Free Electrons

Embedded Linux Experts

  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
/*
 *  arch/arm/include/asm/uaccess.h
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#ifndef _ASMARM_UACCESS_H
#define _ASMARM_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/string.h>
#include <linux/thread_info.h>
#include <asm/errno.h>
#include <asm/memory.h>
#include <asm/domain.h>
#include <asm/unified.h>
#include <asm/compiler.h>

#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
#include <asm-generic/uaccess-unaligned.h>
#else
#define __get_user_unaligned __get_user
#define __put_user_unaligned __put_user
#endif

#define VERIFY_READ 0
#define VERIFY_WRITE 1

/*
 * 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;
};

extern int fixup_exception(struct pt_regs *regs);

/*
 * These two are intentionally not defined anywhere - if the kernel
 * code generates any references to them, that's a bug.
 */
extern int __get_user_bad(void);
extern int __put_user_bad(void);

/*
 * Note that this is actually 0x1,0000,0000
 */
#define KERNEL_DS	0x00000000
#define get_ds()	(KERNEL_DS)

#ifdef CONFIG_MMU

#define USER_DS		TASK_SIZE
#define get_fs()	(current_thread_info()->addr_limit)

static inline void set_fs(mm_segment_t fs)
{
	current_thread_info()->addr_limit = fs;
	modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
}

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

#define __addr_ok(addr) ({ \
	unsigned long flag; \
	__asm__("cmp %2, %0; movlo %0, #0" \
		: "=&r" (flag) \
		: "0" (current_thread_info()->addr_limit), "r" (addr) \
		: "cc"); \
	(flag == 0); })

/* We use 33-bit arithmetic here... */
#define __range_ok(addr,size) ({ \
	unsigned long flag, roksum; \
	__chk_user_ptr(addr);	\
	__asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
		: "=&r" (flag), "=&r" (roksum) \
		: "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
		: "cc"); \
	flag; })

/*
 * Single-value transfer routines.  They automatically use the right
 * size if we just have the right pointer type.  Note that the functions
 * which read from user space (*get_*) need to take care not to leak
 * kernel data even if the calling code is buggy and fails to check
 * the return value.  This means zeroing out the destination variable
 * or buffer on error.  Normally this is done out of line by the
 * fixup code, but there are a few places where it intrudes on the
 * main code path.  When we only write to user space, there is no
 * problem.
 */
extern int __get_user_1(void *);
extern int __get_user_2(void *);
extern int __get_user_4(void *);
extern int __get_user_lo8(void *);
extern int __get_user_8(void *);

#define __GUP_CLOBBER_1	"lr", "cc"
#ifdef CONFIG_CPU_USE_DOMAINS
#define __GUP_CLOBBER_2	"ip", "lr", "cc"
#else
#define __GUP_CLOBBER_2 "lr", "cc"
#endif
#define __GUP_CLOBBER_4	"lr", "cc"
#define __GUP_CLOBBER_lo8 "lr", "cc"
#define __GUP_CLOBBER_8	"lr", "cc"

#define __get_user_x(__r2,__p,__e,__l,__s)				\
	   __asm__ __volatile__ (					\
		__asmeq("%0", "r0") __asmeq("%1", "r2")			\
		__asmeq("%3", "r1")					\
		"bl	__get_user_" #__s				\
		: "=&r" (__e), "=r" (__r2)				\
		: "0" (__p), "r" (__l)					\
		: __GUP_CLOBBER_##__s)

/* narrowing a double-word get into a single 32bit word register: */
#ifdef __ARMEB__
#define __get_user_xb(__r2, __p, __e, __l, __s)				\
	__get_user_x(__r2, __p, __e, __l, lo8)
#else
#define __get_user_xb __get_user_x
#endif

#define __get_user_check(x,p)							\
	({								\
		unsigned long __limit = current_thread_info()->addr_limit - 1; \
		register const typeof(*(p)) __user *__p asm("r0") = (p);\
		register typeof(x) __r2 asm("r2");			\
		register unsigned long __l asm("r1") = __limit;		\
		register int __e asm("r0");				\
		switch (sizeof(*(__p))) {				\
		case 1:							\
			__get_user_x(__r2, __p, __e, __l, 1);		\
			break;						\
		case 2:							\
			__get_user_x(__r2, __p, __e, __l, 2);		\
			break;						\
		case 4:							\
			__get_user_x(__r2, __p, __e, __l, 4);		\
			break;						\
		case 8:							\
			if (sizeof((x)) < 8)				\
				__get_user_xb(__r2, __p, __e, __l, 4);	\
			else						\
				__get_user_x(__r2, __p, __e, __l, 8);	\
			break;						\
		default: __e = __get_user_bad(); break;			\
		}							\
		x = (typeof(*(p))) __r2;				\
		__e;							\
	})

#define get_user(x,p)							\
	({								\
		might_fault();						\
		__get_user_check(x,p);					\
	 })

extern int __put_user_1(void *, unsigned int);
extern int __put_user_2(void *, unsigned int);
extern int __put_user_4(void *, unsigned int);
extern int __put_user_8(void *, unsigned long long);

#define __put_user_x(__r2,__p,__e,__l,__s)				\
	   __asm__ __volatile__ (					\
		__asmeq("%0", "r0") __asmeq("%2", "r2")			\
		__asmeq("%3", "r1")					\
		"bl	__put_user_" #__s				\
		: "=&r" (__e)						\
		: "0" (__p), "r" (__r2), "r" (__l)			\
		: "ip", "lr", "cc")

#define __put_user_check(x,p)							\
	({								\
		unsigned long __limit = current_thread_info()->addr_limit - 1; \
		const typeof(*(p)) __user *__tmp_p = (p);		\
		register const typeof(*(p)) __r2 asm("r2") = (x);	\
		register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \
		register unsigned long __l asm("r1") = __limit;		\
		register int __e asm("r0");				\
		switch (sizeof(*(__p))) {				\
		case 1:							\
			__put_user_x(__r2, __p, __e, __l, 1);		\
			break;						\
		case 2:							\
			__put_user_x(__r2, __p, __e, __l, 2);		\
			break;						\
		case 4:							\
			__put_user_x(__r2, __p, __e, __l, 4);		\
			break;						\
		case 8:							\
			__put_user_x(__r2, __p, __e, __l, 8);		\
			break;						\
		default: __e = __put_user_bad(); break;			\
		}							\
		__e;							\
	})

#define put_user(x,p)							\
	({								\
		might_fault();						\
		__put_user_check(x,p);					\
	 })

#else /* CONFIG_MMU */

/*
 * uClinux has only one addr space, so has simplified address limits.
 */
#define USER_DS			KERNEL_DS

#define segment_eq(a,b)		(1)
#define __addr_ok(addr)		((void)(addr),1)
#define __range_ok(addr,size)	((void)(addr),0)
#define get_fs()		(KERNEL_DS)

static inline void set_fs(mm_segment_t fs)
{
}

#define get_user(x,p)	__get_user(x,p)
#define put_user(x,p)	__put_user(x,p)

#endif /* CONFIG_MMU */

#define access_ok(type,addr,size)	(__range_ok(addr,size) == 0)

#define user_addr_max() \
	(segment_eq(get_fs(), KERNEL_DS) ? ~0UL : get_fs())

/*
 * The "__xxx" versions of the user access functions do not verify the
 * address space - it must have been done previously with a separate
 * "access_ok()" call.
 *
 * The "xxx_error" versions set the third argument to EFAULT if an
 * error occurs, and leave it unchanged on success.  Note that these
 * versions are void (ie, don't return a value as such).
 */
#define __get_user(x,ptr)						\
({									\
	long __gu_err = 0;						\
	__get_user_err((x),(ptr),__gu_err);				\
	__gu_err;							\
})

#define __get_user_error(x,ptr,err)					\
({									\
	__get_user_err((x),(ptr),err);					\
	(void) 0;							\
})

#define __get_user_err(x,ptr,err)					\
do {									\
	unsigned long __gu_addr = (unsigned long)(ptr);			\
	unsigned long __gu_val;						\
	__chk_user_ptr(ptr);						\
	might_fault();							\
	switch (sizeof(*(ptr))) {					\
	case 1:	__get_user_asm_byte(__gu_val,__gu_addr,err);	break;	\
	case 2:	__get_user_asm_half(__gu_val,__gu_addr,err);	break;	\
	case 4:	__get_user_asm_word(__gu_val,__gu_addr,err);	break;	\
	default: (__gu_val) = __get_user_bad();				\
	}								\
	(x) = (__typeof__(*(ptr)))__gu_val;				\
} while (0)

#define __get_user_asm_byte(x,addr,err)				\
	__asm__ __volatile__(					\
	"1:	" TUSER(ldrb) "	%1,[%2],#0\n"			\
	"2:\n"							\
	"	.pushsection .fixup,\"ax\"\n"			\
	"	.align	2\n"					\
	"3:	mov	%0, %3\n"				\
	"	mov	%1, #0\n"				\
	"	b	2b\n"					\
	"	.popsection\n"					\
	"	.pushsection __ex_table,\"a\"\n"		\
	"	.align	3\n"					\
	"	.long	1b, 3b\n"				\
	"	.popsection"					\
	: "+r" (err), "=&r" (x)					\
	: "r" (addr), "i" (-EFAULT)				\
	: "cc")

#ifndef __ARMEB__
#define __get_user_asm_half(x,__gu_addr,err)			\
({								\
	unsigned long __b1, __b2;				\
	__get_user_asm_byte(__b1, __gu_addr, err);		\
	__get_user_asm_byte(__b2, __gu_addr + 1, err);		\
	(x) = __b1 | (__b2 << 8);				\
})
#else
#define __get_user_asm_half(x,__gu_addr,err)			\
({								\
	unsigned long __b1, __b2;				\
	__get_user_asm_byte(__b1, __gu_addr, err);		\
	__get_user_asm_byte(__b2, __gu_addr + 1, err);		\
	(x) = (__b1 << 8) | __b2;				\
})
#endif

#define __get_user_asm_word(x,addr,err)				\
	__asm__ __volatile__(					\
	"1:	" TUSER(ldr) "	%1,[%2],#0\n"			\
	"2:\n"							\
	"	.pushsection .fixup,\"ax\"\n"			\
	"	.align	2\n"					\
	"3:	mov	%0, %3\n"				\
	"	mov	%1, #0\n"				\
	"	b	2b\n"					\
	"	.popsection\n"					\
	"	.pushsection __ex_table,\"a\"\n"		\
	"	.align	3\n"					\
	"	.long	1b, 3b\n"				\
	"	.popsection"					\
	: "+r" (err), "=&r" (x)					\
	: "r" (addr), "i" (-EFAULT)				\
	: "cc")

#define __put_user(x,ptr)						\
({									\
	long __pu_err = 0;						\
	__put_user_err((x),(ptr),__pu_err);				\
	__pu_err;							\
})

#define __put_user_error(x,ptr,err)					\
({									\
	__put_user_err((x),(ptr),err);					\
	(void) 0;							\
})

#define __put_user_err(x,ptr,err)					\
do {									\
	unsigned long __pu_addr = (unsigned long)(ptr);			\
	__typeof__(*(ptr)) __pu_val = (x);				\
	__chk_user_ptr(ptr);						\
	might_fault();							\
	switch (sizeof(*(ptr))) {					\
	case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);	break;	\
	case 2: __put_user_asm_half(__pu_val,__pu_addr,err);	break;	\
	case 4: __put_user_asm_word(__pu_val,__pu_addr,err);	break;	\
	case 8:	__put_user_asm_dword(__pu_val,__pu_addr,err);	break;	\
	default: __put_user_bad();					\
	}								\
} while (0)

#define __put_user_asm_byte(x,__pu_addr,err)			\
	__asm__ __volatile__(					\
	"1:	" TUSER(strb) "	%1,[%2],#0\n"			\
	"2:\n"							\
	"	.pushsection .fixup,\"ax\"\n"			\
	"	.align	2\n"					\
	"3:	mov	%0, %3\n"				\
	"	b	2b\n"					\
	"	.popsection\n"					\
	"	.pushsection __ex_table,\"a\"\n"		\
	"	.align	3\n"					\
	"	.long	1b, 3b\n"				\
	"	.popsection"					\
	: "+r" (err)						\
	: "r" (x), "r" (__pu_addr), "i" (-EFAULT)		\
	: "cc")

#ifndef __ARMEB__
#define __put_user_asm_half(x,__pu_addr,err)			\
({								\
	unsigned long __temp = (unsigned long)(x);		\
	__put_user_asm_byte(__temp, __pu_addr, err);		\
	__put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);	\
})
#else
#define __put_user_asm_half(x,__pu_addr,err)			\
({								\
	unsigned long __temp = (unsigned long)(x);		\
	__put_user_asm_byte(__temp >> 8, __pu_addr, err);	\
	__put_user_asm_byte(__temp, __pu_addr + 1, err);	\
})
#endif

#define __put_user_asm_word(x,__pu_addr,err)			\
	__asm__ __volatile__(					\
	"1:	" TUSER(str) "	%1,[%2],#0\n"			\
	"2:\n"							\
	"	.pushsection .fixup,\"ax\"\n"			\
	"	.align	2\n"					\
	"3:	mov	%0, %3\n"				\
	"	b	2b\n"					\
	"	.popsection\n"					\
	"	.pushsection __ex_table,\"a\"\n"		\
	"	.align	3\n"					\
	"	.long	1b, 3b\n"				\
	"	.popsection"					\
	: "+r" (err)						\
	: "r" (x), "r" (__pu_addr), "i" (-EFAULT)		\
	: "cc")

#ifndef __ARMEB__
#define	__reg_oper0	"%R2"
#define	__reg_oper1	"%Q2"
#else
#define	__reg_oper0	"%Q2"
#define	__reg_oper1	"%R2"
#endif

#define __put_user_asm_dword(x,__pu_addr,err)			\
	__asm__ __volatile__(					\
 ARM(	"1:	" TUSER(str) "	" __reg_oper1 ", [%1], #4\n"	) \
 ARM(	"2:	" TUSER(str) "	" __reg_oper0 ", [%1]\n"	) \
 THUMB(	"1:	" TUSER(str) "	" __reg_oper1 ", [%1]\n"	) \
 THUMB(	"2:	" TUSER(str) "	" __reg_oper0 ", [%1, #4]\n"	) \
	"3:\n"							\
	"	.pushsection .fixup,\"ax\"\n"			\
	"	.align	2\n"					\
	"4:	mov	%0, %3\n"				\
	"	b	3b\n"					\
	"	.popsection\n"					\
	"	.pushsection __ex_table,\"a\"\n"		\
	"	.align	3\n"					\
	"	.long	1b, 4b\n"				\
	"	.long	2b, 4b\n"				\
	"	.popsection"					\
	: "+r" (err), "+r" (__pu_addr)				\
	: "r" (x), "i" (-EFAULT)				\
	: "cc")


#ifdef CONFIG_MMU
extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n);
extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n);
#else
#define __copy_from_user(to,from,n)	(memcpy(to, (void __force *)from, n), 0)
#define __copy_to_user(to,from,n)	(memcpy((void __force *)to, from, n), 0)
#define __clear_user(addr,n)		(memset((void __force *)addr, 0, n), 0)
#endif

static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
	if (access_ok(VERIFY_READ, from, n))
		n = __copy_from_user(to, from, n);
	else /* security hole - plug it */
		memset(to, 0, n);
	return n;
}

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

#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user

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

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 /* _ASMARM_UACCESS_H */