#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