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/string.h> 10 11 #include <asm/segment.h> 12 13 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) 14 15 #ifndef KERNEL_DS 16 #define KERNEL_DS MAKE_MM_SEG(~0UL) 17 #endif 18 19 #ifndef USER_DS 20 #define USER_DS MAKE_MM_SEG(TASK_SIZE - 1) 21 #endif 22 23 #ifndef get_fs 24 #define get_ds() (KERNEL_DS) 25 #define get_fs() (current_thread_info()->addr_limit) 26 27 static inline void set_fs(mm_segment_t fs) 28 { 29 current_thread_info()->addr_limit = fs; 30 } 31 #endif 32 33 #ifndef segment_eq 34 #define segment_eq(a, b) ((a).seg == (b).seg) 35 #endif 36 37 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size)) 38 39 /* 40 * The architecture should really override this if possible, at least 41 * doing a check on the get_fs() 42 */ 43 #ifndef __access_ok 44 static inline int __access_ok(unsigned long addr, unsigned long size) 45 { 46 return 1; 47 } 48 #endif 49 50 /* 51 * These are the main single-value transfer routines. They automatically 52 * use the right size if we just have the right pointer type. 53 * This version just falls back to copy_{from,to}_user, which should 54 * provide a fast-path for small values. 55 */ 56 #define __put_user(x, ptr) \ 57 ({ \ 58 __typeof__(*(ptr)) __x = (x); \ 59 int __pu_err = -EFAULT; \ 60 __chk_user_ptr(ptr); \ 61 switch (sizeof (*(ptr))) { \ 62 case 1: \ 63 case 2: \ 64 case 4: \ 65 case 8: \ 66 __pu_err = __put_user_fn(sizeof (*(ptr)), \ 67 ptr, &__x); \ 68 break; \ 69 default: \ 70 __put_user_bad(); \ 71 break; \ 72 } \ 73 __pu_err; \ 74 }) 75 76 #define put_user(x, ptr) \ 77 ({ \ 78 void *__p = (ptr); \ 79 might_fault(); \ 80 access_ok(VERIFY_WRITE, __p, sizeof(*ptr)) ? \ 81 __put_user((x), ((__typeof__(*(ptr)) *)__p)) : \ 82 -EFAULT; \ 83 }) 84 85 #ifndef __put_user_fn 86 87 static inline int __put_user_fn(size_t size, void __user *ptr, void *x) 88 { 89 #ifdef CONFIG_ARCH_HAS_RAW_COPY_USER 90 return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0; 91 #else 92 return unlikely(__copy_to_user(ptr, x, size)) ? -EFAULT : 0; 93 #endif 94 } 95 96 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k) 97 98 #endif 99 100 extern int __put_user_bad(void) __attribute__((noreturn)); 101 102 #define __get_user(x, ptr) \ 103 ({ \ 104 int __gu_err = -EFAULT; \ 105 __chk_user_ptr(ptr); \ 106 switch (sizeof(*(ptr))) { \ 107 case 1: { \ 108 unsigned char __x = 0; \ 109 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 110 ptr, &__x); \ 111 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 112 break; \ 113 }; \ 114 case 2: { \ 115 unsigned short __x = 0; \ 116 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 117 ptr, &__x); \ 118 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 119 break; \ 120 }; \ 121 case 4: { \ 122 unsigned int __x = 0; \ 123 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 124 ptr, &__x); \ 125 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 126 break; \ 127 }; \ 128 case 8: { \ 129 unsigned long long __x = 0; \ 130 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 131 ptr, &__x); \ 132 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 133 break; \ 134 }; \ 135 default: \ 136 __get_user_bad(); \ 137 break; \ 138 } \ 139 __gu_err; \ 140 }) 141 142 #define get_user(x, ptr) \ 143 ({ \ 144 const void *__p = (ptr); \ 145 might_fault(); \ 146 access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \ 147 __get_user((x), (__typeof__(*(ptr)) *)__p) : \ 148 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \ 149 }) 150 151 #ifndef __get_user_fn 152 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) 153 { 154 #ifdef CONFIG_ARCH_HAS_RAW_COPY_USER 155 return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0; 156 #else 157 return unlikely(__copy_from_user(x, ptr, size)) ? -EFAULT : 0; 158 #endif 159 } 160 161 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) 162 163 #endif 164 165 extern int __get_user_bad(void) __attribute__((noreturn)); 166 167 #ifndef CONFIG_ARCH_HAS_RAW_COPY_USER 168 169 #ifndef __copy_from_user_inatomic 170 #define __copy_from_user_inatomic __copy_from_user 171 #endif 172 173 #ifndef __copy_to_user_inatomic 174 #define __copy_to_user_inatomic __copy_to_user 175 #endif 176 177 static inline long copy_from_user(void *to, 178 const void __user * from, unsigned long n) 179 { 180 unsigned long res = n; 181 might_fault(); 182 if (likely(access_ok(VERIFY_READ, from, n))) 183 res = __copy_from_user(to, from, n); 184 if (unlikely(res)) 185 memset(to + (n - res), 0, res); 186 return res; 187 } 188 189 static inline long copy_to_user(void __user *to, 190 const void *from, unsigned long n) 191 { 192 might_fault(); 193 if (access_ok(VERIFY_WRITE, to, n)) 194 return __copy_to_user(to, from, n); 195 else 196 return n; 197 } 198 #endif 199 200 /* 201 * Copy a null terminated string from userspace. 202 */ 203 #ifndef __strncpy_from_user 204 static inline long 205 __strncpy_from_user(char *dst, const char __user *src, long count) 206 { 207 char *tmp; 208 strncpy(dst, (const char __force *)src, count); 209 for (tmp = dst; *tmp && count > 0; tmp++, count--) 210 ; 211 return (tmp - dst); 212 } 213 #endif 214 215 static inline long 216 strncpy_from_user(char *dst, const char __user *src, long count) 217 { 218 if (!access_ok(VERIFY_READ, src, 1)) 219 return -EFAULT; 220 return __strncpy_from_user(dst, src, count); 221 } 222 223 /* 224 * Return the size of a string (including the ending 0) 225 * 226 * Return 0 on exception, a value greater than N if too long 227 */ 228 #ifndef __strnlen_user 229 #define __strnlen_user(s, n) (strnlen((s), (n)) + 1) 230 #endif 231 232 /* 233 * Unlike strnlen, strnlen_user includes the nul terminator in 234 * its returned count. Callers should check for a returned value 235 * greater than N as an indication the string is too long. 236 */ 237 static inline long strnlen_user(const char __user *src, long n) 238 { 239 if (!access_ok(VERIFY_READ, src, 1)) 240 return 0; 241 return __strnlen_user(src, n); 242 } 243 244 static inline long strlen_user(const char __user *src) 245 { 246 return strnlen_user(src, 32767); 247 } 248 249 /* 250 * Zero Userspace 251 */ 252 #ifndef __clear_user 253 static inline __must_check unsigned long 254 __clear_user(void __user *to, unsigned long n) 255 { 256 memset((void __force *)to, 0, n); 257 return 0; 258 } 259 #endif 260 261 static inline __must_check unsigned long 262 clear_user(void __user *to, unsigned long n) 263 { 264 might_fault(); 265 if (!access_ok(VERIFY_WRITE, to, n)) 266 return n; 267 268 return __clear_user(to, n); 269 } 270 271 #include <asm/extable.h> 272 273 #endif /* __ASM_GENERIC_UACCESS_H */ 274