diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-i386/uaccess.h | 46 |
1 files changed, 34 insertions, 12 deletions
diff --git a/include/asm-i386/uaccess.h b/include/asm-i386/uaccess.h index d0d253277be..54d905ebc63 100644 --- a/include/asm-i386/uaccess.h +++ b/include/asm-i386/uaccess.h @@ -390,8 +390,12 @@ unsigned long __must_check __copy_to_user_ll(void __user *to, const void *from, unsigned long n); unsigned long __must_check __copy_from_user_ll(void *to, const void __user *from, unsigned long n); +unsigned long __must_check __copy_from_user_ll_nozero(void *to, + const void __user *from, unsigned long n); unsigned long __must_check __copy_from_user_ll_nocache(void *to, const void __user *from, unsigned long n); +unsigned long __must_check __copy_from_user_ll_nocache_nozero(void *to, + const void __user *from, unsigned long n); /* * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault @@ -463,11 +467,36 @@ __copy_to_user(void __user *to, const void *from, unsigned long n) * atomic context and will fail rather than sleep. In this case the * uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h * for explanation of why this is needed. - * FIXME this isn't implimented yet EMXIF */ static __always_inline unsigned long __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) { + /* Avoid zeroing the tail if the copy fails.. + * If 'n' is constant and 1, 2, or 4, we do still zero on a failure, + * but as the zeroing behaviour is only significant when n is not + * constant, that shouldn't be a problem. + */ + if (__builtin_constant_p(n)) { + unsigned long ret; + + switch (n) { + case 1: + __get_user_size(*(u8 *)to, from, 1, ret, 1); + return ret; + case 2: + __get_user_size(*(u16 *)to, from, 2, ret, 2); + return ret; + case 4: + __get_user_size(*(u32 *)to, from, 4, ret, 4); + return ret; + } + } + return __copy_from_user_ll_nozero(to, from, n); +} +static __always_inline unsigned long +__copy_from_user(void *to, const void __user *from, unsigned long n) +{ + might_sleep(); if (__builtin_constant_p(n)) { unsigned long ret; @@ -488,9 +517,10 @@ __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) #define ARCH_HAS_NOCACHE_UACCESS -static __always_inline unsigned long __copy_from_user_inatomic_nocache(void *to, +static __always_inline unsigned long __copy_from_user_nocache(void *to, const void __user *from, unsigned long n) { + might_sleep(); if (__builtin_constant_p(n)) { unsigned long ret; @@ -510,17 +540,9 @@ static __always_inline unsigned long __copy_from_user_inatomic_nocache(void *to, } static __always_inline unsigned long -__copy_from_user(void *to, const void __user *from, unsigned long n) +__copy_from_user_inatomic_nocache(void *to, const void __user *from, unsigned long n) { - might_sleep(); - return __copy_from_user_inatomic(to, from, n); -} - -static __always_inline unsigned long -__copy_from_user_nocache(void *to, const void __user *from, unsigned long n) -{ - might_sleep(); - return __copy_from_user_inatomic_nocache(to, from, n); + return __copy_from_user_ll_nocache_nozero(to, from, n); } unsigned long __must_check copy_to_user(void __user *to, |