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/*
* Copyright 2008 Vitaly Mayatskikh <vmayatsk@redhat.com>
* 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/asm.h>
.macro ALIGN_DESTINATION
#ifdef FIX_ALIGNMENT
/* check for bad alignment of destination */
movl %edi,%ecx
andl $7,%ecx
jz 102f /* already aligned */
subl $8,%ecx
negl %ecx
subl %ecx,%edx
100: movb (%rsi),%al
101: movb %al,(%rdi)
incq %rsi
incq %rdi
decl %ecx
jnz 100b
102:
.section .fixup,"ax"
103: addl %ecx,%edx /* ecx is zerorest also */
jmp copy_user_handle_tail
.previous
_ASM_EXTABLE(100b,103b)
_ASM_EXTABLE(101b,103b)
#endif
.endm
/*
* copy_user_nocache - Uncached memory copy with exception handling
* This will force destination out of cache for more performance.
*
* Note: Cached memory copy is used when destination or size is not
* naturally aligned. That is:
* - Require 8-byte alignment when size is 8 bytes or larger.
* - Require 4-byte alignment when size is 4 bytes.
*/
ENTRY(__copy_user_nocache)
CFI_STARTPROC
/* If size is less than 8 bytes, go to 4-byte copy */
cmpl $8,%edx
jb .L_4b_nocache_copy_entry
/* If destination is not 8-byte aligned, "cache" copy to align it */
ALIGN_DESTINATION
/* Set 4x8-byte copy count and remainder */
movl %edx,%ecx
andl $63,%edx
shrl $6,%ecx
jz .L_8b_nocache_copy_entry /* jump if count is 0 */
/* Perform 4x8-byte nocache loop-copy */
.L_4x8b_nocache_copy_loop:
1: movq (%rsi),%r8
2: movq 1*8(%rsi),%r9
3: movq 2*8(%rsi),%r10
4: movq 3*8(%rsi),%r11
5: movnti %r8,(%rdi)
6: movnti %r9,1*8(%rdi)
7: movnti %r10,2*8(%rdi)
8: movnti %r11,3*8(%rdi)
9: movq 4*8(%rsi),%r8
10: movq 5*8(%rsi),%r9
11: movq 6*8(%rsi),%r10
12: movq 7*8(%rsi),%r11
13: movnti %r8,4*8(%rdi)
14: movnti %r9,5*8(%rdi)
15: movnti %r10,6*8(%rdi)
16: movnti %r11,7*8(%rdi)
leaq 64(%rsi),%rsi
leaq 64(%rdi),%rdi
decl %ecx
jnz .L_4x8b_nocache_copy_loop
/* Set 8-byte copy count and remainder */
.L_8b_nocache_copy_entry:
movl %edx,%ecx
andl $7,%edx
shrl $3,%ecx
jz .L_4b_nocache_copy_entry /* jump if count is 0 */
/* Perform 8-byte nocache loop-copy */
.L_8b_nocache_copy_loop:
20: movq (%rsi),%r8
21: movnti %r8,(%rdi)
leaq 8(%rsi),%rsi
leaq 8(%rdi),%rdi
decl %ecx
jnz .L_8b_nocache_copy_loop
/* If no byte left, we're done */
.L_4b_nocache_copy_entry:
andl %edx,%edx
jz .L_finish_copy
/* If destination is not 4-byte aligned, go to byte copy: */
movl %edi,%ecx
andl $3,%ecx
jnz .L_1b_cache_copy_entry
/* Set 4-byte copy count (1 or 0) and remainder */
movl %edx,%ecx
andl $3,%edx
shrl $2,%ecx
jz .L_1b_cache_copy_entry /* jump if count is 0 */
/* Perform 4-byte nocache copy: */
30: movl (%rsi),%r8d
31: movnti %r8d,(%rdi)
leaq 4(%rsi),%rsi
leaq 4(%rdi),%rdi
/* If no bytes left, we're done: */
andl %edx,%edx
jz .L_finish_copy
/* Perform byte "cache" loop-copy for the remainder */
.L_1b_cache_copy_entry:
movl %edx,%ecx
.L_1b_cache_copy_loop:
40: movb (%rsi),%al
41: movb %al,(%rdi)
incq %rsi
incq %rdi
decl %ecx
jnz .L_1b_cache_copy_loop
/* Finished copying; fence the prior stores */
.L_finish_copy:
xorl %eax,%eax
sfence
ret
.section .fixup,"ax"
.L_fixup_4x8b_copy:
shll $6,%ecx
addl %ecx,%edx
jmp .L_fixup_handle_tail
.L_fixup_8b_copy:
lea (%rdx,%rcx,8),%rdx
jmp .L_fixup_handle_tail
.L_fixup_4b_copy:
lea (%rdx,%rcx,4),%rdx
jmp .L_fixup_handle_tail
.L_fixup_1b_copy:
movl %ecx,%edx
.L_fixup_handle_tail:
sfence
jmp copy_user_handle_tail
.previous
_ASM_EXTABLE(1b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(2b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(3b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(4b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(5b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(6b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(7b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(8b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(9b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(10b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(11b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(12b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(13b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(14b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(15b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(16b,.L_fixup_4x8b_copy)
_ASM_EXTABLE(20b,.L_fixup_8b_copy)
_ASM_EXTABLE(21b,.L_fixup_8b_copy)
_ASM_EXTABLE(30b,.L_fixup_4b_copy)
_ASM_EXTABLE(31b,.L_fixup_4b_copy)
_ASM_EXTABLE(40b,.L_fixup_1b_copy)
_ASM_EXTABLE(41b,.L_fixup_1b_copy)
CFI_ENDPROC
ENDPROC(__copy_user_nocache)
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