[PATCH] s390: const pointer uaccess

Using __typeof__(*ptr) on a pointer to const makes the __x variable in
__get_user const as well.  The latest gcc will refuse to write to it.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 22 insertions, 6 deletions

diff --git a/include/asm-s390/uaccess.h b/include/asm-s390/uaccess.h
index 38a5cf8ab9e3..10a619da4761 100644
--- a/include/asm-s390/uaccess.h
+++ b/include/asm-s390/uaccess.h
@@ -200,21 +200,37 @@ extern int __put_user_bad(void) __attribute__((noreturn));
 
 #define __get_user(x, ptr)                                      \
 ({                                                              \
-        __typeof__(*(ptr)) __x;                                 \
         int __gu_err;                                           \
         __chk_user_ptr(ptr);                                    \
         switch (sizeof(*(ptr))) {                               \
-        case 1:                                                 \
-        case 2:                                                 \
-        case 4:                                                 \
-        case 8:                                                 \
+        case 1: {                                               \
+                unsigned char __x;                              \
+                __get_user_asm(__x, ptr, __gu_err);             \
+                (x) = (__typeof__(*(ptr))) __x;                 \
+                break;                                          \
+        };                                                      \
+        case 2: {                                               \
+                unsigned short __x;                             \
+                __get_user_asm(__x, ptr, __gu_err);             \
+                (x) = (__typeof__(*(ptr))) __x;                 \
+                break;                                          \
+        };                                                      \
+        case 4: {                                               \
+                unsigned int __x;                               \
+                __get_user_asm(__x, ptr, __gu_err);             \
+                (x) = (__typeof__(*(ptr))) __x;                 \
+                break;                                          \
+        };                                                      \
+        case 8: {                                               \
+                unsigned long long __x;                         \
                 __get_user_asm(__x, ptr, __gu_err);             \
+                (x) = (__typeof__(*(ptr))) __x;                 \
                 break;                                          \
+        };                                                      \
         default:                                                \
                 __get_user_bad();                               \
                 break;                                          \
         }                                                       \
-        (x) = __x;                                              \
         __gu_err;                                               \
 })