android_kernel_xiaomi_sm8350/arch/x86_64/lib/putuser.S
Alexander Nyberg 3a6fd752a5 [PATCH] x86_64: Bug in new out of line put_user()
The new out of line put_user() assembly on x86_64 changes %rcx without
telling GCC about it causing things like:

http://bugme.osdl.org/show_bug.cgi?id=4515 

See to it that %rcx is not changed (made it consistent with get_user()).

Signed-off-by: Alexander Nyberg <alexn@telia.com>
Signed-off-by: ak@suse.de
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-21 07:59:51 -07:00

99 lines
1.7 KiB
ArmAsm

/*
* __put_user functions.
*
* (C) Copyright 1998 Linus Torvalds
* (C) Copyright 2005 Andi Kleen
*
* These functions have a non-standard call interface
* to make them more efficient, especially as they
* return an error value in addition to the "real"
* return value.
*/
/*
* __put_user_X
*
* Inputs: %rcx contains the address
* %rdx contains new value
*
* Outputs: %rax is error code (0 or -EFAULT)
*
* %r8 is destroyed.
*
* These functions should not modify any other registers,
* as they get called from within inline assembly.
*/
#include <linux/linkage.h>
#include <asm/page.h>
#include <asm/errno.h>
#include <asm/offset.h>
#include <asm/thread_info.h>
.text
.p2align 4
.globl __put_user_1
__put_user_1:
GET_THREAD_INFO(%r8)
cmpq threadinfo_addr_limit(%r8),%rcx
jae bad_put_user
1: movb %dl,(%rcx)
xorl %eax,%eax
ret
.p2align 4
.globl __put_user_2
__put_user_2:
GET_THREAD_INFO(%r8)
addq $1,%rcx
jc 20f
cmpq threadinfo_addr_limit(%r8),%rcx
jae 20f
2: decq %rcx
movw %dx,(%rcx)
xorl %eax,%eax
ret
20: decq %rcx
jmp bad_put_user
.p2align 4
.globl __put_user_4
__put_user_4:
GET_THREAD_INFO(%r8)
addq $3,%rcx
jc 30f
cmpq threadinfo_addr_limit(%r8),%rcx
jae 30f
3: subq $3,%rcx
movl %edx,(%rcx)
xorl %eax,%eax
ret
30: subq $3,%rcx
jmp bad_put_user
.p2align 4
.globl __put_user_8
__put_user_8:
GET_THREAD_INFO(%r8)
addq $7,%rcx
jc 40f
cmpq threadinfo_addr_limit(%r8),%rcx
jae 40f
4: subq $7,%rcx
movq %rdx,(%rcx)
xorl %eax,%eax
ret
40: subq $7,%rcx
jmp bad_put_user
bad_put_user:
movq $(-EFAULT),%rax
ret
.section __ex_table,"a"
.quad 1b,bad_put_user
.quad 2b,bad_put_user
.quad 3b,bad_put_user
.quad 4b,bad_put_user
.previous