projects / mirror_ubuntu-artful-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 8d379dad | 1 | #include <linux/linkage.h> |
| cd4d09ec | 2 | #include <asm/cpufeatures.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) |