1 #ifndef _ASM_X86_UACCESS_H 2 #define _ASM_X86_UACCESS_H 3 /* 4 * User space memory access functions 5 */ 6 #include <linux/errno.h> 7 #include <linux/compiler.h> 8 #include <linux/thread_info.h> 9 #include <linux/prefetch.h> 10 #include <linux/string.h> 11 #include <asm/asm.h> 12 #include <asm/page.h> 13 14 #define VERIFY_READ 0 15 #define VERIFY_WRITE 1 16 17 /* 18 * The fs value determines whether argument validity checking should be 19 * performed or not. If get_fs() == USER_DS, checking is performed, with 20 * get_fs() == KERNEL_DS, checking is bypassed. 21 * 22 * For historical reasons, these macros are grossly misnamed. 23 */ 24 25 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) 26 27 #define KERNEL_DS MAKE_MM_SEG(-1UL) 28 #define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX) 29 30 #define get_ds() (KERNEL_DS) 31 #define get_fs() (current_thread_info()->addr_limit) 32 #define set_fs(x) (current_thread_info()->addr_limit = (x)) 33 34 #define segment_eq(a, b) ((a).seg == (b).seg) 35 36 #define __addr_ok(addr) \ 37 ((unsigned long __force)(addr) < \ 38 (current_thread_info()->addr_limit.seg)) 39 40 /* 41 * Test whether a block of memory is a valid user space address. 42 * Returns 0 if the range is valid, nonzero otherwise. 43 * 44 * This is equivalent to the following test: 45 * (u33)addr + (u33)size >= (u33)current->addr_limit.seg (u65 for x86_64) 46 * 47 * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry... 48 */ 49 50 #define __range_not_ok(addr, size) \ 51 ({ \ 52 unsigned long flag, roksum; \ 53 __chk_user_ptr(addr); \ 54 asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \ 55 : "=&r" (flag), "=r" (roksum) \ 56 : "1" (addr), "g" ((long)(size)), \ 57 "rm" (current_thread_info()->addr_limit.seg)); \ 58 flag; \ 59 }) 60 61 /** 62 * access_ok: - Checks if a user space pointer is valid 63 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that 64 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe 65 * to write to a block, it is always safe to read from it. 66 * @addr: User space pointer to start of block to check 67 * @size: Size of block to check 68 * 69 * Context: User context only. This function may sleep. 70 * 71 * Checks if a pointer to a block of memory in user space is valid. 72 * 73 * Returns true (nonzero) if the memory block may be valid, false (zero) 74 * if it is definitely invalid. 75 * 76 * Note that, depending on architecture, this function probably just 77 * checks that the pointer is in the user space range - after calling 78 * this function, memory access functions may still return -EFAULT. 79 */ 80 #define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0)) 81 82 /* 83 * The exception table consists of pairs of addresses: the first is the 84 * address of an instruction that is allowed to fault, and the second is 85 * the address at which the program should continue. No registers are 86 * modified, so it is entirely up to the continuation code to figure out 87 * what to do. 88 * 89 * All the routines below use bits of fixup code that are out of line 90 * with the main instruction path. This means when everything is well, 91 * we don't even have to jump over them. Further, they do not intrude 92 * on our cache or tlb entries. 93 */ 94 95 struct exception_table_entry { 96 unsigned long insn, fixup; 97 }; 98 99 extern int fixup_exception(struct pt_regs *regs); 100 101 /* 102 * These are the main single-value transfer routines. They automatically 103 * use the right size if we just have the right pointer type. 104 * 105 * This gets kind of ugly. We want to return _two_ values in "get_user()" 106 * and yet we don't want to do any pointers, because that is too much 107 * of a performance impact. Thus we have a few rather ugly macros here, 108 * and hide all the ugliness from the user. 109 * 110 * The "__xxx" versions of the user access functions are versions that 111 * do not verify the address space, that must have been done previously 112 * with a separate "access_ok()" call (this is used when we do multiple 113 * accesses to the same area of user memory). 114 */ 115 116 extern int __get_user_1(void); 117 extern int __get_user_2(void); 118 extern int __get_user_4(void); 119 extern int __get_user_8(void); 120 extern int __get_user_bad(void); 121 122 #define __get_user_x(size, ret, x, ptr) \ 123 asm volatile("call __get_user_" #size \ 124 : "=a" (ret), "=d" (x) \ 125 : "0" (ptr)) \ 126 127 /* Careful: we have to cast the result to the type of the pointer 128 * for sign reasons */ 129 130 /** 131 * get_user: - Get a simple variable from user space. 132 * @x: Variable to store result. 133 * @ptr: Source address, in user space. 134 * 135 * Context: User context only. This function may sleep. 136 * 137 * This macro copies a single simple variable from user space to kernel 138 * space. It supports simple types like char and int, but not larger 139 * data types like structures or arrays. 140 * 141 * @ptr must have pointer-to-simple-variable type, and the result of 142 * dereferencing @ptr must be assignable to @x without a cast. 143 * 144 * Returns zero on success, or -EFAULT on error. 145 * On error, the variable @x is set to zero. 146 */ 147 #ifdef CONFIG_X86_32 148 #define __get_user_8(__ret_gu, __val_gu, ptr) \ 149 __get_user_x(X, __ret_gu, __val_gu, ptr) 150 #else 151 #define __get_user_8(__ret_gu, __val_gu, ptr) \ 152 __get_user_x(8, __ret_gu, __val_gu, ptr) 153 #endif 154 155 #define get_user(x, ptr) \ 156 ({ \ 157 int __ret_gu; \ 158 unsigned long __val_gu; \ 159 __chk_user_ptr(ptr); \ 160 might_fault(); \ 161 switch (sizeof(*(ptr))) { \ 162 case 1: \ 163 __get_user_x(1, __ret_gu, __val_gu, ptr); \ 164 break; \ 165 case 2: \ 166 __get_user_x(2, __ret_gu, __val_gu, ptr); \ 167 break; \ 168 case 4: \ 169 __get_user_x(4, __ret_gu, __val_gu, ptr); \ 170 break; \ 171 case 8: \ 172 __get_user_8(__ret_gu, __val_gu, ptr); \ 173 break; \ 174 default: \ 175 __get_user_x(X, __ret_gu, __val_gu, ptr); \ 176 break; \ 177 } \ 178 (x) = (__typeof__(*(ptr)))__val_gu; \ 179 __ret_gu; \ 180 }) 181 182 #define __put_user_x(size, x, ptr, __ret_pu) \ 183 asm volatile("call __put_user_" #size : "=a" (__ret_pu) \ 184 : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") 185 186 187 188 #ifdef CONFIG_X86_32 189 #define __put_user_asm_u64(x, addr, err, errret) \ 190 asm volatile("1: movl %%eax,0(%2)\n" \ 191 "2: movl %%edx,4(%2)\n" \ 192 "3:\n" \ 193 ".section .fixup,\"ax\"\n" \ 194 "4: movl %3,%0\n" \ 195 " jmp 3b\n" \ 196 ".previous\n" \ 197 _ASM_EXTABLE(1b, 4b) \ 198 _ASM_EXTABLE(2b, 4b) \ 199 : "=r" (err) \ 200 : "A" (x), "r" (addr), "i" (errret), "0" (err)) 201 202 #define __put_user_asm_ex_u64(x, addr) \ 203 asm volatile("1: movl %%eax,0(%1)\n" \ 204 "2: movl %%edx,4(%1)\n" \ 205 "3:\n" \ 206 _ASM_EXTABLE(1b, 2b - 1b) \ 207 _ASM_EXTABLE(2b, 3b - 2b) \ 208 : : "A" (x), "r" (addr)) 209 210 #define __put_user_x8(x, ptr, __ret_pu) \ 211 asm volatile("call __put_user_8" : "=a" (__ret_pu) \ 212 : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") 213 #else 214 #define __put_user_asm_u64(x, ptr, retval, errret) \ 215 __put_user_asm(x, ptr, retval, "q", "", "er", errret) 216 #define __put_user_asm_ex_u64(x, addr) \ 217 __put_user_asm_ex(x, addr, "q", "", "er") 218 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu) 219 #endif 220 221 extern void __put_user_bad(void); 222 223 /* 224 * Strange magic calling convention: pointer in %ecx, 225 * value in %eax(:%edx), return value in %eax. clobbers %rbx 226 */ 227 extern void __put_user_1(void); 228 extern void __put_user_2(void); 229 extern void __put_user_4(void); 230 extern void __put_user_8(void); 231 232 #ifdef CONFIG_X86_WP_WORKS_OK 233 234 /** 235 * put_user: - Write a simple value into user space. 236 * @x: Value to copy to user space. 237 * @ptr: Destination address, in user space. 238 * 239 * Context: User context only. This function may sleep. 240 * 241 * This macro copies a single simple value from kernel space to user 242 * space. It supports simple types like char and int, but not larger 243 * data types like structures or arrays. 244 * 245 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 246 * to the result of dereferencing @ptr. 247 * 248 * Returns zero on success, or -EFAULT on error. 249 */ 250 #define put_user(x, ptr) \ 251 ({ \ 252 int __ret_pu; \ 253 __typeof__(*(ptr)) __pu_val; \ 254 __chk_user_ptr(ptr); \ 255 might_fault(); \ 256 __pu_val = x; \ 257 switch (sizeof(*(ptr))) { \ 258 case 1: \ 259 __put_user_x(1, __pu_val, ptr, __ret_pu); \ 260 break; \ 261 case 2: \ 262 __put_user_x(2, __pu_val, ptr, __ret_pu); \ 263 break; \ 264 case 4: \ 265 __put_user_x(4, __pu_val, ptr, __ret_pu); \ 266 break; \ 267 case 8: \ 268 __put_user_x8(__pu_val, ptr, __ret_pu); \ 269 break; \ 270 default: \ 271 __put_user_x(X, __pu_val, ptr, __ret_pu); \ 272 break; \ 273 } \ 274 __ret_pu; \ 275 }) 276 277 #define __put_user_size(x, ptr, size, retval, errret) \ 278 do { \ 279 retval = 0; \ 280 __chk_user_ptr(ptr); \ 281 switch (size) { \ 282 case 1: \ 283 __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \ 284 break; \ 285 case 2: \ 286 __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \ 287 break; \ 288 case 4: \ 289 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \ 290 break; \ 291 case 8: \ 292 __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval, \ 293 errret); \ 294 break; \ 295 default: \ 296 __put_user_bad(); \ 297 } \ 298 } while (0) 299 300 #define __put_user_size_ex(x, ptr, size) \ 301 do { \ 302 __chk_user_ptr(ptr); \ 303 switch (size) { \ 304 case 1: \ 305 __put_user_asm_ex(x, ptr, "b", "b", "iq"); \ 306 break; \ 307 case 2: \ 308 __put_user_asm_ex(x, ptr, "w", "w", "ir"); \ 309 break; \ 310 case 4: \ 311 __put_user_asm_ex(x, ptr, "l", "k", "ir"); \ 312 break; \ 313 case 8: \ 314 __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \ 315 break; \ 316 default: \ 317 __put_user_bad(); \ 318 } \ 319 } while (0) 320 321 #else 322 323 #define __put_user_size(x, ptr, size, retval, errret) \ 324 do { \ 325 __typeof__(*(ptr))__pus_tmp = x; \ 326 retval = 0; \ 327 \ 328 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \ 329 retval = errret; \ 330 } while (0) 331 332 #define put_user(x, ptr) \ 333 ({ \ 334 int __ret_pu; \ 335 __typeof__(*(ptr))__pus_tmp = x; \ 336 __ret_pu = 0; \ 337 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \ 338 sizeof(*(ptr))) != 0)) \ 339 __ret_pu = -EFAULT; \ 340 __ret_pu; \ 341 }) 342 #endif 343 344 #ifdef CONFIG_X86_32 345 #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() 346 #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad() 347 #else 348 #define __get_user_asm_u64(x, ptr, retval, errret) \ 349 __get_user_asm(x, ptr, retval, "q", "", "=r", errret) 350 #define __get_user_asm_ex_u64(x, ptr) \ 351 __get_user_asm_ex(x, ptr, "q", "", "=r") 352 #endif 353 354 #define __get_user_size(x, ptr, size, retval, errret) \ 355 do { \ 356 retval = 0; \ 357 __chk_user_ptr(ptr); \ 358 switch (size) { \ 359 case 1: \ 360 __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \ 361 break; \ 362 case 2: \ 363 __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \ 364 break; \ 365 case 4: \ 366 __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \ 367 break; \ 368 case 8: \ 369 __get_user_asm_u64(x, ptr, retval, errret); \ 370 break; \ 371 default: \ 372 (x) = __get_user_bad(); \ 373 } \ 374 } while (0) 375 376 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 377 asm volatile("1: mov"itype" %2,%"rtype"1\n" \ 378 "2:\n" \ 379 ".section .fixup,\"ax\"\n" \ 380 "3: mov %3,%0\n" \ 381 " xor"itype" %"rtype"1,%"rtype"1\n" \ 382 " jmp 2b\n" \ 383 ".previous\n" \ 384 _ASM_EXTABLE(1b, 3b) \ 385 : "=r" (err), ltype(x) \ 386 : "m" (__m(addr)), "i" (errret), "0" (err)) 387 388 #define __get_user_size_ex(x, ptr, size) \ 389 do { \ 390 __chk_user_ptr(ptr); \ 391 switch (size) { \ 392 case 1: \ 393 __get_user_asm_ex(x, ptr, "b", "b", "=q"); \ 394 break; \ 395 case 2: \ 396 __get_user_asm_ex(x, ptr, "w", "w", "=r"); \ 397 break; \ 398 case 4: \ 399 __get_user_asm_ex(x, ptr, "l", "k", "=r"); \ 400 break; \ 401 case 8: \ 402 __get_user_asm_ex_u64(x, ptr); \ 403 break; \ 404 default: \ 405 (x) = __get_user_bad(); \ 406 } \ 407 } while (0) 408 409 #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \ 410 asm volatile("1: mov"itype" %1,%"rtype"0\n" \ 411 "2:\n" \ 412 _ASM_EXTABLE(1b, 2b - 1b) \ 413 : ltype(x) : "m" (__m(addr))) 414 415 #define __put_user_nocheck(x, ptr, size) \ 416 ({ \ 417 int __pu_err; \ 418 __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \ 419 __pu_err; \ 420 }) 421 422 #define __get_user_nocheck(x, ptr, size) \ 423 ({ \ 424 int __gu_err; \ 425 unsigned long __gu_val; \ 426 __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ 427 (x) = (__force __typeof__(*(ptr)))__gu_val; \ 428 __gu_err; \ 429 }) 430 431 /* FIXME: this hack is definitely wrong -AK */ 432 struct __large_struct { unsigned long buf[100]; }; 433 #define __m(x) (*(struct __large_struct __user *)(x)) 434 435 /* 436 * Tell gcc we read from memory instead of writing: this is because 437 * we do not write to any memory gcc knows about, so there are no 438 * aliasing issues. 439 */ 440 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 441 asm volatile("1: mov"itype" %"rtype"1,%2\n" \ 442 "2:\n" \ 443 ".section .fixup,\"ax\"\n" \ 444 "3: mov %3,%0\n" \ 445 " jmp 2b\n" \ 446 ".previous\n" \ 447 _ASM_EXTABLE(1b, 3b) \ 448 : "=r"(err) \ 449 : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) 450 451 #define __put_user_asm_ex(x, addr, itype, rtype, ltype) \ 452 asm volatile("1: mov"itype" %"rtype"0,%1\n" \ 453 "2:\n" \ 454 _ASM_EXTABLE(1b, 2b - 1b) \ 455 : : ltype(x), "m" (__m(addr))) 456 457 /* 458 * uaccess_try and catch 459 */ 460 #define uaccess_try do { \ 461 int prev_err = current_thread_info()->uaccess_err; \ 462 current_thread_info()->uaccess_err = 0; \ 463 barrier(); 464 465 #define uaccess_catch(err) \ 466 (err) |= current_thread_info()->uaccess_err; \ 467 current_thread_info()->uaccess_err = prev_err; \ 468 } while (0) 469 470 /** 471 * __get_user: - Get a simple variable from user space, with less checking. 472 * @x: Variable to store result. 473 * @ptr: Source address, in user space. 474 * 475 * Context: User context only. This function may sleep. 476 * 477 * This macro copies a single simple variable from user space to kernel 478 * space. It supports simple types like char and int, but not larger 479 * data types like structures or arrays. 480 * 481 * @ptr must have pointer-to-simple-variable type, and the result of 482 * dereferencing @ptr must be assignable to @x without a cast. 483 * 484 * Caller must check the pointer with access_ok() before calling this 485 * function. 486 * 487 * Returns zero on success, or -EFAULT on error. 488 * On error, the variable @x is set to zero. 489 */ 490 491 #define __get_user(x, ptr) \ 492 __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 493 494 /** 495 * __put_user: - Write a simple value into user space, with less checking. 496 * @x: Value to copy to user space. 497 * @ptr: Destination address, in user space. 498 * 499 * Context: User context only. This function may sleep. 500 * 501 * This macro copies a single simple value from kernel space to user 502 * space. It supports simple types like char and int, but not larger 503 * data types like structures or arrays. 504 * 505 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 506 * to the result of dereferencing @ptr. 507 * 508 * Caller must check the pointer with access_ok() before calling this 509 * function. 510 * 511 * Returns zero on success, or -EFAULT on error. 512 */ 513 514 #define __put_user(x, ptr) \ 515 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 516 517 #define __get_user_unaligned __get_user 518 #define __put_user_unaligned __put_user 519 520 /* 521 * {get|put}_user_try and catch 522 * 523 * get_user_try { 524 * get_user_ex(...); 525 * } get_user_catch(err) 526 */ 527 #define get_user_try uaccess_try 528 #define get_user_catch(err) uaccess_catch(err) 529 530 #define get_user_ex(x, ptr) do { \ 531 unsigned long __gue_val; \ 532 __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr)))); \ 533 (x) = (__force __typeof__(*(ptr)))__gue_val; \ 534 } while (0) 535 536 #ifdef CONFIG_X86_WP_WORKS_OK 537 538 #define put_user_try uaccess_try 539 #define put_user_catch(err) uaccess_catch(err) 540 541 #define put_user_ex(x, ptr) \ 542 __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 543 544 #else /* !CONFIG_X86_WP_WORKS_OK */ 545 546 #define put_user_try do { \ 547 int __uaccess_err = 0; 548 549 #define put_user_catch(err) \ 550 (err) |= __uaccess_err; \ 551 } while (0) 552 553 #define put_user_ex(x, ptr) do { \ 554 __uaccess_err |= __put_user(x, ptr); \ 555 } while (0) 556 557 #endif /* CONFIG_X86_WP_WORKS_OK */ 558 559 /* 560 * movsl can be slow when source and dest are not both 8-byte aligned 561 */ 562 #ifdef CONFIG_X86_INTEL_USERCOPY 563 extern struct movsl_mask { 564 int mask; 565 } ____cacheline_aligned_in_smp movsl_mask; 566 #endif 567 568 #define ARCH_HAS_NOCACHE_UACCESS 1 569 570 #ifdef CONFIG_X86_32 571 # include "uaccess_32.h" 572 #else 573 # include "uaccess_64.h" 574 #endif 575 576 #endif /* _ASM_X86_UACCESS_H */ 577 578