1 /* 2 * arch/arm/include/asm/uaccess.h 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 #ifndef _ASMARM_UACCESS_H 9 #define _ASMARM_UACCESS_H 10 11 /* 12 * User space memory access functions 13 */ 14 #include <linux/string.h> 15 #include <linux/thread_info.h> 16 #include <asm/errno.h> 17 #include <asm/memory.h> 18 #include <asm/domain.h> 19 #include <asm/unified.h> 20 #include <asm/compiler.h> 21 22 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 23 #include <asm-generic/uaccess-unaligned.h> 24 #else 25 #define __get_user_unaligned __get_user 26 #define __put_user_unaligned __put_user 27 #endif 28 29 #define VERIFY_READ 0 30 #define VERIFY_WRITE 1 31 32 /* 33 * The exception table consists of pairs of addresses: the first is the 34 * address of an instruction that is allowed to fault, and the second is 35 * the address at which the program should continue. No registers are 36 * modified, so it is entirely up to the continuation code to figure out 37 * what to do. 38 * 39 * All the routines below use bits of fixup code that are out of line 40 * with the main instruction path. This means when everything is well, 41 * we don't even have to jump over them. Further, they do not intrude 42 * on our cache or tlb entries. 43 */ 44 45 struct exception_table_entry 46 { 47 unsigned long insn, fixup; 48 }; 49 50 extern int fixup_exception(struct pt_regs *regs); 51 52 /* 53 * These two are intentionally not defined anywhere - if the kernel 54 * code generates any references to them, that's a bug. 55 */ 56 extern int __get_user_bad(void); 57 extern int __put_user_bad(void); 58 59 /* 60 * Note that this is actually 0x1,0000,0000 61 */ 62 #define KERNEL_DS 0x00000000 63 #define get_ds() (KERNEL_DS) 64 65 #ifdef CONFIG_MMU 66 67 #define USER_DS TASK_SIZE 68 #define get_fs() (current_thread_info()->addr_limit) 69 70 static inline void set_fs(mm_segment_t fs) 71 { 72 current_thread_info()->addr_limit = fs; 73 modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER); 74 } 75 76 #define segment_eq(a,b) ((a) == (b)) 77 78 #define __addr_ok(addr) ({ \ 79 unsigned long flag; \ 80 __asm__("cmp %2, %0; movlo %0, #0" \ 81 : "=&r" (flag) \ 82 : "0" (current_thread_info()->addr_limit), "r" (addr) \ 83 : "cc"); \ 84 (flag == 0); }) 85 86 /* We use 33-bit arithmetic here... */ 87 #define __range_ok(addr,size) ({ \ 88 unsigned long flag, roksum; \ 89 __chk_user_ptr(addr); \ 90 __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \ 91 : "=&r" (flag), "=&r" (roksum) \ 92 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \ 93 : "cc"); \ 94 flag; }) 95 96 /* 97 * Single-value transfer routines. They automatically use the right 98 * size if we just have the right pointer type. Note that the functions 99 * which read from user space (*get_*) need to take care not to leak 100 * kernel data even if the calling code is buggy and fails to check 101 * the return value. This means zeroing out the destination variable 102 * or buffer on error. Normally this is done out of line by the 103 * fixup code, but there are a few places where it intrudes on the 104 * main code path. When we only write to user space, there is no 105 * problem. 106 */ 107 extern int __get_user_1(void *); 108 extern int __get_user_2(void *); 109 extern int __get_user_4(void *); 110 extern int __get_user_lo8(void *); 111 extern int __get_user_8(void *); 112 113 #define __GUP_CLOBBER_1 "lr", "cc" 114 #ifdef CONFIG_CPU_USE_DOMAINS 115 #define __GUP_CLOBBER_2 "ip", "lr", "cc" 116 #else 117 #define __GUP_CLOBBER_2 "lr", "cc" 118 #endif 119 #define __GUP_CLOBBER_4 "lr", "cc" 120 #define __GUP_CLOBBER_lo8 "lr", "cc" 121 #define __GUP_CLOBBER_8 "lr", "cc" 122 123 #define __get_user_x(__r2,__p,__e,__l,__s) \ 124 __asm__ __volatile__ ( \ 125 __asmeq("%0", "r0") __asmeq("%1", "r2") \ 126 __asmeq("%3", "r1") \ 127 "bl __get_user_" #__s \ 128 : "=&r" (__e), "=r" (__r2) \ 129 : "0" (__p), "r" (__l) \ 130 : __GUP_CLOBBER_##__s) 131 132 /* narrowing a double-word get into a single 32bit word register: */ 133 #ifdef __ARMEB__ 134 #define __get_user_xb(__r2, __p, __e, __l, __s) \ 135 __get_user_x(__r2, __p, __e, __l, lo8) 136 #else 137 #define __get_user_xb __get_user_x 138 #endif 139 140 #define __get_user_check(x,p) \ 141 ({ \ 142 unsigned long __limit = current_thread_info()->addr_limit - 1; \ 143 register const typeof(*(p)) __user *__p asm("r0") = (p);\ 144 register typeof(x) __r2 asm("r2"); \ 145 register unsigned long __l asm("r1") = __limit; \ 146 register int __e asm("r0"); \ 147 switch (sizeof(*(__p))) { \ 148 case 1: \ 149 __get_user_x(__r2, __p, __e, __l, 1); \ 150 break; \ 151 case 2: \ 152 __get_user_x(__r2, __p, __e, __l, 2); \ 153 break; \ 154 case 4: \ 155 __get_user_x(__r2, __p, __e, __l, 4); \ 156 break; \ 157 case 8: \ 158 if (sizeof((x)) < 8) \ 159 __get_user_xb(__r2, __p, __e, __l, 4); \ 160 else \ 161 __get_user_x(__r2, __p, __e, __l, 8); \ 162 break; \ 163 default: __e = __get_user_bad(); break; \ 164 } \ 165 x = (typeof(*(p))) __r2; \ 166 __e; \ 167 }) 168 169 #define get_user(x,p) \ 170 ({ \ 171 might_fault(); \ 172 __get_user_check(x,p); \ 173 }) 174 175 extern int __put_user_1(void *, unsigned int); 176 extern int __put_user_2(void *, unsigned int); 177 extern int __put_user_4(void *, unsigned int); 178 extern int __put_user_8(void *, unsigned long long); 179 180 #define __put_user_x(__r2,__p,__e,__l,__s) \ 181 __asm__ __volatile__ ( \ 182 __asmeq("%0", "r0") __asmeq("%2", "r2") \ 183 __asmeq("%3", "r1") \ 184 "bl __put_user_" #__s \ 185 : "=&r" (__e) \ 186 : "0" (__p), "r" (__r2), "r" (__l) \ 187 : "ip", "lr", "cc") 188 189 #define __put_user_check(x,p) \ 190 ({ \ 191 unsigned long __limit = current_thread_info()->addr_limit - 1; \ 192 const typeof(*(p)) __user *__tmp_p = (p); \ 193 register const typeof(*(p)) __r2 asm("r2") = (x); \ 194 register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \ 195 register unsigned long __l asm("r1") = __limit; \ 196 register int __e asm("r0"); \ 197 switch (sizeof(*(__p))) { \ 198 case 1: \ 199 __put_user_x(__r2, __p, __e, __l, 1); \ 200 break; \ 201 case 2: \ 202 __put_user_x(__r2, __p, __e, __l, 2); \ 203 break; \ 204 case 4: \ 205 __put_user_x(__r2, __p, __e, __l, 4); \ 206 break; \ 207 case 8: \ 208 __put_user_x(__r2, __p, __e, __l, 8); \ 209 break; \ 210 default: __e = __put_user_bad(); break; \ 211 } \ 212 __e; \ 213 }) 214 215 #define put_user(x,p) \ 216 ({ \ 217 might_fault(); \ 218 __put_user_check(x,p); \ 219 }) 220 221 #else /* CONFIG_MMU */ 222 223 /* 224 * uClinux has only one addr space, so has simplified address limits. 225 */ 226 #define USER_DS KERNEL_DS 227 228 #define segment_eq(a,b) (1) 229 #define __addr_ok(addr) ((void)(addr),1) 230 #define __range_ok(addr,size) ((void)(addr),0) 231 #define get_fs() (KERNEL_DS) 232 233 static inline void set_fs(mm_segment_t fs) 234 { 235 } 236 237 #define get_user(x,p) __get_user(x,p) 238 #define put_user(x,p) __put_user(x,p) 239 240 #endif /* CONFIG_MMU */ 241 242 #define access_ok(type,addr,size) (__range_ok(addr,size) == 0) 243 244 #define user_addr_max() \ 245 (segment_eq(get_fs(), KERNEL_DS) ? ~0UL : get_fs()) 246 247 /* 248 * The "__xxx" versions of the user access functions do not verify the 249 * address space - it must have been done previously with a separate 250 * "access_ok()" call. 251 * 252 * The "xxx_error" versions set the third argument to EFAULT if an 253 * error occurs, and leave it unchanged on success. Note that these 254 * versions are void (ie, don't return a value as such). 255 */ 256 #define __get_user(x,ptr) \ 257 ({ \ 258 long __gu_err = 0; \ 259 __get_user_err((x),(ptr),__gu_err); \ 260 __gu_err; \ 261 }) 262 263 #define __get_user_error(x,ptr,err) \ 264 ({ \ 265 __get_user_err((x),(ptr),err); \ 266 (void) 0; \ 267 }) 268 269 #define __get_user_err(x,ptr,err) \ 270 do { \ 271 unsigned long __gu_addr = (unsigned long)(ptr); \ 272 unsigned long __gu_val; \ 273 __chk_user_ptr(ptr); \ 274 might_fault(); \ 275 switch (sizeof(*(ptr))) { \ 276 case 1: __get_user_asm_byte(__gu_val,__gu_addr,err); break; \ 277 case 2: __get_user_asm_half(__gu_val,__gu_addr,err); break; \ 278 case 4: __get_user_asm_word(__gu_val,__gu_addr,err); break; \ 279 default: (__gu_val) = __get_user_bad(); \ 280 } \ 281 (x) = (__typeof__(*(ptr)))__gu_val; \ 282 } while (0) 283 284 #define __get_user_asm_byte(x,addr,err) \ 285 __asm__ __volatile__( \ 286 "1: " TUSER(ldrb) " %1,[%2],#0\n" \ 287 "2:\n" \ 288 " .pushsection .fixup,\"ax\"\n" \ 289 " .align 2\n" \ 290 "3: mov %0, %3\n" \ 291 " mov %1, #0\n" \ 292 " b 2b\n" \ 293 " .popsection\n" \ 294 " .pushsection __ex_table,\"a\"\n" \ 295 " .align 3\n" \ 296 " .long 1b, 3b\n" \ 297 " .popsection" \ 298 : "+r" (err), "=&r" (x) \ 299 : "r" (addr), "i" (-EFAULT) \ 300 : "cc") 301 302 #ifndef __ARMEB__ 303 #define __get_user_asm_half(x,__gu_addr,err) \ 304 ({ \ 305 unsigned long __b1, __b2; \ 306 __get_user_asm_byte(__b1, __gu_addr, err); \ 307 __get_user_asm_byte(__b2, __gu_addr + 1, err); \ 308 (x) = __b1 | (__b2 << 8); \ 309 }) 310 #else 311 #define __get_user_asm_half(x,__gu_addr,err) \ 312 ({ \ 313 unsigned long __b1, __b2; \ 314 __get_user_asm_byte(__b1, __gu_addr, err); \ 315 __get_user_asm_byte(__b2, __gu_addr + 1, err); \ 316 (x) = (__b1 << 8) | __b2; \ 317 }) 318 #endif 319 320 #define __get_user_asm_word(x,addr,err) \ 321 __asm__ __volatile__( \ 322 "1: " TUSER(ldr) " %1,[%2],#0\n" \ 323 "2:\n" \ 324 " .pushsection .fixup,\"ax\"\n" \ 325 " .align 2\n" \ 326 "3: mov %0, %3\n" \ 327 " mov %1, #0\n" \ 328 " b 2b\n" \ 329 " .popsection\n" \ 330 " .pushsection __ex_table,\"a\"\n" \ 331 " .align 3\n" \ 332 " .long 1b, 3b\n" \ 333 " .popsection" \ 334 : "+r" (err), "=&r" (x) \ 335 : "r" (addr), "i" (-EFAULT) \ 336 : "cc") 337 338 #define __put_user(x,ptr) \ 339 ({ \ 340 long __pu_err = 0; \ 341 __put_user_err((x),(ptr),__pu_err); \ 342 __pu_err; \ 343 }) 344 345 #define __put_user_error(x,ptr,err) \ 346 ({ \ 347 __put_user_err((x),(ptr),err); \ 348 (void) 0; \ 349 }) 350 351 #define __put_user_err(x,ptr,err) \ 352 do { \ 353 unsigned long __pu_addr = (unsigned long)(ptr); \ 354 __typeof__(*(ptr)) __pu_val = (x); \ 355 __chk_user_ptr(ptr); \ 356 might_fault(); \ 357 switch (sizeof(*(ptr))) { \ 358 case 1: __put_user_asm_byte(__pu_val,__pu_addr,err); break; \ 359 case 2: __put_user_asm_half(__pu_val,__pu_addr,err); break; \ 360 case 4: __put_user_asm_word(__pu_val,__pu_addr,err); break; \ 361 case 8: __put_user_asm_dword(__pu_val,__pu_addr,err); break; \ 362 default: __put_user_bad(); \ 363 } \ 364 } while (0) 365 366 #define __put_user_asm_byte(x,__pu_addr,err) \ 367 __asm__ __volatile__( \ 368 "1: " TUSER(strb) " %1,[%2],#0\n" \ 369 "2:\n" \ 370 " .pushsection .fixup,\"ax\"\n" \ 371 " .align 2\n" \ 372 "3: mov %0, %3\n" \ 373 " b 2b\n" \ 374 " .popsection\n" \ 375 " .pushsection __ex_table,\"a\"\n" \ 376 " .align 3\n" \ 377 " .long 1b, 3b\n" \ 378 " .popsection" \ 379 : "+r" (err) \ 380 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \ 381 : "cc") 382 383 #ifndef __ARMEB__ 384 #define __put_user_asm_half(x,__pu_addr,err) \ 385 ({ \ 386 unsigned long __temp = (unsigned long)(x); \ 387 __put_user_asm_byte(__temp, __pu_addr, err); \ 388 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \ 389 }) 390 #else 391 #define __put_user_asm_half(x,__pu_addr,err) \ 392 ({ \ 393 unsigned long __temp = (unsigned long)(x); \ 394 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \ 395 __put_user_asm_byte(__temp, __pu_addr + 1, err); \ 396 }) 397 #endif 398 399 #define __put_user_asm_word(x,__pu_addr,err) \ 400 __asm__ __volatile__( \ 401 "1: " TUSER(str) " %1,[%2],#0\n" \ 402 "2:\n" \ 403 " .pushsection .fixup,\"ax\"\n" \ 404 " .align 2\n" \ 405 "3: mov %0, %3\n" \ 406 " b 2b\n" \ 407 " .popsection\n" \ 408 " .pushsection __ex_table,\"a\"\n" \ 409 " .align 3\n" \ 410 " .long 1b, 3b\n" \ 411 " .popsection" \ 412 : "+r" (err) \ 413 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \ 414 : "cc") 415 416 #ifndef __ARMEB__ 417 #define __reg_oper0 "%R2" 418 #define __reg_oper1 "%Q2" 419 #else 420 #define __reg_oper0 "%Q2" 421 #define __reg_oper1 "%R2" 422 #endif 423 424 #define __put_user_asm_dword(x,__pu_addr,err) \ 425 __asm__ __volatile__( \ 426 ARM( "1: " TUSER(str) " " __reg_oper1 ", [%1], #4\n" ) \ 427 ARM( "2: " TUSER(str) " " __reg_oper0 ", [%1]\n" ) \ 428 THUMB( "1: " TUSER(str) " " __reg_oper1 ", [%1]\n" ) \ 429 THUMB( "2: " TUSER(str) " " __reg_oper0 ", [%1, #4]\n" ) \ 430 "3:\n" \ 431 " .pushsection .fixup,\"ax\"\n" \ 432 " .align 2\n" \ 433 "4: mov %0, %3\n" \ 434 " b 3b\n" \ 435 " .popsection\n" \ 436 " .pushsection __ex_table,\"a\"\n" \ 437 " .align 3\n" \ 438 " .long 1b, 4b\n" \ 439 " .long 2b, 4b\n" \ 440 " .popsection" \ 441 : "+r" (err), "+r" (__pu_addr) \ 442 : "r" (x), "i" (-EFAULT) \ 443 : "cc") 444 445 446 #ifdef CONFIG_MMU 447 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n); 448 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n); 449 extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n); 450 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n); 451 extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n); 452 #else 453 #define __copy_from_user(to,from,n) (memcpy(to, (void __force *)from, n), 0) 454 #define __copy_to_user(to,from,n) (memcpy((void __force *)to, from, n), 0) 455 #define __clear_user(addr,n) (memset((void __force *)addr, 0, n), 0) 456 #endif 457 458 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n) 459 { 460 if (access_ok(VERIFY_READ, from, n)) 461 n = __copy_from_user(to, from, n); 462 else /* security hole - plug it */ 463 memset(to, 0, n); 464 return n; 465 } 466 467 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n) 468 { 469 if (access_ok(VERIFY_WRITE, to, n)) 470 n = __copy_to_user(to, from, n); 471 return n; 472 } 473 474 #define __copy_to_user_inatomic __copy_to_user 475 #define __copy_from_user_inatomic __copy_from_user 476 477 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n) 478 { 479 if (access_ok(VERIFY_WRITE, to, n)) 480 n = __clear_user(to, n); 481 return n; 482 } 483 484 extern long strncpy_from_user(char *dest, const char __user *src, long count); 485 486 extern __must_check long strlen_user(const char __user *str); 487 extern __must_check long strnlen_user(const char __user *str, long n); 488 489 #endif /* _ASMARM_UACCESS_H */ 490