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