355 строки
7.2 KiB
ArmAsm
355 строки
7.2 KiB
ArmAsm
/* 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
|
|
.byte \feature /* when feature is set */
|
|
.byte 5
|
|
.byte 5
|
|
.previous
|
|
.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 threadinfo_addr_limit(%rax),%rcx
|
|
jae bad_to_user
|
|
xorl %eax,%eax /* clear zero flag */
|
|
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
|
|
CFI_ENDPROC
|
|
|
|
ENTRY(copy_user_generic)
|
|
CFI_STARTPROC
|
|
movl $1,%ecx /* set zero flag */
|
|
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
|
|
CFI_ENDPROC
|
|
|
|
ENTRY(__copy_from_user_inatomic)
|
|
CFI_STARTPROC
|
|
xorl %ecx,%ecx /* clear zero flag */
|
|
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
|
|
CFI_ENDPROC
|
|
|
|
/* 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 threadinfo_addr_limit(%rax),%rcx
|
|
jae bad_from_user
|
|
movl $1,%ecx /* set zero flag */
|
|
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 */
|
|
bad_from_user:
|
|
CFI_STARTPROC
|
|
movl %edx,%ecx
|
|
xorl %eax,%eax
|
|
rep
|
|
stosb
|
|
bad_to_user:
|
|
movl %edx,%eax
|
|
ret
|
|
CFI_ENDPROC
|
|
END(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
|
|
* ecx zero flag -- if true zero destination on error
|
|
*
|
|
* Output:
|
|
* eax uncopied bytes or 0 if successful.
|
|
*/
|
|
ENTRY(copy_user_generic_unrolled)
|
|
CFI_STARTPROC
|
|
pushq %rbx
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
CFI_REL_OFFSET rbx, 0
|
|
pushq %rcx
|
|
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: movq %r11,(%rdi)
|
|
.Ld2: movq %r8,1*8(%rdi)
|
|
.Ld3: movq %r9,2*8(%rdi)
|
|
.Ld4: movq %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: movq %r11,4*8(%rdi)
|
|
.Ld6: movq %r8,5*8(%rdi)
|
|
.Ld7: movq %r9,6*8(%rdi)
|
|
.Ld8: movq %r10,7*8(%rdi)
|
|
|
|
decq %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: movq %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
|
|
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
|
|
.quad .Ls2,.Ls2e
|
|
.quad .Ls3,.Ls3e
|
|
.quad .Ls4,.Ls4e
|
|
.quad .Ld1,.Ls1e
|
|
.quad .Ld2,.Ls2e
|
|
.quad .Ld3,.Ls3e
|
|
.quad .Ld4,.Ls4e
|
|
.quad .Ls5,.Ls5e
|
|
.quad .Ls6,.Ls6e
|
|
.quad .Ls7,.Ls7e
|
|
.quad .Ls8,.Ls8e
|
|
.quad .Ld5,.Ls5e
|
|
.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
|
|
|
|
/* compute 64-offset for main loop. 8 bytes accuracy with error on the
|
|
pessimistic side. this is gross. it would be better to fix the
|
|
interface. */
|
|
/* eax: zero, ebx: 64 */
|
|
.Ls1e: addl $8,%eax
|
|
.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)
|
|
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_generic)
|
|
|
|
|
|
/* Some CPUs run faster using the string copy instructions.
|
|
This is also a lot simpler. Use them when possible.
|
|
Patch in jmps to this code instead of copying it fully
|
|
to avoid unwanted aliasing in the exception tables. */
|
|
|
|
/* rdi destination
|
|
* rsi source
|
|
* rdx count
|
|
* ecx zero flag
|
|
*
|
|
* Output:
|
|
* eax uncopied bytes or 0 if successfull.
|
|
*
|
|
* 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.
|
|
*/
|
|
ENTRY(copy_user_generic_string)
|
|
CFI_STARTPROC
|
|
movl %ecx,%r8d /* save zero flag */
|
|
movl %edx,%ecx
|
|
shrl $3,%ecx
|
|
andl $7,%edx
|
|
jz 10f
|
|
1: rep
|
|
movsq
|
|
movl %edx,%ecx
|
|
2: rep
|
|
movsb
|
|
9: movl %ecx,%eax
|
|
ret
|
|
|
|
/* multiple of 8 byte */
|
|
10: rep
|
|
movsq
|
|
xor %eax,%eax
|
|
ret
|
|
|
|
/* exception handling */
|
|
3: lea (%rdx,%rcx,8),%rax /* exception on quad loop */
|
|
jmp 6f
|
|
5: movl %ecx,%eax /* exception on byte loop */
|
|
/* eax: left over bytes */
|
|
6: testl %r8d,%r8d /* zero flag set? */
|
|
jz 7f
|
|
movl %eax,%ecx /* initialize x86 loop counter */
|
|
push %rax
|
|
xorl %eax,%eax
|
|
8: rep
|
|
stosb /* zero the rest */
|
|
11: pop %rax
|
|
7: ret
|
|
CFI_ENDPROC
|
|
END(copy_user_generic_c)
|
|
|
|
.section __ex_table,"a"
|
|
.quad 1b,3b
|
|
.quad 2b,5b
|
|
.quad 8b,11b
|
|
.quad 10b,3b
|
|
.previous
|