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Merge branch 'writeback-for-next' of git://git.kernel.org/pub/scm/linux/kernel/git...
[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/thread_info.h>
9 #include <linux/string.h>
10 #include <asm/asm.h>
11 #include <asm/page.h>
12 #include <asm/smap.h>
13
14 #define VERIFY_READ 0
15 #define VERIFY_WRITE 1
16
17 /*
18 * The fs value determines whether argument validity checking should be
19 * performed or not. If get_fs() == USER_DS, checking is performed, with
20 * get_fs() == KERNEL_DS, checking is bypassed.
21 *
22 * For historical reasons, these macros are grossly misnamed.
23 */
24
25 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
26
27 #define KERNEL_DS MAKE_MM_SEG(-1UL)
28 #define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX)
29
30 #define get_ds() (KERNEL_DS)
31 #define get_fs() (current_thread_info()->addr_limit)
32 #define set_fs(x) (current_thread_info()->addr_limit = (x))
33
34 #define segment_eq(a, b) ((a).seg == (b).seg)
35
36 #define user_addr_max() (current_thread_info()->addr_limit.seg)
37 #define __addr_ok(addr) \
38 ((unsigned long __force)(addr) < user_addr_max())
39
40 /*
41 * Test whether a block of memory is a valid user space address.
42 * Returns 0 if the range is valid, nonzero otherwise.
43 *
44 * This is equivalent to the following test:
45 * (u33)addr + (u33)size > (u33)current->addr_limit.seg (u65 for x86_64)
46 *
47 * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry...
48 */
49
50 #define __range_not_ok(addr, size, limit) \
51 ({ \
52 unsigned long flag, roksum; \
53 __chk_user_ptr(addr); \
54 asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \
55 : "=&r" (flag), "=r" (roksum) \
56 : "1" (addr), "g" ((long)(size)), \
57 "rm" (limit)); \
58 flag; \
59 })
60
61 /**
62 * access_ok: - Checks if a user space pointer is valid
63 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
64 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
65 * to write to a block, it is always safe to read from it.
66 * @addr: User space pointer to start of block to check
67 * @size: Size of block to check
68 *
69 * Context: User context only. This function may sleep.
70 *
71 * Checks if a pointer to a block of memory in user space is valid.
72 *
73 * Returns true (nonzero) if the memory block may be valid, false (zero)
74 * if it is definitely invalid.
75 *
76 * Note that, depending on architecture, this function probably just
77 * checks that the pointer is in the user space range - after calling
78 * this function, memory access functions may still return -EFAULT.
79 */
80 #define access_ok(type, addr, size) \
81 (likely(__range_not_ok(addr, size, user_addr_max()) == 0))
82
83 /*
84 * The exception table consists of pairs of addresses relative to the
85 * exception table enty itself: the first is the address of an
86 * instruction that is allowed to fault, and the second is the address
87 * at which the program should continue. No registers are modified,
88 * so it is entirely up to the continuation code to figure out what to
89 * do.
90 *
91 * All the routines below use bits of fixup code that are out of line
92 * with the main instruction path. This means when everything is well,
93 * we don't even have to jump over them. Further, they do not intrude
94 * on our cache or tlb entries.
95 */
96
97 struct exception_table_entry {
98 int insn, fixup;
99 };
100 /* This is not the generic standard exception_table_entry format */
101 #define ARCH_HAS_SORT_EXTABLE
102 #define ARCH_HAS_SEARCH_EXTABLE
103
104 extern int fixup_exception(struct pt_regs *regs);
105 extern int early_fixup_exception(unsigned long *ip);
106
107 /*
108 * These are the main single-value transfer routines. They automatically
109 * use the right size if we just have the right pointer type.
110 *
111 * This gets kind of ugly. We want to return _two_ values in "get_user()"
112 * and yet we don't want to do any pointers, because that is too much
113 * of a performance impact. Thus we have a few rather ugly macros here,
114 * and hide all the ugliness from the user.
115 *
116 * The "__xxx" versions of the user access functions are versions that
117 * do not verify the address space, that must have been done previously
118 * with a separate "access_ok()" call (this is used when we do multiple
119 * accesses to the same area of user memory).
120 */
121
122 extern int __get_user_1(void);
123 extern int __get_user_2(void);
124 extern int __get_user_4(void);
125 extern int __get_user_8(void);
126 extern int __get_user_bad(void);
127
128 #define __get_user_x(size, ret, x, ptr) \
129 asm volatile("call __get_user_" #size \
130 : "=a" (ret), "=d" (x) \
131 : "0" (ptr)) \
132
133 /* Careful: we have to cast the result to the type of the pointer
134 * for sign reasons */
135
136 /**
137 * get_user: - Get a simple variable from user space.
138 * @x: Variable to store result.
139 * @ptr: Source address, in user space.
140 *
141 * Context: User context only. This function may sleep.
142 *
143 * This macro copies a single simple variable from user space to kernel
144 * space. It supports simple types like char and int, but not larger
145 * data types like structures or arrays.
146 *
147 * @ptr must have pointer-to-simple-variable type, and the result of
148 * dereferencing @ptr must be assignable to @x without a cast.
149 *
150 * Returns zero on success, or -EFAULT on error.
151 * On error, the variable @x is set to zero.
152 */
153 #ifdef CONFIG_X86_32
154 #define __get_user_8(__ret_gu, __val_gu, ptr) \
155 __get_user_x(X, __ret_gu, __val_gu, ptr)
156 #else
157 #define __get_user_8(__ret_gu, __val_gu, ptr) \
158 __get_user_x(8, __ret_gu, __val_gu, ptr)
159 #endif
160
161 #define get_user(x, ptr) \
162 ({ \
163 int __ret_gu; \
164 unsigned long __val_gu; \
165 __chk_user_ptr(ptr); \
166 might_fault(); \
167 switch (sizeof(*(ptr))) { \
168 case 1: \
169 __get_user_x(1, __ret_gu, __val_gu, ptr); \
170 break; \
171 case 2: \
172 __get_user_x(2, __ret_gu, __val_gu, ptr); \
173 break; \
174 case 4: \
175 __get_user_x(4, __ret_gu, __val_gu, ptr); \
176 break; \
177 case 8: \
178 __get_user_8(__ret_gu, __val_gu, ptr); \
179 break; \
180 default: \
181 __get_user_x(X, __ret_gu, __val_gu, ptr); \
182 break; \
183 } \
184 (x) = (__typeof__(*(ptr)))__val_gu; \
185 __ret_gu; \
186 })
187
188 #define __put_user_x(size, x, ptr, __ret_pu) \
189 asm volatile("call __put_user_" #size : "=a" (__ret_pu) \
190 : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
191
192
193
194 #ifdef CONFIG_X86_32
195 #define __put_user_asm_u64(x, addr, err, errret) \
196 asm volatile(ASM_STAC "\n" \
197 "1: movl %%eax,0(%2)\n" \
198 "2: movl %%edx,4(%2)\n" \
199 "3: " ASM_CLAC "\n" \
200 ".section .fixup,\"ax\"\n" \
201 "4: movl %3,%0\n" \
202 " jmp 3b\n" \
203 ".previous\n" \
204 _ASM_EXTABLE(1b, 4b) \
205 _ASM_EXTABLE(2b, 4b) \
206 : "=r" (err) \
207 : "A" (x), "r" (addr), "i" (errret), "0" (err))
208
209 #define __put_user_asm_ex_u64(x, addr) \
210 asm volatile(ASM_STAC "\n" \
211 "1: movl %%eax,0(%1)\n" \
212 "2: movl %%edx,4(%1)\n" \
213 "3: " ASM_CLAC "\n" \
214 _ASM_EXTABLE_EX(1b, 2b) \
215 _ASM_EXTABLE_EX(2b, 3b) \
216 : : "A" (x), "r" (addr))
217
218 #define __put_user_x8(x, ptr, __ret_pu) \
219 asm volatile("call __put_user_8" : "=a" (__ret_pu) \
220 : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
221 #else
222 #define __put_user_asm_u64(x, ptr, retval, errret) \
223 __put_user_asm(x, ptr, retval, "q", "", "er", errret)
224 #define __put_user_asm_ex_u64(x, addr) \
225 __put_user_asm_ex(x, addr, "q", "", "er")
226 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
227 #endif
228
229 extern void __put_user_bad(void);
230
231 /*
232 * Strange magic calling convention: pointer in %ecx,
233 * value in %eax(:%edx), return value in %eax. clobbers %rbx
234 */
235 extern void __put_user_1(void);
236 extern void __put_user_2(void);
237 extern void __put_user_4(void);
238 extern void __put_user_8(void);
239
240 #ifdef CONFIG_X86_WP_WORKS_OK
241
242 /**
243 * put_user: - Write a simple value into user space.
244 * @x: Value to copy to user space.
245 * @ptr: Destination address, in user space.
246 *
247 * Context: User context only. This function may sleep.
248 *
249 * This macro copies a single simple value from kernel space to user
250 * space. It supports simple types like char and int, but not larger
251 * data types like structures or arrays.
252 *
253 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
254 * to the result of dereferencing @ptr.
255 *
256 * Returns zero on success, or -EFAULT on error.
257 */
258 #define put_user(x, ptr) \
259 ({ \
260 int __ret_pu; \
261 __typeof__(*(ptr)) __pu_val; \
262 __chk_user_ptr(ptr); \
263 might_fault(); \
264 __pu_val = x; \
265 switch (sizeof(*(ptr))) { \
266 case 1: \
267 __put_user_x(1, __pu_val, ptr, __ret_pu); \
268 break; \
269 case 2: \
270 __put_user_x(2, __pu_val, ptr, __ret_pu); \
271 break; \
272 case 4: \
273 __put_user_x(4, __pu_val, ptr, __ret_pu); \
274 break; \
275 case 8: \
276 __put_user_x8(__pu_val, ptr, __ret_pu); \
277 break; \
278 default: \
279 __put_user_x(X, __pu_val, ptr, __ret_pu); \
280 break; \
281 } \
282 __ret_pu; \
283 })
284
285 #define __put_user_size(x, ptr, size, retval, errret) \
286 do { \
287 retval = 0; \
288 __chk_user_ptr(ptr); \
289 switch (size) { \
290 case 1: \
291 __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \
292 break; \
293 case 2: \
294 __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \
295 break; \
296 case 4: \
297 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \
298 break; \
299 case 8: \
300 __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval, \
301 errret); \
302 break; \
303 default: \
304 __put_user_bad(); \
305 } \
306 } while (0)
307
308 #define __put_user_size_ex(x, ptr, size) \
309 do { \
310 __chk_user_ptr(ptr); \
311 switch (size) { \
312 case 1: \
313 __put_user_asm_ex(x, ptr, "b", "b", "iq"); \
314 break; \
315 case 2: \
316 __put_user_asm_ex(x, ptr, "w", "w", "ir"); \
317 break; \
318 case 4: \
319 __put_user_asm_ex(x, ptr, "l", "k", "ir"); \
320 break; \
321 case 8: \
322 __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \
323 break; \
324 default: \
325 __put_user_bad(); \
326 } \
327 } while (0)
328
329 #else
330
331 #define __put_user_size(x, ptr, size, retval, errret) \
332 do { \
333 __typeof__(*(ptr))__pus_tmp = x; \
334 retval = 0; \
335 \
336 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \
337 retval = errret; \
338 } while (0)
339
340 #define put_user(x, ptr) \
341 ({ \
342 int __ret_pu; \
343 __typeof__(*(ptr))__pus_tmp = x; \
344 __ret_pu = 0; \
345 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \
346 sizeof(*(ptr))) != 0)) \
347 __ret_pu = -EFAULT; \
348 __ret_pu; \
349 })
350 #endif
351
352 #ifdef CONFIG_X86_32
353 #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad()
354 #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad()
355 #else
356 #define __get_user_asm_u64(x, ptr, retval, errret) \
357 __get_user_asm(x, ptr, retval, "q", "", "=r", errret)
358 #define __get_user_asm_ex_u64(x, ptr) \
359 __get_user_asm_ex(x, ptr, "q", "", "=r")
360 #endif
361
362 #define __get_user_size(x, ptr, size, retval, errret) \
363 do { \
364 retval = 0; \
365 __chk_user_ptr(ptr); \
366 switch (size) { \
367 case 1: \
368 __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
369 break; \
370 case 2: \
371 __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
372 break; \
373 case 4: \
374 __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \
375 break; \
376 case 8: \
377 __get_user_asm_u64(x, ptr, retval, errret); \
378 break; \
379 default: \
380 (x) = __get_user_bad(); \
381 } \
382 } while (0)
383
384 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \
385 asm volatile(ASM_STAC "\n" \
386 "1: mov"itype" %2,%"rtype"1\n" \
387 "2: " ASM_CLAC "\n" \
388 ".section .fixup,\"ax\"\n" \
389 "3: mov %3,%0\n" \
390 " xor"itype" %"rtype"1,%"rtype"1\n" \
391 " jmp 2b\n" \
392 ".previous\n" \
393 _ASM_EXTABLE(1b, 3b) \
394 : "=r" (err), ltype(x) \
395 : "m" (__m(addr)), "i" (errret), "0" (err))
396
397 #define __get_user_size_ex(x, ptr, size) \
398 do { \
399 __chk_user_ptr(ptr); \
400 switch (size) { \
401 case 1: \
402 __get_user_asm_ex(x, ptr, "b", "b", "=q"); \
403 break; \
404 case 2: \
405 __get_user_asm_ex(x, ptr, "w", "w", "=r"); \
406 break; \
407 case 4: \
408 __get_user_asm_ex(x, ptr, "l", "k", "=r"); \
409 break; \
410 case 8: \
411 __get_user_asm_ex_u64(x, ptr); \
412 break; \
413 default: \
414 (x) = __get_user_bad(); \
415 } \
416 } while (0)
417
418 #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \
419 asm volatile("1: mov"itype" %1,%"rtype"0\n" \
420 "2:\n" \
421 _ASM_EXTABLE_EX(1b, 2b) \
422 : ltype(x) : "m" (__m(addr)))
423
424 #define __put_user_nocheck(x, ptr, size) \
425 ({ \
426 int __pu_err; \
427 __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \
428 __pu_err; \
429 })
430
431 #define __get_user_nocheck(x, ptr, size) \
432 ({ \
433 int __gu_err; \
434 unsigned long __gu_val; \
435 __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
436 (x) = (__force __typeof__(*(ptr)))__gu_val; \
437 __gu_err; \
438 })
439
440 /* FIXME: this hack is definitely wrong -AK */
441 struct __large_struct { unsigned long buf[100]; };
442 #define __m(x) (*(struct __large_struct __user *)(x))
443
444 /*
445 * Tell gcc we read from memory instead of writing: this is because
446 * we do not write to any memory gcc knows about, so there are no
447 * aliasing issues.
448 */
449 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \
450 asm volatile(ASM_STAC "\n" \
451 "1: mov"itype" %"rtype"1,%2\n" \
452 "2: " ASM_CLAC "\n" \
453 ".section .fixup,\"ax\"\n" \
454 "3: mov %3,%0\n" \
455 " jmp 2b\n" \
456 ".previous\n" \
457 _ASM_EXTABLE(1b, 3b) \
458 : "=r"(err) \
459 : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
460
461 #define __put_user_asm_ex(x, addr, itype, rtype, ltype) \
462 asm volatile("1: mov"itype" %"rtype"0,%1\n" \
463 "2:\n" \
464 _ASM_EXTABLE_EX(1b, 2b) \
465 : : ltype(x), "m" (__m(addr)))
466
467 /*
468 * uaccess_try and catch
469 */
470 #define uaccess_try do { \
471 current_thread_info()->uaccess_err = 0; \
472 stac(); \
473 barrier();
474
475 #define uaccess_catch(err) \
476 clac(); \
477 (err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0); \
478 } while (0)
479
480 /**
481 * __get_user: - Get a simple variable from user space, with less checking.
482 * @x: Variable to store result.
483 * @ptr: Source address, in user space.
484 *
485 * Context: User context only. This function may sleep.
486 *
487 * This macro copies a single simple variable from user space to kernel
488 * space. It supports simple types like char and int, but not larger
489 * data types like structures or arrays.
490 *
491 * @ptr must have pointer-to-simple-variable type, and the result of
492 * dereferencing @ptr must be assignable to @x without a cast.
493 *
494 * Caller must check the pointer with access_ok() before calling this
495 * function.
496 *
497 * Returns zero on success, or -EFAULT on error.
498 * On error, the variable @x is set to zero.
499 */
500
501 #define __get_user(x, ptr) \
502 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
503
504 /**
505 * __put_user: - Write a simple value into user space, with less checking.
506 * @x: Value to copy to user space.
507 * @ptr: Destination address, in user space.
508 *
509 * Context: User context only. This function may sleep.
510 *
511 * This macro copies a single simple value from kernel space to user
512 * space. It supports simple types like char and int, but not larger
513 * data types like structures or arrays.
514 *
515 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
516 * to the result of dereferencing @ptr.
517 *
518 * Caller must check the pointer with access_ok() before calling this
519 * function.
520 *
521 * Returns zero on success, or -EFAULT on error.
522 */
523
524 #define __put_user(x, ptr) \
525 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
526
527 #define __get_user_unaligned __get_user
528 #define __put_user_unaligned __put_user
529
530 /*
531 * {get|put}_user_try and catch
532 *
533 * get_user_try {
534 * get_user_ex(...);
535 * } get_user_catch(err)
536 */
537 #define get_user_try uaccess_try
538 #define get_user_catch(err) uaccess_catch(err)
539
540 #define get_user_ex(x, ptr) do { \
541 unsigned long __gue_val; \
542 __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr)))); \
543 (x) = (__force __typeof__(*(ptr)))__gue_val; \
544 } while (0)
545
546 #ifdef CONFIG_X86_WP_WORKS_OK
547
548 #define put_user_try uaccess_try
549 #define put_user_catch(err) uaccess_catch(err)
550
551 #define put_user_ex(x, ptr) \
552 __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
553
554 #else /* !CONFIG_X86_WP_WORKS_OK */
555
556 #define put_user_try do { \
557 int __uaccess_err = 0;
558
559 #define put_user_catch(err) \
560 (err) |= __uaccess_err; \
561 } while (0)
562
563 #define put_user_ex(x, ptr) do { \
564 __uaccess_err |= __put_user(x, ptr); \
565 } while (0)
566
567 #endif /* CONFIG_X86_WP_WORKS_OK */
568
569 extern unsigned long
570 copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
571 extern __must_check long
572 strncpy_from_user(char *dst, const char __user *src, long count);
573
574 extern __must_check long strlen_user(const char __user *str);
575 extern __must_check long strnlen_user(const char __user *str, long n);
576
577 unsigned long __must_check clear_user(void __user *mem, unsigned long len);
578 unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
579
580 /*
581 * movsl can be slow when source and dest are not both 8-byte aligned
582 */
583 #ifdef CONFIG_X86_INTEL_USERCOPY
584 extern struct movsl_mask {
585 int mask;
586 } ____cacheline_aligned_in_smp movsl_mask;
587 #endif
588
589 #define ARCH_HAS_NOCACHE_UACCESS 1
590
591 #ifdef CONFIG_X86_32
592 # include <asm/uaccess_32.h>
593 #else
594 # include <asm/uaccess_64.h>
595 #endif
596
597 #endif /* _ASM_X86_UACCESS_H */
598
Linux kernel - Deliverables
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