4096/64)-5,   %ecx
  30         .p2align 4
  31 .Loop64:
  32         dec     %rcx
  33         movq    0x8*0(%rsi), %rax
  34         movq    0x8*1(%rsi), %rbx
  35         movq    0x8*2(%rsi), %rdx
  36         movq    0x8*3(%rsi), %r8
  37         movq    0x8*4(%rsi), %r9
  38         movq    0x8*5(%rsi), %r10
  39         movq    0x8*6(%rsi), %r11
  40         movq    0x8*7(%rsi), %r12
  41 
  42         prefetcht0 5*64(%rsi)
  43 
  44         movq    %rax, 0x8*0(%rdi)
  45         movq    %rbx, 0x8*1(%rdi)
  46         movq    %rdx, 0x8*2(%rdi)
  47         movq    %r8,  0x8*3(%rdi)
  48         movq    %r9,  0x8*4(%rdi)
  49         movq    %r10, 0x8*5(%rdi)
  50         movq    %r11, 0x8*6(%rdi)
  51         movq    %r12, 0x8*7(%rdi)
  52 
  53         leaq    64 (%rsi), %rsi
  54         leaq    64 (%rdi), %rdi
  55 
  56         jnz     .Loop64
  57 
  58         movl    $5, %ecx
  59         .p2align 4
  60 .Loop2:
  61         decl    %ecx
  62 
  63         movq    0x8*0(%rsi), %rax
  64         movq    0x8*1(%rsi), %rbx
  65         movq    0x8*2(%rsi), %rdx
  66         movq    0x8*3(%rsi), %r8
  67         movq    0x8*4(%rsi), %r9
  68         movq    0x8*5(%rsi), %r10
  69         movq    0x8*6(%rsi), %r11
  70         movq    0x8*7(%rsi), %r12
  71 
  72         movq    %rax, 0x8*0(%rdi)
  73         movq    %rbx, 0x8*1(%rdi)
  74         movq    %rdx, 0x8*2(%rdi)
  75         movq    %r8,  0x8*3(%rdi)
  76         movq    %r9,  0x8*4(%rdi)
  77         movq    %r10, 0x8*5(%rdi)
  78         movq    %r11, 0x8*6(%rdi)
  79         movq    %r12, 0x8*7(%rdi)
  80 
  81         leaq    64(%rdi), %rdi
  82         leaq    64(%rsi), %rsi
  83         jnz     .Loop2
  84 
  85         movq    (%rsp), %rbx
  86         movq    1*8(%rsp), %r12
  87         addq    $2*8, %rsp
  88         ret
  89 ENDPROC(copy_page_regs)