arch/x86_64/lib/copy_page.S

   1 /* Written 2003 by Andi Kleen, based on a kernel by Evandro Menezes */
   2
   3 /* Don't use streaming store because it's better when the target
   4    ends up in cache. */
   5
   6 /* Could vary the prefetch distance based on SMP/UP */
   7
   8         .globl copy_page
   9         .p2align 4
  10 copy_page:
  11         subq    $3*8,%rsp
  12         movq    %rbx,(%rsp)
  13         movq    %r12,1*8(%rsp)
  14         movq    %r13,2*8(%rsp)
  15
  16         movl    $(4096/64)-5,%ecx
  17         .p2align 4
  18 .Loop64:
  19         dec     %rcx
  20
  21         movq        (%rsi), %rax
  22         movq      8 (%rsi), %rbx
  23         movq     16 (%rsi), %rdx
  24         movq     24 (%rsi), %r8
  25         movq     32 (%rsi), %r9
  26         movq     40 (%rsi), %r10
  27         movq     48 (%rsi), %r11
  28         movq     56 (%rsi), %r12
  29
  30         prefetcht0 5*64(%rsi)
  31
  32         movq     %rax,    (%rdi)
  33         movq     %rbx,  8 (%rdi)
  34         movq     %rdx, 16 (%rdi)
  35         movq     %r8,  24 (%rdi)
  36         movq     %r9,  32 (%rdi)
  37         movq     %r10, 40 (%rdi)
  38         movq     %r11, 48 (%rdi)
  39         movq     %r12, 56 (%rdi)
  40
  41         leaq    64 (%rsi), %rsi
  42         leaq    64 (%rdi), %rdi
  43
  44         jnz     .Loop64
  45
  46         movl    $5,%ecx
  47         .p2align 4
  48 .Loop2:
  49         decl   %ecx
  50
  51         movq        (%rsi), %rax
  52         movq      8 (%rsi), %rbx
  53         movq     16 (%rsi), %rdx
  54         movq     24 (%rsi), %r8
  55         movq     32 (%rsi), %r9
  56         movq     40 (%rsi), %r10
  57         movq     48 (%rsi), %r11
  58         movq     56 (%rsi), %r12
  59
  60         movq     %rax,    (%rdi)
  61         movq     %rbx,  8 (%rdi)
  62         movq     %rdx, 16 (%rdi)
  63         movq     %r8,  24 (%rdi)
  64         movq     %r9,  32 (%rdi)
  65         movq     %r10, 40 (%rdi)
  66         movq     %r11, 48 (%rdi)
  67         movq     %r12, 56 (%rdi)
  68
  69         leaq    64(%rdi),%rdi
  70         leaq    64(%rsi),%rsi
  71
  72         jnz     .Loop2
  73
  74         movq    (%rsp),%rbx
  75         movq    1*8(%rsp),%r12
  76         movq    2*8(%rsp),%r13
  77         addq    $3*8,%rsp
  78         ret
  79
  80         /* C stepping K8 run faster using the string copy instructions.
  81            It is also a lot simpler. Use this when possible */
  82
  83 #include <asm/cpufeature.h>
  84
  85         .section .altinstructions,"a"
  86         .align 8
  87         .quad  copy_page
  88         .quad  copy_page_c
  89         .byte  X86_FEATURE_K8_C
  90         .byte  copy_page_c_end-copy_page_c
  91         .byte  copy_page_c_end-copy_page_c
  92         .previous
  93
  94         .section .altinstr_replacement,"ax"
  95 copy_page_c:
  96         movl $4096/8,%ecx
  97         rep
  98         movsq
  99         ret
 100 copy_page_c_end:
 101         .previous