1 #ifndef __LINUX_UACCESS_H__
2 #define __LINUX_UACCESS_H__
4 #include <asm/uaccess.h>
6 #ifndef ARCH_HAS_NOCACHE_UACCESS
8 static inline unsigned long __copy_from_user_inatomic_nocache(void *to,
9 const void __user *from, unsigned long n)
11 return __copy_from_user_inatomic(to, from, n);
14 static inline unsigned long __copy_from_user_nocache(void *to,
15 const void __user *from, unsigned long n)
17 return __copy_from_user(to, from, n);
20 #endif /* ARCH_HAS_NOCACHE_UACCESS */
23 * probe_kernel_address(): safely attempt to read from a location
24 * @addr: address to read from - its type is type typeof(retval)*
25 * @retval: read into this variable
27 * Safely read from address @addr into variable @revtal. If a kernel fault
28 * happens, handle that and return -EFAULT.
29 * We ensure that the __get_user() is executed in atomic context so that
30 * do_page_fault() doesn't attempt to take mmap_sem. This makes
31 * probe_kernel_address() suitable for use within regions where the caller
32 * already holds mmap_sem, or other locks which nest inside mmap_sem.
34 #define probe_kernel_address(addr, retval) \
38 inc_preempt_count(); \
39 ret = __get_user(retval, addr); \
40 dec_preempt_count(); \
44 #endif /* __LINUX_UACCESS_H__ */