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;
72 /* Returns 0 if exception not found and fixup otherwise. */
73 extern unsigned long search_exception_table(unsigned long);
76 * architectures with an MMU should override these two
78 #ifndef __copy_from_user
79 static inline __must_check long __copy_from_user(void *to,
80 const void __user * from, unsigned long n)
82 if (__builtin_constant_p(n)) {
85 *(u8 *)to = *(u8 __force *)from;
88 *(u16 *)to = *(u16 __force *)from;
91 *(u32 *)to = *(u32 __force *)from;
95 *(u64 *)to = *(u64 __force *)from;
103 memcpy(to, (const void __force *)from, n);
108 #ifndef __copy_to_user
109 static inline __must_check long __copy_to_user(void __user *to,
110 const void *from, unsigned long n)
112 if (__builtin_constant_p(n)) {
115 *(u8 __force *)to = *(u8 *)from;
118 *(u16 __force *)to = *(u16 *)from;
121 *(u32 __force *)to = *(u32 *)from;
125 *(u64 __force *)to = *(u64 *)from;
133 memcpy((void __force *)to, from, n);
139 * These are the main single-value transfer routines. They automatically
140 * use the right size if we just have the right pointer type.
141 * This version just falls back to copy_{from,to}_user, which should
142 * provide a fast-path for small values.
144 #define __put_user(x, ptr) \
146 __typeof__(*(ptr)) __x = (x); \
147 int __pu_err = -EFAULT; \
148 __chk_user_ptr(ptr); \
149 switch (sizeof (*(ptr))) { \
154 __pu_err = __put_user_fn(sizeof (*(ptr)), \
164 #define put_user(x, ptr) \
168 access_ok(VERIFY_WRITE, __p, sizeof(*ptr)) ? \
169 __put_user((x), ((__typeof__(*(ptr)) *)__p)) : \
173 #ifndef __put_user_fn
175 static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
177 size = __copy_to_user(ptr, x, size);
178 return size ? -EFAULT : size;
181 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
185 extern int __put_user_bad(void) __attribute__((noreturn));
187 #define __get_user(x, ptr) \
189 int __gu_err = -EFAULT; \
190 __chk_user_ptr(ptr); \
191 switch (sizeof(*(ptr))) { \
194 __gu_err = __get_user_fn(sizeof (*(ptr)), \
196 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
200 unsigned short __x; \
201 __gu_err = __get_user_fn(sizeof (*(ptr)), \
203 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
208 __gu_err = __get_user_fn(sizeof (*(ptr)), \
210 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
214 unsigned long long __x; \
215 __gu_err = __get_user_fn(sizeof (*(ptr)), \
217 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
227 #define get_user(x, ptr) \
229 const void *__p = (ptr); \
231 access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \
232 __get_user((x), (__typeof__(*(ptr)) *)__p) : \
233 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \
236 #ifndef __get_user_fn
237 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
239 size_t n = __copy_from_user(x, ptr, size);
241 memset(x + (size - n), 0, n);
247 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
251 extern int __get_user_bad(void) __attribute__((noreturn));
253 #ifndef __copy_from_user_inatomic
254 #define __copy_from_user_inatomic __copy_from_user
257 #ifndef __copy_to_user_inatomic
258 #define __copy_to_user_inatomic __copy_to_user
261 static inline long copy_from_user(void *to,
262 const void __user * from, unsigned long n)
264 unsigned long res = n;
266 if (likely(access_ok(VERIFY_READ, from, n)))
267 res = __copy_from_user(to, from, n);
269 memset(to + (n - res), 0, res);
273 static inline long copy_to_user(void __user *to,
274 const void *from, unsigned long n)
277 if (access_ok(VERIFY_WRITE, to, n))
278 return __copy_to_user(to, from, n);
284 * Copy a null terminated string from userspace.
286 #ifndef __strncpy_from_user
288 __strncpy_from_user(char *dst, const char __user *src, long count)
291 strncpy(dst, (const char __force *)src, count);
292 for (tmp = dst; *tmp && count > 0; tmp++, count--)
299 strncpy_from_user(char *dst, const char __user *src, long count)
301 if (!access_ok(VERIFY_READ, src, 1))
303 return __strncpy_from_user(dst, src, count);
307 * Return the size of a string (including the ending 0)
309 * Return 0 on exception, a value greater than N if too long
311 #ifndef __strnlen_user
312 #define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
316 * Unlike strnlen, strnlen_user includes the nul terminator in
317 * its returned count. Callers should check for a returned value
318 * greater than N as an indication the string is too long.
320 static inline long strnlen_user(const char __user *src, long n)
322 if (!access_ok(VERIFY_READ, src, 1))
324 return __strnlen_user(src, n);
327 static inline long strlen_user(const char __user *src)
329 return strnlen_user(src, 32767);
336 static inline __must_check unsigned long
337 __clear_user(void __user *to, unsigned long n)
339 memset((void __force *)to, 0, n);
344 static inline __must_check unsigned long
345 clear_user(void __user *to, unsigned long n)
348 if (!access_ok(VERIFY_WRITE, to, n))
351 return __clear_user(to, n);
354 #endif /* __ASM_GENERIC_UACCESS_H */