x86: adapt x86_64 getuser functions.

Instead of doing a sub after the addition, use the
offset directly at the memory operand of the mov instructions.
This is the way i386 do.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 12 insertions, 21 deletions

diff --git a/arch/x86/lib/getuser_64.S b/arch/x86/lib/getuser_64.S
index 2b003d313480..df37d3a9ba2a 100644
--- a/arch/x86/lib/getuser_64.S
+++ b/arch/x86/lib/getuser_64.S
@@ -47,49 +47,40 @@ ENDPROC(__get_user_1)
 
 ENTRY(__get_user_2)
         CFI_STARTPROC
-        GET_THREAD_INFO(%rdx)
         addq $1,%rax
-        jc 20f
+        jc bad_get_user
+        GET_THREAD_INFO(%rdx)
         cmpq threadinfo_addr_limit(%rdx),%rax
-        jae 20f
-        decq   %rax
-2:      movzwl (%rax),%edx
+        jae bad_get_user
+2:      movzwl -1(%rax),%edx
         xorl %eax,%eax
         ret
-20:     decq    %rax
-        jmp     bad_get_user
         CFI_ENDPROC
 ENDPROC(__get_user_2)
 
 ENTRY(__get_user_4)
         CFI_STARTPROC
-        GET_THREAD_INFO(%rdx)
         addq $3,%rax
-        jc 30f
+        jc bad_get_user
+        GET_THREAD_INFO(%rdx)
         cmpq threadinfo_addr_limit(%rdx),%rax
-        jae 30f
-        subq $3,%rax
-3:      movl (%rax),%edx
+        jae bad_get_user
+3:      movl -3(%rax),%edx
         xorl %eax,%eax
         ret
-30:     subq $3,%rax
-        jmp bad_get_user
         CFI_ENDPROC
 ENDPROC(__get_user_4)
 
 ENTRY(__get_user_8)
         CFI_STARTPROC
-        GET_THREAD_INFO(%rdx)
         addq $7,%rax
-        jc 40f
+        jc bad_get_user
+        GET_THREAD_INFO(%rdx)
         cmpq threadinfo_addr_limit(%rdx),%rax
-        jae     40f
-        subq    $7,%rax
-4:      movq (%rax),%rdx
+        jae     bad_get_user
+4:      movq -7(%rax),%rdx
         xorl %eax,%eax
         ret
-40:     subq $7,%rax
-        jmp bad_get_user
         CFI_ENDPROC
 ENDPROC(__get_user_8)