tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#include <linux/linkage.h>
2#include <asm/export.h>
3
4/*
5 * Most CPUs support enhanced REP MOVSB/STOSB instructions. It is
6 * recommended to use this when possible and we do use them by default.
7 * If enhanced REP MOVSB/STOSB is not available, try to use fast string.
8 * Otherwise, use original.
9 */
10
11/*
12 * Zero a page.
13 * %rdi - page
14 */
15ENTRY(clear_page_rep)
16 movl $4096/8,%ecx
17 xorl %eax,%eax
18 rep stosq
19 ret
20ENDPROC(clear_page_rep)
21EXPORT_SYMBOL_GPL(clear_page_rep)
22
23ENTRY(clear_page_orig)
24 xorl %eax,%eax
25 movl $4096/64,%ecx
26 .p2align 4
27.Lloop:
28 decl %ecx
29#define PUT(x) movq %rax,x*8(%rdi)
30 movq %rax,(%rdi)
31 PUT(1)
32 PUT(2)
33 PUT(3)
34 PUT(4)
35 PUT(5)
36 PUT(6)
37 PUT(7)
38 leaq 64(%rdi),%rdi
39 jnz .Lloop
40 nop
41 ret
42ENDPROC(clear_page_orig)
43EXPORT_SYMBOL_GPL(clear_page_orig)
44
45ENTRY(clear_page_erms)
46 movl $4096,%ecx
47 xorl %eax,%eax
48 rep stosb
49 ret
50ENDPROC(clear_page_erms)
51EXPORT_SYMBOL_GPL(clear_page_erms)