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 *); 110 111 #define __GUP_CLOBBER_1 "lr", "cc" 112 #ifdef CONFIG_CPU_USE_DOMAINS 113 #define __GUP_CLOBBER_2 "ip", "lr", "cc" 114 #else 115 #define __GUP_CLOBBER_2 "lr", "cc" 116 #endif 117 #define __GUP_CLOBBER_4 "lr", "cc" 118 119 #define __get_user_x(__r2,__p,__e,__l,__s) \ 120 __asm__ __volatile__ ( \ 121 __asmeq("%0", "r0") __asmeq("%1", "r2") \ 122 __asmeq("%3", "r1") \ 123 "bl __get_user_" #__s \ 124 : "=&r" (__e), "=r" (__r2) \ 125 : "0" (__p), "r" (__l) \ 126 : __GUP_CLOBBER_##__s) 127 128 #define __get_user_check(x,p) \ 129 ({ \ 130 unsigned long __limit = current_thread_info()->addr_limit - 1; \ 131 register const typeof(*(p)) __user *__p asm("r0") = (p);\ 132 register unsigned long __r2 asm("r2"); \ 133 register unsigned long __l asm("r1") = __limit; \ 134 register int __e asm("r0"); \ 135 switch (sizeof(*(__p))) { \ 136 case 1: \ 137 __get_user_x(__r2, __p, __e, __l, 1); \ 138 break; \ 139 case 2: \ 140 __get_user_x(__r2, __p, __e, __l, 2); \ 141 break; \ 142 case 4: \ 143 __get_user_x(__r2, __p, __e, __l, 4); \ 144 break; \ 145 default: __e = __get_user_bad(); break; \ 146 } \ 147 x = (typeof(*(p))) __r2; \ 148 __e; \ 149 }) 150 151 #define get_user(x,p) \ 152 ({ \ 153 might_fault(); \ 154 __get_user_check(x,p); \ 155 }) 156 157 extern int __put_user_1(void *, unsigned int); 158 extern int __put_user_2(void *, unsigned int); 159 extern int __put_user_4(void *, unsigned int); 160 extern int __put_user_8(void *, unsigned long long); 161 162 #define __put_user_x(__r2,__p,__e,__l,__s) \ 163 __asm__ __volatile__ ( \ 164 __asmeq("%0", "r0") __asmeq("%2", "r2") \ 165 __asmeq("%3", "r1") \ 166 "bl __put_user_" #__s \ 167 : "=&r" (__e) \ 168 : "0" (__p), "r" (__r2), "r" (__l) \ 169 : "ip", "lr", "cc") 170 171 #define __put_user_check(x,p) \ 172 ({ \ 173 unsigned long __limit = current_thread_info()->addr_limit - 1; \ 174 register const typeof(*(p)) __r2 asm("r2") = (x); \ 175 register const typeof(*(p)) __user *__p asm("r0") = (p);\ 176 register unsigned long __l asm("r1") = __limit; \ 177 register int __e asm("r0"); \ 178 switch (sizeof(*(__p))) { \ 179 case 1: \ 180 __put_user_x(__r2, __p, __e, __l, 1); \ 181 break; \ 182 case 2: \ 183 __put_user_x(__r2, __p, __e, __l, 2); \ 184 break; \ 185 case 4: \ 186 __put_user_x(__r2, __p, __e, __l, 4); \ 187 break; \ 188 case 8: \ 189 __put_user_x(__r2, __p, __e, __l, 8); \ 190 break; \ 191 default: __e = __put_user_bad(); break; \ 192 } \ 193 __e; \ 194 }) 195 196 #define put_user(x,p) \ 197 ({ \ 198 might_fault(); \ 199 __put_user_check(x,p); \ 200 }) 201 202 #else /* CONFIG_MMU */ 203 204 /* 205 * uClinux has only one addr space, so has simplified address limits. 206 */ 207 #define USER_DS KERNEL_DS 208 209 #define segment_eq(a,b) (1) 210 #define __addr_ok(addr) ((void)(addr),1) 211 #define __range_ok(addr,size) ((void)(addr),0) 212 #define get_fs() (KERNEL_DS) 213 214 static inline void set_fs(mm_segment_t fs) 215 { 216 } 217 218 #define get_user(x,p) __get_user(x,p) 219 #define put_user(x,p) __put_user(x,p) 220 221 #endif /* CONFIG_MMU */ 222 223 #define access_ok(type,addr,size) (__range_ok(addr,size) == 0) 224 225 #define user_addr_max() \ 226 (segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL) 227 228 /* 229 * The "__xxx" versions of the user access functions do not verify the 230 * address space - it must have been done previously with a separate 231 * "access_ok()" call. 232 * 233 * The "xxx_error" versions set the third argument to EFAULT if an 234 * error occurs, and leave it unchanged on success. Note that these 235 * versions are void (ie, don't return a value as such). 236 */ 237 #define __get_user(x,ptr) \ 238 ({ \ 239 long __gu_err = 0; \ 240 __get_user_err((x),(ptr),__gu_err); \ 241 __gu_err; \ 242 }) 243 244 #define __get_user_error(x,ptr,err) \ 245 ({ \ 246 __get_user_err((x),(ptr),err); \ 247 (void) 0; \ 248 }) 249 250 #define __get_user_err(x,ptr,err) \ 251 do { \ 252 unsigned long __gu_addr = (unsigned long)(ptr); \ 253 unsigned long __gu_val; \ 254 __chk_user_ptr(ptr); \ 255 might_fault(); \ 256 switch (sizeof(*(ptr))) { \ 257 case 1: __get_user_asm_byte(__gu_val,__gu_addr,err); break; \ 258 case 2: __get_user_asm_half(__gu_val,__gu_addr,err); break; \ 259 case 4: __get_user_asm_word(__gu_val,__gu_addr,err); break; \ 260 default: (__gu_val) = __get_user_bad(); \ 261 } \ 262 (x) = (__typeof__(*(ptr)))__gu_val; \ 263 } while (0) 264 265 #define __get_user_asm_byte(x,addr,err) \ 266 __asm__ __volatile__( \ 267 "1: " TUSER(ldrb) " %1,[%2],#0\n" \ 268 "2:\n" \ 269 " .pushsection .fixup,\"ax\"\n" \ 270 " .align 2\n" \ 271 "3: mov %0, %3\n" \ 272 " mov %1, #0\n" \ 273 " b 2b\n" \ 274 " .popsection\n" \ 275 " .pushsection __ex_table,\"a\"\n" \ 276 " .align 3\n" \ 277 " .long 1b, 3b\n" \ 278 " .popsection" \ 279 : "+r" (err), "=&r" (x) \ 280 : "r" (addr), "i" (-EFAULT) \ 281 : "cc") 282 283 #ifndef __ARMEB__ 284 #define __get_user_asm_half(x,__gu_addr,err) \ 285 ({ \ 286 unsigned long __b1, __b2; \ 287 __get_user_asm_byte(__b1, __gu_addr, err); \ 288 __get_user_asm_byte(__b2, __gu_addr + 1, err); \ 289 (x) = __b1 | (__b2 << 8); \ 290 }) 291 #else 292 #define __get_user_asm_half(x,__gu_addr,err) \ 293 ({ \ 294 unsigned long __b1, __b2; \ 295 __get_user_asm_byte(__b1, __gu_addr, err); \ 296 __get_user_asm_byte(__b2, __gu_addr + 1, err); \ 297 (x) = (__b1 << 8) | __b2; \ 298 }) 299 #endif 300 301 #define __get_user_asm_word(x,addr,err) \ 302 __asm__ __volatile__( \ 303 "1: " TUSER(ldr) " %1,[%2],#0\n" \ 304 "2:\n" \ 305 " .pushsection .fixup,\"ax\"\n" \ 306 " .align 2\n" \ 307 "3: mov %0, %3\n" \ 308 " mov %1, #0\n" \ 309 " b 2b\n" \ 310 " .popsection\n" \ 311 " .pushsection __ex_table,\"a\"\n" \ 312 " .align 3\n" \ 313 " .long 1b, 3b\n" \ 314 " .popsection" \ 315 : "+r" (err), "=&r" (x) \ 316 : "r" (addr), "i" (-EFAULT) \ 317 : "cc") 318 319 #define __put_user(x,ptr) \ 320 ({ \ 321 long __pu_err = 0; \ 322 __put_user_err((x),(ptr),__pu_err); \ 323 __pu_err; \ 324 }) 325 326 #define __put_user_error(x,ptr,err) \ 327 ({ \ 328 __put_user_err((x),(ptr),err); \ 329 (void) 0; \ 330 }) 331 332 #define __put_user_err(x,ptr,err) \ 333 do { \ 334 unsigned long __pu_addr = (unsigned long)(ptr); \ 335 __typeof__(*(ptr)) __pu_val = (x); \ 336 __chk_user_ptr(ptr); \ 337 might_fault(); \ 338 switch (sizeof(*(ptr))) { \ 339 case 1: __put_user_asm_byte(__pu_val,__pu_addr,err); break; \ 340 case 2: __put_user_asm_half(__pu_val,__pu_addr,err); break; \ 341 case 4: __put_user_asm_word(__pu_val,__pu_addr,err); break; \ 342 case 8: __put_user_asm_dword(__pu_val,__pu_addr,err); break; \ 343 default: __put_user_bad(); \ 344 } \ 345 } while (0) 346 347 #define __put_user_asm_byte(x,__pu_addr,err) \ 348 __asm__ __volatile__( \ 349 "1: " TUSER(strb) " %1,[%2],#0\n" \ 350 "2:\n" \ 351 " .pushsection .fixup,\"ax\"\n" \ 352 " .align 2\n" \ 353 "3: mov %0, %3\n" \ 354 " b 2b\n" \ 355 " .popsection\n" \ 356 " .pushsection __ex_table,\"a\"\n" \ 357 " .align 3\n" \ 358 " .long 1b, 3b\n" \ 359 " .popsection" \ 360 : "+r" (err) \ 361 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \ 362 : "cc") 363 364 #ifndef __ARMEB__ 365 #define __put_user_asm_half(x,__pu_addr,err) \ 366 ({ \ 367 unsigned long __temp = (unsigned long)(x); \ 368 __put_user_asm_byte(__temp, __pu_addr, err); \ 369 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \ 370 }) 371 #else 372 #define __put_user_asm_half(x,__pu_addr,err) \ 373 ({ \ 374 unsigned long __temp = (unsigned long)(x); \ 375 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \ 376 __put_user_asm_byte(__temp, __pu_addr + 1, err); \ 377 }) 378 #endif 379 380 #define __put_user_asm_word(x,__pu_addr,err) \ 381 __asm__ __volatile__( \ 382 "1: " TUSER(str) " %1,[%2],#0\n" \ 383 "2:\n" \ 384 " .pushsection .fixup,\"ax\"\n" \ 385 " .align 2\n" \ 386 "3: mov %0, %3\n" \ 387 " b 2b\n" \ 388 " .popsection\n" \ 389 " .pushsection __ex_table,\"a\"\n" \ 390 " .align 3\n" \ 391 " .long 1b, 3b\n" \ 392 " .popsection" \ 393 : "+r" (err) \ 394 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \ 395 : "cc") 396 397 #ifndef __ARMEB__ 398 #define __reg_oper0 "%R2" 399 #define __reg_oper1 "%Q2" 400 #else 401 #define __reg_oper0 "%Q2" 402 #define __reg_oper1 "%R2" 403 #endif 404 405 #define __put_user_asm_dword(x,__pu_addr,err) \ 406 __asm__ __volatile__( \ 407 ARM( "1: " TUSER(str) " " __reg_oper1 ", [%1], #4\n" ) \ 408 ARM( "2: " TUSER(str) " " __reg_oper0 ", [%1]\n" ) \ 409 THUMB( "1: " TUSER(str) " " __reg_oper1 ", [%1]\n" ) \ 410 THUMB( "2: " TUSER(str) " " __reg_oper0 ", [%1, #4]\n" ) \ 411 "3:\n" \ 412 " .pushsection .fixup,\"ax\"\n" \ 413 " .align 2\n" \ 414 "4: mov %0, %3\n" \ 415 " b 3b\n" \ 416 " .popsection\n" \ 417 " .pushsection __ex_table,\"a\"\n" \ 418 " .align 3\n" \ 419 " .long 1b, 4b\n" \ 420 " .long 2b, 4b\n" \ 421 " .popsection" \ 422 : "+r" (err), "+r" (__pu_addr) \ 423 : "r" (x), "i" (-EFAULT) \ 424 : "cc") 425 426 427 #ifdef CONFIG_MMU 428 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n); 429 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n); 430 extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n); 431 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n); 432 extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n); 433 #else 434 #define __copy_from_user(to,from,n) (memcpy(to, (void __force *)from, n), 0) 435 #define __copy_to_user(to,from,n) (memcpy((void __force *)to, from, n), 0) 436 #define __clear_user(addr,n) (memset((void __force *)addr, 0, n), 0) 437 #endif 438 439 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n) 440 { 441 if (access_ok(VERIFY_READ, from, n)) 442 n = __copy_from_user(to, from, n); 443 else /* security hole - plug it */ 444 memset(to, 0, n); 445 return n; 446 } 447 448 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n) 449 { 450 if (access_ok(VERIFY_WRITE, to, n)) 451 n = __copy_to_user(to, from, n); 452 return n; 453 } 454 455 #define __copy_to_user_inatomic __copy_to_user 456 #define __copy_from_user_inatomic __copy_from_user 457 458 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n) 459 { 460 if (access_ok(VERIFY_WRITE, to, n)) 461 n = __clear_user(to, n); 462 return n; 463 } 464 465 extern long strncpy_from_user(char *dest, const char __user *src, long count); 466 467 extern __must_check long strlen_user(const char __user *str); 468 extern __must_check long strnlen_user(const char __user *str, long n); 469 470 #endif /* _ASMARM_UACCESS_H */ 471