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authorThomas Gleixner <tglx@linutronix.de>2007-10-11 11:17:08 +0200
committerThomas Gleixner <tglx@linutronix.de>2007-10-11 11:17:08 +0200
commit185f3d38900f750a4566f87cde6a178f3595a115 (patch)
treed463f6da1af452b1bbdf476828ea88427087f255 /arch/x86/lib/clear_page_64.S
parent51b2833060f26258ea2da091c7b9c6a358ac9dd2 (diff)
downloadop-kernel-dev-185f3d38900f750a4566f87cde6a178f3595a115.zip
op-kernel-dev-185f3d38900f750a4566f87cde6a178f3595a115.tar.gz
x86_64: move lib
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/lib/clear_page_64.S')
-rw-r--r--arch/x86/lib/clear_page_64.S59
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/x86/lib/clear_page_64.S b/arch/x86/lib/clear_page_64.S
new file mode 100644
index 0000000..9a10a78
--- /dev/null
+++ b/arch/x86/lib/clear_page_64.S
@@ -0,0 +1,59 @@
+#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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