1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __ASM_GENERIC_UACCESS_H 3 #define __ASM_GENERIC_UACCESS_H 4 5 /* 6 * User space memory access functions, these should work 7 * on any machine that has kernel and user data in the same 8 * address space, e.g. all NOMMU machines. 9 */ 10 #include <linux/string.h> 11 12 #ifdef CONFIG_UACCESS_MEMCPY 13 #include <asm/unaligned.h> 14 15 static __always_inline int 16 __get_user_fn(size_t size, const void __user *from, void *to) 17 { 18 BUILD_BUG_ON(!__builtin_constant_p(size)); 19 20 switch (size) { 21 case 1: 22 *(u8 *)to = *((u8 __force *)from); 23 return 0; 24 case 2: 25 *(u16 *)to = get_unaligned((u16 __force *)from); 26 return 0; 27 case 4: 28 *(u32 *)to = get_unaligned((u32 __force *)from); 29 return 0; 30 case 8: 31 *(u64 *)to = get_unaligned((u64 __force *)from); 32 return 0; 33 default: 34 BUILD_BUG(); 35 return 0; 36 } 37 38 } 39 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) 40 41 static __always_inline int 42 __put_user_fn(size_t size, void __user *to, void *from) 43 { 44 BUILD_BUG_ON(!__builtin_constant_p(size)); 45 46 switch (size) { 47 case 1: 48 *(u8 __force *)to = *(u8 *)from; 49 return 0; 50 case 2: 51 put_unaligned(*(u16 *)from, (u16 __force *)to); 52 return 0; 53 case 4: 54 put_unaligned(*(u32 *)from, (u32 __force *)to); 55 return 0; 56 case 8: 57 put_unaligned(*(u64 *)from, (u64 __force *)to); 58 return 0; 59 default: 60 BUILD_BUG(); 61 return 0; 62 } 63 } 64 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k) 65 66 #define __get_kernel_nofault(dst, src, type, err_label) \ 67 do { \ 68 *((type *)dst) = get_unaligned((type *)(src)); \ 69 if (0) /* make sure the label looks used to the compiler */ \ 70 goto err_label; \ 71 } while (0) 72 73 #define __put_kernel_nofault(dst, src, type, err_label) \ 74 do { \ 75 put_unaligned(*((type *)src), (type *)(dst)); \ 76 if (0) /* make sure the label looks used to the compiler */ \ 77 goto err_label; \ 78 } while (0) 79 80 #define HAVE_GET_KERNEL_NOFAULT 1 81 82 static inline __must_check unsigned long 83 raw_copy_from_user(void *to, const void __user * from, unsigned long n) 84 { 85 memcpy(to, (const void __force *)from, n); 86 return 0; 87 } 88 89 static inline __must_check unsigned long 90 raw_copy_to_user(void __user *to, const void *from, unsigned long n) 91 { 92 memcpy((void __force *)to, from, n); 93 return 0; 94 } 95 #define INLINE_COPY_FROM_USER 96 #define INLINE_COPY_TO_USER 97 #endif /* CONFIG_UACCESS_MEMCPY */ 98 99 #ifdef CONFIG_SET_FS 100 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) 101 102 #ifndef KERNEL_DS 103 #define KERNEL_DS MAKE_MM_SEG(~0UL) 104 #endif 105 106 #ifndef USER_DS 107 #define USER_DS MAKE_MM_SEG(TASK_SIZE - 1) 108 #endif 109 110 #ifndef get_fs 111 #define get_fs() (current_thread_info()->addr_limit) 112 113 static inline void set_fs(mm_segment_t fs) 114 { 115 current_thread_info()->addr_limit = fs; 116 } 117 #endif 118 119 #ifndef uaccess_kernel 120 #define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) 121 #endif 122 123 #ifndef user_addr_max 124 #define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) 125 #endif 126 127 #endif /* CONFIG_SET_FS */ 128 129 #define access_ok(addr, size) __access_ok((unsigned long)(addr),(size)) 130 131 /* 132 * The architecture should really override this if possible, at least 133 * doing a check on the get_fs() 134 */ 135 #ifndef __access_ok 136 static inline int __access_ok(unsigned long addr, unsigned long size) 137 { 138 return 1; 139 } 140 #endif 141 142 /* 143 * These are the main single-value transfer routines. They automatically 144 * use the right size if we just have the right pointer type. 145 * This version just falls back to copy_{from,to}_user, which should 146 * provide a fast-path for small values. 147 */ 148 #define __put_user(x, ptr) \ 149 ({ \ 150 __typeof__(*(ptr)) __x = (x); \ 151 int __pu_err = -EFAULT; \ 152 __chk_user_ptr(ptr); \ 153 switch (sizeof (*(ptr))) { \ 154 case 1: \ 155 case 2: \ 156 case 4: \ 157 case 8: \ 158 __pu_err = __put_user_fn(sizeof (*(ptr)), \ 159 ptr, &__x); \ 160 break; \ 161 default: \ 162 __put_user_bad(); \ 163 break; \ 164 } \ 165 __pu_err; \ 166 }) 167 168 #define put_user(x, ptr) \ 169 ({ \ 170 void __user *__p = (ptr); \ 171 might_fault(); \ 172 access_ok(__p, sizeof(*ptr)) ? \ 173 __put_user((x), ((__typeof__(*(ptr)) __user *)__p)) : \ 174 -EFAULT; \ 175 }) 176 177 #ifndef __put_user_fn 178 179 static inline int __put_user_fn(size_t size, void __user *ptr, void *x) 180 { 181 return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0; 182 } 183 184 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k) 185 186 #endif 187 188 extern int __put_user_bad(void) __attribute__((noreturn)); 189 190 #define __get_user(x, ptr) \ 191 ({ \ 192 int __gu_err = -EFAULT; \ 193 __chk_user_ptr(ptr); \ 194 switch (sizeof(*(ptr))) { \ 195 case 1: { \ 196 unsigned char __x = 0; \ 197 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 198 ptr, &__x); \ 199 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 200 break; \ 201 }; \ 202 case 2: { \ 203 unsigned short __x = 0; \ 204 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 205 ptr, &__x); \ 206 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 207 break; \ 208 }; \ 209 case 4: { \ 210 unsigned int __x = 0; \ 211 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 212 ptr, &__x); \ 213 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 214 break; \ 215 }; \ 216 case 8: { \ 217 unsigned long long __x = 0; \ 218 __gu_err = __get_user_fn(sizeof (*(ptr)), \ 219 ptr, &__x); \ 220 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 221 break; \ 222 }; \ 223 default: \ 224 __get_user_bad(); \ 225 break; \ 226 } \ 227 __gu_err; \ 228 }) 229 230 #define get_user(x, ptr) \ 231 ({ \ 232 const void __user *__p = (ptr); \ 233 might_fault(); \ 234 access_ok(__p, sizeof(*ptr)) ? \ 235 __get_user((x), (__typeof__(*(ptr)) __user *)__p) :\ 236 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \ 237 }) 238 239 #ifndef __get_user_fn 240 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) 241 { 242 return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0; 243 } 244 245 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) 246 247 #endif 248 249 extern int __get_user_bad(void) __attribute__((noreturn)); 250 251 /* 252 * Zero Userspace 253 */ 254 #ifndef __clear_user 255 static inline __must_check unsigned long 256 __clear_user(void __user *to, unsigned long n) 257 { 258 memset((void __force *)to, 0, n); 259 return 0; 260 } 261 #endif 262 263 static inline __must_check unsigned long 264 clear_user(void __user *to, unsigned long n) 265 { 266 might_fault(); 267 if (!access_ok(to, n)) 268 return n; 269 270 return __clear_user(to, n); 271 } 272 273 #include <asm/extable.h> 274 275 __must_check long strncpy_from_user(char *dst, const char __user *src, 276 long count); 277 __must_check long strnlen_user(const char __user *src, long n); 278 279 #endif /* __ASM_GENERIC_UACCESS_H */ 280