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Commit 663aa96d authored by Glauber Costa's avatar Glauber Costa Committed by Ingo Molnar
Browse files

x86: change testing logic in putuser_64.S. 



Instead of operating over a register we need to put back
into normal state afterwards (the memory position), just
sub from rbx, which is trashed anyway. We can save a few instructions.

Also, this is the i386 way.

Signed-off-by: default avatarGlauber Costa <gcosta@redhat.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 0ada3164

arch/x86/lib/putuser_64.S

+12 −21
Original line number Diff line number Diff line
@@ -46,48 +46,39 @@ ENDPROC(__put_user_1) 
ENTRY(__put_user_2)

	CFI_STARTPROC

	GET_THREAD_INFO(%rbx)

	addq $1,%rcx

	jc 20f

	cmpq TI_addr_limit(%rbx),%rcx

	jae 20f

	decq %rcx

	mov TI_addr_limit(%rbx),%rbx

	sub  $1, %rbx

	cmpq %rbx ,%rcx

	jae  bad_put_user

2:	movw %ax,(%rcx)

	xorl %eax,%eax

	ret

20:	decq %rcx

	jmp bad_put_user

	CFI_ENDPROC

ENDPROC(__put_user_2)



ENTRY(__put_user_4)

	CFI_STARTPROC

	GET_THREAD_INFO(%rbx)

	addq $3,%rcx

	jc 30f

	cmpq TI_addr_limit(%rbx),%rcx

	jae 30f

	subq $3,%rcx

	mov TI_addr_limit(%rbx),%rbx

	sub  $3, %rbx

	cmp  %rbx, %rcx

	jae bad_put_user

3:	movl %eax,(%rcx)

	xorl %eax,%eax

	ret

30:	subq $3,%rcx

	jmp bad_put_user

	CFI_ENDPROC

ENDPROC(__put_user_4)



ENTRY(__put_user_8)

	CFI_STARTPROC

	GET_THREAD_INFO(%rbx)

	addq $7,%rcx

	jc 40f

	cmpq TI_addr_limit(%rbx),%rcx

	jae 40f

	subq $7,%rcx

	mov TI_addr_limit(%rbx),%rbx

	sub  $7, %rbx

	cmp  %rbx, %rcx

	jae bad_put_user

4:	movq %rax,(%rcx)

	xorl %eax,%eax

	ret

40:	subq $7,%rcx

	jmp bad_put_user

	CFI_ENDPROC

ENDPROC(__put_user_8)