summaryrefslogtreecommitdiffstats
path: root/kernel/arch/powerpc/include/asm/uaccess.h
blob: 2a8ebae0936beb0f6b3ec46eafaf979f0d8ddedd (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
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
#ifndef _ARCH_POWERPC_UACCESS_H
#define _ARCH_POWERPC_UACCESS_H

#ifdef __KERNEL__
#ifndef __ASSEMBLY__

#include <linux/sched.h>
#include <linux/errno.h>
#include <asm/asm-compat.h>
#include <asm/processor.h>
#include <asm/page.h>

#define VERIFY_READ	0
#define VERIFY_WRITE	1

/*
 * 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.
 *
 * The fs/ds values are now the highest legal address in the "segment".
 * This simplifies the checking in the routines below.
 */

#define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })

#define KERNEL_DS	MAKE_MM_SEG(~0UL)
#ifdef __powerpc64__
/* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
#define USER_DS		MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
#else
#define USER_DS		MAKE_MM_SEG(TASK_SIZE - 1)
#endif

#define get_ds()	(KERNEL_DS)
#define get_fs()	(current->thread.fs)
#define set_fs(val)	(current->thread.fs = (val))

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

#define user_addr_max()	(get_fs().seg)

#ifdef __powerpc64__
/*
 * This check is sufficient because there is a large enough
 * gap between user addresses and the kernel addresses
 */
#define __access_ok(addr, size, segment)	\
	(((addr) <= (segment).seg) && ((size) <= (segment).seg))

#else

#define __access_ok(addr, size, segment)	\
	(((addr) <= (segment).seg) &&		\
	 (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))

#endif

#define access_ok(type, addr, size)		\
	(__chk_user_ptr(addr),			\
	 __access_ok((__force unsigned long)(addr), (size), get_fs()))

/*
 * 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;
	unsigned long 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 ugliness 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)))

#define __get_user_inatomic(x, ptr) \
	__get_user_nosleep((x), (ptr), sizeof(*(ptr)))
#define __put_user_inatomic(x, ptr) \
	__put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

#define __get_user_unaligned __get_user
#define __put_user_unaligned __put_user

extern long __put_user_bad(void);

/*
 * 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 " %1,0(%2)	# put_user\n"		\
		"2:\n"						\
		".section .fixup,\"ax\"\n"			\
		"3:	li %0,%3\n"				\
		"	b 2b\n"					\
		".previous\n"					\
		".section __ex_table,\"a\"\n"			\
			PPC_LONG_ALIGN "\n"			\
			PPC_LONG "1b,3b\n"			\
		".previous"					\
		: "=r" (err)					\
		: "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))

#ifdef __powerpc64__
#define __put_user_asm2(x, ptr, retval)				\
	  __put_user_asm(x, ptr, retval, "std")
#else /* __powerpc64__ */
#define __put_user_asm2(x, addr, err)				\
	__asm__ __volatile__(					\
		"1:	stw %1,0(%2)\n"				\
		"2:	stw %1+1,4(%2)\n"			\
		"3:\n"						\
		".section .fixup,\"ax\"\n"			\
		"4:	li %0,%3\n"				\
		"	b 3b\n"					\
		".previous\n"					\
		".section __ex_table,\"a\"\n"			\
			PPC_LONG_ALIGN "\n"			\
			PPC_LONG "1b,4b\n"			\
			PPC_LONG "2b,4b\n"			\
		".previous"					\
		: "=r" (err)					\
		: "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
#endif /* __powerpc64__ */

#define __put_user_size(x, ptr, size, retval)			\
do {								\
	retval = 0;						\
	switch (size) {						\
	  case 1: __put_user_asm(x, ptr, retval, "stb"); break;	\
	  case 2: __put_user_asm(x, ptr, retval, "sth"); break;	\
	  case 4: __put_user_asm(x, ptr, retval, "stw"); break;	\
	  case 8: __put_user_asm2(x, ptr, retval); break;	\
	  default: __put_user_bad();				\
	}							\
} while (0)

#define __put_user_nocheck(x, ptr, size)			\
({								\
	long __pu_err;						\
	__typeof__(*(ptr)) __user *__pu_addr = (ptr);		\
	if (!is_kernel_addr((unsigned long)__pu_addr))		\
		might_fault();					\
	__chk_user_ptr(ptr);					\
	__put_user_size((x), __pu_addr, (size), __pu_err);	\
	__pu_err;						\
})

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

#define __put_user_nosleep(x, ptr, size)			\
({								\
	long __pu_err;						\
	__typeof__(*(ptr)) __user *__pu_addr = (ptr);		\
	__chk_user_ptr(ptr);					\
	__put_user_size((x), __pu_addr, (size), __pu_err);	\
	__pu_err;						\
})


extern long __get_user_bad(void);

#define __get_user_asm(x, addr, err, op)		\
	__asm__ __volatile__(				\
		"1:	"op" %1,0(%2)	# get_user\n"	\
		"2:\n"					\
		".section .fixup,\"ax\"\n"		\
		"3:	li %0,%3\n"			\
		"	li %1,0\n"			\
		"	b 2b\n"				\
		".previous\n"				\
		".section __ex_table,\"a\"\n"		\
			PPC_LONG_ALIGN "\n"		\
			PPC_LONG "1b,3b\n"		\
		".previous"				\
		: "=r" (err), "=r" (x)			\
		: "b" (addr), "i" (-EFAULT), "0" (err))

#ifdef __powerpc64__
#define __get_user_asm2(x, addr, err)			\
	__get_user_asm(x, addr, err, "ld")
#else /* __powerpc64__ */
#define __get_user_asm2(x, addr, err)			\
	__asm__ __volatile__(				\
		"1:	lwz %1,0(%2)\n"			\
		"2:	lwz %1+1,4(%2)\n"		\
		"3:\n"					\
		".section .fixup,\"ax\"\n"		\
		"4:	li %0,%3\n"			\
		"	li %1,0\n"			\
		"	li %1+1,0\n"			\
		"	b 3b\n"				\
		".previous\n"				\
		".section __ex_table,\"a\"\n"		\
			PPC_LONG_ALIGN "\n"		\
			PPC_LONG "1b,4b\n"		\
			PPC_LONG "2b,4b\n"		\
		".previous"				\
		: "=r" (err), "=&r" (x)			\
		: "b" (addr), "i" (-EFAULT), "0" (err))
#endif /* __powerpc64__ */

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

#define __get_user_nocheck(x, ptr, size)			\
({								\
	long __gu_err;						\
	unsigned long __gu_val;					\
	__typeof__(*(ptr)) __user *__gu_addr = (ptr);	\
	__chk_user_ptr(ptr);					\
	if (!is_kernel_addr((unsigned long)__gu_addr))		\
		might_fault();					\
	__get_user_size(__gu_val, __gu_addr, (size), __gu_err);	\
	(x) = (__typeof__(*(ptr)))__gu_val;			\
	__gu_err;						\
})

#ifndef __powerpc64__
#define __get_user64_nocheck(x, ptr, size)			\
({								\
	long __gu_err;						\
	long long __gu_val;					\
	__typeof__(*(ptr)) __user *__gu_addr = (ptr);	\
	__chk_user_ptr(ptr);					\
	if (!is_kernel_addr((unsigned long)__gu_addr))		\
		might_fault();					\
	__get_user_size(__gu_val, __gu_addr, (size), __gu_err);	\
	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
	__gu_err;						\
})
#endif /* __powerpc64__ */

#define __get_user_check(x, ptr, size)					\
({									\
	long __gu_err = -EFAULT;					\
	unsigned long  __gu_val = 0;					\
	__typeof__(*(ptr)) __user *__gu_addr = (ptr);		\
	might_fault();							\
	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;							\
})

#define __get_user_nosleep(x, ptr, size)			\
({								\
	long __gu_err;						\
	unsigned long __gu_val;					\
	__typeof__(*(ptr)) __user *__gu_addr = (ptr);	\
	__chk_user_ptr(ptr);					\
	__get_user_size(__gu_val, __gu_addr, (size), __gu_err);	\
	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
	__gu_err;						\
})


/* more complex routines */

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

#ifndef __powerpc64__

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

	if (access_ok(VERIFY_READ, from, n))
		return __copy_tofrom_user((__force void __user *)to, from, n);
	if ((unsigned long)from < TASK_SIZE) {
		over = (unsigned long)from + n - TASK_SIZE;
		return __copy_tofrom_user((__force void __user *)to, from,
				n - over) + over;
	}
	return n;
}

static inline unsigned long copy_to_user(void __user *to,
		const void *from, unsigned long n)
{
	unsigned long over;

	if (access_ok(VERIFY_WRITE, to, n))
		return __copy_tofrom_user(to, (__force void __user *)from, n);
	if ((unsigned long)to < TASK_SIZE) {
		over = (unsigned long)to + n - TASK_SIZE;
		return __copy_tofrom_user(to, (__force void __user *)from,
				n - over) + over;
	}
	return n;
}

#else /* __powerpc64__ */

#define __copy_in_user(to, from, size) \
	__copy_tofrom_user((to), (from), (size))

extern unsigned long copy_from_user(void *to, const void __user *from,
				    unsigned long n);
extern unsigned long copy_to_user(void __user *to, const void *from,
				  unsigned long n);
extern unsigned long copy_in_user(void __user *to, const void __user *from,
				  unsigned long n);

#endif /* __powerpc64__ */

static inline unsigned long __copy_from_user_inatomic(void *to,
		const void __user *from, unsigned long n)
{
	if (__builtin_constant_p(n) && (n <= 8)) {
		unsigned long ret = 1;

		switch (n) {
		case 1:
			__get_user_size(*(u8 *)to, from, 1, ret);
			break;
		case 2:
			__get_user_size(*(u16 *)to, from, 2, ret);
			break;
		case 4:
			__get_user_size(*(u32 *)to, from, 4, ret);
			break;
		case 8:
			__get_user_size(*(u64 *)to, from, 8, ret);
			break;
		}
		if (ret == 0)
			return 0;
	}
	return __copy_tofrom_user((__force void __user *)to, from, n);
}

static inline unsigned long __copy_to_user_inatomic(void __user *to,
		const void *from, unsigned long n)
{
	if (__builtin_constant_p(n) && (n <= 8)) {
		unsigned long ret = 1;

		switch (n) {
		case 1:
			__put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
			break;
		case 2:
			__put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
			break;
		case 4:
			__put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
			break;
		case 8:
			__put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
			break;
		}
		if (ret == 0)
			return 0;
	}
	return __copy_tofrom_user(to, (__force const void __user *)from, n);
}

static inline unsigned long __copy_from_user(void *to,
		const void __user *from, unsigned long size)
{
	might_fault();
	return __copy_from_user_inatomic(to, from, size);
}

static inline unsigned long __copy_to_user(void __user *to,
		const void *from, unsigned long size)
{
	might_fault();
	return __copy_to_user_inatomic(to, from, size);
}

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

static inline unsigned long clear_user(void __user *addr, unsigned long size)
{
	might_fault();
	if (likely(access_ok(VERIFY_WRITE, addr, size)))
		return __clear_user(addr, size);
	if ((unsigned long)addr < TASK_SIZE) {
		unsigned long over = (unsigned long)addr + size - TASK_SIZE;
		return __clear_user(addr, size - over) + over;
	}
	return size;
}

extern long strncpy_from_user(char *dst, 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  /* __ASSEMBLY__ */
#endif /* __KERNEL__ */

#endif	/* _ARCH_POWERPC_UACCESS_H */