1 #ifndef __ASM_GENERIC_UACCESS_H
2 #define __ASM_GENERIC_UACCESS_H
5 * User space memory access functions, these should work
6 * on any machine that has kernel and user data in the same
7 * address space, e.g. all NOMMU machines.
9 #include <linux/sched.h>
10 #include <linux/string.h>
12 #include <asm/segment.h>
14 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
17 #define KERNEL_DS MAKE_MM_SEG(~0UL)
21 #define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
25 #define get_ds() (KERNEL_DS)
26 #define get_fs() (current_thread_info()->addr_limit)
28 static inline void set_fs(mm_segment_t fs)
30 current_thread_info()->addr_limit = fs;
35 #define segment_eq(a, b) ((a).seg == (b).seg)
39 #define VERIFY_WRITE 1
41 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size))
44 * The architecture should really override this if possible, at least
45 * doing a check on the get_fs()
48 static inline int __access_ok(unsigned long addr, unsigned long size)
55 * The exception table consists of pairs of addresses: the first is the
56 * address of an instruction that is allowed to fault, and the second is
57 * the address at which the program should continue. No registers are
58 * modified, so it is entirely up to the continuation code to figure out
61 * All the routines below use bits of fixup code that are out of line
62 * with the main instruction path. This means when everything is well,
63 * we don't even have to jump over them. Further, they do not intrude
64 * on our cache or tlb entries.
67 struct exception_table_entry
69 unsigned long insn, fixup;
73 * architectures with an MMU should override these two
75 #ifndef __copy_from_user
76 static inline __must_check long __copy_from_user(void *to,
77 const void __user * from, unsigned long n)
79 if (__builtin_constant_p(n)) {
82 *(u8 *)to = *(u8 __force *)from;
85 *(u16 *)to = *(u16 __force *)from;
88 *(u32 *)to = *(u32 __force *)from;
92 *(u64 *)to = *(u64 __force *)from;
100 memcpy(to, (const void __force *)from, n);
105 #ifndef __copy_to_user
106 static inline __must_check long __copy_to_user(void __user *to,
107 const void *from, unsigned long n)
109 if (__builtin_constant_p(n)) {
112 *(u8 __force *)to = *(u8 *)from;
115 *(u16 __force *)to = *(u16 *)from;
118 *(u32 __force *)to = *(u32 *)from;
122 *(u64 __force *)to = *(u64 *)from;
130 memcpy((void __force *)to, from, n);
136 * These are the main single-value transfer routines. They automatically
137 * use the right size if we just have the right pointer type.
138 * This version just falls back to copy_{from,to}_user, which should
139 * provide a fast-path for small values.
141 #define __put_user(x, ptr) \
143 __typeof__(*(ptr)) __x = (x); \
144 int __pu_err = -EFAULT; \
145 __chk_user_ptr(ptr); \
146 switch (sizeof (*(ptr))) { \
151 __pu_err = __put_user_fn(sizeof (*(ptr)), \
161 #define put_user(x, ptr) \
165 access_ok(VERIFY_WRITE, __p, sizeof(*ptr)) ? \
166 __put_user((x), ((__typeof__(*(ptr)) *)__p)) : \
170 #ifndef __put_user_fn
172 static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
174 size = __copy_to_user(ptr, x, size);
175 return size ? -EFAULT : size;
178 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
182 extern int __put_user_bad(void) __attribute__((noreturn));
184 #define __get_user(x, ptr) \
186 int __gu_err = -EFAULT; \
187 __chk_user_ptr(ptr); \
188 switch (sizeof(*(ptr))) { \
191 __gu_err = __get_user_fn(sizeof (*(ptr)), \
193 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
197 unsigned short __x; \
198 __gu_err = __get_user_fn(sizeof (*(ptr)), \
200 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
205 __gu_err = __get_user_fn(sizeof (*(ptr)), \
207 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
211 unsigned long long __x; \
212 __gu_err = __get_user_fn(sizeof (*(ptr)), \
214 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
224 #define get_user(x, ptr) \
226 const void *__p = (ptr); \
228 access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \
229 __get_user((x), (__typeof__(*(ptr)) *)__p) : \
230 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \
233 #ifndef __get_user_fn
234 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
236 size_t n = __copy_from_user(x, ptr, size);
238 memset(x + (size - n), 0, n);
244 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
248 extern int __get_user_bad(void) __attribute__((noreturn));
250 #ifndef __copy_from_user_inatomic
251 #define __copy_from_user_inatomic __copy_from_user
254 #ifndef __copy_to_user_inatomic
255 #define __copy_to_user_inatomic __copy_to_user
258 static inline long copy_from_user(void *to,
259 const void __user * from, unsigned long n)
261 unsigned long res = n;
263 if (likely(access_ok(VERIFY_READ, from, n)))
264 res = __copy_from_user(to, from, n);
266 memset(to + (n - res), 0, res);
270 static inline long copy_to_user(void __user *to,
271 const void *from, unsigned long n)
274 if (access_ok(VERIFY_WRITE, to, n))
275 return __copy_to_user(to, from, n);
281 * Copy a null terminated string from userspace.
283 #ifndef __strncpy_from_user
285 __strncpy_from_user(char *dst, const char __user *src, long count)
288 strncpy(dst, (const char __force *)src, count);
289 for (tmp = dst; *tmp && count > 0; tmp++, count--)
296 strncpy_from_user(char *dst, const char __user *src, long count)
298 if (!access_ok(VERIFY_READ, src, 1))
300 return __strncpy_from_user(dst, src, count);
304 * Return the size of a string (including the ending 0)
306 * Return 0 on exception, a value greater than N if too long
308 #ifndef __strnlen_user
309 #define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
313 * Unlike strnlen, strnlen_user includes the nul terminator in
314 * its returned count. Callers should check for a returned value
315 * greater than N as an indication the string is too long.
317 static inline long strnlen_user(const char __user *src, long n)
319 if (!access_ok(VERIFY_READ, src, 1))
321 return __strnlen_user(src, n);
324 static inline long strlen_user(const char __user *src)
326 return strnlen_user(src, 32767);
333 static inline __must_check unsigned long
334 __clear_user(void __user *to, unsigned long n)
336 memset((void __force *)to, 0, n);
341 static inline __must_check unsigned long
342 clear_user(void __user *to, unsigned long n)
345 if (!access_ok(VERIFY_WRITE, to, n))
348 return __clear_user(to, n);
351 #endif /* __ASM_GENERIC_UACCESS_H */