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Commit 3a6fd752 authored by Alexander Nyberg's avatar Alexander Nyberg Committed by Linus Torvalds
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[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: default avatarAlexander Nyberg <alexn@telia.com>
Signed-off-by: default avatar <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 6d9c5d94

arch/x86_64/lib/getuser.S

+2 −2
Original line number Original line Diff line number Diff line
@@ -78,9 +78,9 @@ __get_user_4: 
__get_user_8:

__get_user_8:

	GET_THREAD_INFO(%r8)

	GET_THREAD_INFO(%r8)

	addq $7,%rcx

	addq $7,%rcx

	jc bad_get_user

	jc 40f

	cmpq threadinfo_addr_limit(%r8),%rcx

	cmpq threadinfo_addr_limit(%r8),%rcx

	jae	bad_get_user

	jae	40f

	subq	$7,%rcx

	subq	$7,%rcx

4:	movq (%rcx),%rdx

4:	movq (%rcx),%rdx

	xorl %eax,%eax

	xorl %eax,%eax

arch/x86_64/lib/putuser.S

+18 −9
Original line number Original line Diff line number Diff line
@@ -46,36 +46,45 @@ __put_user_1: 
__put_user_2:

__put_user_2:

	GET_THREAD_INFO(%r8)

	GET_THREAD_INFO(%r8)

	addq $1,%rcx

	addq $1,%rcx

	jc bad_put_user

	jc 20f

	cmpq threadinfo_addr_limit(%r8),%rcx

	cmpq threadinfo_addr_limit(%r8),%rcx

	jae	 bad_put_user

	jae 20f

2:	movw %dx,-1(%rcx)

2:	decq %rcx

	movw %dx,(%rcx)

	xorl %eax,%eax

	xorl %eax,%eax

	ret

	ret

20:	decq %rcx

	jmp bad_put_user





	.p2align 4

	.p2align 4

.globl __put_user_4

.globl __put_user_4

__put_user_4:

__put_user_4:

	GET_THREAD_INFO(%r8)

	GET_THREAD_INFO(%r8)

	addq $3,%rcx

	addq $3,%rcx

	jc bad_put_user

	jc 30f

	cmpq threadinfo_addr_limit(%r8),%rcx

	cmpq threadinfo_addr_limit(%r8),%rcx

	jae bad_put_user

	jae 30f

3:	movl %edx,-3(%rcx)

3:	subq $3,%rcx

	movl %edx,(%rcx)

	xorl %eax,%eax

	xorl %eax,%eax

	ret

	ret

30:	subq $3,%rcx

	jmp bad_put_user





	.p2align 4

	.p2align 4

.globl __put_user_8

.globl __put_user_8

__put_user_8:

__put_user_8:

	GET_THREAD_INFO(%r8)

	GET_THREAD_INFO(%r8)

	addq $7,%rcx

	addq $7,%rcx

	jc bad_put_user

	jc 40f

	cmpq threadinfo_addr_limit(%r8),%rcx

	cmpq threadinfo_addr_limit(%r8),%rcx

	jae	bad_put_user

	jae 40f

4:	movq %rdx,-7(%rcx)

4:	subq $7,%rcx

	movq %rdx,(%rcx)

	xorl %eax,%eax

	xorl %eax,%eax

	ret

	ret

40:	subq $7,%rcx

	jmp bad_put_user





bad_put_user:

bad_put_user:

	movq $(-EFAULT),%rax

	movq $(-EFAULT),%rax