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/kasan-checks.h> 9 #include <linux/thread_info.h> 10 #include <linux/string.h> 11 #include <asm/asm.h> 12 #include <asm/page.h> 13 #include <asm/smap.h> 14 15 #define VERIFY_READ 0 16 #define VERIFY_WRITE 1 17 18 /* 19 * The fs value determines whether argument validity checking should be 20 * performed or not. If get_fs() == USER_DS, checking is performed, with 21 * get_fs() == KERNEL_DS, checking is bypassed. 22 * 23 * For historical reasons, these macros are grossly misnamed. 24 */ 25 26 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) 27 28 #define KERNEL_DS MAKE_MM_SEG(-1UL) 29 #define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX) 30 31 #define get_ds() (KERNEL_DS) 32 #define get_fs() (current->thread.addr_limit) 33 #define set_fs(x) (current->thread.addr_limit = (x)) 34 35 #define segment_eq(a, b) ((a).seg == (b).seg) 36 37 #define user_addr_max() (current->thread.addr_limit.seg) 38 #define __addr_ok(addr) \ 39 ((unsigned long __force)(addr) < user_addr_max()) 40 41 /* 42 * Test whether a block of memory is a valid user space address. 43 * Returns 0 if the range is valid, nonzero otherwise. 44 */ 45 static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit) 46 { 47 /* 48 * If we have used "sizeof()" for the size, 49 * we know it won't overflow the limit (but 50 * it might overflow the 'addr', so it's 51 * important to subtract the size from the 52 * limit, not add it to the address). 53 */ 54 if (__builtin_constant_p(size)) 55 return unlikely(addr > limit - size); 56 57 /* Arbitrary sizes? Be careful about overflow */ 58 addr += size; 59 if (unlikely(addr < size)) 60 return true; 61 return unlikely(addr > limit); 62 } 63 64 #define __range_not_ok(addr, size, limit) \ 65 ({ \ 66 __chk_user_ptr(addr); \ 67 __chk_range_not_ok((unsigned long __force)(addr), size, limit); \ 68 }) 69 70 /** 71 * access_ok: - Checks if a user space pointer is valid 72 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that 73 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe 74 * to write to a block, it is always safe to read from it. 75 * @addr: User space pointer to start of block to check 76 * @size: Size of block to check 77 * 78 * Context: User context only. This function may sleep if pagefaults are 79 * enabled. 80 * 81 * Checks if a pointer to a block of memory in user space is valid. 82 * 83 * Returns true (nonzero) if the memory block may be valid, false (zero) 84 * if it is definitely invalid. 85 * 86 * Note that, depending on architecture, this function probably just 87 * checks that the pointer is in the user space range - after calling 88 * this function, memory access functions may still return -EFAULT. 89 */ 90 #define access_ok(type, addr, size) \ 91 likely(!__range_not_ok(addr, size, user_addr_max())) 92 93 /* 94 * The exception table consists of triples of addresses relative to the 95 * exception table entry itself. The first address is of an instruction 96 * that is allowed to fault, the second is the target at which the program 97 * should continue. The third is a handler function to deal with the fault 98 * caused by the instruction in the first field. 99 * 100 * All the routines below use bits of fixup code that are out of line 101 * with the main instruction path. This means when everything is well, 102 * we don't even have to jump over them. Further, they do not intrude 103 * on our cache or tlb entries. 104 */ 105 106 struct exception_table_entry { 107 int insn, fixup, handler; 108 }; 109 110 #define ARCH_HAS_RELATIVE_EXTABLE 111 112 #define swap_ex_entry_fixup(a, b, tmp, delta) \ 113 do { \ 114 (a)->fixup = (b)->fixup + (delta); \ 115 (b)->fixup = (tmp).fixup - (delta); \ 116 (a)->handler = (b)->handler + (delta); \ 117 (b)->handler = (tmp).handler - (delta); \ 118 } while (0) 119 120 extern int fixup_exception(struct pt_regs *regs, int trapnr); 121 extern bool ex_has_fault_handler(unsigned long ip); 122 extern void early_fixup_exception(struct pt_regs *regs, int trapnr); 123 124 /* 125 * These are the main single-value transfer routines. They automatically 126 * use the right size if we just have the right pointer type. 127 * 128 * This gets kind of ugly. We want to return _two_ values in "get_user()" 129 * and yet we don't want to do any pointers, because that is too much 130 * of a performance impact. Thus we have a few rather ugly macros here, 131 * and hide all the ugliness from the user. 132 * 133 * The "__xxx" versions of the user access functions are versions that 134 * do not verify the address space, that must have been done previously 135 * with a separate "access_ok()" call (this is used when we do multiple 136 * accesses to the same area of user memory). 137 */ 138 139 extern int __get_user_1(void); 140 extern int __get_user_2(void); 141 extern int __get_user_4(void); 142 extern int __get_user_8(void); 143 extern int __get_user_bad(void); 144 145 #define __uaccess_begin() stac() 146 #define __uaccess_end() clac() 147 148 /* 149 * This is a type: either unsigned long, if the argument fits into 150 * that type, or otherwise unsigned long long. 151 */ 152 #define __inttype(x) \ 153 __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) 154 155 /** 156 * get_user: - Get a simple variable from user space. 157 * @x: Variable to store result. 158 * @ptr: Source address, in user space. 159 * 160 * Context: User context only. This function may sleep if pagefaults are 161 * enabled. 162 * 163 * This macro copies a single simple variable from user space to kernel 164 * space. It supports simple types like char and int, but not larger 165 * data types like structures or arrays. 166 * 167 * @ptr must have pointer-to-simple-variable type, and the result of 168 * dereferencing @ptr must be assignable to @x without a cast. 169 * 170 * Returns zero on success, or -EFAULT on error. 171 * On error, the variable @x is set to zero. 172 */ 173 /* 174 * Careful: we have to cast the result to the type of the pointer 175 * for sign reasons. 176 * 177 * The use of _ASM_DX as the register specifier is a bit of a 178 * simplification, as gcc only cares about it as the starting point 179 * and not size: for a 64-bit value it will use %ecx:%edx on 32 bits 180 * (%ecx being the next register in gcc's x86 register sequence), and 181 * %rdx on 64 bits. 182 * 183 * Clang/LLVM cares about the size of the register, but still wants 184 * the base register for something that ends up being a pair. 185 */ 186 #define get_user(x, ptr) \ 187 ({ \ 188 int __ret_gu; \ 189 register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \ 190 register void *__sp asm(_ASM_SP); \ 191 __chk_user_ptr(ptr); \ 192 might_fault(); \ 193 asm volatile("call __get_user_%P4" \ 194 : "=a" (__ret_gu), "=r" (__val_gu), "+r" (__sp) \ 195 : "0" (ptr), "i" (sizeof(*(ptr)))); \ 196 (x) = (__force __typeof__(*(ptr))) __val_gu; \ 197 __builtin_expect(__ret_gu, 0); \ 198 }) 199 200 #define __put_user_x(size, x, ptr, __ret_pu) \ 201 asm volatile("call __put_user_" #size : "=a" (__ret_pu) \ 202 : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") 203 204 205 206 #ifdef CONFIG_X86_32 207 #define __put_user_asm_u64(x, addr, err, errret) \ 208 asm volatile("\n" \ 209 "1: movl %%eax,0(%2)\n" \ 210 "2: movl %%edx,4(%2)\n" \ 211 "3:" \ 212 ".section .fixup,\"ax\"\n" \ 213 "4: movl %3,%0\n" \ 214 " jmp 3b\n" \ 215 ".previous\n" \ 216 _ASM_EXTABLE(1b, 4b) \ 217 _ASM_EXTABLE(2b, 4b) \ 218 : "=r" (err) \ 219 : "A" (x), "r" (addr), "i" (errret), "0" (err)) 220 221 #define __put_user_asm_ex_u64(x, addr) \ 222 asm volatile("\n" \ 223 "1: movl %%eax,0(%1)\n" \ 224 "2: movl %%edx,4(%1)\n" \ 225 "3:" \ 226 _ASM_EXTABLE_EX(1b, 2b) \ 227 _ASM_EXTABLE_EX(2b, 3b) \ 228 : : "A" (x), "r" (addr)) 229 230 #define __put_user_x8(x, ptr, __ret_pu) \ 231 asm volatile("call __put_user_8" : "=a" (__ret_pu) \ 232 : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") 233 #else 234 #define __put_user_asm_u64(x, ptr, retval, errret) \ 235 __put_user_asm(x, ptr, retval, "q", "", "er", errret) 236 #define __put_user_asm_ex_u64(x, addr) \ 237 __put_user_asm_ex(x, addr, "q", "", "er") 238 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu) 239 #endif 240 241 extern void __put_user_bad(void); 242 243 /* 244 * Strange magic calling convention: pointer in %ecx, 245 * value in %eax(:%edx), return value in %eax. clobbers %rbx 246 */ 247 extern void __put_user_1(void); 248 extern void __put_user_2(void); 249 extern void __put_user_4(void); 250 extern void __put_user_8(void); 251 252 /** 253 * put_user: - Write a simple value into user space. 254 * @x: Value to copy to user space. 255 * @ptr: Destination address, in user space. 256 * 257 * Context: User context only. This function may sleep if pagefaults are 258 * enabled. 259 * 260 * This macro copies a single simple value from kernel space to user 261 * space. It supports simple types like char and int, but not larger 262 * data types like structures or arrays. 263 * 264 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 265 * to the result of dereferencing @ptr. 266 * 267 * Returns zero on success, or -EFAULT on error. 268 */ 269 #define put_user(x, ptr) \ 270 ({ \ 271 int __ret_pu; \ 272 __typeof__(*(ptr)) __pu_val; \ 273 __chk_user_ptr(ptr); \ 274 might_fault(); \ 275 __pu_val = x; \ 276 switch (sizeof(*(ptr))) { \ 277 case 1: \ 278 __put_user_x(1, __pu_val, ptr, __ret_pu); \ 279 break; \ 280 case 2: \ 281 __put_user_x(2, __pu_val, ptr, __ret_pu); \ 282 break; \ 283 case 4: \ 284 __put_user_x(4, __pu_val, ptr, __ret_pu); \ 285 break; \ 286 case 8: \ 287 __put_user_x8(__pu_val, ptr, __ret_pu); \ 288 break; \ 289 default: \ 290 __put_user_x(X, __pu_val, ptr, __ret_pu); \ 291 break; \ 292 } \ 293 __builtin_expect(__ret_pu, 0); \ 294 }) 295 296 #define __put_user_size(x, ptr, size, retval, errret) \ 297 do { \ 298 retval = 0; \ 299 __chk_user_ptr(ptr); \ 300 switch (size) { \ 301 case 1: \ 302 __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \ 303 break; \ 304 case 2: \ 305 __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \ 306 break; \ 307 case 4: \ 308 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \ 309 break; \ 310 case 8: \ 311 __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval, \ 312 errret); \ 313 break; \ 314 default: \ 315 __put_user_bad(); \ 316 } \ 317 } while (0) 318 319 /* 320 * This doesn't do __uaccess_begin/end - the exception handling 321 * around it must do that. 322 */ 323 #define __put_user_size_ex(x, ptr, size) \ 324 do { \ 325 __chk_user_ptr(ptr); \ 326 switch (size) { \ 327 case 1: \ 328 __put_user_asm_ex(x, ptr, "b", "b", "iq"); \ 329 break; \ 330 case 2: \ 331 __put_user_asm_ex(x, ptr, "w", "w", "ir"); \ 332 break; \ 333 case 4: \ 334 __put_user_asm_ex(x, ptr, "l", "k", "ir"); \ 335 break; \ 336 case 8: \ 337 __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \ 338 break; \ 339 default: \ 340 __put_user_bad(); \ 341 } \ 342 } while (0) 343 344 #ifdef CONFIG_X86_32 345 #define __get_user_asm_u64(x, ptr, retval, errret) \ 346 ({ \ 347 __typeof__(ptr) __ptr = (ptr); \ 348 asm volatile(ASM_STAC "\n" \ 349 "1: movl %2,%%eax\n" \ 350 "2: movl %3,%%edx\n" \ 351 "3: " ASM_CLAC "\n" \ 352 ".section .fixup,\"ax\"\n" \ 353 "4: mov %4,%0\n" \ 354 " xorl %%eax,%%eax\n" \ 355 " xorl %%edx,%%edx\n" \ 356 " jmp 3b\n" \ 357 ".previous\n" \ 358 _ASM_EXTABLE(1b, 4b) \ 359 _ASM_EXTABLE(2b, 4b) \ 360 : "=r" (retval), "=A"(x) \ 361 : "m" (__m(__ptr)), "m" __m(((u32 *)(__ptr)) + 1), \ 362 "i" (errret), "0" (retval)); \ 363 }) 364 365 #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad() 366 #else 367 #define __get_user_asm_u64(x, ptr, retval, errret) \ 368 __get_user_asm(x, ptr, retval, "q", "", "=r", errret) 369 #define __get_user_asm_ex_u64(x, ptr) \ 370 __get_user_asm_ex(x, ptr, "q", "", "=r") 371 #endif 372 373 #define __get_user_size(x, ptr, size, retval, errret) \ 374 do { \ 375 retval = 0; \ 376 __chk_user_ptr(ptr); \ 377 switch (size) { \ 378 case 1: \ 379 __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \ 380 break; \ 381 case 2: \ 382 __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \ 383 break; \ 384 case 4: \ 385 __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \ 386 break; \ 387 case 8: \ 388 __get_user_asm_u64(x, ptr, retval, errret); \ 389 break; \ 390 default: \ 391 (x) = __get_user_bad(); \ 392 } \ 393 } while (0) 394 395 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 396 asm volatile("\n" \ 397 "1: mov"itype" %2,%"rtype"1\n" \ 398 "2:\n" \ 399 ".section .fixup,\"ax\"\n" \ 400 "3: mov %3,%0\n" \ 401 " xor"itype" %"rtype"1,%"rtype"1\n" \ 402 " jmp 2b\n" \ 403 ".previous\n" \ 404 _ASM_EXTABLE(1b, 3b) \ 405 : "=r" (err), ltype(x) \ 406 : "m" (__m(addr)), "i" (errret), "0" (err)) 407 408 /* 409 * This doesn't do __uaccess_begin/end - the exception handling 410 * around it must do that. 411 */ 412 #define __get_user_size_ex(x, ptr, size) \ 413 do { \ 414 __chk_user_ptr(ptr); \ 415 switch (size) { \ 416 case 1: \ 417 __get_user_asm_ex(x, ptr, "b", "b", "=q"); \ 418 break; \ 419 case 2: \ 420 __get_user_asm_ex(x, ptr, "w", "w", "=r"); \ 421 break; \ 422 case 4: \ 423 __get_user_asm_ex(x, ptr, "l", "k", "=r"); \ 424 break; \ 425 case 8: \ 426 __get_user_asm_ex_u64(x, ptr); \ 427 break; \ 428 default: \ 429 (x) = __get_user_bad(); \ 430 } \ 431 } while (0) 432 433 #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \ 434 asm volatile("1: mov"itype" %1,%"rtype"0\n" \ 435 "2:\n" \ 436 ".section .fixup,\"ax\"\n" \ 437 "3:xor"itype" %"rtype"0,%"rtype"0\n" \ 438 " jmp 2b\n" \ 439 ".previous\n" \ 440 _ASM_EXTABLE_EX(1b, 3b) \ 441 : ltype(x) : "m" (__m(addr))) 442 443 #define __put_user_nocheck(x, ptr, size) \ 444 ({ \ 445 int __pu_err; \ 446 __uaccess_begin(); \ 447 __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \ 448 __uaccess_end(); \ 449 __builtin_expect(__pu_err, 0); \ 450 }) 451 452 #define __get_user_nocheck(x, ptr, size) \ 453 ({ \ 454 int __gu_err; \ 455 __inttype(*(ptr)) __gu_val; \ 456 __uaccess_begin(); \ 457 __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ 458 __uaccess_end(); \ 459 (x) = (__force __typeof__(*(ptr)))__gu_val; \ 460 __builtin_expect(__gu_err, 0); \ 461 }) 462 463 /* FIXME: this hack is definitely wrong -AK */ 464 struct __large_struct { unsigned long buf[100]; }; 465 #define __m(x) (*(struct __large_struct __user *)(x)) 466 467 /* 468 * Tell gcc we read from memory instead of writing: this is because 469 * we do not write to any memory gcc knows about, so there are no 470 * aliasing issues. 471 */ 472 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 473 asm volatile("\n" \ 474 "1: mov"itype" %"rtype"1,%2\n" \ 475 "2:\n" \ 476 ".section .fixup,\"ax\"\n" \ 477 "3: mov %3,%0\n" \ 478 " jmp 2b\n" \ 479 ".previous\n" \ 480 _ASM_EXTABLE(1b, 3b) \ 481 : "=r"(err) \ 482 : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) 483 484 #define __put_user_asm_ex(x, addr, itype, rtype, ltype) \ 485 asm volatile("1: mov"itype" %"rtype"0,%1\n" \ 486 "2:\n" \ 487 _ASM_EXTABLE_EX(1b, 2b) \ 488 : : ltype(x), "m" (__m(addr))) 489 490 /* 491 * uaccess_try and catch 492 */ 493 #define uaccess_try do { \ 494 current->thread.uaccess_err = 0; \ 495 __uaccess_begin(); \ 496 barrier(); 497 498 #define uaccess_catch(err) \ 499 __uaccess_end(); \ 500 (err) |= (current->thread.uaccess_err ? -EFAULT : 0); \ 501 } while (0) 502 503 /** 504 * __get_user: - Get a simple variable from user space, with less checking. 505 * @x: Variable to store result. 506 * @ptr: Source address, in user space. 507 * 508 * Context: User context only. This function may sleep if pagefaults are 509 * enabled. 510 * 511 * This macro copies a single simple variable from user space to kernel 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 the result of 516 * dereferencing @ptr must be assignable to @x without a cast. 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 * On error, the variable @x is set to zero. 523 */ 524 525 #define __get_user(x, ptr) \ 526 __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 527 528 /** 529 * __put_user: - Write a simple value into user space, with less checking. 530 * @x: Value to copy to user space. 531 * @ptr: Destination address, in user space. 532 * 533 * Context: User context only. This function may sleep if pagefaults are 534 * enabled. 535 * 536 * This macro copies a single simple value from kernel space to user 537 * space. It supports simple types like char and int, but not larger 538 * data types like structures or arrays. 539 * 540 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 541 * to the result of dereferencing @ptr. 542 * 543 * Caller must check the pointer with access_ok() before calling this 544 * function. 545 * 546 * Returns zero on success, or -EFAULT on error. 547 */ 548 549 #define __put_user(x, ptr) \ 550 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 551 552 #define __get_user_unaligned __get_user 553 #define __put_user_unaligned __put_user 554 555 /* 556 * {get|put}_user_try and catch 557 * 558 * get_user_try { 559 * get_user_ex(...); 560 * } get_user_catch(err) 561 */ 562 #define get_user_try uaccess_try 563 #define get_user_catch(err) uaccess_catch(err) 564 565 #define get_user_ex(x, ptr) do { \ 566 unsigned long __gue_val; \ 567 __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr)))); \ 568 (x) = (__force __typeof__(*(ptr)))__gue_val; \ 569 } while (0) 570 571 #define put_user_try uaccess_try 572 #define put_user_catch(err) uaccess_catch(err) 573 574 #define put_user_ex(x, ptr) \ 575 __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 576 577 extern unsigned long 578 copy_from_user_nmi(void *to, const void __user *from, unsigned long n); 579 extern __must_check long 580 strncpy_from_user(char *dst, const char __user *src, long count); 581 582 extern __must_check long strlen_user(const char __user *str); 583 extern __must_check long strnlen_user(const char __user *str, long n); 584 585 unsigned long __must_check clear_user(void __user *mem, unsigned long len); 586 unsigned long __must_check __clear_user(void __user *mem, unsigned long len); 587 588 extern void __cmpxchg_wrong_size(void) 589 __compiletime_error("Bad argument size for cmpxchg"); 590 591 #define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size) \ 592 ({ \ 593 int __ret = 0; \ 594 __typeof__(ptr) __uval = (uval); \ 595 __typeof__(*(ptr)) __old = (old); \ 596 __typeof__(*(ptr)) __new = (new); \ 597 __uaccess_begin(); \ 598 switch (size) { \ 599 case 1: \ 600 { \ 601 asm volatile("\n" \ 602 "1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n" \ 603 "2:\n" \ 604 "\t.section .fixup, \"ax\"\n" \ 605 "3:\tmov %3, %0\n" \ 606 "\tjmp 2b\n" \ 607 "\t.previous\n" \ 608 _ASM_EXTABLE(1b, 3b) \ 609 : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ 610 : "i" (-EFAULT), "q" (__new), "1" (__old) \ 611 : "memory" \ 612 ); \ 613 break; \ 614 } \ 615 case 2: \ 616 { \ 617 asm volatile("\n" \ 618 "1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n" \ 619 "2:\n" \ 620 "\t.section .fixup, \"ax\"\n" \ 621 "3:\tmov %3, %0\n" \ 622 "\tjmp 2b\n" \ 623 "\t.previous\n" \ 624 _ASM_EXTABLE(1b, 3b) \ 625 : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ 626 : "i" (-EFAULT), "r" (__new), "1" (__old) \ 627 : "memory" \ 628 ); \ 629 break; \ 630 } \ 631 case 4: \ 632 { \ 633 asm volatile("\n" \ 634 "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" \ 635 "2:\n" \ 636 "\t.section .fixup, \"ax\"\n" \ 637 "3:\tmov %3, %0\n" \ 638 "\tjmp 2b\n" \ 639 "\t.previous\n" \ 640 _ASM_EXTABLE(1b, 3b) \ 641 : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ 642 : "i" (-EFAULT), "r" (__new), "1" (__old) \ 643 : "memory" \ 644 ); \ 645 break; \ 646 } \ 647 case 8: \ 648 { \ 649 if (!IS_ENABLED(CONFIG_X86_64)) \ 650 __cmpxchg_wrong_size(); \ 651 \ 652 asm volatile("\n" \ 653 "1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n" \ 654 "2:\n" \ 655 "\t.section .fixup, \"ax\"\n" \ 656 "3:\tmov %3, %0\n" \ 657 "\tjmp 2b\n" \ 658 "\t.previous\n" \ 659 _ASM_EXTABLE(1b, 3b) \ 660 : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ 661 : "i" (-EFAULT), "r" (__new), "1" (__old) \ 662 : "memory" \ 663 ); \ 664 break; \ 665 } \ 666 default: \ 667 __cmpxchg_wrong_size(); \ 668 } \ 669 __uaccess_end(); \ 670 *__uval = __old; \ 671 __ret; \ 672 }) 673 674 #define user_atomic_cmpxchg_inatomic(uval, ptr, old, new) \ 675 ({ \ 676 access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \ 677 __user_atomic_cmpxchg_inatomic((uval), (ptr), \ 678 (old), (new), sizeof(*(ptr))) : \ 679 -EFAULT; \ 680 }) 681 682 /* 683 * movsl can be slow when source and dest are not both 8-byte aligned 684 */ 685 #ifdef CONFIG_X86_INTEL_USERCOPY 686 extern struct movsl_mask { 687 int mask; 688 } ____cacheline_aligned_in_smp movsl_mask; 689 #endif 690 691 #define ARCH_HAS_NOCACHE_UACCESS 1 692 693 #ifdef CONFIG_X86_32 694 # include <asm/uaccess_32.h> 695 #else 696 # include <asm/uaccess_64.h> 697 #endif 698 699 unsigned long __must_check _copy_from_user(void *to, const void __user *from, 700 unsigned n); 701 unsigned long __must_check _copy_to_user(void __user *to, const void *from, 702 unsigned n); 703 704 extern void __compiletime_error("usercopy buffer size is too small") 705 __bad_copy_user(void); 706 707 static inline void copy_user_overflow(int size, unsigned long count) 708 { 709 WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count); 710 } 711 712 static __always_inline unsigned long __must_check 713 copy_from_user(void *to, const void __user *from, unsigned long n) 714 { 715 int sz = __compiletime_object_size(to); 716 717 might_fault(); 718 719 kasan_check_write(to, n); 720 721 if (likely(sz < 0 || sz >= n)) { 722 check_object_size(to, n, false); 723 n = _copy_from_user(to, from, n); 724 } else if (!__builtin_constant_p(n)) 725 copy_user_overflow(sz, n); 726 else 727 __bad_copy_user(); 728 729 return n; 730 } 731 732 static __always_inline unsigned long __must_check 733 copy_to_user(void __user *to, const void *from, unsigned long n) 734 { 735 int sz = __compiletime_object_size(from); 736 737 kasan_check_read(from, n); 738 739 might_fault(); 740 741 if (likely(sz < 0 || sz >= n)) { 742 check_object_size(from, n, true); 743 n = _copy_to_user(to, from, n); 744 } else if (!__builtin_constant_p(n)) 745 copy_user_overflow(sz, n); 746 else 747 __bad_copy_user(); 748 749 return n; 750 } 751 752 /* 753 * We rely on the nested NMI work to allow atomic faults from the NMI path; the 754 * nested NMI paths are careful to preserve CR2. 755 * 756 * Caller must use pagefault_enable/disable, or run in interrupt context, 757 * and also do a uaccess_ok() check 758 */ 759 #define __copy_from_user_nmi __copy_from_user_inatomic 760 761 /* 762 * The "unsafe" user accesses aren't really "unsafe", but the naming 763 * is a big fat warning: you have to not only do the access_ok() 764 * checking before using them, but you have to surround them with the 765 * user_access_begin/end() pair. 766 */ 767 #define user_access_begin() __uaccess_begin() 768 #define user_access_end() __uaccess_end() 769 770 #define unsafe_put_user(x, ptr, err_label) \ 771 do { \ 772 int __pu_err; \ 773 __put_user_size((x), (ptr), sizeof(*(ptr)), __pu_err, -EFAULT); \ 774 if (unlikely(__pu_err)) goto err_label; \ 775 } while (0) 776 777 #define unsafe_get_user(x, ptr, err_label) \ 778 do { \ 779 int __gu_err; \ 780 unsigned long __gu_val; \ 781 __get_user_size(__gu_val, (ptr), sizeof(*(ptr)), __gu_err, -EFAULT); \ 782 (x) = (__force __typeof__(*(ptr)))__gu_val; \ 783 if (unlikely(__gu_err)) goto err_label; \ 784 } while (0) 785 786 #endif /* _ASM_X86_UACCESS_H */ 787 788