]>
Commit | Line | Data |
---|---|---|
8d379dad | 1 | #include <linux/linkage.h> |
6620ef28 | 2 | #include <asm/cpufeature.h> |
e365c9df | 3 | #include <asm/alternative-asm.h> |
8d379dad | 4 | |
1da177e4 | 5 | /* |
6620ef28 BP |
6 | * Most CPUs support enhanced REP MOVSB/STOSB instructions. It is |
7 | * recommended to use this when possible and we do use them by default. | |
8 | * If enhanced REP MOVSB/STOSB is not available, try to use fast string. | |
9 | * Otherwise, use original. | |
10 | */ | |
11 | ||
12 | /* | |
13 | * Zero a page. | |
14 | * %rdi - page | |
15 | */ | |
16 | ENTRY(clear_page) | |
6620ef28 BP |
17 | |
18 | ALTERNATIVE_2 "jmp clear_page_orig", "", X86_FEATURE_REP_GOOD, \ | |
19 | "jmp clear_page_c_e", X86_FEATURE_ERMS | |
20 | ||
8d379dad JB |
21 | movl $4096/8,%ecx |
22 | xorl %eax,%eax | |
23 | rep stosq | |
24 | ret | |
6620ef28 | 25 | ENDPROC(clear_page) |
8d379dad | 26 | |
6620ef28 | 27 | ENTRY(clear_page_orig) |
e365c9df | 28 | |
7bcd3f34 AK |
29 | xorl %eax,%eax |
30 | movl $4096/64,%ecx | |
31 | .p2align 4 | |
32 | .Lloop: | |
33 | decl %ecx | |
34 | #define PUT(x) movq %rax,x*8(%rdi) | |
35 | movq %rax,(%rdi) | |
36 | PUT(1) | |
37 | PUT(2) | |
38 | PUT(3) | |
39 | PUT(4) | |
40 | PUT(5) | |
41 | PUT(6) | |
42 | PUT(7) | |
43 | leaq 64(%rdi),%rdi | |
44 | jnz .Lloop | |
45 | nop | |
46 | ret | |
6620ef28 | 47 | ENDPROC(clear_page_orig) |
7bcd3f34 | 48 | |
6620ef28 | 49 | ENTRY(clear_page_c_e) |
6620ef28 BP |
50 | movl $4096,%ecx |
51 | xorl %eax,%eax | |
52 | rep stosb | |
53 | ret | |
6620ef28 | 54 | ENDPROC(clear_page_c_e) |