Blame - arch/x86/lib/clear_page_64.S - kernel/msm

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Jan Beulich	8d379da	2006-09-26 10:52:32 +0200	[diff] [blame]	1	#include <linux/linkage.h>
				2	#include <asm/dwarf2.h>
Fenghua Yu	e365c9d	2011-05-17 15:29:14 -0700	[diff] [blame]	3	#include <asm/alternative-asm.h>
Jan Beulich	8d379da	2006-09-26 10:52:32 +0200	[diff] [blame]	4
Linus Torvalds	1da177e	2005-04-16 15:20:36 -0700	[diff] [blame]	5	/*
				6	* Zero a page.
				7	* rdi page
				8	*/
Mike Galbraith	9e31499	2009-06-30 15:00:20 +0200	[diff] [blame]	9	ENTRY(clear_page_c)
Jan Beulich	8d379da	2006-09-26 10:52:32 +0200	[diff] [blame]	10	CFI_STARTPROC
				11	movl $4096/8,%ecx
				12	xorl %eax,%eax
				13	rep stosq
				14	ret
				15	CFI_ENDPROC
Mike Galbraith	9e31499	2009-06-30 15:00:20 +0200	[diff] [blame]	16	ENDPROC(clear_page_c)
Jan Beulich	8d379da	2006-09-26 10:52:32 +0200	[diff] [blame]	17
Fenghua Yu	e365c9d	2011-05-17 15:29:14 -0700	[diff] [blame]	18	ENTRY(clear_page_c_e)
				19	CFI_STARTPROC
				20	movl $4096,%ecx
				21	xorl %eax,%eax
				22	rep stosb
				23	ret
				24	CFI_ENDPROC
				25	ENDPROC(clear_page_c_e)
				26
Jan Beulich	8d379da	2006-09-26 10:52:32 +0200	[diff] [blame]	27	ENTRY(clear_page)
				28	CFI_STARTPROC
Andi Kleen	7bcd3f3	2006-02-03 21:51:02 +0100	[diff] [blame]	29	xorl %eax,%eax
				30	movl $4096/64,%ecx
				31	.p2align 4
				32	.Lloop:
				33	decl %ecx
				34	#define PUT(x) movq %rax,x*8(%rdi)
				35	movq %rax,(%rdi)
				36	PUT(1)
				37	PUT(2)
				38	PUT(3)
				39	PUT(4)
				40	PUT(5)
				41	PUT(6)
				42	PUT(7)
				43	leaq 64(%rdi),%rdi
				44	jnz .Lloop
				45	nop
				46	ret
Jan Beulich	8d379da	2006-09-26 10:52:32 +0200	[diff] [blame]	47	CFI_ENDPROC
				48	.Lclear_page_end:
				49	ENDPROC(clear_page)
Andi Kleen	7bcd3f3	2006-02-03 21:51:02 +0100	[diff] [blame]	50
Fenghua Yu	e365c9d	2011-05-17 15:29:14 -0700	[diff] [blame]	51	/*
				52	* Some CPUs support enhanced REP MOVSB/STOSB instructions.
				53	* It is recommended to use this when possible.
				54	* If enhanced REP MOVSB/STOSB is not available, try to use fast string.
				55	* Otherwise, use original function.
				56	*
				57	*/
Andi Kleen	7bcd3f3	2006-02-03 21:51:02 +0100	[diff] [blame]	58
				59	#include <asm/cpufeature.h>
				60
Jan Beulich	8d379da	2006-09-26 10:52:32 +0200	[diff] [blame]	61	.section .altinstr_replacement,"ax"
				62	1: .byte 0xeb /* jmp <disp8> */
				63	.byte (clear_page_c - clear_page) - (2f - 1b) /* offset */
Fenghua Yu	e365c9d	2011-05-17 15:29:14 -0700	[diff] [blame]	64	2: .byte 0xeb /* jmp <disp8> */
				65	.byte (clear_page_c_e - clear_page) - (3f - 2b) /* offset */
				66	3:
Jan Beulich	8d379da	2006-09-26 10:52:32 +0200	[diff] [blame]	67	.previous
Andi Kleen	7bcd3f3	2006-02-03 21:51:02 +0100	[diff] [blame]	68	.section .altinstructions,"a"
Fenghua Yu	e365c9d	2011-05-17 15:29:14 -0700	[diff] [blame]	69	altinstruction_entry clear_page,1b,X86_FEATURE_REP_GOOD,\
				70	.Lclear_page_end-clear_page, 2b-1b
				71	altinstruction_entry clear_page,2b,X86_FEATURE_ERMS, \
				72	.Lclear_page_end-clear_page,3b-2b
Andi Kleen	7bcd3f3	2006-02-03 21:51:02 +0100	[diff] [blame]	73	.previous