x86: don't save ebx in putuser_32.S.

Clobber it in the inline asm macros, and let the compiler do this for us.

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>

2 files changed, 7 insertions, 16 deletions

diff --git a/arch/x86/lib/putuser_32.S b/arch/x86/lib/putuser_32.S
index f58fba109d18..5b2a926f0e28 100644
--- a/arch/x86/lib/putuser_32.S
+++ b/arch/x86/lib/putuser_32.S
@@ -26,14 +26,8 @@
  */
 
 #define ENTER   CFI_STARTPROC ; \
-                pushl %ebx ; \
-                CFI_ADJUST_CFA_OFFSET 4 ; \
-                CFI_REL_OFFSET ebx, 0 ; \
                 GET_THREAD_INFO(%ebx)
-#define EXIT    popl %ebx ; \
-                CFI_ADJUST_CFA_OFFSET -4 ; \
-                CFI_RESTORE ebx ; \
-                ret ; \
+#define EXIT    ret ; \
                 CFI_ENDPROC
 
 .text
@@ -81,10 +75,7 @@ ENTRY(__put_user_8)
 ENDPROC(__put_user_8)
 
 bad_put_user:
-        CFI_STARTPROC simple
-        CFI_DEF_CFA esp, 2*4
-        CFI_OFFSET eip, -1*4
-        CFI_OFFSET ebx, -2*4
+        CFI_STARTPROC
         movl $-14,%eax
         EXIT
 END(bad_put_user)
diff --git a/include/asm-x86/uaccess_32.h b/include/asm-x86/uaccess_32.h
index 8e7595c1f34e..0ecfe47ad60d 100644
--- a/include/asm-x86/uaccess_32.h
+++ b/include/asm-x86/uaccess_32.h
@@ -188,23 +188,23 @@ extern void __put_user_8(void);
 
 #define __put_user_1(x, ptr)                                    \
         asm volatile("call __put_user_1" : "=a" (__ret_pu)      \
-                     : "0" ((typeof(*(ptr)))(x)), "c" (ptr))
+                     : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
 
 #define __put_user_2(x, ptr)                                    \
         asm volatile("call __put_user_2" : "=a" (__ret_pu)      \
-                     : "0" ((typeof(*(ptr)))(x)), "c" (ptr))
+                     : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
 
 #define __put_user_4(x, ptr)                                    \
         asm volatile("call __put_user_4" : "=a" (__ret_pu)      \
-                     : "0" ((typeof(*(ptr)))(x)), "c" (ptr))
+                     : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
 
 #define __put_user_8(x, ptr)                                    \
         asm volatile("call __put_user_8" : "=a" (__ret_pu)      \
-                     : "A" ((typeof(*(ptr)))(x)), "c" (ptr))
+                     : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
 
 #define __put_user_X(x, ptr)                                    \
         asm volatile("call __put_user_X" : "=a" (__ret_pu)      \
-                     : "c" (ptr))
+                     : "c" (ptr): "ebx")
 
 /**
  * put_user: - Write a simple value into user space.