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/string.h> 10 #include <asm/asm.h> 11 #include <asm/page.h> 12 #include <asm/smap.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 user_addr_max() (current_thread_info()->addr_limit.seg) 37 #define __addr_ok(addr) \ 38 ((unsigned long __force)(addr) < user_addr_max()) 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, limit) \ 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" (limit)); \ 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) \ 81 (likely(__range_not_ok(addr, size, user_addr_max()) == 0)) 82 83 /* 84 * The exception table consists of pairs of addresses relative to the 85 * exception table enty itself: the first is the address of an 86 * instruction that is allowed to fault, and the second is the address 87 * at which the program should continue. No registers are modified, 88 * so it is entirely up to the continuation code to figure out what to 89 * do. 90 * 91 * All the routines below use bits of fixup code that are out of line 92 * with the main instruction path. This means when everything is well, 93 * we don't even have to jump over them. Further, they do not intrude 94 * on our cache or tlb entries. 95 */ 96 97 struct exception_table_entry { 98 int insn, fixup; 99 }; 100 /* This is not the generic standard exception_table_entry format */ 101 #define ARCH_HAS_SORT_EXTABLE 102 #define ARCH_HAS_SEARCH_EXTABLE 103 104 extern int fixup_exception(struct pt_regs *regs); 105 extern int early_fixup_exception(unsigned long *ip); 106 107 /* 108 * These are the main single-value transfer routines. They automatically 109 * use the right size if we just have the right pointer type. 110 * 111 * This gets kind of ugly. We want to return _two_ values in "get_user()" 112 * and yet we don't want to do any pointers, because that is too much 113 * of a performance impact. Thus we have a few rather ugly macros here, 114 * and hide all the ugliness from the user. 115 * 116 * The "__xxx" versions of the user access functions are versions that 117 * do not verify the address space, that must have been done previously 118 * with a separate "access_ok()" call (this is used when we do multiple 119 * accesses to the same area of user memory). 120 */ 121 122 extern int __get_user_1(void); 123 extern int __get_user_2(void); 124 extern int __get_user_4(void); 125 extern int __get_user_8(void); 126 extern int __get_user_bad(void); 127 128 #define __get_user_x(size, ret, x, ptr) \ 129 asm volatile("call __get_user_" #size \ 130 : "=a" (ret), "=d" (x) \ 131 : "0" (ptr)) \ 132 133 /* Careful: we have to cast the result to the type of the pointer 134 * for sign reasons */ 135 136 /** 137 * get_user: - Get a simple variable from user space. 138 * @x: Variable to store result. 139 * @ptr: Source address, in user space. 140 * 141 * Context: User context only. This function may sleep. 142 * 143 * This macro copies a single simple variable from user space to kernel 144 * space. It supports simple types like char and int, but not larger 145 * data types like structures or arrays. 146 * 147 * @ptr must have pointer-to-simple-variable type, and the result of 148 * dereferencing @ptr must be assignable to @x without a cast. 149 * 150 * Returns zero on success, or -EFAULT on error. 151 * On error, the variable @x is set to zero. 152 */ 153 #ifdef CONFIG_X86_32 154 #define __get_user_8(__ret_gu, __val_gu, ptr) \ 155 __get_user_x(X, __ret_gu, __val_gu, ptr) 156 #else 157 #define __get_user_8(__ret_gu, __val_gu, ptr) \ 158 __get_user_x(8, __ret_gu, __val_gu, ptr) 159 #endif 160 161 #define get_user(x, ptr) \ 162 ({ \ 163 int __ret_gu; \ 164 unsigned long __val_gu; \ 165 __chk_user_ptr(ptr); \ 166 might_fault(); \ 167 switch (sizeof(*(ptr))) { \ 168 case 1: \ 169 __get_user_x(1, __ret_gu, __val_gu, ptr); \ 170 break; \ 171 case 2: \ 172 __get_user_x(2, __ret_gu, __val_gu, ptr); \ 173 break; \ 174 case 4: \ 175 __get_user_x(4, __ret_gu, __val_gu, ptr); \ 176 break; \ 177 case 8: \ 178 __get_user_8(__ret_gu, __val_gu, ptr); \ 179 break; \ 180 default: \ 181 __get_user_x(X, __ret_gu, __val_gu, ptr); \ 182 break; \ 183 } \ 184 (x) = (__typeof__(*(ptr)))__val_gu; \ 185 __ret_gu; \ 186 }) 187 188 #define __put_user_x(size, x, ptr, __ret_pu) \ 189 asm volatile("call __put_user_" #size : "=a" (__ret_pu) \ 190 : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") 191 192 193 194 #ifdef CONFIG_X86_32 195 #define __put_user_asm_u64(x, addr, err, errret) \ 196 asm volatile(ASM_STAC "\n" \ 197 "1: movl %%eax,0(%2)\n" \ 198 "2: movl %%edx,4(%2)\n" \ 199 "3: " ASM_CLAC "\n" \ 200 ".section .fixup,\"ax\"\n" \ 201 "4: movl %3,%0\n" \ 202 " jmp 3b\n" \ 203 ".previous\n" \ 204 _ASM_EXTABLE(1b, 4b) \ 205 _ASM_EXTABLE(2b, 4b) \ 206 : "=r" (err) \ 207 : "A" (x), "r" (addr), "i" (errret), "0" (err)) 208 209 #define __put_user_asm_ex_u64(x, addr) \ 210 asm volatile(ASM_STAC "\n" \ 211 "1: movl %%eax,0(%1)\n" \ 212 "2: movl %%edx,4(%1)\n" \ 213 "3: " ASM_CLAC "\n" \ 214 _ASM_EXTABLE_EX(1b, 2b) \ 215 _ASM_EXTABLE_EX(2b, 3b) \ 216 : : "A" (x), "r" (addr)) 217 218 #define __put_user_x8(x, ptr, __ret_pu) \ 219 asm volatile("call __put_user_8" : "=a" (__ret_pu) \ 220 : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") 221 #else 222 #define __put_user_asm_u64(x, ptr, retval, errret) \ 223 __put_user_asm(x, ptr, retval, "q", "", "er", errret) 224 #define __put_user_asm_ex_u64(x, addr) \ 225 __put_user_asm_ex(x, addr, "q", "", "er") 226 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu) 227 #endif 228 229 extern void __put_user_bad(void); 230 231 /* 232 * Strange magic calling convention: pointer in %ecx, 233 * value in %eax(:%edx), return value in %eax. clobbers %rbx 234 */ 235 extern void __put_user_1(void); 236 extern void __put_user_2(void); 237 extern void __put_user_4(void); 238 extern void __put_user_8(void); 239 240 #ifdef CONFIG_X86_WP_WORKS_OK 241 242 /** 243 * put_user: - Write a simple value into user space. 244 * @x: Value to copy to user space. 245 * @ptr: Destination address, in user space. 246 * 247 * Context: User context only. This function may sleep. 248 * 249 * This macro copies a single simple value from kernel space to user 250 * space. It supports simple types like char and int, but not larger 251 * data types like structures or arrays. 252 * 253 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 254 * to the result of dereferencing @ptr. 255 * 256 * Returns zero on success, or -EFAULT on error. 257 */ 258 #define put_user(x, ptr) \ 259 ({ \ 260 int __ret_pu; \ 261 __typeof__(*(ptr)) __pu_val; \ 262 __chk_user_ptr(ptr); \ 263 might_fault(); \ 264 __pu_val = x; \ 265 switch (sizeof(*(ptr))) { \ 266 case 1: \ 267 __put_user_x(1, __pu_val, ptr, __ret_pu); \ 268 break; \ 269 case 2: \ 270 __put_user_x(2, __pu_val, ptr, __ret_pu); \ 271 break; \ 272 case 4: \ 273 __put_user_x(4, __pu_val, ptr, __ret_pu); \ 274 break; \ 275 case 8: \ 276 __put_user_x8(__pu_val, ptr, __ret_pu); \ 277 break; \ 278 default: \ 279 __put_user_x(X, __pu_val, ptr, __ret_pu); \ 280 break; \ 281 } \ 282 __ret_pu; \ 283 }) 284 285 #define __put_user_size(x, ptr, size, retval, errret) \ 286 do { \ 287 retval = 0; \ 288 __chk_user_ptr(ptr); \ 289 switch (size) { \ 290 case 1: \ 291 __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \ 292 break; \ 293 case 2: \ 294 __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \ 295 break; \ 296 case 4: \ 297 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \ 298 break; \ 299 case 8: \ 300 __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval, \ 301 errret); \ 302 break; \ 303 default: \ 304 __put_user_bad(); \ 305 } \ 306 } while (0) 307 308 #define __put_user_size_ex(x, ptr, size) \ 309 do { \ 310 __chk_user_ptr(ptr); \ 311 switch (size) { \ 312 case 1: \ 313 __put_user_asm_ex(x, ptr, "b", "b", "iq"); \ 314 break; \ 315 case 2: \ 316 __put_user_asm_ex(x, ptr, "w", "w", "ir"); \ 317 break; \ 318 case 4: \ 319 __put_user_asm_ex(x, ptr, "l", "k", "ir"); \ 320 break; \ 321 case 8: \ 322 __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \ 323 break; \ 324 default: \ 325 __put_user_bad(); \ 326 } \ 327 } while (0) 328 329 #else 330 331 #define __put_user_size(x, ptr, size, retval, errret) \ 332 do { \ 333 __typeof__(*(ptr))__pus_tmp = x; \ 334 retval = 0; \ 335 \ 336 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \ 337 retval = errret; \ 338 } while (0) 339 340 #define put_user(x, ptr) \ 341 ({ \ 342 int __ret_pu; \ 343 __typeof__(*(ptr))__pus_tmp = x; \ 344 __ret_pu = 0; \ 345 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \ 346 sizeof(*(ptr))) != 0)) \ 347 __ret_pu = -EFAULT; \ 348 __ret_pu; \ 349 }) 350 #endif 351 352 #ifdef CONFIG_X86_32 353 #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() 354 #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad() 355 #else 356 #define __get_user_asm_u64(x, ptr, retval, errret) \ 357 __get_user_asm(x, ptr, retval, "q", "", "=r", errret) 358 #define __get_user_asm_ex_u64(x, ptr) \ 359 __get_user_asm_ex(x, ptr, "q", "", "=r") 360 #endif 361 362 #define __get_user_size(x, ptr, size, retval, errret) \ 363 do { \ 364 retval = 0; \ 365 __chk_user_ptr(ptr); \ 366 switch (size) { \ 367 case 1: \ 368 __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \ 369 break; \ 370 case 2: \ 371 __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \ 372 break; \ 373 case 4: \ 374 __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \ 375 break; \ 376 case 8: \ 377 __get_user_asm_u64(x, ptr, retval, errret); \ 378 break; \ 379 default: \ 380 (x) = __get_user_bad(); \ 381 } \ 382 } while (0) 383 384 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 385 asm volatile(ASM_STAC "\n" \ 386 "1: mov"itype" %2,%"rtype"1\n" \ 387 "2: " ASM_CLAC "\n" \ 388 ".section .fixup,\"ax\"\n" \ 389 "3: mov %3,%0\n" \ 390 " xor"itype" %"rtype"1,%"rtype"1\n" \ 391 " jmp 2b\n" \ 392 ".previous\n" \ 393 _ASM_EXTABLE(1b, 3b) \ 394 : "=r" (err), ltype(x) \ 395 : "m" (__m(addr)), "i" (errret), "0" (err)) 396 397 #define __get_user_size_ex(x, ptr, size) \ 398 do { \ 399 __chk_user_ptr(ptr); \ 400 switch (size) { \ 401 case 1: \ 402 __get_user_asm_ex(x, ptr, "b", "b", "=q"); \ 403 break; \ 404 case 2: \ 405 __get_user_asm_ex(x, ptr, "w", "w", "=r"); \ 406 break; \ 407 case 4: \ 408 __get_user_asm_ex(x, ptr, "l", "k", "=r"); \ 409 break; \ 410 case 8: \ 411 __get_user_asm_ex_u64(x, ptr); \ 412 break; \ 413 default: \ 414 (x) = __get_user_bad(); \ 415 } \ 416 } while (0) 417 418 #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \ 419 asm volatile("1: mov"itype" %1,%"rtype"0\n" \ 420 "2:\n" \ 421 _ASM_EXTABLE_EX(1b, 2b) \ 422 : ltype(x) : "m" (__m(addr))) 423 424 #define __put_user_nocheck(x, ptr, size) \ 425 ({ \ 426 int __pu_err; \ 427 __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \ 428 __pu_err; \ 429 }) 430 431 #define __get_user_nocheck(x, ptr, size) \ 432 ({ \ 433 int __gu_err; \ 434 unsigned long __gu_val; \ 435 __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ 436 (x) = (__force __typeof__(*(ptr)))__gu_val; \ 437 __gu_err; \ 438 }) 439 440 /* FIXME: this hack is definitely wrong -AK */ 441 struct __large_struct { unsigned long buf[100]; }; 442 #define __m(x) (*(struct __large_struct __user *)(x)) 443 444 /* 445 * Tell gcc we read from memory instead of writing: this is because 446 * we do not write to any memory gcc knows about, so there are no 447 * aliasing issues. 448 */ 449 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 450 asm volatile(ASM_STAC "\n" \ 451 "1: mov"itype" %"rtype"1,%2\n" \ 452 "2: " ASM_CLAC "\n" \ 453 ".section .fixup,\"ax\"\n" \ 454 "3: mov %3,%0\n" \ 455 " jmp 2b\n" \ 456 ".previous\n" \ 457 _ASM_EXTABLE(1b, 3b) \ 458 : "=r"(err) \ 459 : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) 460 461 #define __put_user_asm_ex(x, addr, itype, rtype, ltype) \ 462 asm volatile("1: mov"itype" %"rtype"0,%1\n" \ 463 "2:\n" \ 464 _ASM_EXTABLE_EX(1b, 2b) \ 465 : : ltype(x), "m" (__m(addr))) 466 467 /* 468 * uaccess_try and catch 469 */ 470 #define uaccess_try do { \ 471 current_thread_info()->uaccess_err = 0; \ 472 stac(); \ 473 barrier(); 474 475 #define uaccess_catch(err) \ 476 clac(); \ 477 (err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0); \ 478 } while (0) 479 480 /** 481 * __get_user: - Get a simple variable from user space, with less checking. 482 * @x: Variable to store result. 483 * @ptr: Source address, in user space. 484 * 485 * Context: User context only. This function may sleep. 486 * 487 * This macro copies a single simple variable from user space to kernel 488 * space. It supports simple types like char and int, but not larger 489 * data types like structures or arrays. 490 * 491 * @ptr must have pointer-to-simple-variable type, and the result of 492 * dereferencing @ptr must be assignable to @x without a cast. 493 * 494 * Caller must check the pointer with access_ok() before calling this 495 * function. 496 * 497 * Returns zero on success, or -EFAULT on error. 498 * On error, the variable @x is set to zero. 499 */ 500 501 #define __get_user(x, ptr) \ 502 __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 503 504 /** 505 * __put_user: - Write a simple value into user space, with less checking. 506 * @x: Value to copy to user space. 507 * @ptr: Destination address, in user space. 508 * 509 * Context: User context only. This function may sleep. 510 * 511 * This macro copies a single simple value from kernel space to user 512 * space. It supports simple types like char and int, but not larger 513 * data types like structures or arrays. 514 * 515 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 516 * to the result of dereferencing @ptr. 517 * 518 * Caller must check the pointer with access_ok() before calling this 519 * function. 520 * 521 * Returns zero on success, or -EFAULT on error. 522 */ 523 524 #define __put_user(x, ptr) \ 525 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 526 527 #define __get_user_unaligned __get_user 528 #define __put_user_unaligned __put_user 529 530 /* 531 * {get|put}_user_try and catch 532 * 533 * get_user_try { 534 * get_user_ex(...); 535 * } get_user_catch(err) 536 */ 537 #define get_user_try uaccess_try 538 #define get_user_catch(err) uaccess_catch(err) 539 540 #define get_user_ex(x, ptr) do { \ 541 unsigned long __gue_val; \ 542 __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr)))); \ 543 (x) = (__force __typeof__(*(ptr)))__gue_val; \ 544 } while (0) 545 546 #ifdef CONFIG_X86_WP_WORKS_OK 547 548 #define put_user_try uaccess_try 549 #define put_user_catch(err) uaccess_catch(err) 550 551 #define put_user_ex(x, ptr) \ 552 __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 553 554 #else /* !CONFIG_X86_WP_WORKS_OK */ 555 556 #define put_user_try do { \ 557 int __uaccess_err = 0; 558 559 #define put_user_catch(err) \ 560 (err) |= __uaccess_err; \ 561 } while (0) 562 563 #define put_user_ex(x, ptr) do { \ 564 __uaccess_err |= __put_user(x, ptr); \ 565 } while (0) 566 567 #endif /* CONFIG_X86_WP_WORKS_OK */ 568 569 extern unsigned long 570 copy_from_user_nmi(void *to, const void __user *from, unsigned long n); 571 extern __must_check long 572 strncpy_from_user(char *dst, const char __user *src, long count); 573 574 extern __must_check long strlen_user(const char __user *str); 575 extern __must_check long strnlen_user(const char __user *str, long n); 576 577 unsigned long __must_check clear_user(void __user *mem, unsigned long len); 578 unsigned long __must_check __clear_user(void __user *mem, unsigned long len); 579 580 /* 581 * movsl can be slow when source and dest are not both 8-byte aligned 582 */ 583 #ifdef CONFIG_X86_INTEL_USERCOPY 584 extern struct movsl_mask { 585 int mask; 586 } ____cacheline_aligned_in_smp movsl_mask; 587 #endif 588 589 #define ARCH_HAS_NOCACHE_UACCESS 1 590 591 #ifdef CONFIG_X86_32 592 # include "uaccess_32.h" 593 #else 594 # include "uaccess_64.h" 595 #endif 596 597 #endif /* _ASM_X86_UACCESS_H */ 598 599