1#ifndef __SCORE_UACCESS_H 2#define __SCORE_UACCESS_H 3 4#include <linux/kernel.h> 5#include <linux/errno.h> 6#include <linux/thread_info.h> 7 8#define VERIFY_READ 0 9#define VERIFY_WRITE 1 10 11#define get_ds() (KERNEL_DS) 12#define get_fs() (current_thread_info()->addr_limit) 13#define segment_eq(a, b) ((a).seg == (b).seg) 14 15/* 16 * Is a address valid? This does a straighforward calculation rather 17 * than tests. 18 * 19 * Address valid if: 20 * - "addr" doesn't have any high-bits set 21 * - AND "size" doesn't have any high-bits set 22 * - AND "addr+size" doesn't have any high-bits set 23 * - OR we are in kernel mode. 24 * 25 * __ua_size() is a trick to avoid runtime checking of positive constant 26 * sizes; for those we already know at compile time that the size is ok. 27 */ 28#define __ua_size(size) \ 29 ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size)) 30 31/* 32 * access_ok: - Checks if a user space pointer is valid 33 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that 34 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe 35 * to write to a block, it is always safe to read from it. 36 * @addr: User space pointer to start of block to check 37 * @size: Size of block to check 38 * 39 * Context: User context only. This function may sleep. 40 * 41 * Checks if a pointer to a block of memory in user space is valid. 42 * 43 * Returns true (nonzero) if the memory block may be valid, false (zero) 44 * if it is definitely invalid. 45 * 46 * Note that, depending on architecture, this function probably just 47 * checks that the pointer is in the user space range - after calling 48 * this function, memory access functions may still return -EFAULT. 49 */ 50 51#define __access_ok(addr, size) \ 52 (((long)((get_fs().seg) & \ 53 ((addr) | ((addr) + (size)) | \ 54 __ua_size(size)))) == 0) 55 56#define access_ok(type, addr, size) \ 57 likely(__access_ok((unsigned long)(addr), (size))) 58 59/* 60 * put_user: - Write a simple value into user space. 61 * @x: Value to copy to user space. 62 * @ptr: Destination address, in user space. 63 * 64 * Context: User context only. This function may sleep. 65 * 66 * This macro copies a single simple value from kernel space to user 67 * space. It supports simple types like char and int, but not larger 68 * data types like structures or arrays. 69 * 70 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 71 * to the result of dereferencing @ptr. 72 * 73 * Returns zero on success, or -EFAULT on error. 74 */ 75#define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr))) 76 77/* 78 * get_user: - Get a simple variable from user space. 79 * @x: Variable to store result. 80 * @ptr: Source address, in user space. 81 * 82 * Context: User context only. This function may sleep. 83 * 84 * This macro copies a single simple variable from user space to kernel 85 * space. It supports simple types like char and int, but not larger 86 * data types like structures or arrays. 87 * 88 * @ptr must have pointer-to-simple-variable type, and the result of 89 * dereferencing @ptr must be assignable to @x without a cast. 90 * 91 * Returns zero on success, or -EFAULT on error. 92 * On error, the variable @x is set to zero. 93 */ 94#define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr))) 95 96/* 97 * __put_user: - Write a simple value into user space, with less checking. 98 * @x: Value to copy to user space. 99 * @ptr: Destination address, in user space. 100 * 101 * Context: User context only. This function may sleep. 102 * 103 * This macro copies a single simple value from kernel space to user 104 * space. It supports simple types like char and int, but not larger 105 * data types like structures or arrays. 106 * 107 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 108 * to the result of dereferencing @ptr. 109 * 110 * Caller must check the pointer with access_ok() before calling this 111 * function. 112 * 113 * Returns zero on success, or -EFAULT on error. 114 */ 115#define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr))) 116 117/* 118 * __get_user: - Get a simple variable from user space, with less checking. 119 * @x: Variable to store result. 120 * @ptr: Source address, in user space. 121 * 122 * Context: User context only. This function may sleep. 123 * 124 * This macro copies a single simple variable from user space to kernel 125 * space. It supports simple types like char and int, but not larger 126 * data types like structures or arrays. 127 * 128 * @ptr must have pointer-to-simple-variable type, and the result of 129 * dereferencing @ptr must be assignable to @x without a cast. 130 * 131 * Caller must check the pointer with access_ok() before calling this 132 * function. 133 * 134 * Returns zero on success, or -EFAULT on error. 135 * On error, the variable @x is set to zero. 136 */ 137#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 138 139struct __large_struct { unsigned long buf[100]; }; 140#define __m(x) (*(struct __large_struct __user *)(x)) 141 142/* 143 * Yuck. We need two variants, one for 64bit operation and one 144 * for 32 bit mode and old iron. 145 */ 146extern void __get_user_unknown(void); 147 148#define __get_user_common(val, size, ptr) \ 149do { \ 150 switch (size) { \ 151 case 1: \ 152 __get_user_asm(val, "lb", ptr); \ 153 break; \ 154 case 2: \ 155 __get_user_asm(val, "lh", ptr); \ 156 break; \ 157 case 4: \ 158 __get_user_asm(val, "lw", ptr); \ 159 break; \ 160 case 8: \ 161 if ((copy_from_user((void *)&val, ptr, 8)) == 0) \ 162 __gu_err = 0; \ 163 else \ 164 __gu_err = -EFAULT; \ 165 break; \ 166 default: \ 167 __get_user_unknown(); \ 168 break; \ 169 } \ 170} while (0) 171 172#define __get_user_nocheck(x, ptr, size) \ 173({ \ 174 long __gu_err = 0; \ 175 __get_user_common((x), size, ptr); \ 176 __gu_err; \ 177}) 178 179#define __get_user_check(x, ptr, size) \ 180({ \ 181 long __gu_err = -EFAULT; \ 182 const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ 183 \ 184 if (likely(access_ok(VERIFY_READ, __gu_ptr, size))) \ 185 __get_user_common((x), size, __gu_ptr); \ 186 \ 187 __gu_err; \ 188}) 189 190#define __get_user_asm(val, insn, addr) \ 191{ \ 192 long __gu_tmp; \ 193 \ 194 __asm__ __volatile__( \ 195 "1:" insn " %1, %3\n" \ 196 "2:\n" \ 197 ".section .fixup,\"ax\"\n" \ 198 "3:li %0, %4\n" \ 199 "j 2b\n" \ 200 ".previous\n" \ 201 ".section __ex_table,\"a\"\n" \ 202 ".word 1b, 3b\n" \ 203 ".previous\n" \ 204 : "=r" (__gu_err), "=r" (__gu_tmp) \ 205 : "0" (0), "o" (__m(addr)), "i" (-EFAULT)); \ 206 \ 207 (val) = (__typeof__(*(addr))) __gu_tmp; \ 208} 209 210/* 211 * Yuck. We need two variants, one for 64bit operation and one 212 * for 32 bit mode and old iron. 213 */ 214#define __put_user_nocheck(val, ptr, size) \ 215({ \ 216 __typeof__(*(ptr)) __pu_val; \ 217 long __pu_err = 0; \ 218 \ 219 __pu_val = (val); \ 220 switch (size) { \ 221 case 1: \ 222 __put_user_asm("sb", ptr); \ 223 break; \ 224 case 2: \ 225 __put_user_asm("sh", ptr); \ 226 break; \ 227 case 4: \ 228 __put_user_asm("sw", ptr); \ 229 break; \ 230 case 8: \ 231 if ((__copy_to_user((void *)ptr, &__pu_val, 8)) == 0) \ 232 __pu_err = 0; \ 233 else \ 234 __pu_err = -EFAULT; \ 235 break; \ 236 default: \ 237 __put_user_unknown(); \ 238 break; \ 239 } \ 240 __pu_err; \ 241}) 242 243 244#define __put_user_check(val, ptr, size) \ 245({ \ 246 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ 247 __typeof__(*(ptr)) __pu_val = (val); \ 248 long __pu_err = -EFAULT; \ 249 \ 250 if (likely(access_ok(VERIFY_WRITE, __pu_addr, size))) { \ 251 switch (size) { \ 252 case 1: \ 253 __put_user_asm("sb", __pu_addr); \ 254 break; \ 255 case 2: \ 256 __put_user_asm("sh", __pu_addr); \ 257 break; \ 258 case 4: \ 259 __put_user_asm("sw", __pu_addr); \ 260 break; \ 261 case 8: \ 262 if ((__copy_to_user((void *)__pu_addr, &__pu_val, 8)) == 0)\ 263 __pu_err = 0; \ 264 else \ 265 __pu_err = -EFAULT; \ 266 break; \ 267 default: \ 268 __put_user_unknown(); \ 269 break; \ 270 } \ 271 } \ 272 __pu_err; \ 273}) 274 275#define __put_user_asm(insn, ptr) \ 276 __asm__ __volatile__( \ 277 "1:" insn " %2, %3\n" \ 278 "2:\n" \ 279 ".section .fixup,\"ax\"\n" \ 280 "3:li %0, %4\n" \ 281 "j 2b\n" \ 282 ".previous\n" \ 283 ".section __ex_table,\"a\"\n" \ 284 ".word 1b, 3b\n" \ 285 ".previous\n" \ 286 : "=r" (__pu_err) \ 287 : "0" (0), "r" (__pu_val), "o" (__m(ptr)), \ 288 "i" (-EFAULT)); 289 290extern void __put_user_unknown(void); 291extern int __copy_tofrom_user(void *to, const void *from, unsigned long len); 292 293static inline unsigned long 294copy_from_user(void *to, const void *from, unsigned long len) 295{ 296 unsigned long over; 297 298 if (access_ok(VERIFY_READ, from, len)) 299 return __copy_tofrom_user(to, from, len); 300 301 if ((unsigned long)from < TASK_SIZE) { 302 over = (unsigned long)from + len - TASK_SIZE; 303 return __copy_tofrom_user(to, from, len - over) + over; 304 } 305 return len; 306} 307 308static inline unsigned long 309copy_to_user(void *to, const void *from, unsigned long len) 310{ 311 unsigned long over; 312 313 if (access_ok(VERIFY_WRITE, to, len)) 314 return __copy_tofrom_user(to, from, len); 315 316 if ((unsigned long)to < TASK_SIZE) { 317 over = (unsigned long)to + len - TASK_SIZE; 318 return __copy_tofrom_user(to, from, len - over) + over; 319 } 320 return len; 321} 322 323#define __copy_from_user(to, from, len) \ 324 __copy_tofrom_user((to), (from), (len)) 325 326#define __copy_to_user(to, from, len) \ 327 __copy_tofrom_user((to), (from), (len)) 328 329static inline unsigned long 330__copy_to_user_inatomic(void *to, const void *from, unsigned long len) 331{ 332 return __copy_to_user(to, from, len); 333} 334 335static inline unsigned long 336__copy_from_user_inatomic(void *to, const void *from, unsigned long len) 337{ 338 return __copy_from_user(to, from, len); 339} 340 341#define __copy_in_user(to, from, len) __copy_from_user(to, from, len) 342 343static inline unsigned long 344copy_in_user(void *to, const void *from, unsigned long len) 345{ 346 if (access_ok(VERIFY_READ, from, len) && 347 access_ok(VERFITY_WRITE, to, len)) 348 return copy_from_user(to, from, len); 349} 350 351/* 352 * __clear_user: - Zero a block of memory in user space, with less checking. 353 * @to: Destination address, in user space. 354 * @n: Number of bytes to zero. 355 * 356 * Zero a block of memory in user space. Caller must check 357 * the specified block with access_ok() before calling this function. 358 * 359 * Returns number of bytes that could not be cleared. 360 * On success, this will be zero. 361 */ 362extern unsigned long __clear_user(void __user *src, unsigned long size); 363 364static inline unsigned long clear_user(char *src, unsigned long size) 365{ 366 if (access_ok(VERIFY_WRITE, src, size)) 367 return __clear_user(src, size); 368 369 return -EFAULT; 370} 371/* 372 * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking. 373 * @dst: Destination address, in kernel space. This buffer must be at 374 * least @count bytes long. 375 * @src: Source address, in user space. 376 * @count: Maximum number of bytes to copy, including the trailing NUL. 377 * 378 * Copies a NUL-terminated string from userspace to kernel space. 379 * Caller must check the specified block with access_ok() before calling 380 * this function. 381 * 382 * On success, returns the length of the string (not including the trailing 383 * NUL). 384 * 385 * If access to userspace fails, returns -EFAULT (some data may have been 386 * copied). 387 * 388 * If @count is smaller than the length of the string, copies @count bytes 389 * and returns @count. 390 */ 391extern int __strncpy_from_user(char *dst, const char *src, long len); 392 393static inline int strncpy_from_user(char *dst, const char *src, long len) 394{ 395 if (access_ok(VERIFY_READ, src, 1)) 396 return __strncpy_from_user(dst, src, len); 397 398 return -EFAULT; 399} 400 401extern int __strlen_user(const char *src); 402static inline long strlen_user(const char __user *src) 403{ 404 return __strlen_user(src); 405} 406 407extern int __strnlen_user(const char *str, long len); 408static inline long strnlen_user(const char __user *str, long len) 409{ 410 if (!access_ok(VERIFY_READ, str, 0)) 411 return 0; 412 else 413 return __strnlen_user(str, len); 414} 415 416struct exception_table_entry { 417 unsigned long insn; 418 unsigned long fixup; 419}; 420 421extern int fixup_exception(struct pt_regs *regs); 422 423#endif /* __SCORE_UACCESS_H */ 424