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Merge tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
[mirror_ubuntu-artful-kernel.git] / arch / x86 / include / asm / uaccess.h
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 _ASM_EXTABLE_EX(1b, 2b) \
437 : ltype(x) : "m" (__m(addr)))
438
439 #define __put_user_nocheck(x, ptr, size) \
440 ({ \
441 int __pu_err; \
442 __uaccess_begin(); \
443 __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \
444 __uaccess_end(); \
445 __builtin_expect(__pu_err, 0); \
446 })
447
448 #define __get_user_nocheck(x, ptr, size) \
449 ({ \
450 int __gu_err; \
451 __inttype(*(ptr)) __gu_val; \
452 __uaccess_begin(); \
453 __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
454 __uaccess_end(); \
455 (x) = (__force __typeof__(*(ptr)))__gu_val; \
456 __builtin_expect(__gu_err, 0); \
457 })
458
459 /* FIXME: this hack is definitely wrong -AK */
460 struct __large_struct { unsigned long buf[100]; };
461 #define __m(x) (*(struct __large_struct __user *)(x))
462
463 /*
464 * Tell gcc we read from memory instead of writing: this is because
465 * we do not write to any memory gcc knows about, so there are no
466 * aliasing issues.
467 */
468 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \
469 asm volatile("\n" \
470 "1: mov"itype" %"rtype"1,%2\n" \
471 "2:\n" \
472 ".section .fixup,\"ax\"\n" \
473 "3: mov %3,%0\n" \
474 " jmp 2b\n" \
475 ".previous\n" \
476 _ASM_EXTABLE(1b, 3b) \
477 : "=r"(err) \
478 : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
479
480 #define __put_user_asm_ex(x, addr, itype, rtype, ltype) \
481 asm volatile("1: mov"itype" %"rtype"0,%1\n" \
482 "2:\n" \
483 _ASM_EXTABLE_EX(1b, 2b) \
484 : : ltype(x), "m" (__m(addr)))
485
486 /*
487 * uaccess_try and catch
488 */
489 #define uaccess_try do { \
490 current->thread.uaccess_err = 0; \
491 __uaccess_begin(); \
492 barrier();
493
494 #define uaccess_catch(err) \
495 __uaccess_end(); \
496 (err) |= (current->thread.uaccess_err ? -EFAULT : 0); \
497 } while (0)
498
499 /**
500 * __get_user: - Get a simple variable from user space, with less checking.
501 * @x: Variable to store result.
502 * @ptr: Source address, in user space.
503 *
504 * Context: User context only. This function may sleep if pagefaults are
505 * enabled.
506 *
507 * This macro copies a single simple variable from user space to kernel
508 * space. It supports simple types like char and int, but not larger
509 * data types like structures or arrays.
510 *
511 * @ptr must have pointer-to-simple-variable type, and the result of
512 * dereferencing @ptr must be assignable to @x without a cast.
513 *
514 * Caller must check the pointer with access_ok() before calling this
515 * function.
516 *
517 * Returns zero on success, or -EFAULT on error.
518 * On error, the variable @x is set to zero.
519 */
520
521 #define __get_user(x, ptr) \
522 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
523
524 /**
525 * __put_user: - Write a simple value into user space, with less checking.
526 * @x: Value to copy to user space.
527 * @ptr: Destination address, in user space.
528 *
529 * Context: User context only. This function may sleep if pagefaults are
530 * enabled.
531 *
532 * This macro copies a single simple value from kernel space to user
533 * space. It supports simple types like char and int, but not larger
534 * data types like structures or arrays.
535 *
536 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
537 * to the result of dereferencing @ptr.
538 *
539 * Caller must check the pointer with access_ok() before calling this
540 * function.
541 *
542 * Returns zero on success, or -EFAULT on error.
543 */
544
545 #define __put_user(x, ptr) \
546 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
547
548 #define __get_user_unaligned __get_user
549 #define __put_user_unaligned __put_user
550
551 /*
552 * {get|put}_user_try and catch
553 *
554 * get_user_try {
555 * get_user_ex(...);
556 * } get_user_catch(err)
557 */
558 #define get_user_try uaccess_try
559 #define get_user_catch(err) uaccess_catch(err)
560
561 #define get_user_ex(x, ptr) do { \
562 unsigned long __gue_val; \
563 __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr)))); \
564 (x) = (__force __typeof__(*(ptr)))__gue_val; \
565 } while (0)
566
567 #define put_user_try uaccess_try
568 #define put_user_catch(err) uaccess_catch(err)
569
570 #define put_user_ex(x, ptr) \
571 __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
572
573 extern unsigned long
574 copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
575 extern __must_check long
576 strncpy_from_user(char *dst, const char __user *src, long count);
577
578 extern __must_check long strlen_user(const char __user *str);
579 extern __must_check long strnlen_user(const char __user *str, long n);
580
581 unsigned long __must_check clear_user(void __user *mem, unsigned long len);
582 unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
583
584 extern void __cmpxchg_wrong_size(void)
585 __compiletime_error("Bad argument size for cmpxchg");
586
587 #define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size) \
588 ({ \
589 int __ret = 0; \
590 __typeof__(ptr) __uval = (uval); \
591 __typeof__(*(ptr)) __old = (old); \
592 __typeof__(*(ptr)) __new = (new); \
593 __uaccess_begin(); \
594 switch (size) { \
595 case 1: \
596 { \
597 asm volatile("\n" \
598 "1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n" \
599 "2:\n" \
600 "\t.section .fixup, \"ax\"\n" \
601 "3:\tmov %3, %0\n" \
602 "\tjmp 2b\n" \
603 "\t.previous\n" \
604 _ASM_EXTABLE(1b, 3b) \
605 : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
606 : "i" (-EFAULT), "q" (__new), "1" (__old) \
607 : "memory" \
608 ); \
609 break; \
610 } \
611 case 2: \
612 { \
613 asm volatile("\n" \
614 "1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n" \
615 "2:\n" \
616 "\t.section .fixup, \"ax\"\n" \
617 "3:\tmov %3, %0\n" \
618 "\tjmp 2b\n" \
619 "\t.previous\n" \
620 _ASM_EXTABLE(1b, 3b) \
621 : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
622 : "i" (-EFAULT), "r" (__new), "1" (__old) \
623 : "memory" \
624 ); \
625 break; \
626 } \
627 case 4: \
628 { \
629 asm volatile("\n" \
630 "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" \
631 "2:\n" \
632 "\t.section .fixup, \"ax\"\n" \
633 "3:\tmov %3, %0\n" \
634 "\tjmp 2b\n" \
635 "\t.previous\n" \
636 _ASM_EXTABLE(1b, 3b) \
637 : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
638 : "i" (-EFAULT), "r" (__new), "1" (__old) \
639 : "memory" \
640 ); \
641 break; \
642 } \
643 case 8: \
644 { \
645 if (!IS_ENABLED(CONFIG_X86_64)) \
646 __cmpxchg_wrong_size(); \
647 \
648 asm volatile("\n" \
649 "1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n" \
650 "2:\n" \
651 "\t.section .fixup, \"ax\"\n" \
652 "3:\tmov %3, %0\n" \
653 "\tjmp 2b\n" \
654 "\t.previous\n" \
655 _ASM_EXTABLE(1b, 3b) \
656 : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
657 : "i" (-EFAULT), "r" (__new), "1" (__old) \
658 : "memory" \
659 ); \
660 break; \
661 } \
662 default: \
663 __cmpxchg_wrong_size(); \
664 } \
665 __uaccess_end(); \
666 *__uval = __old; \
667 __ret; \
668 })
669
670 #define user_atomic_cmpxchg_inatomic(uval, ptr, old, new) \
671 ({ \
672 access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \
673 __user_atomic_cmpxchg_inatomic((uval), (ptr), \
674 (old), (new), sizeof(*(ptr))) : \
675 -EFAULT; \
676 })
677
678 /*
679 * movsl can be slow when source and dest are not both 8-byte aligned
680 */
681 #ifdef CONFIG_X86_INTEL_USERCOPY
682 extern struct movsl_mask {
683 int mask;
684 } ____cacheline_aligned_in_smp movsl_mask;
685 #endif
686
687 #define ARCH_HAS_NOCACHE_UACCESS 1
688
689 #ifdef CONFIG_X86_32
690 # include <asm/uaccess_32.h>
691 #else
692 # include <asm/uaccess_64.h>
693 #endif
694
695 unsigned long __must_check _copy_from_user(void *to, const void __user *from,
696 unsigned n);
697 unsigned long __must_check _copy_to_user(void __user *to, const void *from,
698 unsigned n);
699
700 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
701 # define copy_user_diag __compiletime_error
702 #else
703 # define copy_user_diag __compiletime_warning
704 #endif
705
706 extern void copy_user_diag("copy_from_user() buffer size is too small")
707 copy_from_user_overflow(void);
708 extern void copy_user_diag("copy_to_user() buffer size is too small")
709 copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
710
711 #undef copy_user_diag
712
713 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
714
715 extern void
716 __compiletime_warning("copy_from_user() buffer size is not provably correct")
717 __copy_from_user_overflow(void) __asm__("copy_from_user_overflow");
718 #define __copy_from_user_overflow(size, count) __copy_from_user_overflow()
719
720 extern void
721 __compiletime_warning("copy_to_user() buffer size is not provably correct")
722 __copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
723 #define __copy_to_user_overflow(size, count) __copy_to_user_overflow()
724
725 #else
726
727 static inline void
728 __copy_from_user_overflow(int size, unsigned long count)
729 {
730 WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
731 }
732
733 #define __copy_to_user_overflow __copy_from_user_overflow
734
735 #endif
736
737 static inline unsigned long __must_check
738 copy_from_user(void *to, const void __user *from, unsigned long n)
739 {
740 int sz = __compiletime_object_size(to);
741
742 might_fault();
743
744 kasan_check_write(to, n);
745
746 /*
747 * While we would like to have the compiler do the checking for us
748 * even in the non-constant size case, any false positives there are
749 * a problem (especially when DEBUG_STRICT_USER_COPY_CHECKS, but even
750 * without - the [hopefully] dangerous looking nature of the warning
751 * would make people go look at the respecitive call sites over and
752 * over again just to find that there's no problem).
753 *
754 * And there are cases where it's just not realistic for the compiler
755 * to prove the count to be in range. For example when multiple call
756 * sites of a helper function - perhaps in different source files -
757 * all doing proper range checking, yet the helper function not doing
758 * so again.
759 *
760 * Therefore limit the compile time checking to the constant size
761 * case, and do only runtime checking for non-constant sizes.
762 */
763
764 if (likely(sz < 0 || sz >= n)) {
765 check_object_size(to, n, false);
766 n = _copy_from_user(to, from, n);
767 } else if (__builtin_constant_p(n))
768 copy_from_user_overflow();
769 else
770 __copy_from_user_overflow(sz, n);
771
772 return n;
773 }
774
775 static inline unsigned long __must_check
776 copy_to_user(void __user *to, const void *from, unsigned long n)
777 {
778 int sz = __compiletime_object_size(from);
779
780 kasan_check_read(from, n);
781
782 might_fault();
783
784 /* See the comment in copy_from_user() above. */
785 if (likely(sz < 0 || sz >= n)) {
786 check_object_size(from, n, true);
787 n = _copy_to_user(to, from, n);
788 } else if (__builtin_constant_p(n))
789 copy_to_user_overflow();
790 else
791 __copy_to_user_overflow(sz, n);
792
793 return n;
794 }
795
796 #undef __copy_from_user_overflow
797 #undef __copy_to_user_overflow
798
799 /*
800 * We rely on the nested NMI work to allow atomic faults from the NMI path; the
801 * nested NMI paths are careful to preserve CR2.
802 *
803 * Caller must use pagefault_enable/disable, or run in interrupt context,
804 * and also do a uaccess_ok() check
805 */
806 #define __copy_from_user_nmi __copy_from_user_inatomic
807
808 /*
809 * The "unsafe" user accesses aren't really "unsafe", but the naming
810 * is a big fat warning: you have to not only do the access_ok()
811 * checking before using them, but you have to surround them with the
812 * user_access_begin/end() pair.
813 */
814 #define user_access_begin() __uaccess_begin()
815 #define user_access_end() __uaccess_end()
816
817 #define unsafe_put_user(x, ptr, err_label) \
818 do { \
819 int __pu_err; \
820 __put_user_size((x), (ptr), sizeof(*(ptr)), __pu_err, -EFAULT); \
821 if (unlikely(__pu_err)) goto err_label; \
822 } while (0)
823
824 #define unsafe_get_user(x, ptr, err_label) \
825 do { \
826 int __gu_err; \
827 unsigned long __gu_val; \
828 __get_user_size(__gu_val, (ptr), sizeof(*(ptr)), __gu_err, -EFAULT); \
829 (x) = (__force __typeof__(*(ptr)))__gu_val; \
830 if (unlikely(__gu_err)) goto err_label; \
831 } while (0)
832
833 #endif /* _ASM_X86_UACCESS_H */
834
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