diff options
Diffstat (limited to 'include/linux/uaccess.h')
| -rw-r--r-- | include/linux/uaccess.h | 40 |
1 files changed, 10 insertions, 30 deletions
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index d6f2c2c5b043..558129af828a 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -75,36 +75,6 @@ static inline unsigned long __copy_from_user_nocache(void *to, #endif /* ARCH_HAS_NOCACHE_UACCESS */ -/** - * probe_kernel_address(): safely attempt to read from a location - * @addr: address to read from - its type is type typeof(retval)* - * @retval: read into this variable - * - * Safely read from address @addr into variable @revtal. If a kernel fault - * happens, handle that and return -EFAULT. - * We ensure that the __get_user() is executed in atomic context so that - * do_page_fault() doesn't attempt to take mmap_sem. This makes - * probe_kernel_address() suitable for use within regions where the caller - * already holds mmap_sem, or other locks which nest inside mmap_sem. - * This must be a macro because __get_user() needs to know the types of the - * args. - * - * We don't include enough header files to be able to do the set_fs(). We - * require that the probe_kernel_address() caller will do that. - */ -#define probe_kernel_address(addr, retval) \ - ({ \ - long ret; \ - mm_segment_t old_fs = get_fs(); \ - \ - set_fs(KERNEL_DS); \ - pagefault_disable(); \ - ret = __copy_from_user_inatomic(&(retval), (__force typeof(retval) __user *)(addr), sizeof(retval)); \ - pagefault_enable(); \ - set_fs(old_fs); \ - ret; \ - }) - /* * probe_kernel_read(): safely attempt to read from a location * @dst: pointer to the buffer that shall take the data @@ -131,4 +101,14 @@ extern long notrace __probe_kernel_write(void *dst, const void *src, size_t size extern long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count); +/** + * probe_kernel_address(): safely attempt to read from a location + * @addr: address to read from + * @retval: read into this variable + * + * Returns 0 on success, or -EFAULT. + */ +#define probe_kernel_address(addr, retval) \ + probe_kernel_read(&retval, addr, sizeof(retval)) + #endif /* __LINUX_UACCESS_H__ */ |