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Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm
[deliverable/linux.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 ".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
Linux kernel - Deliverables
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