summaryrefslogtreecommitdiffstats
path: root/arch/score/include/asm/uaccess.h
blob: 0ef220474d9b2d4eeec79e04228a3bf107460154 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
#ifndef __SCORE_UACCESS_H
#define __SCORE_UACCESS_H

#include <linux/kernel.h>
#include <asm/extable.h>

#define get_ds()		(KERNEL_DS)
#define get_fs()		(current_thread_info()->addr_limit)
#define segment_eq(a, b)	((a).seg == (b).seg)

/*
 * Is a address valid? This does a straighforward calculation rather
 * than tests.
 *
 * Address valid if:
 *  - "addr" doesn't have any high-bits set
 *  - AND "size" doesn't have any high-bits set
 *  - AND "addr+size" doesn't have any high-bits set
 *  - OR we are in kernel mode.
 *
 * __ua_size() is a trick to avoid runtime checking of positive constant
 * sizes; for those we already know at compile time that the size is ok.
 */
#define __ua_size(size)							\
	((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))

/*
 * access_ok: - Checks if a user space pointer is valid
 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
 *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
 *        to write to a block, it is always safe to read from it.
 * @addr: User space pointer to start of block to check
 * @size: Size of block to check
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * Checks if a pointer to a block of memory in user space is valid.
 *
 * Returns true (nonzero) if the memory block may be valid, false (zero)
 * if it is definitely invalid.
 *
 * Note that, depending on architecture, this function probably just
 * checks that the pointer is in the user space range - after calling
 * this function, memory access functions may still return -EFAULT.
 */

#define __access_ok(addr, size)					\
	(((long)((get_fs().seg) &				\
		 ((addr) | ((addr) + (size)) |			\
		  __ua_size(size)))) == 0)

#define access_ok(type, addr, size)				\
	likely(__access_ok((unsigned long)(addr), (size)))

/*
 * put_user: - Write a simple value into user space.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))

/*
 * get_user: - Get a simple variable from user space.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))

/*
 * __put_user: - Write a simple value into user space, with less checking.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))

/*
 * __get_user: - Get a simple variable from user space, with less checking.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))

struct __large_struct { unsigned long buf[100]; };
#define __m(x) (*(struct __large_struct __user *)(x))

/*
 * Yuck.  We need two variants, one for 64bit operation and one
 * for 32 bit mode and old iron.
 */
extern void __get_user_unknown(void);

#define __get_user_common(val, size, ptr)				\
do {									\
	switch (size) {							\
	case 1:								\
		__get_user_asm(val, "lb", ptr);				\
		break;							\
	case 2:								\
		__get_user_asm(val, "lh", ptr);				\
		 break;							\
	case 4:								\
		__get_user_asm(val, "lw", ptr);				\
		 break;							\
	case 8: 							\
		if (__copy_from_user((void *)&val, ptr, 8) == 0)	\
			__gu_err = 0;					\
		else							\
			__gu_err = -EFAULT;				\
		break;							\
	default:							\
		__get_user_unknown();					\
		break;							\
	}								\
} while (0)

#define __get_user_nocheck(x, ptr, size)				\
({									\
	long __gu_err = 0;						\
	__get_user_common((x), size, ptr);				\
	__gu_err;							\
})

#define __get_user_check(x, ptr, size)					\
({									\
	long __gu_err = -EFAULT;					\
	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
									\
	if (likely(access_ok(VERIFY_READ, __gu_ptr, size)))		\
		__get_user_common((x), size, __gu_ptr);			\
	else								\
		(x) = 0;						\
									\
	__gu_err;							\
})

#define __get_user_asm(val, insn, addr)					\
{									\
	long __gu_tmp;							\
									\
	__asm__ __volatile__(						\
		"1:" insn " %1, %3\n"					\
		"2:\n"							\
		".section .fixup,\"ax\"\n"				\
		"3:li	%0, %4\n"					\
		"li	%1, 0\n"					\
		"j	2b\n"						\
		".previous\n"						\
		".section __ex_table,\"a\"\n"				\
		".word	1b, 3b\n"					\
		".previous\n"						\
		: "=r" (__gu_err), "=r" (__gu_tmp)			\
		: "0" (0), "o" (__m(addr)), "i" (-EFAULT));		\
									\
		(val) = (__typeof__(*(addr))) __gu_tmp;			\
}

/*
 * Yuck.  We need two variants, one for 64bit operation and one
 * for 32 bit mode and old iron.
 */
#define __put_user_nocheck(val, ptr, size)				\
({									\
	__typeof__(*(ptr)) __pu_val;					\
	long __pu_err = 0;						\
									\
	__pu_val = (val);						\
	switch (size) {							\
	case 1:								\
		__put_user_asm("sb", ptr);				\
		break;							\
	case 2:								\
		__put_user_asm("sh", ptr);				\
		break;							\
	case 4:								\
		__put_user_asm("sw", ptr);				\
		break;							\
	case 8: 							\
		if ((__copy_to_user((void *)ptr, &__pu_val, 8)) == 0)	\
			__pu_err = 0;					\
		else							\
			__pu_err = -EFAULT;				\
		break;							\
	default:							\
		 __put_user_unknown();					\
		 break;							\
	}								\
	__pu_err;							\
})


#define __put_user_check(val, ptr, size)				\
({									\
	__typeof__(*(ptr)) __user *__pu_addr = (ptr);			\
	__typeof__(*(ptr)) __pu_val = (val);				\
	long __pu_err = -EFAULT;					\
									\
	if (likely(access_ok(VERIFY_WRITE, __pu_addr, size))) {		\
		switch (size) {						\
		case 1:							\
			__put_user_asm("sb", __pu_addr);		\
			break;						\
		case 2:							\
			__put_user_asm("sh", __pu_addr);		\
			break;						\
		case 4:							\
			__put_user_asm("sw", __pu_addr);		\
			break;						\
		case 8: 						\
			if ((__copy_to_user((void *)__pu_addr, &__pu_val, 8)) == 0)\
				__pu_err = 0;				\
			else						\
				__pu_err = -EFAULT;			\
			break;						\
		default:						\
			__put_user_unknown();				\
			break;						\
		}							\
	}								\
	__pu_err;							\
})

#define __put_user_asm(insn, ptr)					\
	__asm__ __volatile__(						\
		"1:" insn " %2, %3\n"					\
		"2:\n"							\
		".section .fixup,\"ax\"\n"				\
		"3:li %0, %4\n"						\
		"j 2b\n"						\
		".previous\n"						\
		".section __ex_table,\"a\"\n"				\
		".word 1b, 3b\n"					\
		".previous\n"						\
		: "=r" (__pu_err)					\
		: "0" (0), "r" (__pu_val), "o" (__m(ptr)),		\
		  "i" (-EFAULT));

extern void __put_user_unknown(void);
extern int __copy_tofrom_user(void *to, const void *from, unsigned long len);

static inline unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long len)
{
	return __copy_tofrom_user(to, (__force const void *)from, len);
}

static inline unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long len)
{
	return __copy_tofrom_user((__force void *)to, from, len);
}

#define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER

/*
 * __clear_user: - Zero a block of memory in user space, with less checking.
 * @to:   Destination address, in user space.
 * @n:    Number of bytes to zero.
 *
 * Zero a block of memory in user space.  Caller must check
 * the specified block with access_ok() before calling this function.
 *
 * Returns number of bytes that could not be cleared.
 * On success, this will be zero.
 */
extern unsigned long __clear_user(void __user *src, unsigned long size);

static inline unsigned long clear_user(char *src, unsigned long size)
{
	if (access_ok(VERIFY_WRITE, src, size))
		return __clear_user(src, size);

	return -EFAULT;
}
/*
 * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 * @dst:   Destination address, in kernel space.  This buffer must be at
 *         least @count bytes long.
 * @src:   Source address, in user space.
 * @count: Maximum number of bytes to copy, including the trailing NUL.
 *
 * Copies a NUL-terminated string from userspace to kernel space.
 * Caller must check the specified block with access_ok() before calling
 * this function.
 *
 * On success, returns the length of the string (not including the trailing
 * NUL).
 *
 * If access to userspace fails, returns -EFAULT (some data may have been
 * copied).
 *
 * If @count is smaller than the length of the string, copies @count bytes
 * and returns @count.
 */
extern int __strncpy_from_user(char *dst, const char *src, long len);

static inline int strncpy_from_user(char *dst, const char *src, long len)
{
	if (access_ok(VERIFY_READ, src, 1))
		return __strncpy_from_user(dst, src, len);

	return -EFAULT;
}

extern int __strnlen_user(const char *str, long len);
static inline long strnlen_user(const char __user *str, long len)
{
	if (!access_ok(VERIFY_READ, str, 0))
		return 0;
	else		
		return __strnlen_user(str, len);
}

#endif /* __SCORE_UACCESS_H */