aboutsummaryrefslogtreecommitdiffstats
path: root/include/asm-s390/uaccess.h
blob: a7f43a251f81b5e4feb14e3c84428f4a99d1bd82 (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
/*
 *  include/asm-s390/uaccess.h
 *
 *  S390 version
 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Hartmut Penner (hp@de.ibm.com),
 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
 *
 *  Derived from "include/asm-i386/uaccess.h"
 */
#ifndef __S390_UACCESS_H
#define __S390_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/sched.h>
#include <linux/errno.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.
 */

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


#define KERNEL_DS       MAKE_MM_SEG(0)
#define USER_DS         MAKE_MM_SEG(1)

#define get_ds()        (KERNEL_DS)
#define get_fs()        (current->thread.mm_segment)

#ifdef __s390x__
#define set_fs(x) \
({									\
	unsigned long __pto;						\
	current->thread.mm_segment = (x);				\
	__pto = current->thread.mm_segment.ar4 ?			\
		S390_lowcore.user_asce : S390_lowcore.kernel_asce;	\
	asm volatile ("lctlg 7,7,%0" : : "m" (__pto) );			\
})
#else
#define set_fs(x) \
({									\
	unsigned long __pto;						\
	current->thread.mm_segment = (x);				\
	__pto = current->thread.mm_segment.ar4 ?			\
		S390_lowcore.user_asce : S390_lowcore.kernel_asce;	\
	asm volatile ("lctl  7,7,%0" : : "m" (__pto) );			\
})
#endif

#define segment_eq(a,b) ((a).ar4 == (b).ar4)


#define __access_ok(addr,size) (1)

#define access_ok(type,addr,size) __access_ok(addr,size)

/* this function will go away soon - use access_ok() instead */
extern inline int __deprecated verify_area(int type, const void __user *addr,
						unsigned long size)
{
	return access_ok(type, addr, size) ? 0 : -EFAULT;
}

/*
 * 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;
};

#ifndef __s390x__
#define __uaccess_fixup \
	".section .fixup,\"ax\"\n"	\
	"2: lhi    %0,%4\n"		\
	"   bras   1,3f\n"		\
	"   .long  1b\n"		\
	"3: l      1,0(1)\n"		\
	"   br     1\n"			\
	".previous\n"			\
	".section __ex_table,\"a\"\n"	\
	"   .align 4\n"			\
	"   .long  0b,2b\n"		\
	".previous"
#define __uaccess_clobber "cc", "1"
#else /* __s390x__ */
#define __uaccess_fixup \
	".section .fixup,\"ax\"\n"	\
	"2: lghi   %0,%4\n"		\
	"   jg     1b\n"		\
	".previous\n"			\
	".section __ex_table,\"a\"\n"	\
	"   .align 8\n"			\
	"   .quad  0b,2b\n"		\
	".previous"
#define __uaccess_clobber "cc"
#endif /* __s390x__ */

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 */
#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
#define __put_user_asm(x, ptr, err) \
({								\
	err = 0;						\
	asm volatile(						\
		"0: mvcs  0(%1,%2),%3,%0\n"			\
		"1:\n"						\
		__uaccess_fixup					\
		: "+&d" (err)					\
		: "d" (sizeof(*(ptr))), "a" (ptr), "Q" (x),	\
		  "K" (-EFAULT)					\
		: __uaccess_clobber );				\
})
#else
#define __put_user_asm(x, ptr, err) \
({								\
	err = 0;						\
	asm volatile(						\
		"0: mvcs  0(%1,%2),0(%3),%0\n"			\
		"1:\n"						\
		__uaccess_fixup					\
		: "+&d" (err)					\
		: "d" (sizeof(*(ptr))), "a" (ptr), "a" (&(x)),	\
		  "K" (-EFAULT), "m" (x)			\
		: __uaccess_clobber );				\
})
#endif

#ifndef __CHECKER__
#define __put_user(x, ptr) \
({								\
	__typeof__(*(ptr)) __x = (x);				\
	int __pu_err;						\
	switch (sizeof (*(ptr))) {				\
	case 1:							\
	case 2:							\
	case 4:							\
	case 8:							\
		__put_user_asm(__x, ptr, __pu_err);		\
		break;						\
	default:						\
		__put_user_bad();				\
		break;						\
	 }							\
	__pu_err;						\
})
#else
#define __put_user(x, ptr)			\
({						\
	void __user *p;				\
	p = (ptr);				\
	0;					\
})
#endif

#define put_user(x, ptr)					\
({								\
	might_sleep();						\
	__put_user(x, ptr);					\
})


extern int __put_user_bad(void) __attribute__((noreturn));

#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
#define __get_user_asm(x, ptr, err) \
({								\
	err = 0;						\
	asm volatile (						\
		"0: mvcp  %O1(%2,%R1),0(%3),%0\n"		\
		"1:\n"						\
		__uaccess_fixup					\
		: "+&d" (err), "=Q" (x)				\
		: "d" (sizeof(*(ptr))), "a" (ptr),		\
		  "K" (-EFAULT)					\
		: __uaccess_clobber );				\
})
#else
#define __get_user_asm(x, ptr, err) \
({								\
	err = 0;						\
	asm volatile (						\
		"0: mvcp  0(%2,%5),0(%3),%0\n"			\
		"1:\n"						\
		__uaccess_fixup					\
		: "+&d" (err), "=m" (x)				\
		: "d" (sizeof(*(ptr))), "a" (ptr),		\
		  "K" (-EFAULT), "a" (&(x))			\
		: __uaccess_clobber );				\
})
#endif

#ifndef __CHECKER__
#define __get_user(x, ptr)					\
({								\
	__typeof__(*(ptr)) __x;					\
	int __gu_err;						\
	switch (sizeof(*(ptr))) {				\
	case 1:							\
	case 2:							\
	case 4:							\
	case 8:							\
		__get_user_asm(__x, ptr, __gu_err);		\
		break;						\
	default:						\
		__get_user_bad();				\
		break;						\
	}							\
	(x) = __x;						\
	__gu_err;						\
})
#else
#define __get_user(x, ptr)			\
({						\
	void __user *p;				\
	p = (ptr);				\
	0;					\
})
#endif


#define get_user(x, ptr)					\
({								\
	might_sleep();						\
	__get_user(x, ptr);					\
})

extern int __get_user_bad(void) __attribute__((noreturn));

#define __put_user_unaligned __put_user
#define __get_user_unaligned __get_user

extern long __copy_to_user_asm(const void *from, long n, void __user *to);

/**
 * __copy_to_user: - Copy a block of data into user space, with less checking.
 * @to:   Destination address, in user space.
 * @from: Source address, in kernel space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from kernel space to user space.  Caller must check
 * the specified block with access_ok() before calling this function.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 */
static inline unsigned long
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
	return __copy_to_user_asm(from, n, to);
}

#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user

/**
 * copy_to_user: - Copy a block of data into user space.
 * @to:   Destination address, in user space.
 * @from: Source address, in kernel space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from kernel space to user space.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 */
static inline unsigned long
copy_to_user(void __user *to, const void *from, unsigned long n)
{
	might_sleep();
	if (access_ok(VERIFY_WRITE, to, n))
		n = __copy_to_user(to, from, n);
	return n;
}

extern long __copy_from_user_asm(void *to, long n, const void __user *from);

/**
 * __copy_from_user: - Copy a block of data from user space, with less checking.
 * @to:   Destination address, in kernel space.
 * @from: Source address, in user space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from user space to kernel space.  Caller must check
 * the specified block with access_ok() before calling this function.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 *
 * If some data could not be copied, this function will pad the copied
 * data to the requested size using zero bytes.
 */
static inline unsigned long
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
	return __copy_from_user_asm(to, n, from);
}

/**
 * copy_from_user: - Copy a block of data from user space.
 * @to:   Destination address, in kernel space.
 * @from: Source address, in user space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from user space to kernel space.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 *
 * If some data could not be copied, this function will pad the copied
 * data to the requested size using zero bytes.
 */
static inline unsigned long
copy_from_user(void *to, const void __user *from, unsigned long n)
{
	might_sleep();
	if (access_ok(VERIFY_READ, from, n))
		n = __copy_from_user(to, from, n);
	else
		memset(to, 0, n);
	return n;
}

extern unsigned long __copy_in_user_asm(const void __user *from, long n,
							void __user *to);

static inline unsigned long
__copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
	return __copy_in_user_asm(from, n, to);
}

static inline unsigned long
copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
	might_sleep();
	if (__access_ok(from,n) && __access_ok(to,n))
		n = __copy_in_user_asm(from, n, to);
	return n;
}

/*
 * Copy a null terminated string from userspace.
 */
extern long __strncpy_from_user_asm(long count, char *dst,
					const char __user *src);

static inline long
strncpy_from_user(char *dst, const char __user *src, long count)
{
        long res = -EFAULT;
        might_sleep();
        if (access_ok(VERIFY_READ, src, 1))
                res = __strncpy_from_user_asm(count, dst, src);
        return res;
}


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

static inline unsigned long
strnlen_user(const char __user * src, unsigned long n)
{
	might_sleep();
	return __strnlen_user_asm(n, src);
}

/**
 * strlen_user: - Get the size of a string in user space.
 * @str: The string to measure.
 *
 * Context: User context only.  This function may sleep.
 *
 * Get the size of a NUL-terminated string in user space.
 *
 * Returns the size of the string INCLUDING the terminating NUL.
 * On exception, returns 0.
 *
 * If there is a limit on the length of a valid string, you may wish to
 * consider using strnlen_user() instead.
 */
#define strlen_user(str) strnlen_user(str, ~0UL)

/*
 * Zero Userspace
 */

extern long __clear_user_asm(void __user *to, long n);

static inline unsigned long
__clear_user(void __user *to, unsigned long n)
{
	return __clear_user_asm(to, n);
}

static inline unsigned long
clear_user(void __user *to, unsigned long n)
{
	might_sleep();
	if (access_ok(VERIFY_WRITE, to, n))
		n = __clear_user_asm(to, n);
	return n;
}

#endif /* __S390_UACCESS_H */