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warning removal
[cor_2_6_31.git] / arch / x86 / include / asm / uaccess.h
blobd2c6c930b491916843e76d2c6838e53b5890301b
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/prefetch.h>
10 #include <linux/string.h>
11 #include <asm/asm.h>
12 #include <asm/page.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 __addr_ok(addr) \
37 ((unsigned long __force)(addr) < \
38 (current_thread_info()->addr_limit.seg))
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) \
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" (current_thread_info()->addr_limit.seg)); \
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) (likely(__range_not_ok(addr, size) == 0))
81
82 /*
83 * The exception table consists of pairs of addresses: the first is the
84 * address of an instruction that is allowed to fault, and the second is
85 * the address at which the program should continue. No registers are
86 * modified, so it is entirely up to the continuation code to figure out
87 * what to do.
88 *
89 * All the routines below use bits of fixup code that are out of line
90 * with the main instruction path. This means when everything is well,
91 * we don't even have to jump over them. Further, they do not intrude
92 * on our cache or tlb entries.
93 */
94
95 struct exception_table_entry {
96 unsigned long insn, fixup;
97 };
98
99 extern int fixup_exception(struct pt_regs *regs);
100
101 /*
102 * These are the main single-value transfer routines. They automatically
103 * use the right size if we just have the right pointer type.
104 *
105 * This gets kind of ugly. We want to return _two_ values in "get_user()"
106 * and yet we don't want to do any pointers, because that is too much
107 * of a performance impact. Thus we have a few rather ugly macros here,
108 * and hide all the ugliness from the user.
109 *
110 * The "__xxx" versions of the user access functions are versions that
111 * do not verify the address space, that must have been done previously
112 * with a separate "access_ok()" call (this is used when we do multiple
113 * accesses to the same area of user memory).
114 */
115
116 extern int __get_user_1(void);
117 extern int __get_user_2(void);
118 extern int __get_user_4(void);
119 extern int __get_user_8(void);
120 extern int __get_user_bad(void);
121
122 #define __get_user_x(size, ret, x, ptr) \
123 asm volatile("call __get_user_" #size \
124 : "=a" (ret), "=d" (x) \
125 : "0" (ptr)) \
126
127 /* Careful: we have to cast the result to the type of the pointer
128 * for sign reasons */
129
130 /**
131 * get_user: - Get a simple variable from user space.
132 * @x: Variable to store result.
133 * @ptr: Source address, in user space.
134 *
135 * Context: User context only. This function may sleep.
136 *
137 * This macro copies a single simple variable from user space to kernel
138 * space. It supports simple types like char and int, but not larger
139 * data types like structures or arrays.
140 *
141 * @ptr must have pointer-to-simple-variable type, and the result of
142 * dereferencing @ptr must be assignable to @x without a cast.
143 *
144 * Returns zero on success, or -EFAULT on error.
145 * On error, the variable @x is set to zero.
146 */
147 #ifdef CONFIG_X86_32
148 #define __get_user_8(__ret_gu, __val_gu, ptr) \
149 __get_user_x(X, __ret_gu, __val_gu, ptr)
150 #else
151 #define __get_user_8(__ret_gu, __val_gu, ptr) \
152 __get_user_x(8, __ret_gu, __val_gu, ptr)
153 #endif
154
155 #define get_user(x, ptr) \
156 ({ \
157 int __ret_gu; \
158 unsigned long __val_gu; \
159 __chk_user_ptr(ptr); \
160 might_fault(); \
161 switch (sizeof(*(ptr))) { \
162 case 1: \
163 __get_user_x(1, __ret_gu, __val_gu, ptr); \
164 break; \
165 case 2: \
166 __get_user_x(2, __ret_gu, __val_gu, ptr); \
167 break; \
168 case 4: \
169 __get_user_x(4, __ret_gu, __val_gu, ptr); \
170 break; \
171 case 8: \
172 __get_user_8(__ret_gu, __val_gu, ptr); \
173 break; \
174 default: \
175 __get_user_x(X, __ret_gu, __val_gu, ptr); \
176 break; \
177 } \
178 (x) = (__typeof__(*(ptr)))__val_gu; \
179 __ret_gu; \
180 })
181
182 #define __put_user_x(size, x, ptr, __ret_pu) \
183 asm volatile("call __put_user_" #size : "=a" (__ret_pu) \
184 : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
185
186
187
188 #ifdef CONFIG_X86_32
189 #define __put_user_asm_u64(x, addr, err, errret) \
190 asm volatile("1: movl %%eax,0(%2)\n" \
191 "2: movl %%edx,4(%2)\n" \
192 "3:\n" \
193 ".section .fixup,\"ax\"\n" \
194 "4: movl %3,%0\n" \
195 " jmp 3b\n" \
196 ".previous\n" \
197 _ASM_EXTABLE(1b, 4b) \
198 _ASM_EXTABLE(2b, 4b) \
199 : "=r" (err) \
200 : "A" (x), "r" (addr), "i" (errret), "0" (err))
201
202 #define __put_user_asm_ex_u64(x, addr) \
203 asm volatile("1: movl %%eax,0(%1)\n" \
204 "2: movl %%edx,4(%1)\n" \
205 "3:\n" \
206 _ASM_EXTABLE(1b, 2b - 1b) \
207 _ASM_EXTABLE(2b, 3b - 2b) \
208 : : "A" (x), "r" (addr))
209
210 #define __put_user_x8(x, ptr, __ret_pu) \
211 asm volatile("call __put_user_8" : "=a" (__ret_pu) \
212 : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
213 #else
214 #define __put_user_asm_u64(x, ptr, retval, errret) \
215 __put_user_asm(x, ptr, retval, "q", "", "er", errret)
216 #define __put_user_asm_ex_u64(x, addr) \
217 __put_user_asm_ex(x, addr, "q", "", "er")
218 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
219 #endif
220
221 extern void __put_user_bad(void);
222
223 /*
224 * Strange magic calling convention: pointer in %ecx,
225 * value in %eax(:%edx), return value in %eax. clobbers %rbx
226 */
227 extern void __put_user_1(void);
228 extern void __put_user_2(void);
229 extern void __put_user_4(void);
230 extern void __put_user_8(void);
231
232 #ifdef CONFIG_X86_WP_WORKS_OK
233
234 /**
235 * put_user: - Write a simple value into user space.
236 * @x: Value to copy to user space.
237 * @ptr: Destination address, in user space.
238 *
239 * Context: User context only. This function may sleep.
240 *
241 * This macro copies a single simple value from kernel space to user
242 * space. It supports simple types like char and int, but not larger
243 * data types like structures or arrays.
244 *
245 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
246 * to the result of dereferencing @ptr.
247 *
248 * Returns zero on success, or -EFAULT on error.
249 */
250 #define put_user(x, ptr) \
251 ({ \
252 int __ret_pu; \
253 __typeof__(*(ptr)) __pu_val; \
254 __chk_user_ptr(ptr); \
255 might_fault(); \
256 __pu_val = x; \
257 switch (sizeof(*(ptr))) { \
258 case 1: \
259 __put_user_x(1, __pu_val, ptr, __ret_pu); \
260 break; \
261 case 2: \
262 __put_user_x(2, __pu_val, ptr, __ret_pu); \
263 break; \
264 case 4: \
265 __put_user_x(4, __pu_val, ptr, __ret_pu); \
266 break; \
267 case 8: \
268 __put_user_x8(__pu_val, ptr, __ret_pu); \
269 break; \
270 default: \
271 __put_user_x(X, __pu_val, ptr, __ret_pu); \
272 break; \
273 } \
274 __ret_pu; \
275 })
276
277 #define __put_user_size(x, ptr, size, retval, errret) \
278 do { \
279 retval = 0; \
280 __chk_user_ptr(ptr); \
281 switch (size) { \
282 case 1: \
283 __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \
284 break; \
285 case 2: \
286 __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \
287 break; \
288 case 4: \
289 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \
290 break; \
291 case 8: \
292 __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval, \
293 errret); \
294 break; \
295 default: \
296 __put_user_bad(); \
297 } \
298 } while (0)
299
300 #define __put_user_size_ex(x, ptr, size) \
301 do { \
302 __chk_user_ptr(ptr); \
303 switch (size) { \
304 case 1: \
305 __put_user_asm_ex(x, ptr, "b", "b", "iq"); \
306 break; \
307 case 2: \
308 __put_user_asm_ex(x, ptr, "w", "w", "ir"); \
309 break; \
310 case 4: \
311 __put_user_asm_ex(x, ptr, "l", "k", "ir"); \
312 break; \
313 case 8: \
314 __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \
315 break; \
316 default: \
317 __put_user_bad(); \
318 } \
319 } while (0)
320
321 #else
322
323 #define __put_user_size(x, ptr, size, retval, errret) \
324 do { \
325 __typeof__(*(ptr))__pus_tmp = x; \
326 retval = 0; \
327 \
328 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \
329 retval = errret; \
330 } while (0)
331
332 #define put_user(x, ptr) \
333 ({ \
334 int __ret_pu; \
335 __typeof__(*(ptr))__pus_tmp = x; \
336 __ret_pu = 0; \
337 if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \
338 sizeof(*(ptr))) != 0)) \
339 __ret_pu = -EFAULT; \
340 __ret_pu; \
341 })
342 #endif
343
344 #ifdef CONFIG_X86_32
345 #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad()
346 #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad()
347 #else
348 #define __get_user_asm_u64(x, ptr, retval, errret) \
349 __get_user_asm(x, ptr, retval, "q", "", "=r", errret)
350 #define __get_user_asm_ex_u64(x, ptr) \
351 __get_user_asm_ex(x, ptr, "q", "", "=r")
352 #endif
353
354 #define __get_user_size(x, ptr, size, retval, errret) \
355 do { \
356 retval = 0; \
357 __chk_user_ptr(ptr); \
358 switch (size) { \
359 case 1: \
360 __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
361 break; \
362 case 2: \
363 __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
364 break; \
365 case 4: \
366 __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \
367 break; \
368 case 8: \
369 __get_user_asm_u64(x, ptr, retval, errret); \
370 break; \
371 default: \
372 (x) = __get_user_bad(); \
373 } \
374 } while (0)
375
376 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \
377 asm volatile("1: mov"itype" %2,%"rtype"1\n" \
378 "2:\n" \
379 ".section .fixup,\"ax\"\n" \
380 "3: mov %3,%0\n" \
381 " xor"itype" %"rtype"1,%"rtype"1\n" \
382 " jmp 2b\n" \
383 ".previous\n" \
384 _ASM_EXTABLE(1b, 3b) \
385 : "=r" (err), ltype(x) \
386 : "m" (__m(addr)), "i" (errret), "0" (err))
387
388 #define __get_user_size_ex(x, ptr, size) \
389 do { \
390 __chk_user_ptr(ptr); \
391 switch (size) { \
392 case 1: \
393 __get_user_asm_ex(x, ptr, "b", "b", "=q"); \
394 break; \
395 case 2: \
396 __get_user_asm_ex(x, ptr, "w", "w", "=r"); \
397 break; \
398 case 4: \
399 __get_user_asm_ex(x, ptr, "l", "k", "=r"); \
400 break; \
401 case 8: \
402 __get_user_asm_ex_u64(x, ptr); \
403 break; \
404 default: \
405 (x) = __get_user_bad(); \
406 } \
407 } while (0)
408
409 #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \
410 asm volatile("1: mov"itype" %1,%"rtype"0\n" \
411 "2:\n" \
412 _ASM_EXTABLE(1b, 2b - 1b) \
413 : ltype(x) : "m" (__m(addr)))
414
415 #define __put_user_nocheck(x, ptr, size) \
416 ({ \
417 int __pu_err; \
418 __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \
419 __pu_err; \
420 })
421
422 #define __get_user_nocheck(x, ptr, size) \
423 ({ \
424 int __gu_err; \
425 unsigned long __gu_val; \
426 __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
427 (x) = (__force __typeof__(*(ptr)))__gu_val; \
428 __gu_err; \
429 })
430
431 /* FIXME: this hack is definitely wrong -AK */
432 struct __large_struct { unsigned long buf[100]; };
433 #define __m(x) (*(struct __large_struct __user *)(x))
434
435 /*
436 * Tell gcc we read from memory instead of writing: this is because
437 * we do not write to any memory gcc knows about, so there are no
438 * aliasing issues.
439 */
440 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \
441 asm volatile("1: mov"itype" %"rtype"1,%2\n" \
442 "2:\n" \
443 ".section .fixup,\"ax\"\n" \
444 "3: mov %3,%0\n" \
445 " jmp 2b\n" \
446 ".previous\n" \
447 _ASM_EXTABLE(1b, 3b) \
448 : "=r"(err) \
449 : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
450
451 #define __put_user_asm_ex(x, addr, itype, rtype, ltype) \
452 asm volatile("1: mov"itype" %"rtype"0,%1\n" \
453 "2:\n" \
454 _ASM_EXTABLE(1b, 2b - 1b) \
455 : : ltype(x), "m" (__m(addr)))
456
457 /*
458 * uaccess_try and catch
459 */
460 #define uaccess_try do { \
461 int prev_err = current_thread_info()->uaccess_err; \
462 current_thread_info()->uaccess_err = 0; \
463 barrier();
464
465 #define uaccess_catch(err) \
466 (err) |= current_thread_info()->uaccess_err; \
467 current_thread_info()->uaccess_err = prev_err; \
468 } while (0)
469
470 /**
471 * __get_user: - Get a simple variable from user space, with less checking.
472 * @x: Variable to store result.
473 * @ptr: Source address, in user space.
474 *
475 * Context: User context only. This function may sleep.
476 *
477 * This macro copies a single simple variable from user space to kernel
478 * space. It supports simple types like char and int, but not larger
479 * data types like structures or arrays.
480 *
481 * @ptr must have pointer-to-simple-variable type, and the result of
482 * dereferencing @ptr must be assignable to @x without a cast.
483 *
484 * Caller must check the pointer with access_ok() before calling this
485 * function.
486 *
487 * Returns zero on success, or -EFAULT on error.
488 * On error, the variable @x is set to zero.
489 */
490
491 #define __get_user(x, ptr) \
492 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
493
494 /**
495 * __put_user: - Write a simple value into user space, with less checking.
496 * @x: Value to copy to user space.
497 * @ptr: Destination address, in user space.
498 *
499 * Context: User context only. This function may sleep.
500 *
501 * This macro copies a single simple value from kernel space to user
502 * space. It supports simple types like char and int, but not larger
503 * data types like structures or arrays.
504 *
505 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
506 * to the result of dereferencing @ptr.
507 *
508 * Caller must check the pointer with access_ok() before calling this
509 * function.
510 *
511 * Returns zero on success, or -EFAULT on error.
512 */
513
514 #define __put_user(x, ptr) \
515 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
516
517 #define __get_user_unaligned __get_user
518 #define __put_user_unaligned __put_user
519
520 /*
521 * {get|put}_user_try and catch
522 *
523 * get_user_try {
524 * get_user_ex(...);
525 * } get_user_catch(err)
526 */
527 #define get_user_try uaccess_try
528 #define get_user_catch(err) uaccess_catch(err)
529
530 #define get_user_ex(x, ptr) do { \
531 unsigned long __gue_val; \
532 __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr)))); \
533 (x) = (__force __typeof__(*(ptr)))__gue_val; \
534 } while (0)
535
536 #ifdef CONFIG_X86_WP_WORKS_OK
537
538 #define put_user_try uaccess_try
539 #define put_user_catch(err) uaccess_catch(err)
540
541 #define put_user_ex(x, ptr) \
542 __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
543
544 #else /* !CONFIG_X86_WP_WORKS_OK */
545
546 #define put_user_try do { \
547 int __uaccess_err = 0;
548
549 #define put_user_catch(err) \
550 (err) |= __uaccess_err; \
551 } while (0)
552
553 #define put_user_ex(x, ptr) do { \
554 __uaccess_err |= __put_user(x, ptr); \
555 } while (0)
556
557 #endif /* CONFIG_X86_WP_WORKS_OK */
558
559 /*
560 * movsl can be slow when source and dest are not both 8-byte aligned
561 */
562 #ifdef CONFIG_X86_INTEL_USERCOPY
563 extern struct movsl_mask {
564 int mask;
565 } ____cacheline_aligned_in_smp movsl_mask;
566 #endif
567
568 #define ARCH_HAS_NOCACHE_UACCESS 1
569
570 #ifdef CONFIG_X86_32
571 # include "uaccess_32.h"
572 #else
573 # define ARCH_HAS_SEARCH_EXTABLE
574 # include "uaccess_64.h"
575 #endif
576
577 #endif /* _ASM_X86_UACCESS_H */
578
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