diff options
Diffstat (limited to 'include/asm-i386/uaccess.h')
| -rw-r--r-- | include/asm-i386/uaccess.h | 70 |
1 files changed, 65 insertions, 5 deletions
diff --git a/include/asm-i386/uaccess.h b/include/asm-i386/uaccess.h index 371457b1ceb..54d905ebc63 100644 --- a/include/asm-i386/uaccess.h +++ b/include/asm-i386/uaccess.h @@ -4,7 +4,6 @@ /* * User space memory access functions */ -#include <linux/config.h> #include <linux/errno.h> #include <linux/thread_info.h> #include <linux/prefetch.h> @@ -59,7 +58,7 @@ extern struct movsl_mask { __chk_user_ptr(addr); \ asm("addl %3,%1 ; sbbl %0,%0; cmpl %1,%4; sbbl $0,%0" \ :"=&r" (flag), "=r" (sum) \ - :"1" (addr),"g" ((int)(size)),"g" (current_thread_info()->addr_limit.seg)); \ + :"1" (addr),"g" ((int)(size)),"rm" (current_thread_info()->addr_limit.seg)); \ flag; }) /** @@ -391,6 +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 @@ -457,10 +462,41 @@ __copy_to_user(void __user *to, const void *from, unsigned long n) * * If some data could not be copied, this function will pad the copied * data to the requested size using zero bytes. + * + * An alternate version - __copy_from_user_inatomic() - may be called from + * 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. */ 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; @@ -479,12 +515,36 @@ __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) return __copy_from_user_ll(to, from, n); } +#define ARCH_HAS_NOCACHE_UACCESS + +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; + + 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_nocache(to, from, n); +} + 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); + return __copy_from_user_ll_nocache_nozero(to, from, n); } + unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n); unsigned long __must_check copy_from_user(void *to, |