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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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