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authorEric W. Biederman <ebiederm@xmission.com>2006-03-23 02:59:35 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-23 07:38:04 -0800
commit30e931d4092713cecd6b8c2fd70f268efaa6e428 (patch)
treee7425d6e23720399d4f1a3078e63e03d62ca1d63 /include/asm-i386
parent4f88651125e2ca8b106b6f65b65ea45776517bf3 (diff)
[PATCH] i386: Add a temporary to make put_user more type safe
In some code I am developing I had occasion to change the type of a variable. This made the value put_user was putting to user space wrong. But the code continued to build cleanly without errors. Introducing a temporary fixes this problem and at least with gcc-3.3.5 does not cause gcc any problems with optimizing out the temporary. gcc-4.x using SSA internally ought to be even better at optimizing out temporaries, so I don't expect a temporary to become a problem. Especially because in all correct cases the types on both sides of the assignment to the temporary are the same. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/asm-i386')
-rw-r--r--include/asm-i386/uaccess.h12
1 files changed, 7 insertions, 5 deletions
diff --git a/include/asm-i386/uaccess.h b/include/asm-i386/uaccess.h
index 3f1337c3420..371457b1ceb 100644
--- a/include/asm-i386/uaccess.h
+++ b/include/asm-i386/uaccess.h
@@ -197,13 +197,15 @@ extern void __put_user_8(void);
#define put_user(x,ptr) \
({ int __ret_pu; \
+ __typeof__(*(ptr)) __pu_val; \
__chk_user_ptr(ptr); \
+ __pu_val = x; \
switch(sizeof(*(ptr))) { \
- case 1: __put_user_1(x, ptr); break; \
- case 2: __put_user_2(x, ptr); break; \
- case 4: __put_user_4(x, ptr); break; \
- case 8: __put_user_8(x, ptr); break; \
- default:__put_user_X(x, ptr); break; \
+ case 1: __put_user_1(__pu_val, ptr); break; \
+ case 2: __put_user_2(__pu_val, ptr); break; \
+ case 4: __put_user_4(__pu_val, ptr); break; \
+ case 8: __put_user_8(__pu_val, ptr); break; \
+ default:__put_user_X(__pu_val, ptr); break; \
} \
__ret_pu; \
})