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>

diff --git a/arch/x86/lib/putuser_32.S b/arch/x86/lib/putuser_32.S
index f58fba1..5b2a926 100644 (file)
--- 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 8e7595c..0ecfe47 100644 (file)
--- 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.