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#ifndef __i386_UACCESS_H
2
#define __i386_UACCESS_H
3
 
4
/*
5
 * User space memory access functions
6
 */
7
#include <linux/config.h>
8
#include <linux/errno.h>
9
#include <linux/thread_info.h>
10
#include <linux/prefetch.h>
11
#include <linux/string.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
 
28
#define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFFUL)
29
#define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
30
 
31
#define get_ds()        (KERNEL_DS)
32
#define get_fs()        (current_thread_info()->addr_limit)
33
#define set_fs(x)       (current_thread_info()->addr_limit = (x))
34
 
35
#define segment_eq(a,b) ((a).seg == (b).seg)
36
 
37
/*
38
 * movsl can be slow when source and dest are not both 8-byte aligned
39
 */
40
#ifdef CONFIG_X86_INTEL_USERCOPY
41
extern struct movsl_mask {
42
        int mask;
43
} ____cacheline_aligned_in_smp movsl_mask;
44
#endif
45
 
46
#define __addr_ok(addr) ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))
47
 
48
/*
49
 * Test whether a block of memory is a valid user space address.
50
 * Returns 0 if the range is valid, nonzero otherwise.
51
 *
52
 * This is equivalent to the following test:
53
 * (u33)addr + (u33)size >= (u33)current->addr_limit.seg
54
 *
55
 * This needs 33-bit arithmetic. We have a carry...
56
 */
57
#define __range_ok(addr,size) ({ \
58
        unsigned long flag,sum; \
59
        asm("addl %3,%1 ; sbbl %0,%0; cmpl %1,%4; sbbl $0,%0" \
60
                :"=&r" (flag), "=r" (sum) \
61
                :"1" (addr),"g" ((int)(size)),"g" (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
 * verify_area: - Obsolete, use access_ok()
87
 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE
88
 * @addr: User space pointer to start of block to check
89
 * @size: Size of block to check
90
 *
91
 * Context: User context only.  This function may sleep.
92
 *
93
 * This function has been replaced by access_ok().
94
 *
95
 * Checks if a pointer to a block of memory in user space is valid.
96
 *
97
 * Returns zero if the memory block may be valid, -EFAULT
98
 * if it is definitely invalid.
99
 *
100
 * See access_ok() for more details.
101
 */
102
static inline int verify_area(int type, const void __user * addr, unsigned long size)
103
{
104
        return access_ok(type,addr,size) ? 0 : -EFAULT;
105
}
106
 
107
 
108
/*
109
 * The exception table consists of pairs of addresses: the first is the
110
 * address of an instruction that is allowed to fault, and the second is
111
 * the address at which the program should continue.  No registers are
112
 * modified, so it is entirely up to the continuation code to figure out
113
 * what to do.
114
 *
115
 * All the routines below use bits of fixup code that are out of line
116
 * with the main instruction path.  This means when everything is well,
117
 * we don't even have to jump over them.  Further, they do not intrude
118
 * on our cache or tlb entries.
119
 */
120
 
121
struct exception_table_entry
122
{
123
        unsigned long insn, fixup;
124
};
125
 
126
extern int fixup_exception(struct pt_regs *regs);
127
 
128
/*
129
 * These are the main single-value transfer routines.  They automatically
130
 * use the right size if we just have the right pointer type.
131
 *
132
 * This gets kind of ugly. We want to return _two_ values in "get_user()"
133
 * and yet we don't want to do any pointers, because that is too much
134
 * of a performance impact. Thus we have a few rather ugly macros here,
135
 * and hide all the ugliness from the user.
136
 *
137
 * The "__xxx" versions of the user access functions are versions that
138
 * do not verify the address space, that must have been done previously
139
 * with a separate "access_ok()" call (this is used when we do multiple
140
 * accesses to the same area of user memory).
141
 */
142
 
143
extern void __get_user_1(void);
144
extern void __get_user_2(void);
145
extern void __get_user_4(void);
146
 
147
#define __get_user_x(size,ret,x,ptr) \
148
        __asm__ __volatile__("call __get_user_" #size \
149
                :"=a" (ret),"=d" (x) \
150
                :"0" (ptr))
151
 
152
 
153
/* Careful: we have to cast the result to the type of the pointer for sign reasons */
154
/**
155
 * get_user: - Get a simple variable from user space.
156
 * @x:   Variable to store result.
157
 * @ptr: Source address, in user space.
158
 *
159
 * Context: User context only.  This function may sleep.
160
 *
161
 * This macro copies a single simple variable from user space to kernel
162
 * space.  It supports simple types like char and int, but not larger
163
 * data types like structures or arrays.
164
 *
165
 * @ptr must have pointer-to-simple-variable type, and the result of
166
 * dereferencing @ptr must be assignable to @x without a cast.
167
 *
168
 * Returns zero on success, or -EFAULT on error.
169
 * On error, the variable @x is set to zero.
170
 */
171
#define get_user(x,ptr)                                                 \
172
({      int __ret_gu,__val_gu;                                          \
173
        switch(sizeof (*(ptr))) {                                       \
174
        case 1:  __get_user_x(1,__ret_gu,__val_gu,ptr); break;          \
175
        case 2:  __get_user_x(2,__ret_gu,__val_gu,ptr); break;          \
176
        case 4:  __get_user_x(4,__ret_gu,__val_gu,ptr); break;          \
177
        default: __get_user_x(X,__ret_gu,__val_gu,ptr); break;          \
178
        }                                                               \
179
        (x) = (__typeof__(*(ptr)))__val_gu;                             \
180
        __ret_gu;                                                       \
181
})
182
 
183
extern void __put_user_bad(void);
184
 
185
/**
186
 * put_user: - Write a simple value into user space.
187
 * @x:   Value to copy to user space.
188
 * @ptr: Destination address, in user space.
189
 *
190
 * Context: User context only.  This function may sleep.
191
 *
192
 * This macro copies a single simple value from kernel space to user
193
 * space.  It supports simple types like char and int, but not larger
194
 * data types like structures or arrays.
195
 *
196
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
197
 * to the result of dereferencing @ptr.
198
 *
199
 * Returns zero on success, or -EFAULT on error.
200
 */
201
#define put_user(x,ptr)                                                 \
202
  __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
203
 
204
 
205
/**
206
 * __get_user: - Get a simple variable from user space, with less checking.
207
 * @x:   Variable to store result.
208
 * @ptr: Source address, in user space.
209
 *
210
 * Context: User context only.  This function may sleep.
211
 *
212
 * This macro copies a single simple variable from user space to kernel
213
 * space.  It supports simple types like char and int, but not larger
214
 * data types like structures or arrays.
215
 *
216
 * @ptr must have pointer-to-simple-variable type, and the result of
217
 * dereferencing @ptr must be assignable to @x without a cast.
218
 *
219
 * Caller must check the pointer with access_ok() before calling this
220
 * function.
221
 *
222
 * Returns zero on success, or -EFAULT on error.
223
 * On error, the variable @x is set to zero.
224
 */
225
#define __get_user(x,ptr) \
226
  __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
227
 
228
 
229
/**
230
 * __put_user: - Write a simple value into user space, with less checking.
231
 * @x:   Value to copy to user space.
232
 * @ptr: Destination address, in user space.
233
 *
234
 * Context: User context only.  This function may sleep.
235
 *
236
 * This macro copies a single simple value from kernel space to user
237
 * space.  It supports simple types like char and int, but not larger
238
 * data types like structures or arrays.
239
 *
240
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
241
 * to the result of dereferencing @ptr.
242
 *
243
 * Caller must check the pointer with access_ok() before calling this
244
 * function.
245
 *
246
 * Returns zero on success, or -EFAULT on error.
247
 */
248
#define __put_user(x,ptr) \
249
  __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
250
 
251
#define __put_user_nocheck(x,ptr,size)                          \
252
({                                                              \
253
        long __pu_err;                                          \
254
        __put_user_size((x),(ptr),(size),__pu_err,-EFAULT);     \
255
        __pu_err;                                               \
256
})
257
 
258
 
259
#define __put_user_check(x,ptr,size)                                    \
260
({                                                                      \
261
        long __pu_err = -EFAULT;                                        \
262
        __typeof__(*(ptr)) *__pu_addr = (ptr);                          \
263
        might_sleep();                                          \
264
        if (access_ok(VERIFY_WRITE,__pu_addr,size))                     \
265
                __put_user_size((x),__pu_addr,(size),__pu_err,-EFAULT); \
266
        __pu_err;                                                       \
267
})                                                      
268
 
269
#define __put_user_u64(x, addr, err)                            \
270
        __asm__ __volatile__(                                   \
271
                "1:     movl %%eax,0(%2)\n"                     \
272
                "2:     movl %%edx,4(%2)\n"                     \
273
                "3:\n"                                          \
274
                ".section .fixup,\"ax\"\n"                      \
275
                "4:     movl %3,%0\n"                           \
276
                "       jmp 3b\n"                               \
277
                ".previous\n"                                   \
278
                ".section __ex_table,\"a\"\n"                   \
279
                "       .align 4\n"                             \
280
                "       .long 1b,4b\n"                          \
281
                "       .long 2b,4b\n"                          \
282
                ".previous"                                     \
283
                : "=r"(err)                                     \
284
                : "A" (x), "r" (addr), "i"(-EFAULT), "0"(err))
285
 
286
#ifdef CONFIG_X86_WP_WORKS_OK
287
 
288
#define __put_user_size(x,ptr,size,retval,errret)                       \
289
do {                                                                    \
290
        retval = 0;                                                     \
291
        switch (size) {                                                 \
292
        case 1: __put_user_asm(x,ptr,retval,"b","b","iq",errret);break; \
293
        case 2: __put_user_asm(x,ptr,retval,"w","w","ir",errret);break; \
294
        case 4: __put_user_asm(x,ptr,retval,"l","","ir",errret); break; \
295
        case 8: __put_user_u64((__typeof__(*ptr))(x),ptr,retval); break;\
296
          default: __put_user_bad();                                    \
297
        }                                                               \
298
} while (0)
299
 
300
#else
301
 
302
#define __put_user_size(x,ptr,size,retval,errret)                       \
303
do {                                                                    \
304
        __typeof__(*(ptr)) __pus_tmp = x;                               \
305
        retval = 0;                                                     \
306
                                                                        \
307
        if(unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0))     \
308
                retval = errret;                                        \
309
} while (0)
310
 
311
#endif
312
struct __large_struct { unsigned long buf[100]; };
313
#define __m(x) (*(struct __large_struct *)(x))
314
 
315
/*
316
 * Tell gcc we read from memory instead of writing: this is because
317
 * we do not write to any memory gcc knows about, so there are no
318
 * aliasing issues.
319
 */
320
#define __put_user_asm(x, addr, err, itype, rtype, ltype, errret)       \
321
        __asm__ __volatile__(                                           \
322
                "1:     mov"itype" %"rtype"1,%2\n"                      \
323
                "2:\n"                                                  \
324
                ".section .fixup,\"ax\"\n"                              \
325
                "3:     movl %3,%0\n"                                   \
326
                "       jmp 2b\n"                                       \
327
                ".previous\n"                                           \
328
                ".section __ex_table,\"a\"\n"                           \
329
                "       .align 4\n"                                     \
330
                "       .long 1b,3b\n"                                  \
331
                ".previous"                                             \
332
                : "=r"(err)                                             \
333
                : ltype (x), "m"(__m(addr)), "i"(errret), "0"(err))
334
 
335
 
336
#define __get_user_nocheck(x,ptr,size)                          \
337
({                                                              \
338
        long __gu_err, __gu_val;                                \
339
        __get_user_size(__gu_val,(ptr),(size),__gu_err,-EFAULT);\
340
        (x) = (__typeof__(*(ptr)))__gu_val;                     \
341
        __gu_err;                                               \
342
})
343
 
344
extern long __get_user_bad(void);
345
 
346
#define __get_user_size(x,ptr,size,retval,errret)                       \
347
do {                                                                    \
348
        retval = 0;                                                     \
349
        switch (size) {                                                 \
350
        case 1: __get_user_asm(x,ptr,retval,"b","b","=q",errret);break; \
351
        case 2: __get_user_asm(x,ptr,retval,"w","w","=r",errret);break; \
352
        case 4: __get_user_asm(x,ptr,retval,"l","","=r",errret);break;  \
353
        default: (x) = __get_user_bad();                                \
354
        }                                                               \
355
} while (0)
356
 
357
#define __get_user_asm(x, addr, err, itype, rtype, ltype, errret)       \
358
        __asm__ __volatile__(                                           \
359
                "1:     mov"itype" %2,%"rtype"1\n"                      \
360
                "2:\n"                                                  \
361
                ".section .fixup,\"ax\"\n"                              \
362
                "3:     movl %3,%0\n"                                   \
363
                "       xor"itype" %"rtype"1,%"rtype"1\n"               \
364
                "       jmp 2b\n"                                       \
365
                ".previous\n"                                           \
366
                ".section __ex_table,\"a\"\n"                           \
367
                "       .align 4\n"                                     \
368
                "       .long 1b,3b\n"                                  \
369
                ".previous"                                             \
370
                : "=r"(err), ltype (x)                                  \
371
                : "m"(__m(addr)), "i"(errret), "0"(err))
372
 
373
 
374
unsigned long __copy_to_user_ll(void __user *to, const void *from, unsigned long n);
375
unsigned long __copy_from_user_ll(void *to, const void __user *from, unsigned long n);
376
 
377
/*
378
 * Here we special-case 1, 2 and 4-byte copy_*_user invocations.  On a fault
379
 * we return the initial request size (1, 2 or 4), as copy_*_user should do.
380
 * If a store crosses a page boundary and gets a fault, the x86 will not write
381
 * anything, so this is accurate.
382
 */
383
 
384
/**
385
 * __copy_to_user: - Copy a block of data into user space, with less checking.
386
 * @to:   Destination address, in user space.
387
 * @from: Source address, in kernel space.
388
 * @n:    Number of bytes to copy.
389
 *
390
 * Context: User context only.  This function may sleep.
391
 *
392
 * Copy data from kernel space to user space.  Caller must check
393
 * the specified block with access_ok() before calling this function.
394
 *
395
 * Returns number of bytes that could not be copied.
396
 * On success, this will be zero.
397
 */
398
static inline unsigned long
399
__copy_to_user(void __user *to, const void *from, unsigned long n)
400
{
401
        if (__builtin_constant_p(n)) {
402
                unsigned long ret;
403
 
404
                switch (n) {
405
                case 1:
406
                        __put_user_size(*(u8 *)from, (u8 *)to, 1, ret, 1);
407
                        return ret;
408
                case 2:
409
                        __put_user_size(*(u16 *)from, (u16 *)to, 2, ret, 2);
410
                        return ret;
411
                case 4:
412
                        __put_user_size(*(u32 *)from, (u32 *)to, 4, ret, 4);
413
                        return ret;
414
                }
415
        }
416
        return __copy_to_user_ll(to, from, n);
417
}
418
 
419
/**
420
 * __copy_from_user: - Copy a block of data from user space, with less checking.
421
 * @to:   Destination address, in kernel space.
422
 * @from: Source address, in user space.
423
 * @n:    Number of bytes to copy.
424
 *
425
 * Context: User context only.  This function may sleep.
426
 *
427
 * Copy data from user space to kernel space.  Caller must check
428
 * the specified block with access_ok() before calling this function.
429
 *
430
 * Returns number of bytes that could not be copied.
431
 * On success, this will be zero.
432
 *
433
 * If some data could not be copied, this function will pad the copied
434
 * data to the requested size using zero bytes.
435
 */
436
static inline unsigned long
437
__copy_from_user(void *to, const void __user *from, unsigned long n)
438
{
439
        if (__builtin_constant_p(n)) {
440
                unsigned long ret;
441
 
442
                switch (n) {
443
                case 1:
444
                        __get_user_size(*(u8 *)to, from, 1, ret, 1);
445
                        return ret;
446
                case 2:
447
                        __get_user_size(*(u16 *)to, from, 2, ret, 2);
448
                        return ret;
449
                case 4:
450
                        __get_user_size(*(u32 *)to, from, 4, ret, 4);
451
                        return ret;
452
                }
453
        }
454
        return __copy_from_user_ll(to, from, n);
455
}
456
 
457
/**
458
 * copy_to_user: - Copy a block of data into user space.
459
 * @to:   Destination address, in user space.
460
 * @from: Source address, in kernel space.
461
 * @n:    Number of bytes to copy.
462
 *
463
 * Context: User context only.  This function may sleep.
464
 *
465
 * Copy data from kernel space to user space.
466
 *
467
 * Returns number of bytes that could not be copied.
468
 * On success, this will be zero.
469
 */
470
static inline unsigned long
471
copy_to_user(void __user *to, const void *from, unsigned long n)
472
{
475 giacomo 473
        memcpy(to, from, n);
474
        return 0;
422 giacomo 475
}
476
 
477
/**
478
 * copy_from_user: - Copy a block of data from user space.
479
 * @to:   Destination address, in kernel space.
480
 * @from: Source address, in user space.
481
 * @n:    Number of bytes to copy.
482
 *
483
 * Context: User context only.  This function may sleep.
484
 *
485
 * Copy data from user space to kernel space.
486
 *
487
 * Returns number of bytes that could not be copied.
488
 * On success, this will be zero.
489
 *
490
 * If some data could not be copied, this function will pad the copied
491
 * data to the requested size using zero bytes.
492
 */
493
static inline unsigned long
494
copy_from_user(void *to, const void __user *from, unsigned long n)
495
{
475 giacomo 496
        memcpy(to, from, n);
497
        return 0;
422 giacomo 498
}
499
 
500
long strncpy_from_user(char *dst, const char __user *src, long count);
501
long __strncpy_from_user(char *dst, const char __user *src, long count);
502
 
503
/**
504
 * strlen_user: - Get the size of a string in user space.
505
 * @str: The string to measure.
506
 *
507
 * Context: User context only.  This function may sleep.
508
 *
509
 * Get the size of a NUL-terminated string in user space.
510
 *
511
 * Returns the size of the string INCLUDING the terminating NUL.
512
 * On exception, returns 0.
513
 *
514
 * If there is a limit on the length of a valid string, you may wish to
515
 * consider using strnlen_user() instead.
516
 */
517
#define strlen_user(str) strnlen_user(str, ~0UL >> 1)
518
 
519
long strnlen_user(const char __user *str, long n);
520
unsigned long clear_user(void __user *mem, unsigned long len);
521
unsigned long __clear_user(void __user *mem, unsigned long len);
522
 
523
#endif /* __i386_UACCESS_H */