summaryrefslogtreecommitdiffstats
path: root/include/asm-alpha/uaccess.h
blob: 22de3b434a22a59d7f16bce6520787efab1fc8f9 (plain) (blame)
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
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
#ifndef __ALPHA_UACCESS_H
#define __ALPHA_UACCESS_H

#include <linux/errno.h>
#include <linux/sched.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 VERIFY_READ	0
#define VERIFY_WRITE	1

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

#define segment_eq(a,b)	((a).seg == (b).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" doesn't have any high-bits set
 *  - OR we are in kernel mode.
 */
#define __access_ok(addr,size,segment) \
	(((segment).seg & (addr | size | (addr+size))) == 0)

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

/*
 * 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)),get_fs())
#define get_user(x,ptr) \
  __get_user_check((x),(ptr),sizeof(*(ptr)),get_fs())

/*
 * 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.
 */

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) = (__typeof__(*(ptr))) __gu_val;			\
	__gu_err;						\
})

#define __get_user_check(x,ptr,size,segment)				\
({									\
	long __gu_err = -EFAULT;					\
	unsigned long __gu_val = 0;					\
	const __typeof__(*(ptr)) __user *__gu_addr = (ptr);		\
	if (__access_ok((unsigned long)__gu_addr,size,segment)) {	\
		__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) = (__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"						\
	".section __ex_table,\"a\"\n"			\
	"	.long 1b - .\n"				\
	"	lda %0, 2b-1b(%1)\n"			\
	".previous"					\
		: "=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"						\
	".section __ex_table,\"a\"\n"			\
	"	.long 1b - .\n"				\
	"	lda %0, 2b-1b(%1)\n"			\
	".previous"					\
		: "=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"						\
	".section __ex_table,\"a\"\n"			\
	"	.long 1b - .\n"				\
	"	lda %0, 2b-1b(%1)\n"			\
	".previous"					\
		: "=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"						\
	".section __ex_table,\"a\"\n"			\
	"	.long 1b - .\n"				\
	"	lda %0, 2b-1b(%1)\n"			\
	".previous"					\
		: "=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"								\
	".section __ex_table,\"a\"\n"					\
	"	.long 1b - .\n"						\
	"	lda %0, 3b-1b(%2)\n"					\
	"	.long 2b - .\n"						\
	"	lda %0, 3b-2b(%2)\n"					\
	".previous"							\
		: "=&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"								\
	".section __ex_table,\"a\"\n"					\
	"	.long 1b - .\n"						\
	"	lda %0, 2b-1b(%1)\n"					\
	".previous"							\
		: "=&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,segment)				\
({									\
	long __pu_err = -EFAULT;					\
	__typeof__(*(ptr)) __user *__pu_addr = (ptr);			\
	if (__access_ok((unsigned long)__pu_addr,size,segment)) {	\
		__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"							\
	".section __ex_table,\"a\"\n"				\
	"	.long 1b - .\n"					\
	"	lda $31,2b-1b(%0)\n"				\
	".previous"						\
		: "=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"							\
	".section __ex_table,\"a\"\n"				\
	"	.long 1b - .\n"					\
	"	lda $31,2b-1b(%0)\n"				\
	".previous"						\
		: "=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"							\
	".section __ex_table,\"a\"\n"				\
	"	.long 1b - .\n"					\
	"	lda $31,2b-1b(%0)\n"				\
	".previous"						\
		: "=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"							\
	".section __ex_table,\"a\"\n"				\
	"	.long 1b - .\n"					\
	"	lda $31,2b-1b(%0)\n"				\
	".previous"						\
		: "=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"							\
	".section __ex_table,\"a\"\n"				\
	"	.long 1b - .\n"					\
	"	lda $31, 5b-1b(%0)\n"				\
	"	.long 2b - .\n"					\
	"	lda $31, 5b-2b(%0)\n"				\
	"	.long 3b - .\n"					\
	"	lda $31, 5b-3b(%0)\n"				\
	"	.long 4b - .\n"					\
	"	lda $31, 5b-4b(%0)\n"				\
	".previous"						\
		: "=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"							\
	".section __ex_table,\"a\"\n"				\
	"	.long 1b - .\n"					\
	"	lda $31, 3b-1b(%0)\n"				\
	"	.long 2b - .\n"					\
	"	lda $31, 3b-2b(%0)\n"				\
	".previous"						\
		: "=r"(__pu_err),				\
	  	  "=&r"(__pu_tmp1), "=&r"(__pu_tmp2)		\
		: "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
}
#endif


/*
 * Complex access routines
 */

/* This little bit of silliness is to get the GP loaded for a function
   that ordinarily wouldn't.  Otherwise we could have it done by the macro
   directly, which can be optimized the linker.  */
#ifdef MODULE
#define __module_address(sym)		"r"(sym),
#define __module_call(ra, arg, sym)	"jsr $" #ra ",(%" #arg ")," #sym
#else
#define __module_address(sym)
#define __module_call(ra, arg, sym)	"bsr $" #ra "," #sym " !samegp"
#endif

extern void __copy_user(void);

extern inline long
__copy_tofrom_user_nocheck(void *to, const void *from, long len)
{
	register void * __cu_to __asm__("$6") = to;
	register const void * __cu_from __asm__("$7") = from;
	register long __cu_len __asm__("$0") = len;

	__asm__ __volatile__(
		__module_call(28, 3, __copy_user)
		: "=r" (__cu_len), "=r" (__cu_from), "=r" (__cu_to)
		: __module_address(__copy_user)
		  "0" (__cu_len), "1" (__cu_from), "2" (__cu_to)
		: "$1","$2","$3","$4","$5","$28","memory");

	return __cu_len;
}

extern inline long
__copy_tofrom_user(void *to, const void *from, long len, const void __user *validate)
{
	if (__access_ok((unsigned long)validate, len, get_fs()))
		len = __copy_tofrom_user_nocheck(to, from, len);
	return len;
}

#define __copy_to_user(to,from,n)					\
({									\
	__chk_user_ptr(to);						\
	__copy_tofrom_user_nocheck((__force void *)(to),(from),(n));	\
})
#define __copy_from_user(to,from,n)					\
({									\
	__chk_user_ptr(from);						\
	__copy_tofrom_user_nocheck((to),(__force void *)(from),(n));	\
})

#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user


extern inline long
copy_to_user(void __user *to, const void *from, long n)
{
	return __copy_tofrom_user((__force void *)to, from, n, to);
}

extern inline long
copy_from_user(void *to, const void __user *from, long n)
{
	return __copy_tofrom_user(to, (__force void *)from, n, from);
}

extern void __do_clear_user(void);

extern inline long
__clear_user(void __user *to, long len)
{
	register void __user * __cl_to __asm__("$6") = to;
	register long __cl_len __asm__("$0") = len;
	__asm__ __volatile__(
		__module_call(28, 2, __do_clear_user)
		: "=r"(__cl_len), "=r"(__cl_to)
		: __module_address(__do_clear_user)
		  "0"(__cl_len), "1"(__cl_to)
		: "$1","$2","$3","$4","$5","$28","memory");
	return __cl_len;
}

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

#undef __module_address
#undef __module_call

/* Returns: -EFAULT if exception before terminator, N if the entire
   buffer filled, else strlen.  */

extern long __strncpy_from_user(char *__to, const char __user *__from, long __to_len);

extern inline long
strncpy_from_user(char *to, const char __user *from, long n)
{
	long ret = -EFAULT;
	if (__access_ok((unsigned long)from, 0, get_fs()))
		ret = __strncpy_from_user(to, from, n);
	return ret;
}

/* Returns: 0 if bad, string length+1 (memory size) of string if ok */
extern long __strlen_user(const char __user *);

extern inline long strlen_user(const char __user *str)
{
	return access_ok(VERIFY_READ,str,0) ? __strlen_user(str) : 0;
}

/* Returns: 0 if exception before NUL or reaching the supplied limit (N),
 * a value greater than N if the limit would be exceeded, else strlen.  */
extern long __strnlen_user(const char __user *, long);

extern inline long strnlen_user(const char __user *str, long n)
{
	return access_ok(VERIFY_READ,str,0) ? __strnlen_user(str, n) : 0;
}

/*
 * About the exception table:
 *
 * - insn is a 32-bit pc-relative offset from the faulting insn.
 * - nextinsn is a 16-bit offset off of the faulting instruction
 *   (not off of the *next* instruction as branches are).
 * - errreg is the register in which to place -EFAULT.
 * - valreg is the final target register for the load sequence
 *   and will be zeroed.
 *
 * Either errreg or valreg may be $31, in which case nothing happens.
 *
 * The exception fixup information "just so happens" to be arranged
 * as in a MEM format instruction.  This lets us emit our three
 * values like so:
 *
 *      lda valreg, nextinsn(errreg)
 *
 */

struct exception_table_entry
{
	signed int insn;
	union exception_fixup {
		unsigned unit;
		struct {
			signed int nextinsn : 16;
			unsigned int errreg : 5;
			unsigned int valreg : 5;
		} bits;
	} fixup;
};

/* Returns the new pc */
#define fixup_exception(map_reg, fixup, pc)			\
({								\
	if ((fixup)->fixup.bits.valreg != 31)			\
		map_reg((fixup)->fixup.bits.valreg) = 0;	\
	if ((fixup)->fixup.bits.errreg != 31)			\
		map_reg((fixup)->fixup.bits.errreg) = -EFAULT;	\
	(pc) + (fixup)->fixup.bits.nextinsn;			\
})


#endif /* __ALPHA_UACCESS_H */