CoCalc -- usercopy.c

GitHub Repository: awilliam/linux-vfio
Path: blob/master/arch/m32r/lib/usercopy.c
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1
/*
2
 * User address space access functions.
3
 * The non inlined parts of asm-m32r/uaccess.h are here.
4
 *
5
 * Copyright 1997 Andi Kleen <[email protected]>
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 * Copyright 1997 Linus Torvalds
7
 * Copyright 2001, 2002, 2004 Hirokazu Takata
8
 */
9
#include <linux/prefetch.h>
10
#include <linux/string.h>
11
#include <linux/thread_info.h>
12
#include <asm/uaccess.h>
13

14
unsigned long
15
__generic_copy_to_user(void __user *to, const void *from, unsigned long n)
16
{
17
	prefetch(from);
18
	if (access_ok(VERIFY_WRITE, to, n))
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		__copy_user(to,from,n);
20
	return n;
21
}
22

23
unsigned long
24
__generic_copy_from_user(void *to, const void __user *from, unsigned long n)
25
{
26
	prefetchw(to);
27
	if (access_ok(VERIFY_READ, from, n))
28
		__copy_user_zeroing(to,from,n);
29
	else
30
		memset(to, 0, n);
31
	return n;
32
}
33

34

35
/*
36
 * Copy a null terminated string from userspace.
37
 */
38

39
#ifdef CONFIG_ISA_DUAL_ISSUE
40

41
#define __do_strncpy_from_user(dst,src,count,res)			\
42
do {									\
43
	int __d0, __d1, __d2;						\
44
	__asm__ __volatile__(						\
45
		"	beqz	%1, 2f\n"				\
46
		"	.fillinsn\n"					\
47
		"0:	ldb	r14, @%3    ||	addi	%3, #1\n"	\
48
		"	stb	r14, @%4    ||	addi	%4, #1\n"	\
49
		"	beqz	r14, 1f\n"				\
50
		"	addi	%1, #-1\n"				\
51
		"	bnez	%1, 0b\n"				\
52
		"	.fillinsn\n"					\
53
		"1:	sub	%0, %1\n"				\
54
		"	.fillinsn\n"					\
55
		"2:\n"							\
56
		".section .fixup,\"ax\"\n"				\
57
		"	.balign 4\n"					\
58
		"3:	seth	r14, #high(2b)\n"			\
59
		"	or3	r14, r14, #low(2b)\n"			\
60
		"	jmp	r14	    ||	ldi	%0, #%5\n"	\
61
		".previous\n"						\
62
		".section __ex_table,\"a\"\n"				\
63
		"	.balign 4\n"					\
64
		"	.long 0b,3b\n"					\
65
		".previous"						\
66
		: "=&r"(res), "=&r"(count), "=&r" (__d0), "=&r" (__d1),	\
67
		  "=&r" (__d2)						\
68
		: "i"(-EFAULT), "0"(count), "1"(count), "3"(src), 	\
69
		  "4"(dst)						\
70
		: "r14", "cbit", "memory");				\
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} while (0)
72

73
#else /* not CONFIG_ISA_DUAL_ISSUE */
74

75
#define __do_strncpy_from_user(dst,src,count,res)			\
76
do {									\
77
	int __d0, __d1, __d2;						\
78
	__asm__ __volatile__(						\
79
		"	beqz	%1, 2f\n"				\
80
		"	.fillinsn\n"					\
81
		"0:	ldb	r14, @%3\n"				\
82
		"	stb	r14, @%4\n"				\
83
		"	addi	%3, #1\n"				\
84
		"	addi	%4, #1\n"				\
85
		"	beqz	r14, 1f\n"				\
86
		"	addi	%1, #-1\n"				\
87
		"	bnez	%1, 0b\n"				\
88
		"	.fillinsn\n"					\
89
		"1:	sub	%0, %1\n"				\
90
		"	.fillinsn\n"					\
91
		"2:\n"							\
92
		".section .fixup,\"ax\"\n"				\
93
		"	.balign 4\n"					\
94
		"3:	ldi	%0, #%5\n"				\
95
		"	seth	r14, #high(2b)\n"			\
96
		"	or3	r14, r14, #low(2b)\n"			\
97
		"	jmp	r14\n"					\
98
		".previous\n"						\
99
		".section __ex_table,\"a\"\n"				\
100
		"	.balign 4\n"					\
101
		"	.long 0b,3b\n"					\
102
		".previous"						\
103
		: "=&r"(res), "=&r"(count), "=&r" (__d0), "=&r" (__d1),	\
104
		  "=&r" (__d2)						\
105
		: "i"(-EFAULT), "0"(count), "1"(count), "3"(src),	\
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		  "4"(dst)						\
107
		: "r14", "cbit", "memory");				\
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} while (0)
109

110
#endif /* CONFIG_ISA_DUAL_ISSUE */
111

112
long
113
__strncpy_from_user(char *dst, const char __user *src, long count)
114
{
115
	long res;
116
	__do_strncpy_from_user(dst, src, count, res);
117
	return res;
118
}
119

120
long
121
strncpy_from_user(char *dst, const char __user *src, long count)
122
{
123
	long res = -EFAULT;
124
	if (access_ok(VERIFY_READ, src, 1))
125
		__do_strncpy_from_user(dst, src, count, res);
126
	return res;
127
}
128

129

130
/*
131
 * Zero Userspace
132
 */
133

134
#ifdef CONFIG_ISA_DUAL_ISSUE
135

136
#define __do_clear_user(addr,size)					\
137
do {									\
138
	int __dst, __c;							\
139
  	__asm__ __volatile__(						\
140
		"	beqz	%1, 9f\n"				\
141
		"	and3	r14, %0, #3\n"				\
142
		"	bnez	r14, 2f\n"				\
143
		"	and3	r14, %1, #3\n"				\
144
		"	bnez	r14, 2f\n"				\
145
		"	and3	%1, %1, #3\n"				\
146
		"	beqz	%2, 2f\n"				\
147
		"	addi	%0, #-4\n"				\
148
		"	.fillinsn\n"					\
149
		"0:	; word clear \n"				\
150
		"	st	%6, @+%0    ||	addi	%2, #-1\n"	\
151
		"	bnez	%2, 0b\n"				\
152
		"	beqz	%1, 9f\n"				\
153
		"	.fillinsn\n"					\
154
		"2:	; byte clear \n"				\
155
		"	stb	%6, @%0	    ||	addi	%1, #-1\n"	\
156
		"	addi	%0, #1\n"				\
157
		"	bnez	%1, 2b\n"				\
158
		"	.fillinsn\n"					\
159
		"9:\n"							\
160
		".section .fixup,\"ax\"\n"				\
161
		"	.balign 4\n"					\
162
		"4:	slli	%2, #2\n"				\
163
		"	seth	r14, #high(9b)\n"			\
164
		"	or3	r14, r14, #low(9b)\n"			\
165
		"	jmp	r14	    ||	add	%1, %2\n"	\
166
		".previous\n"						\
167
		".section __ex_table,\"a\"\n"				\
168
		"	.balign 4\n"					\
169
		"	.long 0b,4b\n"					\
170
		"	.long 2b,9b\n"					\
171
		".previous\n"						\
172
		: "=&r"(__dst), "=&r"(size), "=&r"(__c)			\
173
		: "0"(addr), "1"(size), "2"(size / 4), "r"(0)		\
174
		: "r14", "cbit", "memory");				\
175
} while (0)
176

177
#else /* not CONFIG_ISA_DUAL_ISSUE */
178

179
#define __do_clear_user(addr,size)					\
180
do {									\
181
	int __dst, __c;							\
182
  	__asm__ __volatile__(						\
183
		"	beqz	%1, 9f\n"				\
184
		"	and3	r14, %0, #3\n"				\
185
		"	bnez	r14, 2f\n"				\
186
		"	and3	r14, %1, #3\n"				\
187
		"	bnez	r14, 2f\n"				\
188
		"	and3	%1, %1, #3\n"				\
189
		"	beqz	%2, 2f\n"				\
190
		"	addi	%0, #-4\n"				\
191
		"	.fillinsn\n"					\
192
		"0:	st	%6, @+%0	; word clear \n"	\
193
		"	addi	%2, #-1\n"				\
194
		"	bnez	%2, 0b\n"				\
195
		"	beqz	%1, 9f\n"				\
196
		"	.fillinsn\n"					\
197
		"2:	stb	%6, @%0		; byte clear \n"	\
198
		"	addi	%1, #-1\n"				\
199
		"	addi	%0, #1\n"				\
200
		"	bnez	%1, 2b\n"				\
201
		"	.fillinsn\n"					\
202
		"9:\n"							\
203
		".section .fixup,\"ax\"\n"				\
204
		"	.balign 4\n"					\
205
		"4:	slli	%2, #2\n"				\
206
		"	add	%1, %2\n"				\
207
		"	seth	r14, #high(9b)\n"			\
208
		"	or3	r14, r14, #low(9b)\n"			\
209
		"	jmp	r14\n"					\
210
		".previous\n"						\
211
		".section __ex_table,\"a\"\n"				\
212
		"	.balign 4\n"					\
213
		"	.long 0b,4b\n"					\
214
		"	.long 2b,9b\n"					\
215
		".previous\n"						\
216
		: "=&r"(__dst), "=&r"(size), "=&r"(__c)			\
217
		: "0"(addr), "1"(size), "2"(size / 4), "r"(0)		\
218
		: "r14", "cbit", "memory");				\
219
} while (0)
220

221
#endif /* not CONFIG_ISA_DUAL_ISSUE */
222

223
unsigned long
224
clear_user(void __user *to, unsigned long n)
225
{
226
	if (access_ok(VERIFY_WRITE, to, n))
227
		__do_clear_user(to, n);
228
	return n;
229
}
230

231
unsigned long
232
__clear_user(void __user *to, unsigned long n)
233
{
234
	__do_clear_user(to, n);
235
	return n;
236
}
237

238
/*
239
 * Return the size of a string (including the ending 0)
240
 *
241
 * Return 0 on exception, a value greater than N if too long
242
 */
243

244
#ifdef CONFIG_ISA_DUAL_ISSUE
245

246
long strnlen_user(const char __user *s, long n)
247
{
248
	unsigned long mask = -__addr_ok(s);
249
	unsigned long res;
250

251
	__asm__ __volatile__(
252
		"	and	%0, %5	    ||	mv	r1, %1\n"
253
		"	beqz	%0, strnlen_exit\n"
254
		"	and3	r0, %1, #3\n"
255
		"	bnez	r0, strnlen_byte_loop\n"
256
		"	cmpui	%0, #4\n"
257
		"	bc	strnlen_byte_loop\n"
258
		"strnlen_word_loop:\n"
259
		"0:	ld	r0, @%1+\n"
260
		"	pcmpbz	r0\n"
261
		"	bc	strnlen_last_bytes_fixup\n"
262
		"	addi	%0, #-4\n"
263
		"	beqz	%0, strnlen_exit\n"
264
		"	bgtz	%0, strnlen_word_loop\n"
265
		"strnlen_last_bytes:\n"
266
		"	mv	%0, %4\n"
267
		"strnlen_last_bytes_fixup:\n"
268
		"	addi	%1, #-4\n"
269
		"strnlen_byte_loop:\n"
270
		"1:	ldb	r0, @%1	    ||	addi	%0, #-1\n"
271
		"	beqz	r0, strnlen_exit\n"
272
		"	addi	%1, #1\n"
273
		"	bnez	%0, strnlen_byte_loop\n"
274
		"strnlen_exit:\n"
275
		"	sub	%1, r1\n"
276
		"	add3	%0, %1, #1\n"
277
		"	.fillinsn\n"
278
		"9:\n"
279
		".section .fixup,\"ax\"\n"
280
		"	.balign 4\n"
281
		"4:	addi	%1, #-4\n"
282
		"	.fillinsn\n"
283
		"5:	seth	r1, #high(9b)\n"
284
		"	or3	r1, r1, #low(9b)\n"
285
		"	jmp	r1	    ||	ldi	%0, #0\n"
286
		".previous\n"
287
		".section __ex_table,\"a\"\n"
288
		"	.balign 4\n"
289
		"	.long 0b,4b\n"
290
		"	.long 1b,5b\n"
291
		".previous"
292
		: "=&r" (res), "=r" (s)
293
		: "0" (n), "1" (s), "r" (n & 3), "r" (mask), "r"(0x01010101)
294
		: "r0", "r1", "cbit");
295

296
	/* NOTE: strnlen_user() algorithm:
297
	 * {
298
	 *   char *p;
299
	 *   for (p = s; n-- && *p != '\0'; ++p)
300
	 *     ;
301
	 *   return p - s + 1;
302
	 * }
303
	 */
304

305
	/* NOTE: If a null char. exists, return 0.
306
	 * if ((x - 0x01010101) & ~x & 0x80808080)\n"
307
	 *   return 0;\n"
308
	 */
309

310
	return res & mask;
311
}
312

313
#else /* not CONFIG_ISA_DUAL_ISSUE */
314

315
long strnlen_user(const char __user *s, long n)
316
{
317
	unsigned long mask = -__addr_ok(s);
318
	unsigned long res;
319

320
	__asm__ __volatile__(
321
		"	and	%0, %5\n"
322
		"	mv	r1, %1\n"
323
		"	beqz	%0, strnlen_exit\n"
324
		"	and3	r0, %1, #3\n"
325
		"	bnez	r0, strnlen_byte_loop\n"
326
		"	cmpui	%0, #4\n"
327
		"	bc	strnlen_byte_loop\n"
328
		"	sll3	r3, %6, #7\n"
329
		"strnlen_word_loop:\n"
330
		"0:	ld	r0, @%1+\n"
331
		"	not	r2, r0\n"
332
		"	sub	r0, %6\n"
333
		"	and	r2, r3\n"
334
		"	and	r2, r0\n"
335
		"	bnez	r2, strnlen_last_bytes_fixup\n"
336
		"	addi	%0, #-4\n"
337
		"	beqz	%0, strnlen_exit\n"
338
		"	bgtz	%0, strnlen_word_loop\n"
339
		"strnlen_last_bytes:\n"
340
		"	mv	%0, %4\n"
341
		"strnlen_last_bytes_fixup:\n"
342
		"	addi	%1, #-4\n"
343
		"strnlen_byte_loop:\n"
344
		"1:	ldb	r0, @%1\n"
345
		"	addi	%0, #-1\n"
346
		"	beqz	r0, strnlen_exit\n"
347
		"	addi	%1, #1\n"
348
		"	bnez	%0, strnlen_byte_loop\n"
349
		"strnlen_exit:\n"
350
		"	sub	%1, r1\n"
351
		"	add3	%0, %1, #1\n"
352
		"	.fillinsn\n"
353
		"9:\n"
354
		".section .fixup,\"ax\"\n"
355
		"	.balign 4\n"
356
		"4:	addi	%1, #-4\n"
357
		"	.fillinsn\n"
358
		"5:	ldi	%0, #0\n"
359
		"	seth	r1, #high(9b)\n"
360
		"	or3	r1, r1, #low(9b)\n"
361
		"	jmp	r1\n"
362
		".previous\n"
363
		".section __ex_table,\"a\"\n"
364
		"	.balign 4\n"
365
		"	.long 0b,4b\n"
366
		"	.long 1b,5b\n"
367
		".previous"
368
		: "=&r" (res), "=r" (s)
369
		: "0" (n), "1" (s), "r" (n & 3), "r" (mask), "r"(0x01010101)
370
		: "r0", "r1", "r2", "r3", "cbit");
371

372
	/* NOTE: strnlen_user() algorithm:
373
	 * {
374
	 *   char *p;
375
	 *   for (p = s; n-- && *p != '\0'; ++p)
376
	 *     ;
377
	 *   return p - s + 1;
378
	 * }
379
	 */
380

381
	/* NOTE: If a null char. exists, return 0.
382
	 * if ((x - 0x01010101) & ~x & 0x80808080)\n"
383
	 *   return 0;\n"
384
	 */
385

386
	return res & mask;
387
}
388

389
#endif /* CONFIG_ISA_DUAL_ISSUE */
390

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