linux-vybrid_public/arch/x86/lib/copy_user_nocache_64.S

/* Copyright 2002 Andi Kleen, SuSE Labs.
 * Subject to the GNU Public License v2.
 *
 * Functions to copy from and to user space.
 */

#include <linux/linkage.h>
#include <asm/dwarf2.h>

#define FIX_ALIGNMENT 1

#include <asm/current.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/cpufeature.h>

/*
 * copy_user_nocache - Uncached memory copy with exception handling
 * This will force destination/source out of cache for more performance.
 *
 * Input:
 * rdi destination
 * rsi source
 * rdx count
 * rcx zero flag	when 1 zero on exception
 *
 * Output:
 * eax uncopied bytes or 0 if successful.
 */
ENTRY(__copy_user_nocache)
	CFI_STARTPROC
	pushq %rbx
	CFI_ADJUST_CFA_OFFSET 8
	CFI_REL_OFFSET rbx, 0
	pushq %rcx		/* save zero flag */
	CFI_ADJUST_CFA_OFFSET 8
	CFI_REL_OFFSET rcx, 0

	xorl %eax,%eax		/* zero for the exception handler */

#ifdef FIX_ALIGNMENT
	/* check for bad alignment of destination */
	movl %edi,%ecx
	andl $7,%ecx
	jnz  .Lbad_alignment
.Lafter_bad_alignment:
#endif

	movq %rdx,%rcx

	movl $64,%ebx
	shrq $6,%rdx
	decq %rdx
	js   .Lhandle_tail

	.p2align 4
.Lloop:
.Ls1:	movq (%rsi),%r11
.Ls2:	movq 1*8(%rsi),%r8
.Ls3:	movq 2*8(%rsi),%r9
.Ls4:	movq 3*8(%rsi),%r10
.Ld1:	movnti %r11,(%rdi)
.Ld2:	movnti %r8,1*8(%rdi)
.Ld3:	movnti %r9,2*8(%rdi)
.Ld4:	movnti %r10,3*8(%rdi)

.Ls5:	movq 4*8(%rsi),%r11
.Ls6:	movq 5*8(%rsi),%r8
.Ls7:	movq 6*8(%rsi),%r9
.Ls8:	movq 7*8(%rsi),%r10
.Ld5:	movnti %r11,4*8(%rdi)
.Ld6:	movnti %r8,5*8(%rdi)
.Ld7:	movnti %r9,6*8(%rdi)
.Ld8:	movnti %r10,7*8(%rdi)

	dec  %rdx

	leaq 64(%rsi),%rsi
	leaq 64(%rdi),%rdi

	jns  .Lloop

	.p2align 4
.Lhandle_tail:
	movl %ecx,%edx
	andl $63,%ecx
	shrl $3,%ecx
	jz   .Lhandle_7
	movl $8,%ebx
	.p2align 4
.Lloop_8:
.Ls9:	movq (%rsi),%r8
.Ld9:	movnti %r8,(%rdi)
	decl %ecx
	leaq 8(%rdi),%rdi
	leaq 8(%rsi),%rsi
	jnz .Lloop_8

.Lhandle_7:
	movl %edx,%ecx
	andl $7,%ecx
	jz   .Lende
	.p2align 4
.Lloop_1:
.Ls10:	movb (%rsi),%bl
.Ld10:	movb %bl,(%rdi)
	incq %rdi
	incq %rsi
	decl %ecx
	jnz .Lloop_1

	CFI_REMEMBER_STATE
.Lende:
	popq %rcx
	CFI_ADJUST_CFA_OFFSET -8
	CFI_RESTORE %rcx
	popq %rbx
	CFI_ADJUST_CFA_OFFSET -8
	CFI_RESTORE rbx
	sfence
	ret
	CFI_RESTORE_STATE

#ifdef FIX_ALIGNMENT
	/* align destination */
	.p2align 4
.Lbad_alignment:
	movl $8,%r9d
	subl %ecx,%r9d
	movl %r9d,%ecx
	cmpq %r9,%rdx
	jz   .Lhandle_7
	js   .Lhandle_7
.Lalign_1:
.Ls11:	movb (%rsi),%bl
.Ld11:	movb %bl,(%rdi)
	incq %rsi
	incq %rdi
	decl %ecx
	jnz .Lalign_1
	subq %r9,%rdx
	jmp .Lafter_bad_alignment
#endif

	/* table sorted by exception address */
	.section __ex_table,"a"
	.align 8
	.quad .Ls1,.Ls1e	/* .Ls[1-4] - 0 bytes copied */
	.quad .Ls2,.Ls1e
	.quad .Ls3,.Ls1e
	.quad .Ls4,.Ls1e
	.quad .Ld1,.Ls1e	/* .Ld[1-4] - 0..24 bytes coped */
	.quad .Ld2,.Ls2e
	.quad .Ld3,.Ls3e
	.quad .Ld4,.Ls4e
	.quad .Ls5,.Ls5e	/* .Ls[5-8] - 32 bytes copied */
	.quad .Ls6,.Ls5e
	.quad .Ls7,.Ls5e
	.quad .Ls8,.Ls5e
	.quad .Ld5,.Ls5e	/* .Ld[5-8] - 32..56 bytes copied */
	.quad .Ld6,.Ls6e
	.quad .Ld7,.Ls7e
	.quad .Ld8,.Ls8e
	.quad .Ls9,.Le_quad
	.quad .Ld9,.Le_quad
	.quad .Ls10,.Le_byte
	.quad .Ld10,.Le_byte
#ifdef FIX_ALIGNMENT
	.quad .Ls11,.Lzero_rest
	.quad .Ld11,.Lzero_rest
#endif
	.quad .Le5,.Le_zero
	.previous

	/* eax: zero, ebx: 64 */
.Ls1e: 	addl $8,%eax	/* eax: bytes left uncopied: Ls1e: 64 .. Ls8e: 8 */
.Ls2e: 	addl $8,%eax
.Ls3e: 	addl $8,%eax
.Ls4e: 	addl $8,%eax
.Ls5e: 	addl $8,%eax
.Ls6e: 	addl $8,%eax
.Ls7e: 	addl $8,%eax
.Ls8e: 	addl $8,%eax
	addq %rbx,%rdi	/* +64 */
	subq %rax,%rdi  /* correct destination with computed offset */

	shlq $6,%rdx	/* loop counter * 64 (stride length) */
	addq %rax,%rdx	/* add offset to loopcnt */
	andl $63,%ecx	/* remaining bytes */
	addq %rcx,%rdx	/* add them */
	jmp .Lzero_rest

	/* exception on quad word loop in tail handling */
	/* ecx:	loopcnt/8, %edx: length, rdi: correct */
.Le_quad:
	shll $3,%ecx
	andl $7,%edx
	addl %ecx,%edx
	/* edx: bytes to zero, rdi: dest, eax:zero */
.Lzero_rest:
	cmpl $0,(%rsp)	/* zero flag set? */
	jz   .Le_zero
	movq %rdx,%rcx
.Le_byte:
	xorl %eax,%eax
.Le5:	rep
	stosb
	/* when there is another exception while zeroing the rest just return */
.Le_zero:
	movq %rdx,%rax
	jmp .Lende
	CFI_ENDPROC
ENDPROC(__copy_user_nocache)