1#ifndef __i386_UACCESS_H 2#define __i386_UACCESS_H 3 4/* 5 * User space memory access functions 6 */ 7#include <linux/errno.h> 8#include <linux/thread_info.h> 9#include <linux/prefetch.h> 10#include <linux/string.h> 11#include <asm/page.h> 12 13#define VERIFY_READ 0 14#define VERIFY_WRITE 1 15 16/* 17 * The fs value determines whether argument validity checking should be 18 * performed or not. If get_fs() == USER_DS, checking is performed, with 19 * get_fs() == KERNEL_DS, checking is bypassed. 20 * 21 * For historical reasons, these macros are grossly misnamed. 22 */ 23 24#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) 25 26 27#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFUL) 28#define USER_DS MAKE_MM_SEG(PAGE_OFFSET) 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/* 37 * movsl can be slow when source and dest are not both 8-byte aligned 38 */ 39#ifdef CONFIG_X86_INTEL_USERCOPY 40extern struct movsl_mask { 41 int mask; 42} ____cacheline_aligned_in_smp movsl_mask; 43#endif 44 45#define __addr_ok(addr) ((unsigned long __force)(addr) < (current_thread_info()->addr_limit.seg)) 46 47/* 48 * Test whether a block of memory is a valid user space address. 49 * Returns 0 if the range is valid, nonzero otherwise. 50 * 51 * This is equivalent to the following test: 52 * (u33)addr + (u33)size >= (u33)current->addr_limit.seg 53 * 54 * This needs 33-bit arithmetic. We have a carry... 55 */ 56#define __range_ok(addr,size) ({ \ 57 unsigned long flag,roksum; \ 58 __chk_user_ptr(addr); \ 59 asm("addl %3,%1 ; sbbl %0,%0; cmpl %1,%4; sbbl $0,%0" \ 60 :"=&r" (flag), "=r" (roksum) \ 61 :"1" (addr),"g" ((int)(size)),"rm" (current_thread_info()->addr_limit.seg)); \ 62 flag; }) 63 64/** 65 * access_ok: - Checks if a user space pointer is valid 66 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that 67 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe 68 * to write to a block, it is always safe to read from it. 69 * @addr: User space pointer to start of block to check 70 * @size: Size of block to check 71 * 72 * Context: User context only. This function may sleep. 73 * 74 * Checks if a pointer to a block of memory in user space is valid. 75 * 76 * Returns true (nonzero) if the memory block may be valid, false (zero) 77 * if it is definitely invalid. 78 * 79 * Note that, depending on architecture, this function probably just 80 * checks that the pointer is in the user space range - after calling 81 * this function, memory access functions may still return -EFAULT. 82 */ 83#define access_ok(type,addr,size) (likely(__range_ok(addr,size) == 0)) 84 85/* 86 * The exception table consists of pairs of addresses: the first is the 87 * address of an instruction that is allowed to fault, and the second is 88 * the address at which the program should continue. No registers are 89 * modified, so it is entirely up to the continuation code to figure out 90 * what to do. 91 * 92 * All the routines below use bits of fixup code that are out of line 93 * with the main instruction path. This means when everything is well, 94 * we don't even have to jump over them. Further, they do not intrude 95 * on our cache or tlb entries. 96 */ 97 98struct exception_table_entry 99{ 100 unsigned long insn, fixup; 101}; 102 103extern int fixup_exception(struct pt_regs *regs); 104 105/* 106 * These are the main single-value transfer routines. They automatically 107 * use the right size if we just have the right pointer type. 108 * 109 * This gets kind of ugly. We want to return _two_ values in "get_user()" 110 * and yet we don't want to do any pointers, because that is too much 111 * of a performance impact. Thus we have a few rather ugly macros here, 112 * and hide all the ugliness from the user. 113 * 114 * The "__xxx" versions of the user access functions are versions that 115 * do not verify the address space, that must have been done previously 116 * with a separate "access_ok()" call (this is used when we do multiple 117 * accesses to the same area of user memory). 118 */ 119 120extern void __get_user_1(void); 121extern void __get_user_2(void); 122extern void __get_user_4(void); 123 124#define __get_user_x(size,ret,x,ptr) \ 125 __asm__ __volatile__("call __get_user_" #size \ 126 :"=a" (ret),"=d" (x) \ 127 :"0" (ptr)) 128 129 130/* Careful: we have to cast the result to the type of the pointer for sign reasons */ 131/** 132 * get_user: - Get a simple variable from user space. 133 * @x: Variable to store result. 134 * @ptr: Source address, in user space. 135 * 136 * Context: User context only. This function may sleep. 137 * 138 * This macro copies a single simple variable from user space to kernel 139 * space. It supports simple types like char and int, but not larger 140 * data types like structures or arrays. 141 * 142 * @ptr must have pointer-to-simple-variable type, and the result of 143 * dereferencing @ptr must be assignable to @x without a cast. 144 * 145 * Returns zero on success, or -EFAULT on error. 146 * On error, the variable @x is set to zero. 147 */ 148#define get_user(x,ptr) \ 149({ int __ret_gu; \ 150 unsigned long __val_gu; \ 151 __chk_user_ptr(ptr); \ 152 switch(sizeof (*(ptr))) { \ 153 case 1: __get_user_x(1,__ret_gu,__val_gu,ptr); break; \ 154 case 2: __get_user_x(2,__ret_gu,__val_gu,ptr); break; \ 155 case 4: __get_user_x(4,__ret_gu,__val_gu,ptr); break; \ 156 default: __get_user_x(X,__ret_gu,__val_gu,ptr); break; \ 157 } \ 158 (x) = (__typeof__(*(ptr)))__val_gu; \ 159 __ret_gu; \ 160}) 161 162extern void __put_user_bad(void); 163 164/* 165 * Strange magic calling convention: pointer in %ecx, 166 * value in %eax(:%edx), return value in %eax, no clobbers. 167 */ 168extern void __put_user_1(void); 169extern void __put_user_2(void); 170extern void __put_user_4(void); 171extern void __put_user_8(void); 172 173#define __put_user_1(x, ptr) __asm__ __volatile__("call __put_user_1":"=a" (__ret_pu):"0" ((typeof(*(ptr)))(x)), "c" (ptr)) 174#define __put_user_2(x, ptr) __asm__ __volatile__("call __put_user_2":"=a" (__ret_pu):"0" ((typeof(*(ptr)))(x)), "c" (ptr)) 175#define __put_user_4(x, ptr) __asm__ __volatile__("call __put_user_4":"=a" (__ret_pu):"0" ((typeof(*(ptr)))(x)), "c" (ptr)) 176#define __put_user_8(x, ptr) __asm__ __volatile__("call __put_user_8":"=a" (__ret_pu):"A" ((typeof(*(ptr)))(x)), "c" (ptr)) 177#define __put_user_X(x, ptr) __asm__ __volatile__("call __put_user_X":"=a" (__ret_pu):"c" (ptr)) 178 179/** 180 * put_user: - Write a simple value into user space. 181 * @x: Value to copy to user space. 182 * @ptr: Destination address, in user space. 183 * 184 * Context: User context only. This function may sleep. 185 * 186 * This macro copies a single simple value from kernel space to user 187 * space. It supports simple types like char and int, but not larger 188 * data types like structures or arrays. 189 * 190 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 191 * to the result of dereferencing @ptr. 192 * 193 * Returns zero on success, or -EFAULT on error. 194 */ 195#ifdef CONFIG_X86_WP_WORKS_OK 196 197#define put_user(x,ptr) \ 198({ int __ret_pu; \ 199 __typeof__(*(ptr)) __pu_val; \ 200 __chk_user_ptr(ptr); \ 201 __pu_val = x; \ 202 switch(sizeof(*(ptr))) { \ 203 case 1: __put_user_1(__pu_val, ptr); break; \ 204 case 2: __put_user_2(__pu_val, ptr); break; \ 205 case 4: __put_user_4(__pu_val, ptr); break; \ 206 case 8: __put_user_8(__pu_val, ptr); break; \ 207 default:__put_user_X(__pu_val, ptr); break; \ 208 } \ 209 __ret_pu; \ 210}) 211 212#else 213#define put_user(x,ptr) \ 214({ \ 215 int __ret_pu; \ 216 __typeof__(*(ptr)) __pus_tmp = x; \ 217 __ret_pu=0; \ 218 if(unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \ 219 sizeof(*(ptr))) != 0)) \ 220 __ret_pu=-EFAULT; \ 221 __ret_pu; \ 222 }) 223 224 225#endif 226 227/** 228 * __get_user: - Get a simple variable from user space, with less checking. 229 * @x: Variable to store result. 230 * @ptr: Source address, in user space. 231 * 232 * Context: User context only. This function may sleep. 233 * 234 * This macro copies a single simple variable from user space to kernel 235 * space. It supports simple types like char and int, but not larger 236 * data types like structures or arrays. 237 * 238 * @ptr must have pointer-to-simple-variable type, and the result of 239 * dereferencing @ptr must be assignable to @x without a cast. 240 * 241 * Caller must check the pointer with access_ok() before calling this 242 * function. 243 * 244 * Returns zero on success, or -EFAULT on error. 245 * On error, the variable @x is set to zero. 246 */ 247#define __get_user(x,ptr) \ 248 __get_user_nocheck((x),(ptr),sizeof(*(ptr))) 249 250 251/** 252 * __put_user: - Write a simple value into user space, with less checking. 253 * @x: Value to copy to user space. 254 * @ptr: Destination address, in user space. 255 * 256 * Context: User context only. This function may sleep. 257 * 258 * This macro copies a single simple value from kernel space to user 259 * space. It supports simple types like char and int, but not larger 260 * data types like structures or arrays. 261 * 262 * @ptr must have pointer-to-simple-variable type, and @x must be assignable 263 * to the result of dereferencing @ptr. 264 * 265 * Caller must check the pointer with access_ok() before calling this 266 * function. 267 * 268 * Returns zero on success, or -EFAULT on error. 269 */ 270#define __put_user(x,ptr) \ 271 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr))) 272 273#define __put_user_nocheck(x,ptr,size) \ 274({ \ 275 long __pu_err; \ 276 __put_user_size((x),(ptr),(size),__pu_err,-EFAULT); \ 277 __pu_err; \ 278}) 279 280 281#define __put_user_u64(x, addr, err) \ 282 __asm__ __volatile__( \ 283 "1: movl %%eax,0(%2)\n" \ 284 "2: movl %%edx,4(%2)\n" \ 285 "3:\n" \ 286 ".section .fixup,\"ax\"\n" \ 287 "4: movl %3,%0\n" \ 288 " jmp 3b\n" \ 289 ".previous\n" \ 290 ".section __ex_table,\"a\"\n" \ 291 " .align 4\n" \ 292 " .long 1b,4b\n" \ 293 " .long 2b,4b\n" \ 294 ".previous" \ 295 : "=r"(err) \ 296 : "A" (x), "r" (addr), "i"(-EFAULT), "0"(err)) 297 298#ifdef CONFIG_X86_WP_WORKS_OK 299 300#define __put_user_size(x,ptr,size,retval,errret) \ 301do { \ 302 retval = 0; \ 303 __chk_user_ptr(ptr); \ 304 switch (size) { \ 305 case 1: __put_user_asm(x,ptr,retval,"b","b","iq",errret);break; \ 306 case 2: __put_user_asm(x,ptr,retval,"w","w","ir",errret);break; \ 307 case 4: __put_user_asm(x,ptr,retval,"l","","ir",errret); break; \ 308 case 8: __put_user_u64((__typeof__(*ptr))(x),ptr,retval); break;\ 309 default: __put_user_bad(); \ 310 } \ 311} while (0) 312 313#else 314 315#define __put_user_size(x,ptr,size,retval,errret) \ 316do { \ 317 __typeof__(*(ptr)) __pus_tmp = x; \ 318 retval = 0; \ 319 \ 320 if(unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \ 321 retval = errret; \ 322} while (0) 323 324#endif 325struct __large_struct { unsigned long buf[100]; }; 326#define __m(x) (*(struct __large_struct __user *)(x)) 327 328/* 329 * Tell gcc we read from memory instead of writing: this is because 330 * we do not write to any memory gcc knows about, so there are no 331 * aliasing issues. 332 */ 333#define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 334 __asm__ __volatile__( \ 335 "1: mov"itype" %"rtype"1,%2\n" \ 336 "2:\n" \ 337 ".section .fixup,\"ax\"\n" \ 338 "3: movl %3,%0\n" \ 339 " jmp 2b\n" \ 340 ".previous\n" \ 341 ".section __ex_table,\"a\"\n" \ 342 " .align 4\n" \ 343 " .long 1b,3b\n" \ 344 ".previous" \ 345 : "=r"(err) \ 346 : ltype (x), "m"(__m(addr)), "i"(errret), "0"(err)) 347 348 349#define __get_user_nocheck(x,ptr,size) \ 350({ \ 351 long __gu_err; \ 352 unsigned long __gu_val; \ 353 __get_user_size(__gu_val,(ptr),(size),__gu_err,-EFAULT);\ 354 (x) = (__typeof__(*(ptr)))__gu_val; \ 355 __gu_err; \ 356}) 357 358extern long __get_user_bad(void); 359 360#define __get_user_size(x,ptr,size,retval,errret) \ 361do { \ 362 retval = 0; \ 363 __chk_user_ptr(ptr); \ 364 switch (size) { \ 365 case 1: __get_user_asm(x,ptr,retval,"b","b","=q",errret);break; \ 366 case 2: __get_user_asm(x,ptr,retval,"w","w","=r",errret);break; \ 367 case 4: __get_user_asm(x,ptr,retval,"l","","=r",errret);break; \ 368 default: (x) = __get_user_bad(); \ 369 } \ 370} while (0) 371 372#define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ 373 __asm__ __volatile__( \ 374 "1: mov"itype" %2,%"rtype"1\n" \ 375 "2:\n" \ 376 ".section .fixup,\"ax\"\n" \ 377 "3: movl %3,%0\n" \ 378 " xor"itype" %"rtype"1,%"rtype"1\n" \ 379 " jmp 2b\n" \ 380 ".previous\n" \ 381 ".section __ex_table,\"a\"\n" \ 382 " .align 4\n" \ 383 " .long 1b,3b\n" \ 384 ".previous" \ 385 : "=r"(err), ltype (x) \ 386 : "m"(__m(addr)), "i"(errret), "0"(err)) 387 388 389unsigned long __must_check __copy_to_user_ll(void __user *to, 390 const void *from, unsigned long n); 391unsigned long __must_check __copy_from_user_ll(void *to, 392 const void __user *from, unsigned long n); 393unsigned long __must_check __copy_from_user_ll_nozero(void *to, 394 const void __user *from, unsigned long n); 395unsigned long __must_check __copy_from_user_ll_nocache(void *to, 396 const void __user *from, unsigned long n); 397unsigned long __must_check __copy_from_user_ll_nocache_nozero(void *to, 398 const void __user *from, unsigned long n); 399 400/** 401 * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking. 402 * @to: Destination address, in user space. 403 * @from: Source address, in kernel space. 404 * @n: Number of bytes to copy. 405 * 406 * Context: User context only. 407 * 408 * Copy data from kernel space to user space. Caller must check 409 * the specified block with access_ok() before calling this function. 410 * The caller should also make sure he pins the user space address 411 * so that the we don't result in page fault and sleep. 412 * 413 * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault 414 * we return the initial request size (1, 2 or 4), as copy_*_user should do. 415 * If a store crosses a page boundary and gets a fault, the x86 will not write 416 * anything, so this is accurate. 417 */ 418 419static __always_inline unsigned long __must_check 420__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n) 421{ 422 if (__builtin_constant_p(n)) { 423 unsigned long ret; 424 425 switch (n) { 426 case 1: 427 __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret, 1); 428 return ret; 429 case 2: 430 __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret, 2); 431 return ret; 432 case 4: 433 __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret, 4); 434 return ret; 435 } 436 } 437 return __copy_to_user_ll(to, from, n); 438} 439 440/** 441 * __copy_to_user: - Copy a block of data into user space, with less checking. 442 * @to: Destination address, in user space. 443 * @from: Source address, in kernel space. 444 * @n: Number of bytes to copy. 445 * 446 * Context: User context only. This function may sleep. 447 * 448 * Copy data from kernel space to user space. Caller must check 449 * the specified block with access_ok() before calling this function. 450 * 451 * Returns number of bytes that could not be copied. 452 * On success, this will be zero. 453 */ 454static __always_inline unsigned long __must_check 455__copy_to_user(void __user *to, const void *from, unsigned long n) 456{ 457 might_sleep(); 458 return __copy_to_user_inatomic(to, from, n); 459} 460 461static __always_inline unsigned long 462__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) 463{ 464 /* Avoid zeroing the tail if the copy fails.. 465 * If 'n' is constant and 1, 2, or 4, we do still zero on a failure, 466 * but as the zeroing behaviour is only significant when n is not 467 * constant, that shouldn't be a problem. 468 */ 469 if (__builtin_constant_p(n)) { 470 unsigned long ret; 471 472 switch (n) { 473 case 1: 474 __get_user_size(*(u8 *)to, from, 1, ret, 1); 475 return ret; 476 case 2: 477 __get_user_size(*(u16 *)to, from, 2, ret, 2); 478 return ret; 479 case 4: 480 __get_user_size(*(u32 *)to, from, 4, ret, 4); 481 return ret; 482 } 483 } 484 return __copy_from_user_ll_nozero(to, from, n); 485} 486 487/** 488 * __copy_from_user: - Copy a block of data from user space, with less checking. 489 * @to: Destination address, in kernel space. 490 * @from: Source address, in user space. 491 * @n: Number of bytes to copy. 492 * 493 * Context: User context only. This function may sleep. 494 * 495 * Copy data from user space to kernel space. Caller must check 496 * the specified block with access_ok() before calling this function. 497 * 498 * Returns number of bytes that could not be copied. 499 * On success, this will be zero. 500 * 501 * If some data could not be copied, this function will pad the copied 502 * data to the requested size using zero bytes. 503 * 504 * An alternate version - __copy_from_user_inatomic() - may be called from 505 * atomic context and will fail rather than sleep. In this case the 506 * uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h 507 * for explanation of why this is needed. 508 */ 509static __always_inline unsigned long 510__copy_from_user(void *to, const void __user *from, unsigned long n) 511{ 512 might_sleep(); 513 if (__builtin_constant_p(n)) { 514 unsigned long ret; 515 516 switch (n) { 517 case 1: 518 __get_user_size(*(u8 *)to, from, 1, ret, 1); 519 return ret; 520 case 2: 521 __get_user_size(*(u16 *)to, from, 2, ret, 2); 522 return ret; 523 case 4: 524 __get_user_size(*(u32 *)to, from, 4, ret, 4); 525 return ret; 526 } 527 } 528 return __copy_from_user_ll(to, from, n); 529} 530 531#define ARCH_HAS_NOCACHE_UACCESS 532 533static __always_inline unsigned long __copy_from_user_nocache(void *to, 534 const void __user *from, unsigned long n) 535{ 536 might_sleep(); 537 if (__builtin_constant_p(n)) { 538 unsigned long ret; 539 540 switch (n) { 541 case 1: 542 __get_user_size(*(u8 *)to, from, 1, ret, 1); 543 return ret; 544 case 2: 545 __get_user_size(*(u16 *)to, from, 2, ret, 2); 546 return ret; 547 case 4: 548 __get_user_size(*(u32 *)to, from, 4, ret, 4); 549 return ret; 550 } 551 } 552 return __copy_from_user_ll_nocache(to, from, n); 553} 554 555static __always_inline unsigned long 556__copy_from_user_inatomic_nocache(void *to, const void __user *from, unsigned long n) 557{ 558 return __copy_from_user_ll_nocache_nozero(to, from, n); 559} 560 561unsigned long __must_check copy_to_user(void __user *to, 562 const void *from, unsigned long n); 563unsigned long __must_check copy_from_user(void *to, 564 const void __user *from, unsigned long n); 565long __must_check strncpy_from_user(char *dst, const char __user *src, 566 long count); 567long __must_check __strncpy_from_user(char *dst, 568 const char __user *src, long count); 569 570/** 571 * strlen_user: - Get the size of a string in user space. 572 * @str: The string to measure. 573 * 574 * Context: User context only. This function may sleep. 575 * 576 * Get the size of a NUL-terminated string in user space. 577 * 578 * Returns the size of the string INCLUDING the terminating NUL. 579 * On exception, returns 0. 580 * 581 * If there is a limit on the length of a valid string, you may wish to 582 * consider using strnlen_user() instead. 583 */ 584#define strlen_user(str) strnlen_user(str, LONG_MAX) 585 586long strnlen_user(const char __user *str, long n); 587unsigned long __must_check clear_user(void __user *mem, unsigned long len); 588unsigned long __must_check __clear_user(void __user *mem, unsigned long len); 589 590#endif /* __i386_UACCESS_H */ 591