diff options
| author | Vitaly Mayatskikh <v.mayatskih@gmail.com> | 2008-07-02 15:48:21 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-07-09 15:51:03 +0200 |
| commit | 1129585a08baf58582c0da91e572cb29e3179acf (patch) | |
| tree | 8ea03668221455bdeff91f885e4458676a89633b | |
| parent | de989ef093623ab5259f885f30be699c431d4006 (diff) | |
x86: introduce copy_user_handle_tail() routine
Introduce generic C routine for handling necessary tail operations after
protection fault in copy_*_user on x86.
Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/lib/usercopy_64.c | 23 | ||||
| -rw-r--r-- | include/asm-x86/uaccess_64.h | 3 |
2 files changed, 26 insertions, 0 deletions
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c index 0c89d1bb0287..f4df6e7c718b 100644 --- a/arch/x86/lib/usercopy_64.c +++ b/arch/x86/lib/usercopy_64.c @@ -158,3 +158,26 @@ unsigned long copy_in_user(void __user *to, const void __user *from, unsigned le } EXPORT_SYMBOL(copy_in_user); +/* + * Try to copy last bytes and clear the rest if needed. + * Since protection fault in copy_from/to_user is not a normal situation, + * it is not necessary to optimize tail handling. + */ +unsigned long +copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest) +{ + char c; + unsigned zero_len; + + for (; len; --len) { + if (__get_user_nocheck(c, from++, sizeof(char))) + break; + if (__put_user_nocheck(c, to++, sizeof(char))) + break; + } + + for (c = 0, zero_len = len; zerorest && zero_len; --zero_len) + if (__put_user_nocheck(c, to++, sizeof(char))) + break; + return len; +} diff --git a/include/asm-x86/uaccess_64.h b/include/asm-x86/uaccess_64.h index 4e3ec004e14a..515d4dce96b5 100644 --- a/include/asm-x86/uaccess_64.h +++ b/include/asm-x86/uaccess_64.h @@ -195,4 +195,7 @@ static inline int __copy_from_user_inatomic_nocache(void *dst, return __copy_user_nocache(dst, src, size, 0); } +unsigned long +copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest); + #endif /* __X86_64_UACCESS_H */ |