diff options
Diffstat (limited to 'arch/x86_64/lib/clear_page.S')
-rw-r--r-- | arch/x86_64/lib/clear_page.S | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/x86_64/lib/clear_page.S b/arch/x86_64/lib/clear_page.S index 43d9fa136180..1f81b79b796c 100644 --- a/arch/x86_64/lib/clear_page.S +++ b/arch/x86_64/lib/clear_page.S | |||
@@ -5,8 +5,46 @@ | |||
5 | .globl clear_page | 5 | .globl clear_page |
6 | .p2align 4 | 6 | .p2align 4 |
7 | clear_page: | 7 | clear_page: |
8 | xorl %eax,%eax | ||
9 | movl $4096/64,%ecx | ||
10 | .p2align 4 | ||
11 | .Lloop: | ||
12 | decl %ecx | ||
13 | #define PUT(x) movq %rax,x*8(%rdi) | ||
14 | movq %rax,(%rdi) | ||
15 | PUT(1) | ||
16 | PUT(2) | ||
17 | PUT(3) | ||
18 | PUT(4) | ||
19 | PUT(5) | ||
20 | PUT(6) | ||
21 | PUT(7) | ||
22 | leaq 64(%rdi),%rdi | ||
23 | jnz .Lloop | ||
24 | nop | ||
25 | ret | ||
26 | clear_page_end: | ||
27 | |||
28 | /* Some CPUs run faster using the string instructions. | ||
29 | It is also a lot simpler. Use this when possible */ | ||
30 | |||
31 | #include <asm/cpufeature.h> | ||
32 | |||
33 | .section .altinstructions,"a" | ||
34 | .align 8 | ||
35 | .quad clear_page | ||
36 | .quad clear_page_c | ||
37 | .byte X86_FEATURE_REP_GOOD | ||
38 | .byte clear_page_end-clear_page | ||
39 | .byte clear_page_c_end-clear_page_c | ||
40 | .previous | ||
41 | |||
42 | .section .altinstr_replacement,"ax" | ||
43 | clear_page_c: | ||
8 | movl $4096/8,%ecx | 44 | movl $4096/8,%ecx |
9 | xorl %eax,%eax | 45 | xorl %eax,%eax |
10 | rep | 46 | rep |
11 | stosq | 47 | stosq |
12 | ret | 48 | ret |
49 | clear_page_c_end: | ||
50 | .previous | ||