summaryrefslogtreecommitdiffstats
path: root/arch/openrisc/include/asm/uaccess.h
blob: 227af1acb8bd71bf3a2e8e1aa8c041d738e3ff76 (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
/*
 * OpenRISC Linux
 *
 * Linux architectural port borrowing liberally from similar works of
 * others.  All original copyrights apply as per the original source
 * declaration.
 *
 * OpenRISC implementation:
 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
 * et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#ifndef __ASM_OPENRISC_UACCESS_H
#define __ASM_OPENRISC_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/prefetch.h>
#include <linux/string.h>
#include <asm/page.h>

/*
 * The fs value determines whether argument validity checking should be
 * performed or not.  If get_fs() == USER_DS, checking is performed, with
 * get_fs() == KERNEL_DS, checking is bypassed.
 *
 * For historical reasons, these macros are grossly misnamed.
 */

/* addr_limit is the maximum accessible address for the task. we misuse
 * the KERNEL_DS and USER_DS values to both assign and compare the
 * addr_limit values through the equally misnamed get/set_fs macros.
 * (see above)
 */

#define KERNEL_DS	(~0UL)
#define get_ds()	(KERNEL_DS)

#define USER_DS		(TASK_SIZE)
#define get_fs()	(current_thread_info()->addr_limit)
#define set_fs(x)	(current_thread_info()->addr_limit = (x))

#define segment_eq(a, b)	((a) == (b))

/* Ensure that the range from addr to addr+size is all within the process'
 * address space
 */
#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size))

/* Ensure that addr is below task's addr_limit */
#define __addr_ok(addr) ((unsigned long) addr < get_fs())

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

/*
 * The exception table consists of pairs of addresses: the first is the
 * address of an instruction that is allowed to fault, and the second is
 * the address at which the program should continue.  No registers are
 * modified, so it is entirely up to the continuation code to figure out
 * what to do.
 *
 * All the routines below use bits of fixup code that are out of line
 * with the main instruction path.  This means when everything is well,
 * we don't even have to jump over them.  Further, they do not intrude
 * on our cache or tlb entries.
 */

struct exception_table_entry {
	unsigned long insn, fixup;
};

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 *
 * This gets kind of ugly. We want to return _two_ values in "get_user()"
 * and yet we don't want to do any pointers, because that is too much
 * of a performance impact. Thus we have a few rather ugly macros here,
 * and hide all the uglyness from the user.
 *
 * The "__xxx" versions of the user access functions are versions that
 * do not verify the address space, that must have been done previously
 * with a separate "access_ok()" call (this is used when we do multiple
 * accesses to the same area of user memory).
 *
 * As we use the same address space for kernel and user data on the
 * PowerPC, we can just do these as direct assignments.  (Of course, the
 * exception handling means that it's no longer "just"...)
 */
#define get_user(x, ptr) \
	__get_user_check((x), (ptr), sizeof(*(ptr)))
#define put_user(x, ptr) \
	__put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

#define __get_user(x, ptr) \
	__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
#define __put_user(x, ptr) \
	__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

extern long __put_user_bad(void);

#define __put_user_nocheck(x, ptr, size)		\
({							\
	long __pu_err;					\
	__put_user_size((x), (ptr), (size), __pu_err);	\
	__pu_err;					\
})

#define __put_user_check(x, ptr, size)					\
({									\
	long __pu_err = -EFAULT;					\
	__typeof__(*(ptr)) *__pu_addr = (ptr);				\
	if (access_ok(VERIFY_WRITE, __pu_addr, size))			\
		__put_user_size((x), __pu_addr, (size), __pu_err);	\
	__pu_err;							\
})

#define __put_user_size(x, ptr, size, retval)				\
do {									\
	retval = 0;							\
	switch (size) {							\
	case 1: __put_user_asm(x, ptr, retval, "l.sb"); break;		\
	case 2: __put_user_asm(x, ptr, retval, "l.sh"); break;		\
	case 4: __put_user_asm(x, ptr, retval, "l.sw"); break;		\
	case 8: __put_user_asm2(x, ptr, retval); break;			\
	default: __put_user_bad();					\
	}								\
} while (0)

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

/*
 * We don't tell gcc that we are accessing memory, but this is OK
 * because we do not write to any memory gcc knows about, so there
 * are no aliasing issues.
 */
#define __put_user_asm(x, addr, err, op)			\
	__asm__ __volatile__(					\
		"1:	"op" 0(%2),%1\n"			\
		"2:\n"						\
		".section .fixup,\"ax\"\n"			\
		"3:	l.addi %0,r0,%3\n"			\
		"	l.j 2b\n"				\
		"	l.nop\n"				\
		".previous\n"					\
		".section __ex_table,\"a\"\n"			\
		"	.align 2\n"				\
		"	.long 1b,3b\n"				\
		".previous"					\
		: "=r"(err)					\
		: "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))

#define __put_user_asm2(x, addr, err)				\
	__asm__ __volatile__(					\
		"1:	l.sw 0(%2),%1\n"			\
		"2:	l.sw 4(%2),%H1\n"			\
		"3:\n"						\
		".section .fixup,\"ax\"\n"			\
		"4:	l.addi %0,r0,%3\n"			\
		"	l.j 3b\n"				\
		"	l.nop\n"				\
		".previous\n"					\
		".section __ex_table,\"a\"\n"			\
		"	.align 2\n"				\
		"	.long 1b,4b\n"				\
		"	.long 2b,4b\n"				\
		".previous"					\
		: "=r"(err)					\
		: "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))

#define __get_user_nocheck(x, ptr, size)			\
({								\
	long __gu_err, __gu_val;				\
	__get_user_size(__gu_val, (ptr), (size), __gu_err);	\
	(x) = (__force __typeof__(*(ptr)))__gu_val;		\
	__gu_err;						\
})

#define __get_user_check(x, ptr, size)					\
({									\
	long __gu_err = -EFAULT, __gu_val = 0;				\
	const __typeof__(*(ptr)) * __gu_addr = (ptr);			\
	if (access_ok(VERIFY_READ, __gu_addr, size))			\
		__get_user_size(__gu_val, __gu_addr, (size), __gu_err);	\
	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
	__gu_err;							\
})

extern long __get_user_bad(void);

#define __get_user_size(x, ptr, size, retval)				\
do {									\
	retval = 0;							\
	switch (size) {							\
	case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break;		\
	case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break;		\
	case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break;		\
	case 8: __get_user_asm2(x, ptr, retval);			\
	default: (x) = __get_user_bad();				\
	}								\
} while (0)

#define __get_user_asm(x, addr, err, op)		\
	__asm__ __volatile__(				\
		"1:	"op" %1,0(%2)\n"		\
		"2:\n"					\
		".section .fixup,\"ax\"\n"		\
		"3:	l.addi %0,r0,%3\n"		\
		"	l.addi %1,r0,0\n"		\
		"	l.j 2b\n"			\
		"	l.nop\n"			\
		".previous\n"				\
		".section __ex_table,\"a\"\n"		\
		"	.align 2\n"			\
		"	.long 1b,3b\n"			\
		".previous"				\
		: "=r"(err), "=r"(x)			\
		: "r"(addr), "i"(-EFAULT), "0"(err))

#define __get_user_asm2(x, addr, err)			\
	__asm__ __volatile__(				\
		"1:	l.lwz %1,0(%2)\n"		\
		"2:	l.lwz %H1,4(%2)\n"		\
		"3:\n"					\
		".section .fixup,\"ax\"\n"		\
		"4:	l.addi %0,r0,%3\n"		\
		"	l.addi %1,r0,0\n"		\
		"	l.addi %H1,r0,0\n"		\
		"	l.j 3b\n"			\
		"	l.nop\n"			\
		".previous\n"				\
		".section __ex_table,\"a\"\n"		\
		"	.align 2\n"			\
		"	.long 1b,4b\n"			\
		"	.long 2b,4b\n"			\
		".previous"				\
		: "=r"(err), "=&r"(x)			\
		: "r"(addr), "i"(-EFAULT), "0"(err))

/* more complex routines */

extern unsigned long __must_check
__copy_tofrom_user(void *to, const void *from, unsigned long size);

#define __copy_from_user(to, from, size) \
	__copy_tofrom_user(to, from, size)
#define __copy_to_user(to, from, size) \
	__copy_tofrom_user(to, from, size)

#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user

static inline unsigned long
copy_from_user(void *to, const void *from, unsigned long n)
{
	unsigned long res = n;

	if (likely(access_ok(VERIFY_READ, from, n)))
		res = __copy_tofrom_user(to, from, n);
	if (unlikely(res))
		memset(to + (n - res), 0, res);
	return res;
}

static inline unsigned long
copy_to_user(void *to, const void *from, unsigned long n)
{
	if (likely(access_ok(VERIFY_WRITE, to, n)))
		n = __copy_tofrom_user(to, from, n);
	return n;
}

extern unsigned long __clear_user(void *addr, unsigned long size);

static inline __must_check unsigned long
clear_user(void *addr, unsigned long size)
{
	if (likely(access_ok(VERIFY_WRITE, addr, size)))
		size = __clear_user(addr, size);
	return size;
}

#define user_addr_max() \
	(uaccess_kernel() ? ~0UL : TASK_SIZE)

extern long strncpy_from_user(char *dest, const char __user *src, long count);

extern __must_check long strlen_user(const char __user *str);
extern __must_check long strnlen_user(const char __user *str, long n);

#endif /* __ASM_OPENRISC_UACCESS_H */