1 /*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
7 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8 * Copyright (C) 2007 Maciej W. Rozycki
9 * Copyright (C) 2014, Imagination Technologies Ltd.
10 */
11 #ifndef _ASM_UACCESS_H
12 #define _ASM_UACCESS_H
13
14 #include <linux/kernel.h>
15 #include <linux/string.h>
16 #include <asm/asm-eva.h>
17 #include <asm/extable.h>
18
19 /*
20 * The fs value determines whether argument validity checking should be
21 * performed or not. If get_fs() == USER_DS, checking is performed, with
22 * get_fs() == KERNEL_DS, checking is bypassed.
23 *
24 * For historical reasons, these macros are grossly misnamed.
25 */
26 #ifdef CONFIG_32BIT
27
28 #ifdef CONFIG_KVM_GUEST
29 #define __UA_LIMIT 0x40000000UL
30 #else
31 #define __UA_LIMIT 0x80000000UL
32 #endif
33
34 #define __UA_ADDR ".word"
35 #define __UA_LA "la"
36 #define __UA_ADDU "addu"
37 #define __UA_t0 "$8"
38 #define __UA_t1 "$9"
39
40 #endif /* CONFIG_32BIT */
41
42 #ifdef CONFIG_64BIT
43
44 extern u64 __ua_limit;
45
46 #define __UA_LIMIT __ua_limit
47
48 #define __UA_ADDR ".dword"
49 #define __UA_LA "dla"
50 #define __UA_ADDU "daddu"
51 #define __UA_t0 "$12"
52 #define __UA_t1 "$13"
53
54 #endif /* CONFIG_64BIT */
55
56 /*
57 * USER_DS is a bitmask that has the bits set that may not be set in a valid
58 * userspace address. Note that we limit 32-bit userspace to 0x7fff8000 but
59 * the arithmetic we're doing only works if the limit is a power of two, so
60 * we use 0x80000000 here on 32-bit kernels. If a process passes an invalid
61 * address in this range it's the process's problem, not ours :-)
62 */
63
64 #ifdef CONFIG_KVM_GUEST
65 #define KERNEL_DS ((mm_segment_t) { 0x80000000UL })
66 #define USER_DS ((mm_segment_t) { 0xC0000000UL })
67 #else
68 #define KERNEL_DS ((mm_segment_t) { 0UL })
69 #define USER_DS ((mm_segment_t) { __UA_LIMIT })
70 #endif
71
72 #define get_fs() (current_thread_info()->addr_limit)
73 #define set_fs(x) (current_thread_info()->addr_limit = (x))
74
75 #define segment_eq(a, b) ((a).seg == (b).seg)
76
77 /*
78 * eva_kernel_access() - determine whether kernel memory access on an EVA system
79 *
80 * Determines whether memory accesses should be performed to kernel memory
81 * on a system using Extended Virtual Addressing (EVA).
82 *
83 * Return: true if a kernel memory access on an EVA system, else false.
84 */
85 static inline bool eva_kernel_access(void)
86 {
87 if (!IS_ENABLED(CONFIG_EVA))
88 return false;
89
90 return uaccess_kernel();
91 }
92
93 /*
94 * Is a address valid? This does a straightforward calculation rather
95 * than tests.
96 *
97 * Address valid if:
98 * - "addr" doesn't have any high-bits set
99 * - AND "size" doesn't have any high-bits set
100 * - AND "addr+size" doesn't have any high-bits set
101 * - OR we are in kernel mode.
102 *
103 * __ua_size() is a trick to avoid runtime checking of positive constant
104 * sizes; for those we already know at compile time that the size is ok.
105 */
106 #define __ua_size(size) \
107 ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
108
109 /*
110 * access_ok: - Checks if a user space pointer is valid
111 * @addr: User space pointer to start of block to check
112 * @size: Size of block to check
113 *
114 * Context: User context only. This function may sleep if pagefaults are
115 * enabled.
116 *
117 * Checks if a pointer to a block of memory in user space is valid.
118 *
119 * Returns true (nonzero) if the memory block may be valid, false (zero)
120 * if it is definitely invalid.
121 *
122 * Note that, depending on architecture, this function probably just
123 * checks that the pointer is in the user space range - after calling
124 * this function, memory access functions may still return -EFAULT.
125 */
126
127 static inline int __access_ok(const void __user *p, unsigned long size)
128 {
129 unsigned long addr = (unsigned long)p;
130 return (get_fs().seg & (addr | (addr + size) | __ua_size(size))) == 0;
131 }
132
133 #define access_ok(addr, size) \
134 likely(__access_ok((addr), (size)))
135
136 /*
137 * put_user: - Write a simple value into user space.
138 * @x: Value to copy to user space.
139 * @ptr: Destination address, in user space.
140 *
141 * Context: User context only. This function may sleep if pagefaults are
142 * enabled.
143 *
144 * This macro copies a single simple value from kernel space to user
145 * space. It supports simple types like char and int, but not larger
146 * data types like structures or arrays.
147 *
148 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
149 * to the result of dereferencing @ptr.
150 *
151 * Returns zero on success, or -EFAULT on error.
152 */
153 #define put_user(x,ptr) \
154 __put_user_check((x), (ptr), sizeof(*(ptr)))
155
156 /*
157 * get_user: - Get a simple variable from user space.
158 * @x: Variable to store result.
159 * @ptr: Source address, in user space.
160 *
161 * Context: User context only. This function may sleep if pagefaults are
162 * enabled.
163 *
164 * This macro copies a single simple variable from user space to kernel
165 * space. It supports simple types like char and int, but not larger
166 * data types like structures or arrays.
167 *
168 * @ptr must have pointer-to-simple-variable type, and the result of
169 * dereferencing @ptr must be assignable to @x without a cast.
170 *
171 * Returns zero on success, or -EFAULT on error.
172 * On error, the variable @x is set to zero.
173 */
174 #define get_user(x,ptr) \
175 __get_user_check((x), (ptr), sizeof(*(ptr)))
176
177 /*
178 * __put_user: - Write a simple value into user space, with less checking.
179 * @x: Value to copy to user space.
180 * @ptr: Destination address, in user space.
181 *
182 * Context: User context only. This function may sleep if pagefaults are
183 * enabled.
184 *
185 * This macro copies a single simple value from kernel space to user
186 * space. It supports simple types like char and int, but not larger
187 * data types like structures or arrays.
188 *
189 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
190 * to the result of dereferencing @ptr.
191 *
192 * Caller must check the pointer with access_ok() before calling this
193 * function.
194 *
195 * Returns zero on success, or -EFAULT on error.
196 */
197 #define __put_user(x,ptr) \
198 __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
199
200 /*
201 * __get_user: - Get a simple variable from user space, with less checking.
202 * @x: Variable to store result.
203 * @ptr: Source address, in user space.
204 *
205 * Context: User context only. This function may sleep if pagefaults are
206 * enabled.
207 *
208 * This macro copies a single simple variable from user space to kernel
209 * space. It supports simple types like char and int, but not larger
210 * data types like structures or arrays.
211 *
212 * @ptr must have pointer-to-simple-variable type, and the result of
213 * dereferencing @ptr must be assignable to @x without a cast.
214 *
215 * Caller must check the pointer with access_ok() before calling this
216 * function.
217 *
218 * Returns zero on success, or -EFAULT on error.
219 * On error, the variable @x is set to zero.
220 */
221 #define __get_user(x,ptr) \
222 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
223
224 struct __large_struct { unsigned long buf[100]; };
225 #define __m(x) (*(struct __large_struct __user *)(x))
226
227 /*
228 * Yuck. We need two variants, one for 64bit operation and one
229 * for 32 bit mode and old iron.
230 */
231 #ifndef CONFIG_EVA
232 #define __get_kernel_common(val, size, ptr) __get_user_common(val, size, ptr)
233 #else
234 /*
235 * Kernel specific functions for EVA. We need to use normal load instructions
236 * to read data from kernel when operating in EVA mode. We use these macros to
237 * avoid redefining __get_user_asm for EVA.
238 */
239 #undef _loadd
240 #undef _loadw
241 #undef _loadh
242 #undef _loadb
243 #ifdef CONFIG_32BIT
244 #define _loadd _loadw
245 #else
246 #define _loadd(reg, addr) "ld " reg ", " addr
247 #endif
248 #define _loadw(reg, addr) "lw " reg ", " addr
249 #define _loadh(reg, addr) "lh " reg ", " addr
250 #define _loadb(reg, addr) "lb " reg ", " addr
251
252 #define __get_kernel_common(val, size, ptr) \
253 do { \
254 switch (size) { \
255 case 1: __get_data_asm(val, _loadb, ptr); break; \
256 case 2: __get_data_asm(val, _loadh, ptr); break; \
257 case 4: __get_data_asm(val, _loadw, ptr); break; \
258 case 8: __GET_DW(val, _loadd, ptr); break; \
259 default: __get_user_unknown(); break; \
260 } \
261 } while (0)
262 #endif
263
264 #ifdef CONFIG_32BIT
265 #define __GET_DW(val, insn, ptr) __get_data_asm_ll32(val, insn, ptr)
266 #endif
267 #ifdef CONFIG_64BIT
268 #define __GET_DW(val, insn, ptr) __get_data_asm(val, insn, ptr)
269 #endif
270
271 extern void __get_user_unknown(void);
272
273 #define __get_user_common(val, size, ptr) \
274 do { \
275 switch (size) { \
276 case 1: __get_data_asm(val, user_lb, ptr); break; \
277 case 2: __get_data_asm(val, user_lh, ptr); break; \
278 case 4: __get_data_asm(val, user_lw, ptr); break; \
279 case 8: __GET_DW(val, user_ld, ptr); break; \
280 default: __get_user_unknown(); break; \
281 } \
282 } while (0)
283
284 #define __get_user_nocheck(x, ptr, size) \
285 ({ \
286 int __gu_err; \
287 \
288 if (eva_kernel_access()) { \
289 __get_kernel_common((x), size, ptr); \
290 } else { \
291 __chk_user_ptr(ptr); \
292 __get_user_common((x), size, ptr); \
293 } \
294 __gu_err; \
295 })
296
297 #define __get_user_check(x, ptr, size) \
298 ({ \
299 int __gu_err = -EFAULT; \
300 const __typeof__(*(ptr)) __user * __gu_ptr = (ptr); \
301 \
302 might_fault(); \
303 if (likely(access_ok( __gu_ptr, size))) { \
304 if (eva_kernel_access()) \
305 __get_kernel_common((x), size, __gu_ptr); \
306 else \
307 __get_user_common((x), size, __gu_ptr); \
308 } else \
309 (x) = 0; \
310 \
311 __gu_err; \
312 })
313
314 #define __get_data_asm(val, insn, addr) \
315 { \
316 long __gu_tmp; \
317 \
318 __asm__ __volatile__( \
319 "1: "insn("%1", "%3")" \n" \
320 "2: \n" \
321 " .insn \n" \
322 " .section .fixup,\"ax\" \n" \
323 "3: li %0, %4 \n" \
324 " move %1, $0 \n" \
325 " j 2b \n" \
326 " .previous \n" \
327 " .section __ex_table,\"a\" \n" \
328 " "__UA_ADDR "\t1b, 3b \n" \
329 " .previous \n" \
330 : "=r" (__gu_err), "=r" (__gu_tmp) \
331 : "0" (0), "o" (__m(addr)), "i" (-EFAULT)); \
332 \
333 (val) = (__typeof__(*(addr))) __gu_tmp; \
334 }
335
336 /*
337 * Get a long long 64 using 32 bit registers.
338 */
339 #define __get_data_asm_ll32(val, insn, addr) \
340 { \
341 union { \
342 unsigned long long l; \
343 __typeof__(*(addr)) t; \
344 } __gu_tmp; \
345 \
346 __asm__ __volatile__( \
347 "1: " insn("%1", "(%3)")" \n" \
348 "2: " insn("%D1", "4(%3)")" \n" \
349 "3: \n" \
350 " .insn \n" \
351 " .section .fixup,\"ax\" \n" \
352 "4: li %0, %4 \n" \
353 " move %1, $0 \n" \
354 " move %D1, $0 \n" \
355 " j 3b \n" \
356 " .previous \n" \
357 " .section __ex_table,\"a\" \n" \
358 " " __UA_ADDR " 1b, 4b \n" \
359 " " __UA_ADDR " 2b, 4b \n" \
360 " .previous \n" \
361 : "=r" (__gu_err), "=&r" (__gu_tmp.l) \
362 : "0" (0), "r" (addr), "i" (-EFAULT)); \
363 \
364 (val) = __gu_tmp.t; \
365 }
366
367 #ifndef CONFIG_EVA
368 #define __put_kernel_common(ptr, size) __put_user_common(ptr, size)
369 #else
370 /*
371 * Kernel specific functions for EVA. We need to use normal load instructions
372 * to read data from kernel when operating in EVA mode. We use these macros to
373 * avoid redefining __get_data_asm for EVA.
374 */
375 #undef _stored
376 #undef _storew
377 #undef _storeh
378 #undef _storeb
379 #ifdef CONFIG_32BIT
380 #define _stored _storew
381 #else
382 #define _stored(reg, addr) "ld " reg ", " addr
383 #endif
384
385 #define _storew(reg, addr) "sw " reg ", " addr
386 #define _storeh(reg, addr) "sh " reg ", " addr
387 #define _storeb(reg, addr) "sb " reg ", " addr
388
389 #define __put_kernel_common(ptr, size) \
390 do { \
391 switch (size) { \
392 case 1: __put_data_asm(_storeb, ptr); break; \
393 case 2: __put_data_asm(_storeh, ptr); break; \
394 case 4: __put_data_asm(_storew, ptr); break; \
395 case 8: __PUT_DW(_stored, ptr); break; \
396 default: __put_user_unknown(); break; \
397 } \
398 } while(0)
399 #endif
400
401 /*
402 * Yuck. We need two variants, one for 64bit operation and one
403 * for 32 bit mode and old iron.
404 */
405 #ifdef CONFIG_32BIT
406 #define __PUT_DW(insn, ptr) __put_data_asm_ll32(insn, ptr)
407 #endif
408 #ifdef CONFIG_64BIT
409 #define __PUT_DW(insn, ptr) __put_data_asm(insn, ptr)
410 #endif
411
412 #define __put_user_common(ptr, size) \
413 do { \
414 switch (size) { \
415 case 1: __put_data_asm(user_sb, ptr); break; \
416 case 2: __put_data_asm(user_sh, ptr); break; \
417 case 4: __put_data_asm(user_sw, ptr); break; \
418 case 8: __PUT_DW(user_sd, ptr); break; \
419 default: __put_user_unknown(); break; \
420 } \
421 } while (0)
422
423 #define __put_user_nocheck(x, ptr, size) \
424 ({ \
425 __typeof__(*(ptr)) __pu_val; \
426 int __pu_err = 0; \
427 \
428 __pu_val = (x); \
429 if (eva_kernel_access()) { \
430 __put_kernel_common(ptr, size); \
431 } else { \
432 __chk_user_ptr(ptr); \
433 __put_user_common(ptr, size); \
434 } \
435 __pu_err; \
436 })
437
438 #define __put_user_check(x, ptr, size) \
439 ({ \
440 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
441 __typeof__(*(ptr)) __pu_val = (x); \
442 int __pu_err = -EFAULT; \
443 \
444 might_fault(); \
445 if (likely(access_ok( __pu_addr, size))) { \
446 if (eva_kernel_access()) \
447 __put_kernel_common(__pu_addr, size); \
448 else \
449 __put_user_common(__pu_addr, size); \
450 } \
451 \
452 __pu_err; \
453 })
454
455 #define __put_data_asm(insn, ptr) \
456 { \
457 __asm__ __volatile__( \
458 "1: "insn("%z2", "%3")" # __put_data_asm \n" \
459 "2: \n" \
460 " .insn \n" \
461 " .section .fixup,\"ax\" \n" \
462 "3: li %0, %4 \n" \
463 " j 2b \n" \
464 " .previous \n" \
465 " .section __ex_table,\"a\" \n" \
466 " " __UA_ADDR " 1b, 3b \n" \
467 " .previous \n" \
468 : "=r" (__pu_err) \
469 : "0" (0), "Jr" (__pu_val), "o" (__m(ptr)), \
470 "i" (-EFAULT)); \
471 }
472
473 #define __put_data_asm_ll32(insn, ptr) \
474 { \
475 __asm__ __volatile__( \
476 "1: "insn("%2", "(%3)")" # __put_data_asm_ll32 \n" \
477 "2: "insn("%D2", "4(%3)")" \n" \
478 "3: \n" \
479 " .insn \n" \
480 " .section .fixup,\"ax\" \n" \
481 "4: li %0, %4 \n" \
482 " j 3b \n" \
483 " .previous \n" \
484 " .section __ex_table,\"a\" \n" \
485 " " __UA_ADDR " 1b, 4b \n" \
486 " " __UA_ADDR " 2b, 4b \n" \
487 " .previous" \
488 : "=r" (__pu_err) \
489 : "0" (0), "r" (__pu_val), "r" (ptr), \
490 "i" (-EFAULT)); \
491 }
492
493 extern void __put_user_unknown(void);
494
495 /*
496 * We're generating jump to subroutines which will be outside the range of
497 * jump instructions
498 */
499 #ifdef MODULE
500 #define __MODULE_JAL(destination) \
501 ".set\tnoat\n\t" \
502 __UA_LA "\t$1, " #destination "\n\t" \
503 "jalr\t$1\n\t" \
504 ".set\tat\n\t"
505 #else
506 #define __MODULE_JAL(destination) \
507 "jal\t" #destination "\n\t"
508 #endif
509
510 #if defined(CONFIG_CPU_DADDI_WORKAROUNDS) || (defined(CONFIG_EVA) && \
511 defined(CONFIG_CPU_HAS_PREFETCH))
512 #define DADDI_SCRATCH "$3"
513 #else
514 #define DADDI_SCRATCH "$0"
515 #endif
516
517 extern size_t __copy_user(void *__to, const void *__from, size_t __n);
518
519 #define __invoke_copy_from(func, to, from, n) \
520 ({ \
521 register void *__cu_to_r __asm__("$4"); \
522 register const void __user *__cu_from_r __asm__("$5"); \
523 register long __cu_len_r __asm__("$6"); \
524 \
525 __cu_to_r = (to); \
526 __cu_from_r = (from); \
527 __cu_len_r = (n); \
528 __asm__ __volatile__( \
529 ".set\tnoreorder\n\t" \
530 __MODULE_JAL(func) \
531 ".set\tnoat\n\t" \
532 __UA_ADDU "\t$1, %1, %2\n\t" \
533 ".set\tat\n\t" \
534 ".set\treorder" \
535 : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r) \
536 : \
537 : "$8", "$9", "$10", "$11", "$12", "$14", "$15", "$24", "$31", \
538 DADDI_SCRATCH, "memory"); \
539 __cu_len_r; \
540 })
541
542 #define __invoke_copy_to(func, to, from, n) \
543 ({ \
544 register void __user *__cu_to_r __asm__("$4"); \
545 register const void *__cu_from_r __asm__("$5"); \
546 register long __cu_len_r __asm__("$6"); \
547 \
548 __cu_to_r = (to); \
549 __cu_from_r = (from); \
550 __cu_len_r = (n); \
551 __asm__ __volatile__( \
552 __MODULE_JAL(func) \
553 : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r) \
554 : \
555 : "$8", "$9", "$10", "$11", "$12", "$14", "$15", "$24", "$31", \
556 DADDI_SCRATCH, "memory"); \
557 __cu_len_r; \
558 })
559
560 #define __invoke_copy_from_kernel(to, from, n) \
561 __invoke_copy_from(__copy_user, to, from, n)
562
563 #define __invoke_copy_to_kernel(to, from, n) \
564 __invoke_copy_to(__copy_user, to, from, n)
565
566 #define ___invoke_copy_in_kernel(to, from, n) \
567 __invoke_copy_from(__copy_user, to, from, n)
568
569 #ifndef CONFIG_EVA
570 #define __invoke_copy_from_user(to, from, n) \
571 __invoke_copy_from(__copy_user, to, from, n)
572
573 #define __invoke_copy_to_user(to, from, n) \
574 __invoke_copy_to(__copy_user, to, from, n)
575
576 #define ___invoke_copy_in_user(to, from, n) \
577 __invoke_copy_from(__copy_user, to, from, n)
578
579 #else
580
581 /* EVA specific functions */
582
583 extern size_t __copy_from_user_eva(void *__to, const void *__from,
584 size_t __n);
585 extern size_t __copy_to_user_eva(void *__to, const void *__from,
586 size_t __n);
587 extern size_t __copy_in_user_eva(void *__to, const void *__from, size_t __n);
588
589 /*
590 * Source or destination address is in userland. We need to go through
591 * the TLB
592 */
593 #define __invoke_copy_from_user(to, from, n) \
594 __invoke_copy_from(__copy_from_user_eva, to, from, n)
595
596 #define __invoke_copy_to_user(to, from, n) \
597 __invoke_copy_to(__copy_to_user_eva, to, from, n)
598
599 #define ___invoke_copy_in_user(to, from, n) \
600 __invoke_copy_from(__copy_in_user_eva, to, from, n)
601
602 #endif /* CONFIG_EVA */
603
604 static inline unsigned long
605 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
606 {
607 if (eva_kernel_access())
608 return __invoke_copy_to_kernel(to, from, n);
609 else
610 return __invoke_copy_to_user(to, from, n);
611 }
612
613 static inline unsigned long
614 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
615 {
616 if (eva_kernel_access())
617 return __invoke_copy_from_kernel(to, from, n);
618 else
619 return __invoke_copy_from_user(to, from, n);
620 }
621
622 #define INLINE_COPY_FROM_USER
623 #define INLINE_COPY_TO_USER
624
625 static inline unsigned long
626 raw_copy_in_user(void __user*to, const void __user *from, unsigned long n)
627 {
628 if (eva_kernel_access())
629 return ___invoke_copy_in_kernel(to, from, n);
630 else
631 return ___invoke_copy_in_user(to, from, n);
632 }
633
634 extern __kernel_size_t __bzero_kernel(void __user *addr, __kernel_size_t size);
635 extern __kernel_size_t __bzero(void __user *addr, __kernel_size_t size);
636
637 /*
638 * __clear_user: - Zero a block of memory in user space, with less checking.
639 * @to: Destination address, in user space.
640 * @n: Number of bytes to zero.
641 *
642 * Zero a block of memory in user space. Caller must check
643 * the specified block with access_ok() before calling this function.
644 *
645 * Returns number of bytes that could not be cleared.
646 * On success, this will be zero.
647 */
648 static inline __kernel_size_t
649 __clear_user(void __user *addr, __kernel_size_t size)
650 {
651 __kernel_size_t res;
652
653 #ifdef CONFIG_CPU_MICROMIPS
654 /* micromips memset / bzero also clobbers t7 & t8 */
655 #define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$15", "$24", "$31"
656 #else
657 #define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$31"
658 #endif /* CONFIG_CPU_MICROMIPS */
659
660 if (eva_kernel_access()) {
661 __asm__ __volatile__(
662 "move\t$4, %1\n\t"
663 "move\t$5, $0\n\t"
664 "move\t$6, %2\n\t"
665 __MODULE_JAL(__bzero_kernel)
666 "move\t%0, $6"
667 : "=r" (res)
668 : "r" (addr), "r" (size)
669 : bzero_clobbers);
670 } else {
671 might_fault();
672 __asm__ __volatile__(
673 "move\t$4, %1\n\t"
674 "move\t$5, $0\n\t"
675 "move\t$6, %2\n\t"
676 __MODULE_JAL(__bzero)
677 "move\t%0, $6"
678 : "=r" (res)
679 : "r" (addr), "r" (size)
680 : bzero_clobbers);
681 }
682
683 return res;
684 }
685
686 #define clear_user(addr,n) \
687 ({ \
688 void __user * __cl_addr = (addr); \
689 unsigned long __cl_size = (n); \
690 if (__cl_size && access_ok(__cl_addr, __cl_size)) \
691 __cl_size = __clear_user(__cl_addr, __cl_size); \
692 __cl_size; \
693 })
694
695 extern long __strncpy_from_kernel_asm(char *__to, const char __user *__from, long __len);
696 extern long __strncpy_from_user_asm(char *__to, const char __user *__from, long __len);
697
698 /*
699 * strncpy_from_user: - Copy a NUL terminated string from userspace.
700 * @dst: Destination address, in kernel space. This buffer must be at
701 * least @count bytes long.
702 * @src: Source address, in user space.
703 * @count: Maximum number of bytes to copy, including the trailing NUL.
704 *
705 * Copies a NUL-terminated string from userspace to kernel space.
706 *
707 * On success, returns the length of the string (not including the trailing
708 * NUL).
709 *
710 * If access to userspace fails, returns -EFAULT (some data may have been
711 * copied).
712 *
713 * If @count is smaller than the length of the string, copies @count bytes
714 * and returns @count.
715 */
716 static inline long
717 strncpy_from_user(char *__to, const char __user *__from, long __len)
718 {
719 long res;
720
721 if (eva_kernel_access()) {
722 __asm__ __volatile__(
723 "move\t$4, %1\n\t"
724 "move\t$5, %2\n\t"
725 "move\t$6, %3\n\t"
726 __MODULE_JAL(__strncpy_from_kernel_asm)
727 "move\t%0, $2"
728 : "=r" (res)
729 : "r" (__to), "r" (__from), "r" (__len)
730 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
731 } else {
732 might_fault();
733 __asm__ __volatile__(
734 "move\t$4, %1\n\t"
735 "move\t$5, %2\n\t"
736 "move\t$6, %3\n\t"
737 __MODULE_JAL(__strncpy_from_user_asm)
738 "move\t%0, $2"
739 : "=r" (res)
740 : "r" (__to), "r" (__from), "r" (__len)
741 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
742 }
743
744 return res;
745 }
746
747 extern long __strnlen_kernel_asm(const char __user *s, long n);
748 extern long __strnlen_user_asm(const char __user *s, long n);
749
750 /*
751 * strnlen_user: - Get the size of a string in user space.
752 * @str: The string to measure.
753 *
754 * Context: User context only. This function may sleep if pagefaults are
755 * enabled.
756 *
757 * Get the size of a NUL-terminated string in user space.
758 *
759 * Returns the size of the string INCLUDING the terminating NUL.
760 * On exception, returns 0.
761 * If the string is too long, returns a value greater than @n.
762 */
763 static inline long strnlen_user(const char __user *s, long n)
764 {
765 long res;
766
767 might_fault();
768 if (eva_kernel_access()) {
769 __asm__ __volatile__(
770 "move\t$4, %1\n\t"
771 "move\t$5, %2\n\t"
772 __MODULE_JAL(__strnlen_kernel_asm)
773 "move\t%0, $2"
774 : "=r" (res)
775 : "r" (s), "r" (n)
776 : "$2", "$4", "$5", __UA_t0, "$31");
777 } else {
778 __asm__ __volatile__(
779 "move\t$4, %1\n\t"
780 "move\t$5, %2\n\t"
781 __MODULE_JAL(__strnlen_user_asm)
782 "move\t%0, $2"
783 : "=r" (res)
784 : "r" (s), "r" (n)
785 : "$2", "$4", "$5", __UA_t0, "$31");
786 }
787
788 return res;
789 }
790
791 #endif /* _ASM_UACCESS_H */