summaryrefslogtreecommitdiff
path: root/arch/alpha/include/asm/uaccess.h
blob: 1b6f25efa247f00034dd3637ccadfdd86140034f (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
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ALPHA_UACCESS_H
#define __ALPHA_UACCESS_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.
 *
 * Or at least it did once upon a time.  Nowadays it is a mask that
 * defines which bits of the address space are off limits.  This is a
 * wee bit faster than the above.
 *
 * For historical reasons, these macros are grossly misnamed.
 */

#define KERNEL_DS	((mm_segment_t) { 0UL })
#define USER_DS		((mm_segment_t) { -0x40000000000UL })

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

#define uaccess_kernel()	(get_fs().seg == KERNEL_DS.seg)

/*
 * Is a address valid? This does a straightforward 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-(size != 0)" doesn't have any high-bits set
 *  - OR we are in kernel mode.
 */
#define __access_ok(addr, size) ({				\
	unsigned long __ao_a = (addr), __ao_b = (size);		\
	unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b;	\
	(get_fs().seg & (__ao_a | __ao_b | __ao_end)) == 0; })

#define access_ok(addr, size)				\
({							\
	__chk_user_ptr(addr);				\
	__access_ok(((unsigned long)(addr)), (size));	\
})

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 *
 * As the alpha uses the same address space for kernel and user
 * data, we can just do these as direct assignments.  (Of course, the
 * exception handling means that it's no longer "just"...)
 *
 * Careful to not
 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
 * (b) require any knowledge of processes at this stage
 */
#define put_user(x, ptr) \
  __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
#define get_user(x, ptr) \
  __get_user_check((x), (ptr), sizeof(*(ptr)))

/*
 * The "__xxx" versions do not do address space checking, useful when
 * doing multiple accesses to the same area (the programmer has to do the
 * checks by hand with "access_ok()")
 */
#define __put_user(x, ptr) \
  __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
#define __get_user(x, ptr) \
  __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  
/*
 * The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to
 * encode the bits we need for resolving the exception.  See the
 * more extensive comments with fixup_inline_exception below for
 * more information.
 */
#define EXC(label,cont,res,err)				\
	".section __ex_table,\"a\"\n"			\
	"	.long "#label"-.\n"			\
	"	lda "#res","#cont"-"#label"("#err")\n"	\
	".previous\n"

extern void __get_user_unknown(void);

#define __get_user_nocheck(x, ptr, size)			\
({								\
	long __gu_err = 0;					\
	unsigned long __gu_val;					\
	__chk_user_ptr(ptr);					\
	switch (size) {						\
	  case 1: __get_user_8(ptr); break;			\
	  case 2: __get_user_16(ptr); break;			\
	  case 4: __get_user_32(ptr); break;			\
	  case 8: __get_user_64(ptr); break;			\
	  default: __get_user_unknown(); break;			\
	}							\
	(x) = (__force __typeof__(*(ptr))) __gu_val;		\
	__gu_err;						\
})

#define __get_user_check(x, ptr, size)				\
({								\
	long __gu_err = -EFAULT;				\
	unsigned long __gu_val = 0;				\
	const __typeof__(*(ptr)) __user *__gu_addr = (ptr);	\
	if (__access_ok((unsigned long)__gu_addr, size)) {	\
		__gu_err = 0;					\
		switch (size) {					\
		  case 1: __get_user_8(__gu_addr); break;	\
		  case 2: __get_user_16(__gu_addr); break;	\
		  case 4: __get_user_32(__gu_addr); break;	\
		  case 8: __get_user_64(__gu_addr); break;	\
		  default: __get_user_unknown(); break;		\
		}						\
	}							\
	(x) = (__force __typeof__(*(ptr))) __gu_val;		\
	__gu_err;						\
})

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

#define __get_user_64(addr)				\
	__asm__("1: ldq %0,%2\n"			\
	"2:\n"						\
	EXC(1b,2b,%0,%1)				\
		: "=r"(__gu_val), "=r"(__gu_err)	\
		: "m"(__m(addr)), "1"(__gu_err))

#define __get_user_32(addr)				\
	__asm__("1: ldl %0,%2\n"			\
	"2:\n"						\
	EXC(1b,2b,%0,%1)				\
		: "=r"(__gu_val), "=r"(__gu_err)	\
		: "m"(__m(addr)), "1"(__gu_err))

#ifdef __alpha_bwx__
/* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */

#define __get_user_16(addr)				\
	__asm__("1: ldwu %0,%2\n"			\
	"2:\n"						\
	EXC(1b,2b,%0,%1)				\
		: "=r"(__gu_val), "=r"(__gu_err)	\
		: "m"(__m(addr)), "1"(__gu_err))

#define __get_user_8(addr)				\
	__asm__("1: ldbu %0,%2\n"			\
	"2:\n"						\
	EXC(1b,2b,%0,%1)				\
		: "=r"(__gu_val), "=r"(__gu_err)	\
		: "m"(__m(addr)), "1"(__gu_err))
#else
/* Unfortunately, we can't get an unaligned access trap for the sub-word
   load, so we have to do a general unaligned operation.  */

#define __get_user_16(addr)						\
{									\
	long __gu_tmp;							\
	__asm__("1: ldq_u %0,0(%3)\n"					\
	"2:	ldq_u %1,1(%3)\n"					\
	"	extwl %0,%3,%0\n"					\
	"	extwh %1,%3,%1\n"					\
	"	or %0,%1,%0\n"						\
	"3:\n"								\
	EXC(1b,3b,%0,%2)						\
	EXC(2b,3b,%0,%2)						\
		: "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err)	\
		: "r"(addr), "2"(__gu_err));				\
}

#define __get_user_8(addr)						\
	__asm__("1: ldq_u %0,0(%2)\n"					\
	"	extbl %0,%2,%0\n"					\
	"2:\n"								\
	EXC(1b,2b,%0,%1)						\
		: "=&r"(__gu_val), "=r"(__gu_err)			\
		: "r"(addr), "1"(__gu_err))
#endif

extern void __put_user_unknown(void);

#define __put_user_nocheck(x, ptr, size)			\
({								\
	long __pu_err = 0;					\
	__chk_user_ptr(ptr);					\
	switch (size) {						\
	  case 1: __put_user_8(x, ptr); break;			\
	  case 2: __put_user_16(x, ptr); break;			\
	  case 4: __put_user_32(x, ptr); break;			\
	  case 8: __put_user_64(x, ptr); break;			\
	  default: __put_user_unknown(); break;			\
	}							\
	__pu_err;						\
})

#define __put_user_check(x, ptr, size)				\
({								\
	long __pu_err = -EFAULT;				\
	__typeof__(*(ptr)) __user *__pu_addr = (ptr);		\
	if (__access_ok((unsigned long)__pu_addr, size)) {	\
		__pu_err = 0;					\
		switch (size) {					\
		  case 1: __put_user_8(x, __pu_addr); break;	\
		  case 2: __put_user_16(x, __pu_addr); break;	\
		  case 4: __put_user_32(x, __pu_addr); break;	\
		  case 8: __put_user_64(x, __pu_addr); break;	\
		  default: __put_user_unknown(); break;		\
		}						\
	}							\
	__pu_err;						\
})

/*
 * The "__put_user_xx()" macros tell gcc they read from memory
 * instead of writing: this is because they do not write to
 * any memory gcc knows about, so there are no aliasing issues
 */
#define __put_user_64(x, addr)					\
__asm__ __volatile__("1: stq %r2,%1\n"				\
	"2:\n"							\
	EXC(1b,2b,$31,%0)					\
		: "=r"(__pu_err)				\
		: "m" (__m(addr)), "rJ" (x), "0"(__pu_err))

#define __put_user_32(x, addr)					\
__asm__ __volatile__("1: stl %r2,%1\n"				\
	"2:\n"							\
	EXC(1b,2b,$31,%0)					\
		: "=r"(__pu_err)				\
		: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))

#ifdef __alpha_bwx__
/* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */

#define __put_user_16(x, addr)					\
__asm__ __volatile__("1: stw %r2,%1\n"				\
	"2:\n"							\
	EXC(1b,2b,$31,%0)					\
		: "=r"(__pu_err)				\
		: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))

#define __put_user_8(x, addr)					\
__asm__ __volatile__("1: stb %r2,%1\n"				\
	"2:\n"							\
	EXC(1b,2b,$31,%0)					\
		: "=r"(__pu_err)				\
		: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
#else
/* Unfortunately, we can't get an unaligned access trap for the sub-word
   write, so we have to do a general unaligned operation.  */

#define __put_user_16(x, addr)					\
{								\
	long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4;	\
	__asm__ __volatile__(					\
	"1:	ldq_u %2,1(%5)\n"				\
	"2:	ldq_u %1,0(%5)\n"				\
	"	inswh %6,%5,%4\n"				\
	"	inswl %6,%5,%3\n"				\
	"	mskwh %2,%5,%2\n"				\
	"	mskwl %1,%5,%1\n"				\
	"	or %2,%4,%2\n"					\
	"	or %1,%3,%1\n"					\
	"3:	stq_u %2,1(%5)\n"				\
	"4:	stq_u %1,0(%5)\n"				\
	"5:\n"							\
	EXC(1b,5b,$31,%0)					\
	EXC(2b,5b,$31,%0)					\
	EXC(3b,5b,$31,%0)					\
	EXC(4b,5b,$31,%0)					\
		: "=r"(__pu_err), "=&r"(__pu_tmp1), 		\
		  "=&r"(__pu_tmp2), "=&r"(__pu_tmp3), 		\
		  "=&r"(__pu_tmp4)				\
		: "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
}

#define __put_user_8(x, addr)					\
{								\
	long __pu_tmp1, __pu_tmp2;				\
	__asm__ __volatile__(					\
	"1:	ldq_u %1,0(%4)\n"				\
	"	insbl %3,%4,%2\n"				\
	"	mskbl %1,%4,%1\n"				\
	"	or %1,%2,%1\n"					\
	"2:	stq_u %1,0(%4)\n"				\
	"3:\n"							\
	EXC(1b,3b,$31,%0)					\
	EXC(2b,3b,$31,%0)					\
		: "=r"(__pu_err), 				\
	  	  "=&r"(__pu_tmp1), "=&r"(__pu_tmp2)		\
		: "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
}
#endif


/*
 * Complex access routines
 */

extern long __copy_user(void *to, const void *from, long len);

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

extern long __clear_user(void __user *to, long len);

extern inline long
clear_user(void __user *to, long len)
{
	if (__access_ok((unsigned long)to, len))
		len = __clear_user(to, len);
	return len;
}

#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 strnlen_user(const char __user *str, long n);

#include <asm/extable.h>

#endif /* __ALPHA_UACCESS_H */