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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / arch / arm / include / asm / uaccess.h
blob98c6b91be4a8addd8212a3f170927e259ffb0e0d
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * arch/arm/include/asm/uaccess.h
4 */
5 #ifndef _ASMARM_UACCESS_H
6 #define _ASMARM_UACCESS_H
7
8 /*
9 * User space memory access functions
10 */
11 #include <linux/string.h>
12 #include <asm/memory.h>
13 #include <asm/domain.h>
14 #include <asm/unified.h>
15 #include <asm/compiler.h>
16
17 #include <asm/extable.h>
18
19 /*
20 * These two functions allow hooking accesses to userspace to increase
21 * system integrity by ensuring that the kernel can not inadvertantly
22 * perform such accesses (eg, via list poison values) which could then
23 * be exploited for priviledge escalation.
24 */
25 static __always_inline unsigned int uaccess_save_and_enable(void)
26 {
27 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
28 unsigned int old_domain = get_domain();
29
30 /* Set the current domain access to permit user accesses */
31 set_domain((old_domain & ~domain_mask(DOMAIN_USER)) |
32 domain_val(DOMAIN_USER, DOMAIN_CLIENT));
33
34 return old_domain;
35 #else
36 return 0;
37 #endif
38 }
39
40 static __always_inline void uaccess_restore(unsigned int flags)
41 {
42 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
43 /* Restore the user access mask */
44 set_domain(flags);
45 #endif
46 }
47
48 /*
49 * These two are intentionally not defined anywhere - if the kernel
50 * code generates any references to them, that's a bug.
51 */
52 extern int __get_user_bad(void);
53 extern int __put_user_bad(void);
54
55 /*
56 * Note that this is actually 0x1,0000,0000
57 */
58 #define KERNEL_DS 0x00000000
59
60 #ifdef CONFIG_MMU
61
62 #define USER_DS TASK_SIZE
63 #define get_fs() (current_thread_info()->addr_limit)
64
65 static inline void set_fs(mm_segment_t fs)
66 {
67 current_thread_info()->addr_limit = fs;
68
69 /*
70 * Prevent a mispredicted conditional call to set_fs from forwarding
71 * the wrong address limit to access_ok under speculation.
72 */
73 dsb(nsh);
74 isb();
75
76 modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
77 }
78
79 #define segment_eq(a, b) ((a) == (b))
80
81 /* We use 33-bit arithmetic here... */
82 #define __range_ok(addr, size) ({ \
83 unsigned long flag, roksum; \
84 __chk_user_ptr(addr); \
85 __asm__(".syntax unified\n" \
86 "adds %1, %2, %3; sbcscc %1, %1, %0; movcc %0, #0" \
87 : "=&r" (flag), "=&r" (roksum) \
88 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
89 : "cc"); \
90 flag; })
91
92 /*
93 * This is a type: either unsigned long, if the argument fits into
94 * that type, or otherwise unsigned long long.
95 */
96 #define __inttype(x) \
97 __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
98
99 /*
100 * Sanitise a uaccess pointer such that it becomes NULL if addr+size
101 * is above the current addr_limit.
102 */
103 #define uaccess_mask_range_ptr(ptr, size) \
104 ((__typeof__(ptr))__uaccess_mask_range_ptr(ptr, size))
105 static inline void __user *__uaccess_mask_range_ptr(const void __user *ptr,
106 size_t size)
107 {
108 void __user *safe_ptr = (void __user *)ptr;
109 unsigned long tmp;
110
111 asm volatile(
112 " .syntax unified\n"
113 " sub %1, %3, #1\n"
114 " subs %1, %1, %0\n"
115 " addhs %1, %1, #1\n"
116 " subshs %1, %1, %2\n"
117 " movlo %0, #0\n"
118 : "+r" (safe_ptr), "=&r" (tmp)
119 : "r" (size), "r" (current_thread_info()->addr_limit)
120 : "cc");
121
122 csdb();
123 return safe_ptr;
124 }
125
126 /*
127 * Single-value transfer routines. They automatically use the right
128 * size if we just have the right pointer type. Note that the functions
129 * which read from user space (*get_*) need to take care not to leak
130 * kernel data even if the calling code is buggy and fails to check
131 * the return value. This means zeroing out the destination variable
132 * or buffer on error. Normally this is done out of line by the
133 * fixup code, but there are a few places where it intrudes on the
134 * main code path. When we only write to user space, there is no
135 * problem.
136 */
137 extern int __get_user_1(void *);
138 extern int __get_user_2(void *);
139 extern int __get_user_4(void *);
140 extern int __get_user_32t_8(void *);
141 extern int __get_user_8(void *);
142 extern int __get_user_64t_1(void *);
143 extern int __get_user_64t_2(void *);
144 extern int __get_user_64t_4(void *);
145
146 #define __GUP_CLOBBER_1 "lr", "cc"
147 #ifdef CONFIG_CPU_USE_DOMAINS
148 #define __GUP_CLOBBER_2 "ip", "lr", "cc"
149 #else
150 #define __GUP_CLOBBER_2 "lr", "cc"
151 #endif
152 #define __GUP_CLOBBER_4 "lr", "cc"
153 #define __GUP_CLOBBER_32t_8 "lr", "cc"
154 #define __GUP_CLOBBER_8 "lr", "cc"
155
156 #define __get_user_x(__r2, __p, __e, __l, __s) \
157 __asm__ __volatile__ ( \
158 __asmeq("%0", "r0") __asmeq("%1", "r2") \
159 __asmeq("%3", "r1") \
160 "bl __get_user_" #__s \
161 : "=&r" (__e), "=r" (__r2) \
162 : "0" (__p), "r" (__l) \
163 : __GUP_CLOBBER_##__s)
164
165 /* narrowing a double-word get into a single 32bit word register: */
166 #ifdef __ARMEB__
167 #define __get_user_x_32t(__r2, __p, __e, __l, __s) \
168 __get_user_x(__r2, __p, __e, __l, 32t_8)
169 #else
170 #define __get_user_x_32t __get_user_x
171 #endif
172
173 /*
174 * storing result into proper least significant word of 64bit target var,
175 * different only for big endian case where 64 bit __r2 lsw is r3:
176 */
177 #ifdef __ARMEB__
178 #define __get_user_x_64t(__r2, __p, __e, __l, __s) \
179 __asm__ __volatile__ ( \
180 __asmeq("%0", "r0") __asmeq("%1", "r2") \
181 __asmeq("%3", "r1") \
182 "bl __get_user_64t_" #__s \
183 : "=&r" (__e), "=r" (__r2) \
184 : "0" (__p), "r" (__l) \
185 : __GUP_CLOBBER_##__s)
186 #else
187 #define __get_user_x_64t __get_user_x
188 #endif
189
190
191 #define __get_user_check(x, p) \
192 ({ \
193 unsigned long __limit = current_thread_info()->addr_limit - 1; \
194 register typeof(*(p)) __user *__p asm("r0") = (p); \
195 register __inttype(x) __r2 asm("r2"); \
196 register unsigned long __l asm("r1") = __limit; \
197 register int __e asm("r0"); \
198 unsigned int __ua_flags = uaccess_save_and_enable(); \
199 switch (sizeof(*(__p))) { \
200 case 1: \
201 if (sizeof((x)) >= 8) \
202 __get_user_x_64t(__r2, __p, __e, __l, 1); \
203 else \
204 __get_user_x(__r2, __p, __e, __l, 1); \
205 break; \
206 case 2: \
207 if (sizeof((x)) >= 8) \
208 __get_user_x_64t(__r2, __p, __e, __l, 2); \
209 else \
210 __get_user_x(__r2, __p, __e, __l, 2); \
211 break; \
212 case 4: \
213 if (sizeof((x)) >= 8) \
214 __get_user_x_64t(__r2, __p, __e, __l, 4); \
215 else \
216 __get_user_x(__r2, __p, __e, __l, 4); \
217 break; \
218 case 8: \
219 if (sizeof((x)) < 8) \
220 __get_user_x_32t(__r2, __p, __e, __l, 4); \
221 else \
222 __get_user_x(__r2, __p, __e, __l, 8); \
223 break; \
224 default: __e = __get_user_bad(); break; \
225 } \
226 uaccess_restore(__ua_flags); \
227 x = (typeof(*(p))) __r2; \
228 __e; \
229 })
230
231 #define get_user(x, p) \
232 ({ \
233 might_fault(); \
234 __get_user_check(x, p); \
235 })
236
237 extern int __put_user_1(void *, unsigned int);
238 extern int __put_user_2(void *, unsigned int);
239 extern int __put_user_4(void *, unsigned int);
240 extern int __put_user_8(void *, unsigned long long);
241
242 #define __put_user_check(__pu_val, __ptr, __err, __s) \
243 ({ \
244 unsigned long __limit = current_thread_info()->addr_limit - 1; \
245 register typeof(__pu_val) __r2 asm("r2") = __pu_val; \
246 register const void __user *__p asm("r0") = __ptr; \
247 register unsigned long __l asm("r1") = __limit; \
248 register int __e asm("r0"); \
249 __asm__ __volatile__ ( \
250 __asmeq("%0", "r0") __asmeq("%2", "r2") \
251 __asmeq("%3", "r1") \
252 "bl __put_user_" #__s \
253 : "=&r" (__e) \
254 : "0" (__p), "r" (__r2), "r" (__l) \
255 : "ip", "lr", "cc"); \
256 __err = __e; \
257 })
258
259 #else /* CONFIG_MMU */
260
261 /*
262 * uClinux has only one addr space, so has simplified address limits.
263 */
264 #define USER_DS KERNEL_DS
265
266 #define segment_eq(a, b) (1)
267 #define __addr_ok(addr) ((void)(addr), 1)
268 #define __range_ok(addr, size) ((void)(addr), 0)
269 #define get_fs() (KERNEL_DS)
270
271 static inline void set_fs(mm_segment_t fs)
272 {
273 }
274
275 #define get_user(x, p) __get_user(x, p)
276 #define __put_user_check __put_user_nocheck
277
278 #endif /* CONFIG_MMU */
279
280 #define access_ok(addr, size) (__range_ok(addr, size) == 0)
281
282 #define user_addr_max() \
283 (uaccess_kernel() ? ~0UL : get_fs())
284
285 #ifdef CONFIG_CPU_SPECTRE
286 /*
287 * When mitigating Spectre variant 1, it is not worth fixing the non-
288 * verifying accessors, because we need to add verification of the
289 * address space there. Force these to use the standard get_user()
290 * version instead.
291 */
292 #define __get_user(x, ptr) get_user(x, ptr)
293 #else
294
295 /*
296 * The "__xxx" versions of the user access functions do not verify the
297 * address space - it must have been done previously with a separate
298 * "access_ok()" call.
299 *
300 * The "xxx_error" versions set the third argument to EFAULT if an
301 * error occurs, and leave it unchanged on success. Note that these
302 * versions are void (ie, don't return a value as such).
303 */
304 #define __get_user(x, ptr) \
305 ({ \
306 long __gu_err = 0; \
307 __get_user_err((x), (ptr), __gu_err); \
308 __gu_err; \
309 })
310
311 #define __get_user_err(x, ptr, err) \
312 do { \
313 unsigned long __gu_addr = (unsigned long)(ptr); \
314 unsigned long __gu_val; \
315 unsigned int __ua_flags; \
316 __chk_user_ptr(ptr); \
317 might_fault(); \
318 __ua_flags = uaccess_save_and_enable(); \
319 switch (sizeof(*(ptr))) { \
320 case 1: __get_user_asm_byte(__gu_val, __gu_addr, err); break; \
321 case 2: __get_user_asm_half(__gu_val, __gu_addr, err); break; \
322 case 4: __get_user_asm_word(__gu_val, __gu_addr, err); break; \
323 default: (__gu_val) = __get_user_bad(); \
324 } \
325 uaccess_restore(__ua_flags); \
326 (x) = (__typeof__(*(ptr)))__gu_val; \
327 } while (0)
328
329 #define __get_user_asm(x, addr, err, instr) \
330 __asm__ __volatile__( \
331 "1: " TUSER(instr) " %1, [%2], #0\n" \
332 "2:\n" \
333 " .pushsection .text.fixup,\"ax\"\n" \
334 " .align 2\n" \
335 "3: mov %0, %3\n" \
336 " mov %1, #0\n" \
337 " b 2b\n" \
338 " .popsection\n" \
339 " .pushsection __ex_table,\"a\"\n" \
340 " .align 3\n" \
341 " .long 1b, 3b\n" \
342 " .popsection" \
343 : "+r" (err), "=&r" (x) \
344 : "r" (addr), "i" (-EFAULT) \
345 : "cc")
346
347 #define __get_user_asm_byte(x, addr, err) \
348 __get_user_asm(x, addr, err, ldrb)
349
350 #if __LINUX_ARM_ARCH__ >= 6
351
352 #define __get_user_asm_half(x, addr, err) \
353 __get_user_asm(x, addr, err, ldrh)
354
355 #else
356
357 #ifndef __ARMEB__
358 #define __get_user_asm_half(x, __gu_addr, err) \
359 ({ \
360 unsigned long __b1, __b2; \
361 __get_user_asm_byte(__b1, __gu_addr, err); \
362 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
363 (x) = __b1 | (__b2 << 8); \
364 })
365 #else
366 #define __get_user_asm_half(x, __gu_addr, err) \
367 ({ \
368 unsigned long __b1, __b2; \
369 __get_user_asm_byte(__b1, __gu_addr, err); \
370 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
371 (x) = (__b1 << 8) | __b2; \
372 })
373 #endif
374
375 #endif /* __LINUX_ARM_ARCH__ >= 6 */
376
377 #define __get_user_asm_word(x, addr, err) \
378 __get_user_asm(x, addr, err, ldr)
379 #endif
380
381
382 #define __put_user_switch(x, ptr, __err, __fn) \
383 do { \
384 const __typeof__(*(ptr)) __user *__pu_ptr = (ptr); \
385 __typeof__(*(ptr)) __pu_val = (x); \
386 unsigned int __ua_flags; \
387 might_fault(); \
388 __ua_flags = uaccess_save_and_enable(); \
389 switch (sizeof(*(ptr))) { \
390 case 1: __fn(__pu_val, __pu_ptr, __err, 1); break; \
391 case 2: __fn(__pu_val, __pu_ptr, __err, 2); break; \
392 case 4: __fn(__pu_val, __pu_ptr, __err, 4); break; \
393 case 8: __fn(__pu_val, __pu_ptr, __err, 8); break; \
394 default: __err = __put_user_bad(); break; \
395 } \
396 uaccess_restore(__ua_flags); \
397 } while (0)
398
399 #define put_user(x, ptr) \
400 ({ \
401 int __pu_err = 0; \
402 __put_user_switch((x), (ptr), __pu_err, __put_user_check); \
403 __pu_err; \
404 })
405
406 #ifdef CONFIG_CPU_SPECTRE
407 /*
408 * When mitigating Spectre variant 1.1, all accessors need to include
409 * verification of the address space.
410 */
411 #define __put_user(x, ptr) put_user(x, ptr)
412
413 #else
414 #define __put_user(x, ptr) \
415 ({ \
416 long __pu_err = 0; \
417 __put_user_switch((x), (ptr), __pu_err, __put_user_nocheck); \
418 __pu_err; \
419 })
420
421 #define __put_user_nocheck(x, __pu_ptr, __err, __size) \
422 do { \
423 unsigned long __pu_addr = (unsigned long)__pu_ptr; \
424 __put_user_nocheck_##__size(x, __pu_addr, __err); \
425 } while (0)
426
427 #define __put_user_nocheck_1 __put_user_asm_byte
428 #define __put_user_nocheck_2 __put_user_asm_half
429 #define __put_user_nocheck_4 __put_user_asm_word
430 #define __put_user_nocheck_8 __put_user_asm_dword
431
432 #define __put_user_asm(x, __pu_addr, err, instr) \
433 __asm__ __volatile__( \
434 "1: " TUSER(instr) " %1, [%2], #0\n" \
435 "2:\n" \
436 " .pushsection .text.fixup,\"ax\"\n" \
437 " .align 2\n" \
438 "3: mov %0, %3\n" \
439 " b 2b\n" \
440 " .popsection\n" \
441 " .pushsection __ex_table,\"a\"\n" \
442 " .align 3\n" \
443 " .long 1b, 3b\n" \
444 " .popsection" \
445 : "+r" (err) \
446 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
447 : "cc")
448
449 #define __put_user_asm_byte(x, __pu_addr, err) \
450 __put_user_asm(x, __pu_addr, err, strb)
451
452 #if __LINUX_ARM_ARCH__ >= 6
453
454 #define __put_user_asm_half(x, __pu_addr, err) \
455 __put_user_asm(x, __pu_addr, err, strh)
456
457 #else
458
459 #ifndef __ARMEB__
460 #define __put_user_asm_half(x, __pu_addr, err) \
461 ({ \
462 unsigned long __temp = (__force unsigned long)(x); \
463 __put_user_asm_byte(__temp, __pu_addr, err); \
464 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \
465 })
466 #else
467 #define __put_user_asm_half(x, __pu_addr, err) \
468 ({ \
469 unsigned long __temp = (__force unsigned long)(x); \
470 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \
471 __put_user_asm_byte(__temp, __pu_addr + 1, err); \
472 })
473 #endif
474
475 #endif /* __LINUX_ARM_ARCH__ >= 6 */
476
477 #define __put_user_asm_word(x, __pu_addr, err) \
478 __put_user_asm(x, __pu_addr, err, str)
479
480 #ifndef __ARMEB__
481 #define __reg_oper0 "%R2"
482 #define __reg_oper1 "%Q2"
483 #else
484 #define __reg_oper0 "%Q2"
485 #define __reg_oper1 "%R2"
486 #endif
487
488 #define __put_user_asm_dword(x, __pu_addr, err) \
489 __asm__ __volatile__( \
490 ARM( "1: " TUSER(str) " " __reg_oper1 ", [%1], #4\n" ) \
491 ARM( "2: " TUSER(str) " " __reg_oper0 ", [%1]\n" ) \
492 THUMB( "1: " TUSER(str) " " __reg_oper1 ", [%1]\n" ) \
493 THUMB( "2: " TUSER(str) " " __reg_oper0 ", [%1, #4]\n" ) \
494 "3:\n" \
495 " .pushsection .text.fixup,\"ax\"\n" \
496 " .align 2\n" \
497 "4: mov %0, %3\n" \
498 " b 3b\n" \
499 " .popsection\n" \
500 " .pushsection __ex_table,\"a\"\n" \
501 " .align 3\n" \
502 " .long 1b, 4b\n" \
503 " .long 2b, 4b\n" \
504 " .popsection" \
505 : "+r" (err), "+r" (__pu_addr) \
506 : "r" (x), "i" (-EFAULT) \
507 : "cc")
508
509 #endif /* !CONFIG_CPU_SPECTRE */
510
511 #ifdef CONFIG_MMU
512 extern unsigned long __must_check
513 arm_copy_from_user(void *to, const void __user *from, unsigned long n);
514
515 static inline unsigned long __must_check
516 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
517 {
518 unsigned int __ua_flags;
519
520 __ua_flags = uaccess_save_and_enable();
521 n = arm_copy_from_user(to, from, n);
522 uaccess_restore(__ua_flags);
523 return n;
524 }
525
526 extern unsigned long __must_check
527 arm_copy_to_user(void __user *to, const void *from, unsigned long n);
528 extern unsigned long __must_check
529 __copy_to_user_std(void __user *to, const void *from, unsigned long n);
530
531 static inline unsigned long __must_check
532 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
533 {
534 #ifndef CONFIG_UACCESS_WITH_MEMCPY
535 unsigned int __ua_flags;
536 __ua_flags = uaccess_save_and_enable();
537 n = arm_copy_to_user(to, from, n);
538 uaccess_restore(__ua_flags);
539 return n;
540 #else
541 return arm_copy_to_user(to, from, n);
542 #endif
543 }
544
545 extern unsigned long __must_check
546 arm_clear_user(void __user *addr, unsigned long n);
547 extern unsigned long __must_check
548 __clear_user_std(void __user *addr, unsigned long n);
549
550 static inline unsigned long __must_check
551 __clear_user(void __user *addr, unsigned long n)
552 {
553 unsigned int __ua_flags = uaccess_save_and_enable();
554 n = arm_clear_user(addr, n);
555 uaccess_restore(__ua_flags);
556 return n;
557 }
558
559 #else
560 static inline unsigned long
561 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
562 {
563 memcpy(to, (const void __force *)from, n);
564 return 0;
565 }
566 static inline unsigned long
567 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
568 {
569 memcpy((void __force *)to, from, n);
570 return 0;
571 }
572 #define __clear_user(addr, n) (memset((void __force *)addr, 0, n), 0)
573 #endif
574 #define INLINE_COPY_TO_USER
575 #define INLINE_COPY_FROM_USER
576
577 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
578 {
579 if (access_ok(to, n))
580 n = __clear_user(to, n);
581 return n;
582 }
583
584 /* These are from lib/ code, and use __get_user() and friends */
585 extern long strncpy_from_user(char *dest, const char __user *src, long count);
586
587 extern __must_check long strnlen_user(const char __user *str, long n);
588
589 #endif /* _ASMARM_UACCESS_H */
Linux with added FPC-III support