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#include <linux/linkage.h>
#include <asm/dwarf2.h>
/*
* Zero a page.
* rdi page
*/
ALIGN
clear_page_c:
CFI_STARTPROC
movl $4096/8,%ecx
xorl %eax,%eax
rep stosq
ret
CFI_ENDPROC
ENDPROC(clear_page)
ENTRY(clear_page)
CFI_STARTPROC
xorl %eax,%eax
movl $4096/64,%ecx
.p2align 4
.Lloop:
decl %ecx
#define PUT(x) movq %rax,x*8(%rdi)
movq %rax,(%rdi)
PUT(1)
PUT(2)
PUT(3)
PUT(4)
PUT(5)
PUT(6)
PUT(7)
leaq 64(%rdi),%rdi
jnz .Lloop
nop
ret
CFI_ENDPROC
.Lclear_page_end:
ENDPROC(clear_page)
/* Some CPUs run faster using the string instructions.
It is also a lot simpler. Use this when possible */
#include <asm/cpufeature.h>
.section .altinstr_replacement,"ax"
1: .byte 0xeb /* jmp <disp8> */
.byte (clear_page_c - clear_page) - (2f - 1b) /* offset */
2:
.previous
.section .altinstructions,"a"
.align 8
.quad clear_page
.quad 1b
.byte X86_FEATURE_REP_GOOD
.byte .Lclear_page_end - clear_page
.byte 2b - 1b
.previous
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