1 #ifndef __ASM_GENERIC_UACCESS_H 2 #define __ASM_GENERIC_UACCESS_H 3 4 /* 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. 8 */ 9 #include <linux/sched.h> 10 #include <linux/string.h> 11 12 #include <asm/segment.h> 13 14 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) 15 16 #ifndef KERNEL_DS 17 #define KERNEL_DS MAKE_MM_SEG(~0UL) 18 #endif 19 20 #ifndef USER_DS 21 #define USER_DS MAKE_MM_SEG(TASK_SIZE - 1) 22 #endif 23 24 #ifndef get_fs 25 #define get_ds() (KERNEL_DS) 26 #define get_fs() (current_thread_info()->addr_limit) 27 28 static inline void set_fs(mm_segment_t fs) 29 { 30 current_thread_info()->addr_limit = fs; 31 } 32 #endif 33 34 #ifndef segment_eq 35 #define segment_eq(a, b) ((a).seg == (b).seg) 36 #endif 37 38 #define VERIFY_READ 0 39 #define VERIFY_WRITE 1 40 41 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size)) 42 43 /* 44 * The architecture should really override this if possible, at least 45 * doing a check on the get_fs() 46 */ 47 #ifndef __access_ok 48 static inline int __access_ok(unsigned long addr, unsigned long size) 49 { 50 return 1; 51 } 52 #endif 53 54 /* 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 59 * what to do. 60 * 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. 65 */ 66 67 struct exception_table_entry 68 { 69 unsigned long insn, fixup; 70 }; 71 72 /* 73 * architectures with an MMU should override these two 74 */ 75 #ifndef __copy_from_user 76 static inline __must_check long __copy_from_user(void *to, 77 const void __user * from, unsigned long n) 78 { 79 if (__builtin_constant_p(n)) { 80 switch(n) { 81 case 1: 82 *(u8 *)to = *(u8 __force *)from; 83 return 0; 84 case 2: 85 *(u16 *)to = *(u16 __force *)from; 86 return 0; 87 case 4: 88 *(u32 *)to = *(u32 __force *)from; 89 return 0; 90 #ifdef CONFIG_64BIT 91 case 8: 92 *(u64 *)to = *(u64 __force *)from; 93 return 0; 94 #endif 95 default: 96 break; 97 } 98 } 99 100 memcpy(to, (const void __force *)from, n); 101 return 0; 102 } 103 #endif 104 105 #ifndef __copy_to_user 106 static inline __must_check long __copy_to_user(void __user *to, 107 const void *from, unsigned long n) 108 { 109 if (__builtin_constant_p(n)) { 110 switch(n) { 111 case 1: 112 *(u8 __force *)to = *(u8 *)from; 113 return 0; 114 case 2: 115 *(u16 __force *)to = *(u16 *)from; 116 return 0; 117 case 4: 118 *(u32 __force *)to = *(u32 *)from; 119 return 0; 120 #ifdef CONFIG_64BIT 121 case 8: 122 *(u64 __force *)to = *(u64 *)from; 123 return 0; 124 #endif 125 default: 126 break; 127 } 128 } 129 130 memcpy((void __force *)to, from, n); 131 return 0; 132 } 133 #endif 134 135 /* 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. 140 */ 141 #define __put_user(x, ptr) \ 142 ({ \ 143 __typeof__(*(ptr)) __x = (x); \ 144 int __pu_err = -EFAULT; \ 145 __chk_user_ptr(ptr); \ 146 switch (sizeof (*(ptr))) { \ 147 case 1: \ 148 case 2: \ 149 case 4: \ 150 case 8: \ 151 __pu_err = __put_user_fn(sizeof (*(ptr)), \ 152 ptr, &__x); \ 153 break; \ 154 default: \ 155 __put_user_bad(); \ 156 break; \ 157 } \ 158 __pu_err; \ 159 }) 160 161 #define put_user(x, ptr) \ 162 ({ \ 163 void *__p = (ptr); \ 164 might_fault(); \ 165 access_ok(VERIFY_WRITE, __p, sizeof(*ptr)) ? \ 166 __put_user((x), ((__typeof__(*(ptr)) *)__p)) : \ 167 -EFAULT; \ 168 }) 169 170 #ifndef __put_user_fn 171 172 static inline int __put_user_fn(size_t size, void __user *ptr, void *x) 173 { 174 size = __copy_to_user(ptr, x, size); 175 return size ? -EFAULT : size; 176 } 177 178 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k) 179 180 #endif 181 182 extern int __put_user_bad(void) __attribute__((noreturn)); 183 184 #define __get_user(x, ptr) \ 185 ({ \ 186 int __gu_err = -EFAULT; \ 187 __chk_user_ptr(ptr); \ 188 switch (sizeof(*(ptr))) { \ 189 case 1: { \ 190 unsigned char __x; \ 191 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 192 ptr, &__x); \ 193 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 194 break; \ 195 }; \ 196 case 2: { \ 197 unsigned short __x; \ 198 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 199 ptr, &__x); \ 200 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 201 break; \ 202 }; \ 203 case 4: { \ 204 unsigned int __x; \ 205 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 206 ptr, &__x); \ 207 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 208 break; \ 209 }; \ 210 case 8: { \ 211 unsigned long long __x; \ 212 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 213 ptr, &__x); \ 214 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 215 break; \ 216 }; \ 217 default: \ 218 __get_user_bad(); \ 219 break; \ 220 } \ 221 __gu_err; \ 222 }) 223 224 #define get_user(x, ptr) \ 225 ({ \ 226 const void *__p = (ptr); \ 227 might_fault(); \ 228 access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \ 229 __get_user((x), (__typeof__(*(ptr)) *)__p) : \ 230 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \ 231 }) 232 233 #ifndef __get_user_fn 234 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) 235 { 236 size_t n = __copy_from_user(x, ptr, size); 237 if (unlikely(n)) { 238 memset(x + (size - n), 0, n); 239 return -EFAULT; 240 } 241 return 0; 242 } 243 244 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) 245 246 #endif 247 248 extern int __get_user_bad(void) __attribute__((noreturn)); 249 250 #ifndef __copy_from_user_inatomic 251 #define __copy_from_user_inatomic __copy_from_user 252 #endif 253 254 #ifndef __copy_to_user_inatomic 255 #define __copy_to_user_inatomic __copy_to_user 256 #endif 257 258 static inline long copy_from_user(void *to, 259 const void __user * from, unsigned long n) 260 { 261 unsigned long res = n; 262 might_fault(); 263 if (likely(access_ok(VERIFY_READ, from, n))) 264 res = __copy_from_user(to, from, n); 265 if (unlikely(res)) 266 memset(to + (n - res), 0, res); 267 return res; 268 } 269 270 static inline long copy_to_user(void __user *to, 271 const void *from, unsigned long n) 272 { 273 might_fault(); 274 if (access_ok(VERIFY_WRITE, to, n)) 275 return __copy_to_user(to, from, n); 276 else 277 return n; 278 } 279 280 /* 281 * Copy a null terminated string from userspace. 282 */ 283 #ifndef __strncpy_from_user 284 static inline long 285 __strncpy_from_user(char *dst, const char __user *src, long count) 286 { 287 char *tmp; 288 strncpy(dst, (const char __force *)src, count); 289 for (tmp = dst; *tmp && count > 0; tmp++, count--) 290 ; 291 return (tmp - dst); 292 } 293 #endif 294 295 static inline long 296 strncpy_from_user(char *dst, const char __user *src, long count) 297 { 298 if (!access_ok(VERIFY_READ, src, 1)) 299 return -EFAULT; 300 return __strncpy_from_user(dst, src, count); 301 } 302 303 /* 304 * Return the size of a string (including the ending 0) 305 * 306 * Return 0 on exception, a value greater than N if too long 307 */ 308 #ifndef __strnlen_user 309 #define __strnlen_user(s, n) (strnlen((s), (n)) + 1) 310 #endif 311 312 /* 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. 316 */ 317 static inline long strnlen_user(const char __user *src, long n) 318 { 319 if (!access_ok(VERIFY_READ, src, 1)) 320 return 0; 321 return __strnlen_user(src, n); 322 } 323 324 static inline long strlen_user(const char __user *src) 325 { 326 return strnlen_user(src, 32767); 327 } 328 329 /* 330 * Zero Userspace 331 */ 332 #ifndef __clear_user 333 static inline __must_check unsigned long 334 __clear_user(void __user *to, unsigned long n) 335 { 336 memset((void __force *)to, 0, n); 337 return 0; 338 } 339 #endif 340 341 static inline __must_check unsigned long 342 clear_user(void __user *to, unsigned long n) 343 { 344 might_fault(); 345 if (!access_ok(VERIFY_WRITE, to, n)) 346 return n; 347 348 return __clear_user(to, n); 349 } 350 351 #endif /* __ASM_GENERIC_UACCESS_H */ 352