mirror of https://gitee.com/openkylin/linux.git
258 lines
5.0 KiB
ArmAsm
258 lines
5.0 KiB
ArmAsm
/*
|
|
* 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/cpufeature.h>
|
|
|
|
.macro ALTERNATIVE_JUMP feature,orig,alt
|
|
0:
|
|
.byte 0xe9 /* 32bit jump */
|
|
.long \orig-1f /* by default jump to orig */
|
|
1:
|
|
.section .altinstr_replacement,"ax"
|
|
2: .byte 0xe9 /* near jump with 32bit immediate */
|
|
.long \alt-1b /* offset */ /* or alternatively to alt */
|
|
.previous
|
|
.section .altinstructions,"a"
|
|
.align 8
|
|
.quad 0b
|
|
.quad 2b
|
|
.word \feature /* when feature is set */
|
|
.byte 5
|
|
.byte 5
|
|
.previous
|
|
.endm
|
|
|
|
.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
|
|
|
|
.section __ex_table,"a"
|
|
.align 8
|
|
.quad 100b,103b
|
|
.quad 101b,103b
|
|
.previous
|
|
#endif
|
|
.endm
|
|
|
|
/* Standard copy_to_user with segment limit checking */
|
|
ENTRY(_copy_to_user)
|
|
CFI_STARTPROC
|
|
GET_THREAD_INFO(%rax)
|
|
movq %rdi,%rcx
|
|
addq %rdx,%rcx
|
|
jc bad_to_user
|
|
cmpq TI_addr_limit(%rax),%rcx
|
|
jae bad_to_user
|
|
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
|
|
CFI_ENDPROC
|
|
ENDPROC(_copy_to_user)
|
|
|
|
/* Standard copy_from_user with segment limit checking */
|
|
ENTRY(_copy_from_user)
|
|
CFI_STARTPROC
|
|
GET_THREAD_INFO(%rax)
|
|
movq %rsi,%rcx
|
|
addq %rdx,%rcx
|
|
jc bad_from_user
|
|
cmpq TI_addr_limit(%rax),%rcx
|
|
jae bad_from_user
|
|
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
|
|
CFI_ENDPROC
|
|
ENDPROC(_copy_from_user)
|
|
|
|
.section .fixup,"ax"
|
|
/* must zero dest */
|
|
ENTRY(bad_from_user)
|
|
bad_from_user:
|
|
CFI_STARTPROC
|
|
movl %edx,%ecx
|
|
xorl %eax,%eax
|
|
rep
|
|
stosb
|
|
bad_to_user:
|
|
movl %edx,%eax
|
|
ret
|
|
CFI_ENDPROC
|
|
ENDPROC(bad_from_user)
|
|
.previous
|
|
|
|
/*
|
|
* copy_user_generic_unrolled - memory copy with exception handling.
|
|
* This version is for CPUs like P4 that don't have efficient micro
|
|
* code for rep movsq
|
|
*
|
|
* Input:
|
|
* rdi destination
|
|
* rsi source
|
|
* rdx count
|
|
*
|
|
* Output:
|
|
* eax uncopied bytes or 0 if successfull.
|
|
*/
|
|
ENTRY(copy_user_generic_unrolled)
|
|
CFI_STARTPROC
|
|
cmpl $8,%edx
|
|
jb 20f /* less then 8 bytes, go to byte copy loop */
|
|
ALIGN_DESTINATION
|
|
movl %edx,%ecx
|
|
andl $63,%edx
|
|
shrl $6,%ecx
|
|
jz 17f
|
|
1: movq (%rsi),%r8
|
|
2: movq 1*8(%rsi),%r9
|
|
3: movq 2*8(%rsi),%r10
|
|
4: movq 3*8(%rsi),%r11
|
|
5: movq %r8,(%rdi)
|
|
6: movq %r9,1*8(%rdi)
|
|
7: movq %r10,2*8(%rdi)
|
|
8: movq %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: movq %r8,4*8(%rdi)
|
|
14: movq %r9,5*8(%rdi)
|
|
15: movq %r10,6*8(%rdi)
|
|
16: movq %r11,7*8(%rdi)
|
|
leaq 64(%rsi),%rsi
|
|
leaq 64(%rdi),%rdi
|
|
decl %ecx
|
|
jnz 1b
|
|
17: movl %edx,%ecx
|
|
andl $7,%edx
|
|
shrl $3,%ecx
|
|
jz 20f
|
|
18: movq (%rsi),%r8
|
|
19: movq %r8,(%rdi)
|
|
leaq 8(%rsi),%rsi
|
|
leaq 8(%rdi),%rdi
|
|
decl %ecx
|
|
jnz 18b
|
|
20: andl %edx,%edx
|
|
jz 23f
|
|
movl %edx,%ecx
|
|
21: movb (%rsi),%al
|
|
22: movb %al,(%rdi)
|
|
incq %rsi
|
|
incq %rdi
|
|
decl %ecx
|
|
jnz 21b
|
|
23: xor %eax,%eax
|
|
ret
|
|
|
|
.section .fixup,"ax"
|
|
30: shll $6,%ecx
|
|
addl %ecx,%edx
|
|
jmp 60f
|
|
40: lea (%rdx,%rcx,8),%rdx
|
|
jmp 60f
|
|
50: movl %ecx,%edx
|
|
60: jmp copy_user_handle_tail /* ecx is zerorest also */
|
|
.previous
|
|
|
|
.section __ex_table,"a"
|
|
.align 8
|
|
.quad 1b,30b
|
|
.quad 2b,30b
|
|
.quad 3b,30b
|
|
.quad 4b,30b
|
|
.quad 5b,30b
|
|
.quad 6b,30b
|
|
.quad 7b,30b
|
|
.quad 8b,30b
|
|
.quad 9b,30b
|
|
.quad 10b,30b
|
|
.quad 11b,30b
|
|
.quad 12b,30b
|
|
.quad 13b,30b
|
|
.quad 14b,30b
|
|
.quad 15b,30b
|
|
.quad 16b,30b
|
|
.quad 18b,40b
|
|
.quad 19b,40b
|
|
.quad 21b,50b
|
|
.quad 22b,50b
|
|
.previous
|
|
CFI_ENDPROC
|
|
ENDPROC(copy_user_generic_unrolled)
|
|
|
|
/* Some CPUs run faster using the string copy instructions.
|
|
* This is also a lot simpler. Use them when possible.
|
|
*
|
|
* Only 4GB of copy is supported. This shouldn't be a problem
|
|
* because the kernel normally only writes from/to page sized chunks
|
|
* even if user space passed a longer buffer.
|
|
* And more would be dangerous because both Intel and AMD have
|
|
* errata with rep movsq > 4GB. If someone feels the need to fix
|
|
* this please consider this.
|
|
*
|
|
* Input:
|
|
* rdi destination
|
|
* rsi source
|
|
* rdx count
|
|
*
|
|
* Output:
|
|
* eax uncopied bytes or 0 if successful.
|
|
*/
|
|
ENTRY(copy_user_generic_string)
|
|
CFI_STARTPROC
|
|
andl %edx,%edx
|
|
jz 4f
|
|
cmpl $8,%edx
|
|
jb 2f /* less than 8 bytes, go to byte copy loop */
|
|
ALIGN_DESTINATION
|
|
movl %edx,%ecx
|
|
shrl $3,%ecx
|
|
andl $7,%edx
|
|
1: rep
|
|
movsq
|
|
2: movl %edx,%ecx
|
|
3: rep
|
|
movsb
|
|
4: xorl %eax,%eax
|
|
ret
|
|
|
|
.section .fixup,"ax"
|
|
11: lea (%rdx,%rcx,8),%rcx
|
|
12: movl %ecx,%edx /* ecx is zerorest also */
|
|
jmp copy_user_handle_tail
|
|
.previous
|
|
|
|
.section __ex_table,"a"
|
|
.align 8
|
|
.quad 1b,11b
|
|
.quad 3b,12b
|
|
.previous
|
|
CFI_ENDPROC
|
|
ENDPROC(copy_user_generic_string)
|