x86_64: move lib

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

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