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: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

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)

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.