mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-15 08:14:15 +08:00
92ed0223ae
I was observing reproducible crashes on the "movw %bx,(%rsi)" instruction below while a process in a recvfrom() system call was copying packet data to user space. The patch below fixes the exception table and causes the crash to no longer reproduce. Please apply. Acked-by: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
234 lines
3.7 KiB
ArmAsm
234 lines
3.7 KiB
ArmAsm
/*
|
|
* Copyright 2002,2003 Andi Kleen, SuSE Labs.
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file COPYING in the main directory of this archive
|
|
* for more details. No warranty for anything given at all.
|
|
*/
|
|
#include <linux/linkage.h>
|
|
#include <asm/errno.h>
|
|
|
|
/*
|
|
* Checksum copy with exception handling.
|
|
* On exceptions src_err_ptr or dst_err_ptr is set to -EFAULT and the
|
|
* destination is zeroed.
|
|
*
|
|
* Input
|
|
* rdi source
|
|
* rsi destination
|
|
* edx len (32bit)
|
|
* ecx sum (32bit)
|
|
* r8 src_err_ptr (int)
|
|
* r9 dst_err_ptr (int)
|
|
*
|
|
* Output
|
|
* eax 64bit sum. undefined in case of exception.
|
|
*
|
|
* Wrappers need to take care of valid exception sum and zeroing.
|
|
* They also should align source or destination to 8 bytes.
|
|
*/
|
|
|
|
.macro source
|
|
10:
|
|
.section __ex_table,"a"
|
|
.align 8
|
|
.quad 10b,.Lbad_source
|
|
.previous
|
|
.endm
|
|
|
|
.macro dest
|
|
20:
|
|
.section __ex_table,"a"
|
|
.align 8
|
|
.quad 20b,.Lbad_dest
|
|
.previous
|
|
.endm
|
|
|
|
.macro ignore L=.Lignore
|
|
30:
|
|
.section __ex_table,"a"
|
|
.align 8
|
|
.quad 30b,\L
|
|
.previous
|
|
.endm
|
|
|
|
|
|
.globl csum_partial_copy_generic
|
|
.p2align 4
|
|
csum_partial_copy_generic:
|
|
cmpl $3*64,%edx
|
|
jle .Lignore
|
|
|
|
.Lignore:
|
|
subq $7*8,%rsp
|
|
movq %rbx,2*8(%rsp)
|
|
movq %r12,3*8(%rsp)
|
|
movq %r14,4*8(%rsp)
|
|
movq %r13,5*8(%rsp)
|
|
movq %rbp,6*8(%rsp)
|
|
|
|
movq %r8,(%rsp)
|
|
movq %r9,1*8(%rsp)
|
|
|
|
movl %ecx,%eax
|
|
movl %edx,%ecx
|
|
|
|
xorl %r9d,%r9d
|
|
movq %rcx,%r12
|
|
|
|
shrq $6,%r12
|
|
jz .Lhandle_tail /* < 64 */
|
|
|
|
clc
|
|
|
|
/* main loop. clear in 64 byte blocks */
|
|
/* r9: zero, r8: temp2, rbx: temp1, rax: sum, rcx: saved length */
|
|
/* r11: temp3, rdx: temp4, r12 loopcnt */
|
|
/* r10: temp5, rbp: temp6, r14 temp7, r13 temp8 */
|
|
.p2align 4
|
|
.Lloop:
|
|
source
|
|
movq (%rdi),%rbx
|
|
source
|
|
movq 8(%rdi),%r8
|
|
source
|
|
movq 16(%rdi),%r11
|
|
source
|
|
movq 24(%rdi),%rdx
|
|
|
|
source
|
|
movq 32(%rdi),%r10
|
|
source
|
|
movq 40(%rdi),%rbp
|
|
source
|
|
movq 48(%rdi),%r14
|
|
source
|
|
movq 56(%rdi),%r13
|
|
|
|
ignore 2f
|
|
prefetcht0 5*64(%rdi)
|
|
2:
|
|
adcq %rbx,%rax
|
|
adcq %r8,%rax
|
|
adcq %r11,%rax
|
|
adcq %rdx,%rax
|
|
adcq %r10,%rax
|
|
adcq %rbp,%rax
|
|
adcq %r14,%rax
|
|
adcq %r13,%rax
|
|
|
|
decl %r12d
|
|
|
|
dest
|
|
movq %rbx,(%rsi)
|
|
dest
|
|
movq %r8,8(%rsi)
|
|
dest
|
|
movq %r11,16(%rsi)
|
|
dest
|
|
movq %rdx,24(%rsi)
|
|
|
|
dest
|
|
movq %r10,32(%rsi)
|
|
dest
|
|
movq %rbp,40(%rsi)
|
|
dest
|
|
movq %r14,48(%rsi)
|
|
dest
|
|
movq %r13,56(%rsi)
|
|
|
|
3:
|
|
|
|
leaq 64(%rdi),%rdi
|
|
leaq 64(%rsi),%rsi
|
|
|
|
jnz .Lloop
|
|
|
|
adcq %r9,%rax
|
|
|
|
/* do last upto 56 bytes */
|
|
.Lhandle_tail:
|
|
/* ecx: count */
|
|
movl %ecx,%r10d
|
|
andl $63,%ecx
|
|
shrl $3,%ecx
|
|
jz .Lfold
|
|
clc
|
|
.p2align 4
|
|
.Lloop_8:
|
|
source
|
|
movq (%rdi),%rbx
|
|
adcq %rbx,%rax
|
|
decl %ecx
|
|
dest
|
|
movq %rbx,(%rsi)
|
|
leaq 8(%rsi),%rsi /* preserve carry */
|
|
leaq 8(%rdi),%rdi
|
|
jnz .Lloop_8
|
|
adcq %r9,%rax /* add in carry */
|
|
|
|
.Lfold:
|
|
/* reduce checksum to 32bits */
|
|
movl %eax,%ebx
|
|
shrq $32,%rax
|
|
addl %ebx,%eax
|
|
adcl %r9d,%eax
|
|
|
|
/* do last upto 6 bytes */
|
|
.Lhandle_7:
|
|
movl %r10d,%ecx
|
|
andl $7,%ecx
|
|
shrl $1,%ecx
|
|
jz .Lhandle_1
|
|
movl $2,%edx
|
|
xorl %ebx,%ebx
|
|
clc
|
|
.p2align 4
|
|
.Lloop_1:
|
|
source
|
|
movw (%rdi),%bx
|
|
adcl %ebx,%eax
|
|
decl %ecx
|
|
dest
|
|
movw %bx,(%rsi)
|
|
leaq 2(%rdi),%rdi
|
|
leaq 2(%rsi),%rsi
|
|
jnz .Lloop_1
|
|
adcl %r9d,%eax /* add in carry */
|
|
|
|
/* handle last odd byte */
|
|
.Lhandle_1:
|
|
testl $1,%r10d
|
|
jz .Lende
|
|
xorl %ebx,%ebx
|
|
source
|
|
movb (%rdi),%bl
|
|
dest
|
|
movb %bl,(%rsi)
|
|
addl %ebx,%eax
|
|
adcl %r9d,%eax /* carry */
|
|
|
|
.Lende:
|
|
movq 2*8(%rsp),%rbx
|
|
movq 3*8(%rsp),%r12
|
|
movq 4*8(%rsp),%r14
|
|
movq 5*8(%rsp),%r13
|
|
movq 6*8(%rsp),%rbp
|
|
addq $7*8,%rsp
|
|
ret
|
|
|
|
/* Exception handlers. Very simple, zeroing is done in the wrappers */
|
|
.Lbad_source:
|
|
movq (%rsp),%rax
|
|
testq %rax,%rax
|
|
jz .Lende
|
|
movl $-EFAULT,(%rax)
|
|
jmp .Lende
|
|
|
|
.Lbad_dest:
|
|
movq 8(%rsp),%rax
|
|
testq %rax,%rax
|
|
jz .Lende
|
|
movl $-EFAULT,(%rax)
|
|
jmp .Lende
|