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 const typeof(*(p)) __user *__tmp_p = (p); \ 175 register const typeof(*(p)) __r2 asm("r2") = (x); \ 176 register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \ 177 register unsigned long __l asm("r1") = __limit; \ 178 register int __e asm("r0"); \ 179 switch (sizeof(*(__p))) { \ 180 case 1: \ 181 __put_user_x(__r2, __p, __e, __l, 1); \ 182 break; \ 183 case 2: \ 184 __put_user_x(__r2, __p, __e, __l, 2); \ 185 break; \ 186 case 4: \ 187 __put_user_x(__r2, __p, __e, __l, 4); \ 188 break; \ 189 case 8: \ 190 __put_user_x(__r2, __p, __e, __l, 8); \ 191 break; \ 192 default: __e = __put_user_bad(); break; \ 193 } \ 194 __e; \ 195 }) 196 197 #define put_user(x,p) \ 198 ({ \ 199 might_fault(); \ 200 __put_user_check(x,p); \ 201 }) 202 203 #else /* CONFIG_MMU */ 204 205 /* 206 * uClinux has only one addr space, so has simplified address limits. 207 */ 208 #define USER_DS KERNEL_DS 209 210 #define segment_eq(a,b) (1) 211 #define __addr_ok(addr) ((void)(addr),1) 212 #define __range_ok(addr,size) ((void)(addr),0) 213 #define get_fs() (KERNEL_DS) 214 215 static inline void set_fs(mm_segment_t fs) 216 { 217 } 218 219 #define get_user(x,p) __get_user(x,p) 220 #define put_user(x,p) __put_user(x,p) 221 222 #endif /* CONFIG_MMU */ 223 224 #define access_ok(type,addr,size) (__range_ok(addr,size) == 0) 225 226 #define user_addr_max() \ 227 (segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL) 228 229 /* 230 * The "__xxx" versions of the user access functions do not verify the 231 * address space - it must have been done previously with a separate 232 * "access_ok()" call. 233 * 234 * The "xxx_error" versions set the third argument to EFAULT if an 235 * error occurs, and leave it unchanged on success. Note that these 236 * versions are void (ie, don't return a value as such). 237 */ 238 #define __get_user(x,ptr) \ 239 ({ \ 240 long __gu_err = 0; \ 241 __get_user_err((x),(ptr),__gu_err); \ 242 __gu_err; \ 243 }) 244 245 #define __get_user_error(x,ptr,err) \ 246 ({ \ 247 __get_user_err((x),(ptr),err); \ 248 (void) 0; \ 249 }) 250 251 #define __get_user_err(x,ptr,err) \ 252 do { \ 253 unsigned long __gu_addr = (unsigned long)(ptr); \ 254 unsigned long __gu_val; \ 255 __chk_user_ptr(ptr); \ 256 might_fault(); \ 257 switch (sizeof(*(ptr))) { \ 258 case 1: __get_user_asm_byte(__gu_val,__gu_addr,err); break; \ 259 case 2: __get_user_asm_half(__gu_val,__gu_addr,err); break; \ 260 case 4: __get_user_asm_word(__gu_val,__gu_addr,err); break; \ 261 default: (__gu_val) = __get_user_bad(); \ 262 } \ 263 (x) = (__typeof__(*(ptr)))__gu_val; \ 264 } while (0) 265 266 #define __get_user_asm_byte(x,addr,err) \ 267 __asm__ __volatile__( \ 268 "1: " TUSER(ldrb) " %1,[%2],#0\n" \ 269 "2:\n" \ 270 " .pushsection .fixup,\"ax\"\n" \ 271 " .align 2\n" \ 272 "3: mov %0, %3\n" \ 273 " mov %1, #0\n" \ 274 " b 2b\n" \ 275 " .popsection\n" \ 276 " .pushsection __ex_table,\"a\"\n" \ 277 " .align 3\n" \ 278 " .long 1b, 3b\n" \ 279 " .popsection" \ 280 : "+r" (err), "=&r" (x) \ 281 : "r" (addr), "i" (-EFAULT) \ 282 : "cc") 283 284 #ifndef __ARMEB__ 285 #define __get_user_asm_half(x,__gu_addr,err) \ 286 ({ \ 287 unsigned long __b1, __b2; \ 288 __get_user_asm_byte(__b1, __gu_addr, err); \ 289 __get_user_asm_byte(__b2, __gu_addr + 1, err); \ 290 (x) = __b1 | (__b2 << 8); \ 291 }) 292 #else 293 #define __get_user_asm_half(x,__gu_addr,err) \ 294 ({ \ 295 unsigned long __b1, __b2; \ 296 __get_user_asm_byte(__b1, __gu_addr, err); \ 297 __get_user_asm_byte(__b2, __gu_addr + 1, err); \ 298 (x) = (__b1 << 8) | __b2; \ 299 }) 300 #endif 301 302 #define __get_user_asm_word(x,addr,err) \ 303 __asm__ __volatile__( \ 304 "1: " TUSER(ldr) " %1,[%2],#0\n" \ 305 "2:\n" \ 306 " .pushsection .fixup,\"ax\"\n" \ 307 " .align 2\n" \ 308 "3: mov %0, %3\n" \ 309 " mov %1, #0\n" \ 310 " b 2b\n" \ 311 " .popsection\n" \ 312 " .pushsection __ex_table,\"a\"\n" \ 313 " .align 3\n" \ 314 " .long 1b, 3b\n" \ 315 " .popsection" \ 316 : "+r" (err), "=&r" (x) \ 317 : "r" (addr), "i" (-EFAULT) \ 318 : "cc") 319 320 #define __put_user(x,ptr) \ 321 ({ \ 322 long __pu_err = 0; \ 323 __put_user_err((x),(ptr),__pu_err); \ 324 __pu_err; \ 325 }) 326 327 #define __put_user_error(x,ptr,err) \ 328 ({ \ 329 __put_user_err((x),(ptr),err); \ 330 (void) 0; \ 331 }) 332 333 #define __put_user_err(x,ptr,err) \ 334 do { \ 335 unsigned long __pu_addr = (unsigned long)(ptr); \ 336 __typeof__(*(ptr)) __pu_val = (x); \ 337 __chk_user_ptr(ptr); \ 338 might_fault(); \ 339 switch (sizeof(*(ptr))) { \ 340 case 1: __put_user_asm_byte(__pu_val,__pu_addr,err); break; \ 341 case 2: __put_user_asm_half(__pu_val,__pu_addr,err); break; \ 342 case 4: __put_user_asm_word(__pu_val,__pu_addr,err); break; \ 343 case 8: __put_user_asm_dword(__pu_val,__pu_addr,err); break; \ 344 default: __put_user_bad(); \ 345 } \ 346 } while (0) 347 348 #define __put_user_asm_byte(x,__pu_addr,err) \ 349 __asm__ __volatile__( \ 350 "1: " TUSER(strb) " %1,[%2],#0\n" \ 351 "2:\n" \ 352 " .pushsection .fixup,\"ax\"\n" \ 353 " .align 2\n" \ 354 "3: mov %0, %3\n" \ 355 " b 2b\n" \ 356 " .popsection\n" \ 357 " .pushsection __ex_table,\"a\"\n" \ 358 " .align 3\n" \ 359 " .long 1b, 3b\n" \ 360 " .popsection" \ 361 : "+r" (err) \ 362 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \ 363 : "cc") 364 365 #ifndef __ARMEB__ 366 #define __put_user_asm_half(x,__pu_addr,err) \ 367 ({ \ 368 unsigned long __temp = (unsigned long)(x); \ 369 __put_user_asm_byte(__temp, __pu_addr, err); \ 370 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \ 371 }) 372 #else 373 #define __put_user_asm_half(x,__pu_addr,err) \ 374 ({ \ 375 unsigned long __temp = (unsigned long)(x); \ 376 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \ 377 __put_user_asm_byte(__temp, __pu_addr + 1, err); \ 378 }) 379 #endif 380 381 #define __put_user_asm_word(x,__pu_addr,err) \ 382 __asm__ __volatile__( \ 383 "1: " TUSER(str) " %1,[%2],#0\n" \ 384 "2:\n" \ 385 " .pushsection .fixup,\"ax\"\n" \ 386 " .align 2\n" \ 387 "3: mov %0, %3\n" \ 388 " b 2b\n" \ 389 " .popsection\n" \ 390 " .pushsection __ex_table,\"a\"\n" \ 391 " .align 3\n" \ 392 " .long 1b, 3b\n" \ 393 " .popsection" \ 394 : "+r" (err) \ 395 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \ 396 : "cc") 397 398 #ifndef __ARMEB__ 399 #define __reg_oper0 "%R2" 400 #define __reg_oper1 "%Q2" 401 #else 402 #define __reg_oper0 "%Q2" 403 #define __reg_oper1 "%R2" 404 #endif 405 406 #define __put_user_asm_dword(x,__pu_addr,err) \ 407 __asm__ __volatile__( \ 408 ARM( "1: " TUSER(str) " " __reg_oper1 ", [%1], #4\n" ) \ 409 ARM( "2: " TUSER(str) " " __reg_oper0 ", [%1]\n" ) \ 410 THUMB( "1: " TUSER(str) " " __reg_oper1 ", [%1]\n" ) \ 411 THUMB( "2: " TUSER(str) " " __reg_oper0 ", [%1, #4]\n" ) \ 412 "3:\n" \ 413 " .pushsection .fixup,\"ax\"\n" \ 414 " .align 2\n" \ 415 "4: mov %0, %3\n" \ 416 " b 3b\n" \ 417 " .popsection\n" \ 418 " .pushsection __ex_table,\"a\"\n" \ 419 " .align 3\n" \ 420 " .long 1b, 4b\n" \ 421 " .long 2b, 4b\n" \ 422 " .popsection" \ 423 : "+r" (err), "+r" (__pu_addr) \ 424 : "r" (x), "i" (-EFAULT) \ 425 : "cc") 426 427 428 #ifdef CONFIG_MMU 429 extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n); 430 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n); 431 extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n); 432 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n); 433 extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n); 434 #else 435 #define __copy_from_user(to,from,n) (memcpy(to, (void __force *)from, n), 0) 436 #define __copy_to_user(to,from,n) (memcpy((void __force *)to, from, n), 0) 437 #define __clear_user(addr,n) (memset((void __force *)addr, 0, n), 0) 438 #endif 439 440 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n) 441 { 442 if (access_ok(VERIFY_READ, from, n)) 443 n = __copy_from_user(to, from, n); 444 else /* security hole - plug it */ 445 memset(to, 0, n); 446 return n; 447 } 448 449 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n) 450 { 451 if (access_ok(VERIFY_WRITE, to, n)) 452 n = __copy_to_user(to, from, n); 453 return n; 454 } 455 456 #define __copy_to_user_inatomic __copy_to_user 457 #define __copy_from_user_inatomic __copy_from_user 458 459 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n) 460 { 461 if (access_ok(VERIFY_WRITE, to, n)) 462 n = __clear_user(to, n); 463 return n; 464 } 465 466 extern long strncpy_from_user(char *dest, const char __user *src, long count); 467 468 extern __must_check long strlen_user(const char __user *str); 469 extern __must_check long strnlen_user(const char __user *str, long n); 470 471 #endif /* _ASMARM_UACCESS_H */ 472