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Merge tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
[deliverable/linux.git] / arch / arm / include / asm / uaccess.h
1 /*
2 * arch/arm/include/asm/uaccess.h
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8 #ifndef _ASMARM_UACCESS_H
9 #define _ASMARM_UACCESS_H
10
11 /*
12 * User space memory access functions
13 */
14 #include <linux/string.h>
15 #include <linux/thread_info.h>
16 #include <asm/errno.h>
17 #include <asm/memory.h>
18 #include <asm/domain.h>
19 #include <asm/unified.h>
20 #include <asm/compiler.h>
21
22 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
23 #include <asm-generic/uaccess-unaligned.h>
24 #else
25 #define __get_user_unaligned __get_user
26 #define __put_user_unaligned __put_user
27 #endif
28
29 #define VERIFY_READ 0
30 #define VERIFY_WRITE 1
31
32 /*
33 * The exception table consists of pairs of addresses: the first is the
34 * address of an instruction that is allowed to fault, and the second is
35 * the address at which the program should continue. No registers are
36 * modified, so it is entirely up to the continuation code to figure out
37 * what to do.
38 *
39 * All the routines below use bits of fixup code that are out of line
40 * with the main instruction path. This means when everything is well,
41 * we don't even have to jump over them. Further, they do not intrude
42 * on our cache or tlb entries.
43 */
44
45 struct exception_table_entry
46 {
47 unsigned long insn, fixup;
48 };
49
50 extern int fixup_exception(struct pt_regs *regs);
51
52 /*
53 * These two functions allow hooking accesses to userspace to increase
54 * system integrity by ensuring that the kernel can not inadvertantly
55 * perform such accesses (eg, via list poison values) which could then
56 * be exploited for priviledge escalation.
57 */
58 static inline unsigned int uaccess_save_and_enable(void)
59 {
60 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
61 unsigned int old_domain = get_domain();
62
63 /* Set the current domain access to permit user accesses */
64 set_domain((old_domain & ~domain_mask(DOMAIN_USER)) |
65 domain_val(DOMAIN_USER, DOMAIN_CLIENT));
66
67 return old_domain;
68 #else
69 return 0;
70 #endif
71 }
72
73 static inline void uaccess_restore(unsigned int flags)
74 {
75 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
76 /* Restore the user access mask */
77 set_domain(flags);
78 #endif
79 }
80
81 /*
82 * These two are intentionally not defined anywhere - if the kernel
83 * code generates any references to them, that's a bug.
84 */
85 extern int __get_user_bad(void);
86 extern int __put_user_bad(void);
87
88 /*
89 * Note that this is actually 0x1,0000,0000
90 */
91 #define KERNEL_DS 0x00000000
92 #define get_ds() (KERNEL_DS)
93
94 #ifdef CONFIG_MMU
95
96 #define USER_DS TASK_SIZE
97 #define get_fs() (current_thread_info()->addr_limit)
98
99 static inline void set_fs(mm_segment_t fs)
100 {
101 current_thread_info()->addr_limit = fs;
102 modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
103 }
104
105 #define segment_eq(a, b) ((a) == (b))
106
107 /* We use 33-bit arithmetic here... */
108 #define __range_ok(addr, size) ({ \
109 unsigned long flag, roksum; \
110 __chk_user_ptr(addr); \
111 __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
112 : "=&r" (flag), "=&r" (roksum) \
113 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
114 : "cc"); \
115 flag; })
116
117 /*
118 * Single-value transfer routines. They automatically use the right
119 * size if we just have the right pointer type. Note that the functions
120 * which read from user space (*get_*) need to take care not to leak
121 * kernel data even if the calling code is buggy and fails to check
122 * the return value. This means zeroing out the destination variable
123 * or buffer on error. Normally this is done out of line by the
124 * fixup code, but there are a few places where it intrudes on the
125 * main code path. When we only write to user space, there is no
126 * problem.
127 */
128 extern int __get_user_1(void *);
129 extern int __get_user_2(void *);
130 extern int __get_user_4(void *);
131 extern int __get_user_32t_8(void *);
132 extern int __get_user_8(void *);
133 extern int __get_user_64t_1(void *);
134 extern int __get_user_64t_2(void *);
135 extern int __get_user_64t_4(void *);
136
137 #define __GUP_CLOBBER_1 "lr", "cc"
138 #ifdef CONFIG_CPU_USE_DOMAINS
139 #define __GUP_CLOBBER_2 "ip", "lr", "cc"
140 #else
141 #define __GUP_CLOBBER_2 "lr", "cc"
142 #endif
143 #define __GUP_CLOBBER_4 "lr", "cc"
144 #define __GUP_CLOBBER_32t_8 "lr", "cc"
145 #define __GUP_CLOBBER_8 "lr", "cc"
146
147 #define __get_user_x(__r2, __p, __e, __l, __s) \
148 __asm__ __volatile__ ( \
149 __asmeq("%0", "r0") __asmeq("%1", "r2") \
150 __asmeq("%3", "r1") \
151 "bl __get_user_" #__s \
152 : "=&r" (__e), "=r" (__r2) \
153 : "0" (__p), "r" (__l) \
154 : __GUP_CLOBBER_##__s)
155
156 /* narrowing a double-word get into a single 32bit word register: */
157 #ifdef __ARMEB__
158 #define __get_user_x_32t(__r2, __p, __e, __l, __s) \
159 __get_user_x(__r2, __p, __e, __l, 32t_8)
160 #else
161 #define __get_user_x_32t __get_user_x
162 #endif
163
164 /*
165 * storing result into proper least significant word of 64bit target var,
166 * different only for big endian case where 64 bit __r2 lsw is r3:
167 */
168 #ifdef __ARMEB__
169 #define __get_user_x_64t(__r2, __p, __e, __l, __s) \
170 __asm__ __volatile__ ( \
171 __asmeq("%0", "r0") __asmeq("%1", "r2") \
172 __asmeq("%3", "r1") \
173 "bl __get_user_64t_" #__s \
174 : "=&r" (__e), "=r" (__r2) \
175 : "0" (__p), "r" (__l) \
176 : __GUP_CLOBBER_##__s)
177 #else
178 #define __get_user_x_64t __get_user_x
179 #endif
180
181
182 #define __get_user_check(x, p) \
183 ({ \
184 unsigned long __limit = current_thread_info()->addr_limit - 1; \
185 register const typeof(*(p)) __user *__p asm("r0") = (p);\
186 register typeof(x) __r2 asm("r2"); \
187 register unsigned long __l asm("r1") = __limit; \
188 register int __e asm("r0"); \
189 unsigned int __ua_flags = uaccess_save_and_enable(); \
190 switch (sizeof(*(__p))) { \
191 case 1: \
192 if (sizeof((x)) >= 8) \
193 __get_user_x_64t(__r2, __p, __e, __l, 1); \
194 else \
195 __get_user_x(__r2, __p, __e, __l, 1); \
196 break; \
197 case 2: \
198 if (sizeof((x)) >= 8) \
199 __get_user_x_64t(__r2, __p, __e, __l, 2); \
200 else \
201 __get_user_x(__r2, __p, __e, __l, 2); \
202 break; \
203 case 4: \
204 if (sizeof((x)) >= 8) \
205 __get_user_x_64t(__r2, __p, __e, __l, 4); \
206 else \
207 __get_user_x(__r2, __p, __e, __l, 4); \
208 break; \
209 case 8: \
210 if (sizeof((x)) < 8) \
211 __get_user_x_32t(__r2, __p, __e, __l, 4); \
212 else \
213 __get_user_x(__r2, __p, __e, __l, 8); \
214 break; \
215 default: __e = __get_user_bad(); break; \
216 } \
217 uaccess_restore(__ua_flags); \
218 x = (typeof(*(p))) __r2; \
219 __e; \
220 })
221
222 #define get_user(x, p) \
223 ({ \
224 might_fault(); \
225 __get_user_check(x, p); \
226 })
227
228 extern int __put_user_1(void *, unsigned int);
229 extern int __put_user_2(void *, unsigned int);
230 extern int __put_user_4(void *, unsigned int);
231 extern int __put_user_8(void *, unsigned long long);
232
233 #define __put_user_check(__pu_val, __ptr, __err, __s) \
234 ({ \
235 unsigned long __limit = current_thread_info()->addr_limit - 1; \
236 register typeof(__pu_val) __r2 asm("r2") = __pu_val; \
237 register const void __user *__p asm("r0") = __ptr; \
238 register unsigned long __l asm("r1") = __limit; \
239 register int __e asm("r0"); \
240 __asm__ __volatile__ ( \
241 __asmeq("%0", "r0") __asmeq("%2", "r2") \
242 __asmeq("%3", "r1") \
243 "bl __put_user_" #__s \
244 : "=&r" (__e) \
245 : "0" (__p), "r" (__r2), "r" (__l) \
246 : "ip", "lr", "cc"); \
247 __err = __e; \
248 })
249
250 #else /* CONFIG_MMU */
251
252 /*
253 * uClinux has only one addr space, so has simplified address limits.
254 */
255 #define USER_DS KERNEL_DS
256
257 #define segment_eq(a, b) (1)
258 #define __addr_ok(addr) ((void)(addr), 1)
259 #define __range_ok(addr, size) ((void)(addr), 0)
260 #define get_fs() (KERNEL_DS)
261
262 static inline void set_fs(mm_segment_t fs)
263 {
264 }
265
266 #define get_user(x, p) __get_user(x, p)
267 #define __put_user_check __put_user_nocheck
268
269 #endif /* CONFIG_MMU */
270
271 #define access_ok(type, addr, size) (__range_ok(addr, size) == 0)
272
273 #define user_addr_max() \
274 (segment_eq(get_fs(), KERNEL_DS) ? ~0UL : get_fs())
275
276 /*
277 * The "__xxx" versions of the user access functions do not verify the
278 * address space - it must have been done previously with a separate
279 * "access_ok()" call.
280 *
281 * The "xxx_error" versions set the third argument to EFAULT if an
282 * error occurs, and leave it unchanged on success. Note that these
283 * versions are void (ie, don't return a value as such).
284 */
285 #define __get_user(x, ptr) \
286 ({ \
287 long __gu_err = 0; \
288 __get_user_err((x), (ptr), __gu_err); \
289 __gu_err; \
290 })
291
292 #define __get_user_error(x, ptr, err) \
293 ({ \
294 __get_user_err((x), (ptr), err); \
295 (void) 0; \
296 })
297
298 #define __get_user_err(x, ptr, err) \
299 do { \
300 unsigned long __gu_addr = (unsigned long)(ptr); \
301 unsigned long __gu_val; \
302 unsigned int __ua_flags; \
303 __chk_user_ptr(ptr); \
304 might_fault(); \
305 __ua_flags = uaccess_save_and_enable(); \
306 switch (sizeof(*(ptr))) { \
307 case 1: __get_user_asm_byte(__gu_val, __gu_addr, err); break; \
308 case 2: __get_user_asm_half(__gu_val, __gu_addr, err); break; \
309 case 4: __get_user_asm_word(__gu_val, __gu_addr, err); break; \
310 default: (__gu_val) = __get_user_bad(); \
311 } \
312 uaccess_restore(__ua_flags); \
313 (x) = (__typeof__(*(ptr)))__gu_val; \
314 } while (0)
315
316 #define __get_user_asm(x, addr, err, instr) \
317 __asm__ __volatile__( \
318 "1: " TUSER(instr) " %1, [%2], #0\n" \
319 "2:\n" \
320 " .pushsection .text.fixup,\"ax\"\n" \
321 " .align 2\n" \
322 "3: mov %0, %3\n" \
323 " mov %1, #0\n" \
324 " b 2b\n" \
325 " .popsection\n" \
326 " .pushsection __ex_table,\"a\"\n" \
327 " .align 3\n" \
328 " .long 1b, 3b\n" \
329 " .popsection" \
330 : "+r" (err), "=&r" (x) \
331 : "r" (addr), "i" (-EFAULT) \
332 : "cc")
333
334 #define __get_user_asm_byte(x, addr, err) \
335 __get_user_asm(x, addr, err, ldrb)
336
337 #ifndef __ARMEB__
338 #define __get_user_asm_half(x, __gu_addr, err) \
339 ({ \
340 unsigned long __b1, __b2; \
341 __get_user_asm_byte(__b1, __gu_addr, err); \
342 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
343 (x) = __b1 | (__b2 << 8); \
344 })
345 #else
346 #define __get_user_asm_half(x, __gu_addr, err) \
347 ({ \
348 unsigned long __b1, __b2; \
349 __get_user_asm_byte(__b1, __gu_addr, err); \
350 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
351 (x) = (__b1 << 8) | __b2; \
352 })
353 #endif
354
355 #define __get_user_asm_word(x, addr, err) \
356 __get_user_asm(x, addr, err, ldr)
357
358
359 #define __put_user_switch(x, ptr, __err, __fn) \
360 do { \
361 const __typeof__(*(ptr)) __user *__pu_ptr = (ptr); \
362 __typeof__(*(ptr)) __pu_val = (x); \
363 unsigned int __ua_flags; \
364 might_fault(); \
365 __ua_flags = uaccess_save_and_enable(); \
366 switch (sizeof(*(ptr))) { \
367 case 1: __fn(__pu_val, __pu_ptr, __err, 1); break; \
368 case 2: __fn(__pu_val, __pu_ptr, __err, 2); break; \
369 case 4: __fn(__pu_val, __pu_ptr, __err, 4); break; \
370 case 8: __fn(__pu_val, __pu_ptr, __err, 8); break; \
371 default: __err = __put_user_bad(); break; \
372 } \
373 uaccess_restore(__ua_flags); \
374 } while (0)
375
376 #define put_user(x, ptr) \
377 ({ \
378 int __pu_err = 0; \
379 __put_user_switch((x), (ptr), __pu_err, __put_user_check); \
380 __pu_err; \
381 })
382
383 #define __put_user(x, ptr) \
384 ({ \
385 long __pu_err = 0; \
386 __put_user_switch((x), (ptr), __pu_err, __put_user_nocheck); \
387 __pu_err; \
388 })
389
390 #define __put_user_error(x, ptr, err) \
391 ({ \
392 __put_user_switch((x), (ptr), (err), __put_user_nocheck); \
393 (void) 0; \
394 })
395
396 #define __put_user_nocheck(x, __pu_ptr, __err, __size) \
397 do { \
398 unsigned long __pu_addr = (unsigned long)__pu_ptr; \
399 __put_user_nocheck_##__size(x, __pu_addr, __err); \
400 } while (0)
401
402 #define __put_user_nocheck_1 __put_user_asm_byte
403 #define __put_user_nocheck_2 __put_user_asm_half
404 #define __put_user_nocheck_4 __put_user_asm_word
405 #define __put_user_nocheck_8 __put_user_asm_dword
406
407 #define __put_user_asm(x, __pu_addr, err, instr) \
408 __asm__ __volatile__( \
409 "1: " TUSER(instr) " %1, [%2], #0\n" \
410 "2:\n" \
411 " .pushsection .text.fixup,\"ax\"\n" \
412 " .align 2\n" \
413 "3: mov %0, %3\n" \
414 " b 2b\n" \
415 " .popsection\n" \
416 " .pushsection __ex_table,\"a\"\n" \
417 " .align 3\n" \
418 " .long 1b, 3b\n" \
419 " .popsection" \
420 : "+r" (err) \
421 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
422 : "cc")
423
424 #define __put_user_asm_byte(x, __pu_addr, err) \
425 __put_user_asm(x, __pu_addr, err, strb)
426
427 #ifndef __ARMEB__
428 #define __put_user_asm_half(x, __pu_addr, err) \
429 ({ \
430 unsigned long __temp = (__force unsigned long)(x); \
431 __put_user_asm_byte(__temp, __pu_addr, err); \
432 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \
433 })
434 #else
435 #define __put_user_asm_half(x, __pu_addr, err) \
436 ({ \
437 unsigned long __temp = (__force unsigned long)(x); \
438 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \
439 __put_user_asm_byte(__temp, __pu_addr + 1, err); \
440 })
441 #endif
442
443 #define __put_user_asm_word(x, __pu_addr, err) \
444 __put_user_asm(x, __pu_addr, err, str)
445
446 #ifndef __ARMEB__
447 #define __reg_oper0 "%R2"
448 #define __reg_oper1 "%Q2"
449 #else
450 #define __reg_oper0 "%Q2"
451 #define __reg_oper1 "%R2"
452 #endif
453
454 #define __put_user_asm_dword(x, __pu_addr, err) \
455 __asm__ __volatile__( \
456 ARM( "1: " TUSER(str) " " __reg_oper1 ", [%1], #4\n" ) \
457 ARM( "2: " TUSER(str) " " __reg_oper0 ", [%1]\n" ) \
458 THUMB( "1: " TUSER(str) " " __reg_oper1 ", [%1]\n" ) \
459 THUMB( "2: " TUSER(str) " " __reg_oper0 ", [%1, #4]\n" ) \
460 "3:\n" \
461 " .pushsection .text.fixup,\"ax\"\n" \
462 " .align 2\n" \
463 "4: mov %0, %3\n" \
464 " b 3b\n" \
465 " .popsection\n" \
466 " .pushsection __ex_table,\"a\"\n" \
467 " .align 3\n" \
468 " .long 1b, 4b\n" \
469 " .long 2b, 4b\n" \
470 " .popsection" \
471 : "+r" (err), "+r" (__pu_addr) \
472 : "r" (x), "i" (-EFAULT) \
473 : "cc")
474
475
476 #ifdef CONFIG_MMU
477 extern unsigned long __must_check
478 arm_copy_from_user(void *to, const void __user *from, unsigned long n);
479
480 static inline unsigned long __must_check
481 __copy_from_user(void *to, const void __user *from, unsigned long n)
482 {
483 unsigned int __ua_flags;
484
485 check_object_size(to, n, false);
486 __ua_flags = uaccess_save_and_enable();
487 n = arm_copy_from_user(to, from, n);
488 uaccess_restore(__ua_flags);
489 return n;
490 }
491
492 extern unsigned long __must_check
493 arm_copy_to_user(void __user *to, const void *from, unsigned long n);
494 extern unsigned long __must_check
495 __copy_to_user_std(void __user *to, const void *from, unsigned long n);
496
497 static inline unsigned long __must_check
498 __copy_to_user(void __user *to, const void *from, unsigned long n)
499 {
500 #ifndef CONFIG_UACCESS_WITH_MEMCPY
501 unsigned int __ua_flags;
502
503 check_object_size(from, n, true);
504 __ua_flags = uaccess_save_and_enable();
505 n = arm_copy_to_user(to, from, n);
506 uaccess_restore(__ua_flags);
507 return n;
508 #else
509 check_object_size(from, n, true);
510 return arm_copy_to_user(to, from, n);
511 #endif
512 }
513
514 extern unsigned long __must_check
515 arm_clear_user(void __user *addr, unsigned long n);
516 extern unsigned long __must_check
517 __clear_user_std(void __user *addr, unsigned long n);
518
519 static inline unsigned long __must_check
520 __clear_user(void __user *addr, unsigned long n)
521 {
522 unsigned int __ua_flags = uaccess_save_and_enable();
523 n = arm_clear_user(addr, n);
524 uaccess_restore(__ua_flags);
525 return n;
526 }
527
528 #else
529 #define __copy_from_user(to, from, n) (memcpy(to, (void __force *)from, n), 0)
530 #define __copy_to_user(to, from, n) (memcpy((void __force *)to, from, n), 0)
531 #define __clear_user(addr, n) (memset((void __force *)addr, 0, n), 0)
532 #endif
533
534 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
535 {
536 if (access_ok(VERIFY_READ, from, n))
537 n = __copy_from_user(to, from, n);
538 else /* security hole - plug it */
539 memset(to, 0, n);
540 return n;
541 }
542
543 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
544 {
545 if (access_ok(VERIFY_WRITE, to, n))
546 n = __copy_to_user(to, from, n);
547 return n;
548 }
549
550 #define __copy_to_user_inatomic __copy_to_user
551 #define __copy_from_user_inatomic __copy_from_user
552
553 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
554 {
555 if (access_ok(VERIFY_WRITE, to, n))
556 n = __clear_user(to, n);
557 return n;
558 }
559
560 /* These are from lib/ code, and use __get_user() and friends */
561 extern long strncpy_from_user(char *dest, const char __user *src, long count);
562
563 extern __must_check long strlen_user(const char __user *str);
564 extern __must_check long strnlen_user(const char __user *str, long n);
565
566 #endif /* _ASMARM_UACCESS_H */
Linux kernel - Deliverables
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