1 /*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
13 */
14
15 #ifndef _ASM_TILE_UACCESS_H
16 #define _ASM_TILE_UACCESS_H
17
18 /*
19 * User space memory access functions
20 */
21 #include <linux/sched.h>
22 #include <linux/mm.h>
23 #include <asm-generic/uaccess-unaligned.h>
24 #include <asm/processor.h>
25 #include <asm/page.h>
26
27 #define VERIFY_READ 0
28 #define VERIFY_WRITE 1
29
30 /*
31 * The fs value determines whether argument validity checking should be
32 * performed or not. If get_fs() == USER_DS, checking is performed, with
33 * get_fs() == KERNEL_DS, checking is bypassed.
34 *
35 * For historical reasons, these macros are grossly misnamed.
36 */
37 #define MAKE_MM_SEG(a) ((mm_segment_t) { (a) })
38
39 #define KERNEL_DS MAKE_MM_SEG(-1UL)
40 #define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
41
42 #define get_ds() (KERNEL_DS)
43 #define get_fs() (current_thread_info()->addr_limit)
44 #define set_fs(x) (current_thread_info()->addr_limit = (x))
45
46 #define segment_eq(a, b) ((a).seg == (b).seg)
47
48 #ifndef __tilegx__
49 /*
50 * We could allow mapping all 16 MB at 0xfc000000, but we set up a
51 * special hack in arch_setup_additional_pages() to auto-create a mapping
52 * for the first 16 KB, and it would seem strange to have different
53 * user-accessible semantics for memory at 0xfc000000 and above 0xfc004000.
54 */
is_arch_mappable_range(unsigned long addr,unsigned long size)55 static inline int is_arch_mappable_range(unsigned long addr,
56 unsigned long size)
57 {
58 return (addr >= MEM_USER_INTRPT &&
59 addr < (MEM_USER_INTRPT + INTRPT_SIZE) &&
60 size <= (MEM_USER_INTRPT + INTRPT_SIZE) - addr);
61 }
62 #define is_arch_mappable_range is_arch_mappable_range
63 #else
64 #define is_arch_mappable_range(addr, size) 0
65 #endif
66
67 /*
68 * Test whether a block of memory is a valid user space address.
69 * Returns 0 if the range is valid, nonzero otherwise.
70 */
71 int __range_ok(unsigned long addr, unsigned long size);
72
73 /**
74 * access_ok: - Checks if a user space pointer is valid
75 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
76 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
77 * to write to a block, it is always safe to read from it.
78 * @addr: User space pointer to start of block to check
79 * @size: Size of block to check
80 *
81 * Context: User context only. This function may sleep.
82 *
83 * Checks if a pointer to a block of memory in user space is valid.
84 *
85 * Returns true (nonzero) if the memory block may be valid, false (zero)
86 * if it is definitely invalid.
87 *
88 * Note that, depending on architecture, this function probably just
89 * checks that the pointer is in the user space range - after calling
90 * this function, memory access functions may still return -EFAULT.
91 */
92 #define access_ok(type, addr, size) ({ \
93 __chk_user_ptr(addr); \
94 likely(__range_ok((unsigned long)(addr), (size)) == 0); \
95 })
96
97 /*
98 * The exception table consists of pairs of addresses: the first is the
99 * address of an instruction that is allowed to fault, and the second is
100 * the address at which the program should continue. No registers are
101 * modified, so it is entirely up to the continuation code to figure out
102 * what to do.
103 *
104 * All the routines below use bits of fixup code that are out of line
105 * with the main instruction path. This means when everything is well,
106 * we don't even have to jump over them. Further, they do not intrude
107 * on our cache or tlb entries.
108 */
109
110 struct exception_table_entry {
111 unsigned long insn, fixup;
112 };
113
114 extern int fixup_exception(struct pt_regs *regs);
115
116 /*
117 * This is a type: either unsigned long, if the argument fits into
118 * that type, or otherwise unsigned long long.
119 */
120 #define __inttype(x) \
121 __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
122
123 /*
124 * Support macros for __get_user().
125 * Note that __get_user() and __put_user() assume proper alignment.
126 */
127
128 #ifdef __LP64__
129 #define _ASM_PTR ".quad"
130 #define _ASM_ALIGN ".align 8"
131 #else
132 #define _ASM_PTR ".long"
133 #define _ASM_ALIGN ".align 4"
134 #endif
135
136 #define __get_user_asm(OP, x, ptr, ret) \
137 asm volatile("1: {" #OP " %1, %2; movei %0, 0 }\n" \
138 ".pushsection .fixup,\"ax\"\n" \
139 "0: { movei %1, 0; movei %0, %3 }\n" \
140 "j 9f\n" \
141 ".section __ex_table,\"a\"\n" \
142 _ASM_ALIGN "\n" \
143 _ASM_PTR " 1b, 0b\n" \
144 ".popsection\n" \
145 "9:" \
146 : "=r" (ret), "=r" (x) \
147 : "r" (ptr), "i" (-EFAULT))
148
149 #ifdef __tilegx__
150 #define __get_user_1(x, ptr, ret) __get_user_asm(ld1u, x, ptr, ret)
151 #define __get_user_2(x, ptr, ret) __get_user_asm(ld2u, x, ptr, ret)
152 #define __get_user_4(x, ptr, ret) __get_user_asm(ld4s, x, ptr, ret)
153 #define __get_user_8(x, ptr, ret) __get_user_asm(ld, x, ptr, ret)
154 #else
155 #define __get_user_1(x, ptr, ret) __get_user_asm(lb_u, x, ptr, ret)
156 #define __get_user_2(x, ptr, ret) __get_user_asm(lh_u, x, ptr, ret)
157 #define __get_user_4(x, ptr, ret) __get_user_asm(lw, x, ptr, ret)
158 #ifdef __LITTLE_ENDIAN
159 #define __lo32(a, b) a
160 #define __hi32(a, b) b
161 #else
162 #define __lo32(a, b) b
163 #define __hi32(a, b) a
164 #endif
165 #define __get_user_8(x, ptr, ret) \
166 ({ \
167 unsigned int __a, __b; \
168 asm volatile("1: { lw %1, %3; addi %2, %3, 4 }\n" \
169 "2: { lw %2, %2; movei %0, 0 }\n" \
170 ".pushsection .fixup,\"ax\"\n" \
171 "0: { movei %1, 0; movei %2, 0 }\n" \
172 "{ movei %0, %4; j 9f }\n" \
173 ".section __ex_table,\"a\"\n" \
174 ".align 4\n" \
175 ".word 1b, 0b\n" \
176 ".word 2b, 0b\n" \
177 ".popsection\n" \
178 "9:" \
179 : "=r" (ret), "=r" (__a), "=&r" (__b) \
180 : "r" (ptr), "i" (-EFAULT)); \
181 (x) = (__force __typeof(x))(__inttype(x)) \
182 (((u64)__hi32(__a, __b) << 32) | \
183 __lo32(__a, __b)); \
184 })
185 #endif
186
187 extern int __get_user_bad(void)
188 __attribute__((warning("sizeof __get_user argument not 1, 2, 4 or 8")));
189
190 /**
191 * __get_user: - Get a simple variable from user space, with less checking.
192 * @x: Variable to store result.
193 * @ptr: Source address, in user space.
194 *
195 * Context: User context only. This function may sleep.
196 *
197 * This macro copies a single simple variable from user space to kernel
198 * space. It supports simple types like char and int, but not larger
199 * data types like structures or arrays.
200 *
201 * @ptr must have pointer-to-simple-variable type, and the result of
202 * dereferencing @ptr must be assignable to @x without a cast.
203 *
204 * Returns zero on success, or -EFAULT on error.
205 * On error, the variable @x is set to zero.
206 *
207 * Caller must check the pointer with access_ok() before calling this
208 * function.
209 */
210 #define __get_user(x, ptr) \
211 ({ \
212 int __ret; \
213 typeof(x) _x; \
214 __chk_user_ptr(ptr); \
215 switch (sizeof(*(ptr))) { \
216 case 1: __get_user_1(_x, ptr, __ret); break; \
217 case 2: __get_user_2(_x, ptr, __ret); break; \
218 case 4: __get_user_4(_x, ptr, __ret); break; \
219 case 8: __get_user_8(_x, ptr, __ret); break; \
220 default: __ret = __get_user_bad(); break; \
221 } \
222 (x) = (typeof(*(ptr))) _x; \
223 __ret; \
224 })
225
226 /* Support macros for __put_user(). */
227
228 #define __put_user_asm(OP, x, ptr, ret) \
229 asm volatile("1: {" #OP " %1, %2; movei %0, 0 }\n" \
230 ".pushsection .fixup,\"ax\"\n" \
231 "0: { movei %0, %3; j 9f }\n" \
232 ".section __ex_table,\"a\"\n" \
233 _ASM_ALIGN "\n" \
234 _ASM_PTR " 1b, 0b\n" \
235 ".popsection\n" \
236 "9:" \
237 : "=r" (ret) \
238 : "r" (ptr), "r" (x), "i" (-EFAULT))
239
240 #ifdef __tilegx__
241 #define __put_user_1(x, ptr, ret) __put_user_asm(st1, x, ptr, ret)
242 #define __put_user_2(x, ptr, ret) __put_user_asm(st2, x, ptr, ret)
243 #define __put_user_4(x, ptr, ret) __put_user_asm(st4, x, ptr, ret)
244 #define __put_user_8(x, ptr, ret) __put_user_asm(st, x, ptr, ret)
245 #else
246 #define __put_user_1(x, ptr, ret) __put_user_asm(sb, x, ptr, ret)
247 #define __put_user_2(x, ptr, ret) __put_user_asm(sh, x, ptr, ret)
248 #define __put_user_4(x, ptr, ret) __put_user_asm(sw, x, ptr, ret)
249 #define __put_user_8(x, ptr, ret) \
250 ({ \
251 u64 __x = (__force __inttype(x))(x); \
252 int __lo = (int) __x, __hi = (int) (__x >> 32); \
253 asm volatile("1: { sw %1, %2; addi %0, %1, 4 }\n" \
254 "2: { sw %0, %3; movei %0, 0 }\n" \
255 ".pushsection .fixup,\"ax\"\n" \
256 "0: { movei %0, %4; j 9f }\n" \
257 ".section __ex_table,\"a\"\n" \
258 ".align 4\n" \
259 ".word 1b, 0b\n" \
260 ".word 2b, 0b\n" \
261 ".popsection\n" \
262 "9:" \
263 : "=&r" (ret) \
264 : "r" (ptr), "r" (__lo32(__lo, __hi)), \
265 "r" (__hi32(__lo, __hi)), "i" (-EFAULT)); \
266 })
267 #endif
268
269 extern int __put_user_bad(void)
270 __attribute__((warning("sizeof __put_user argument not 1, 2, 4 or 8")));
271
272 /**
273 * __put_user: - Write a simple value into user space, with less checking.
274 * @x: Value to copy to user space.
275 * @ptr: Destination address, in user space.
276 *
277 * Context: User context only. This function may sleep.
278 *
279 * This macro copies a single simple value from kernel space to user
280 * space. It supports simple types like char and int, but not larger
281 * data types like structures or arrays.
282 *
283 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
284 * to the result of dereferencing @ptr.
285 *
286 * Caller must check the pointer with access_ok() before calling this
287 * function.
288 *
289 * Returns zero on success, or -EFAULT on error.
290 */
291 #define __put_user(x, ptr) \
292 ({ \
293 int __ret; \
294 typeof(*(ptr)) _x = (x); \
295 __chk_user_ptr(ptr); \
296 switch (sizeof(*(ptr))) { \
297 case 1: __put_user_1(_x, ptr, __ret); break; \
298 case 2: __put_user_2(_x, ptr, __ret); break; \
299 case 4: __put_user_4(_x, ptr, __ret); break; \
300 case 8: __put_user_8(_x, ptr, __ret); break; \
301 default: __ret = __put_user_bad(); break; \
302 } \
303 __ret; \
304 })
305
306 /*
307 * The versions of get_user and put_user without initial underscores
308 * check the address of their arguments to make sure they are not
309 * in kernel space.
310 */
311 #define put_user(x, ptr) \
312 ({ \
313 __typeof__(*(ptr)) __user *__Pu_addr = (ptr); \
314 access_ok(VERIFY_WRITE, (__Pu_addr), sizeof(*(__Pu_addr))) ? \
315 __put_user((x), (__Pu_addr)) : \
316 -EFAULT; \
317 })
318
319 #define get_user(x, ptr) \
320 ({ \
321 __typeof__(*(ptr)) const __user *__Gu_addr = (ptr); \
322 access_ok(VERIFY_READ, (__Gu_addr), sizeof(*(__Gu_addr))) ? \
323 __get_user((x), (__Gu_addr)) : \
324 ((x) = 0, -EFAULT); \
325 })
326
327 /**
328 * __copy_to_user() - copy data into user space, with less checking.
329 * @to: Destination address, in user space.
330 * @from: Source address, in kernel space.
331 * @n: Number of bytes to copy.
332 *
333 * Context: User context only. This function may sleep.
334 *
335 * Copy data from kernel space to user space. Caller must check
336 * the specified block with access_ok() before calling this function.
337 *
338 * Returns number of bytes that could not be copied.
339 * On success, this will be zero.
340 *
341 * An alternate version - __copy_to_user_inatomic() - is designed
342 * to be called from atomic context, typically bracketed by calls
343 * to pagefault_disable() and pagefault_enable().
344 */
345 extern unsigned long __must_check __copy_to_user_inatomic(
346 void __user *to, const void *from, unsigned long n);
347
348 static inline unsigned long __must_check
__copy_to_user(void __user * to,const void * from,unsigned long n)349 __copy_to_user(void __user *to, const void *from, unsigned long n)
350 {
351 might_fault();
352 return __copy_to_user_inatomic(to, from, n);
353 }
354
355 static inline unsigned long __must_check
copy_to_user(void __user * to,const void * from,unsigned long n)356 copy_to_user(void __user *to, const void *from, unsigned long n)
357 {
358 if (access_ok(VERIFY_WRITE, to, n))
359 n = __copy_to_user(to, from, n);
360 return n;
361 }
362
363 /**
364 * __copy_from_user() - copy data from user space, with less checking.
365 * @to: Destination address, in kernel space.
366 * @from: Source address, in user space.
367 * @n: Number of bytes to copy.
368 *
369 * Context: User context only. This function may sleep.
370 *
371 * Copy data from user space to kernel space. Caller must check
372 * the specified block with access_ok() before calling this function.
373 *
374 * Returns number of bytes that could not be copied.
375 * On success, this will be zero.
376 *
377 * If some data could not be copied, this function will pad the copied
378 * data to the requested size using zero bytes.
379 *
380 * An alternate version - __copy_from_user_inatomic() - is designed
381 * to be called from atomic context, typically bracketed by calls
382 * to pagefault_disable() and pagefault_enable(). This version
383 * does *NOT* pad with zeros.
384 */
385 extern unsigned long __must_check __copy_from_user_inatomic(
386 void *to, const void __user *from, unsigned long n);
387 extern unsigned long __must_check __copy_from_user_zeroing(
388 void *to, const void __user *from, unsigned long n);
389
390 static inline unsigned long __must_check
__copy_from_user(void * to,const void __user * from,unsigned long n)391 __copy_from_user(void *to, const void __user *from, unsigned long n)
392 {
393 might_fault();
394 return __copy_from_user_zeroing(to, from, n);
395 }
396
397 static inline unsigned long __must_check
_copy_from_user(void * to,const void __user * from,unsigned long n)398 _copy_from_user(void *to, const void __user *from, unsigned long n)
399 {
400 if (access_ok(VERIFY_READ, from, n))
401 n = __copy_from_user(to, from, n);
402 else
403 memset(to, 0, n);
404 return n;
405 }
406
407 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
408 /*
409 * There are still unprovable places in the generic code as of 2.6.34, so this
410 * option is not really compatible with -Werror, which is more useful in
411 * general.
412 */
413 extern void copy_from_user_overflow(void)
414 __compiletime_warning("copy_from_user() size is not provably correct");
415
copy_from_user(void * to,const void __user * from,unsigned long n)416 static inline unsigned long __must_check copy_from_user(void *to,
417 const void __user *from,
418 unsigned long n)
419 {
420 int sz = __compiletime_object_size(to);
421
422 if (likely(sz == -1 || sz >= n))
423 n = _copy_from_user(to, from, n);
424 else
425 copy_from_user_overflow();
426
427 return n;
428 }
429 #else
430 #define copy_from_user _copy_from_user
431 #endif
432
433 #ifdef __tilegx__
434 /**
435 * __copy_in_user() - copy data within user space, with less checking.
436 * @to: Destination address, in user space.
437 * @from: Source address, in user space.
438 * @n: Number of bytes to copy.
439 *
440 * Context: User context only. This function may sleep.
441 *
442 * Copy data from user space to user space. Caller must check
443 * the specified blocks with access_ok() before calling this function.
444 *
445 * Returns number of bytes that could not be copied.
446 * On success, this will be zero.
447 */
448 extern unsigned long __copy_in_user_inatomic(
449 void __user *to, const void __user *from, unsigned long n);
450
451 static inline unsigned long __must_check
__copy_in_user(void __user * to,const void __user * from,unsigned long n)452 __copy_in_user(void __user *to, const void __user *from, unsigned long n)
453 {
454 might_fault();
455 return __copy_in_user_inatomic(to, from, n);
456 }
457
458 static inline unsigned long __must_check
copy_in_user(void __user * to,const void __user * from,unsigned long n)459 copy_in_user(void __user *to, const void __user *from, unsigned long n)
460 {
461 if (access_ok(VERIFY_WRITE, to, n) && access_ok(VERIFY_READ, from, n))
462 n = __copy_in_user(to, from, n);
463 return n;
464 }
465 #endif
466
467
468 /**
469 * strlen_user: - Get the size of a string in user space.
470 * @str: The string to measure.
471 *
472 * Context: User context only. This function may sleep.
473 *
474 * Get the size of a NUL-terminated string in user space.
475 *
476 * Returns the size of the string INCLUDING the terminating NUL.
477 * On exception, returns 0.
478 *
479 * If there is a limit on the length of a valid string, you may wish to
480 * consider using strnlen_user() instead.
481 */
482 extern long strnlen_user_asm(const char __user *str, long n);
strnlen_user(const char __user * str,long n)483 static inline long __must_check strnlen_user(const char __user *str, long n)
484 {
485 might_fault();
486 return strnlen_user_asm(str, n);
487 }
488 #define strlen_user(str) strnlen_user(str, LONG_MAX)
489
490 /**
491 * strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
492 * @dst: Destination address, in kernel space. This buffer must be at
493 * least @count bytes long.
494 * @src: Source address, in user space.
495 * @count: Maximum number of bytes to copy, including the trailing NUL.
496 *
497 * Copies a NUL-terminated string from userspace to kernel space.
498 * Caller must check the specified block with access_ok() before calling
499 * this function.
500 *
501 * On success, returns the length of the string (not including the trailing
502 * NUL).
503 *
504 * If access to userspace fails, returns -EFAULT (some data may have been
505 * copied).
506 *
507 * If @count is smaller than the length of the string, copies @count bytes
508 * and returns @count.
509 */
510 extern long strncpy_from_user_asm(char *dst, const char __user *src, long);
__strncpy_from_user(char * dst,const char __user * src,long count)511 static inline long __must_check __strncpy_from_user(
512 char *dst, const char __user *src, long count)
513 {
514 might_fault();
515 return strncpy_from_user_asm(dst, src, count);
516 }
strncpy_from_user(char * dst,const char __user * src,long count)517 static inline long __must_check strncpy_from_user(
518 char *dst, const char __user *src, long count)
519 {
520 if (access_ok(VERIFY_READ, src, 1))
521 return __strncpy_from_user(dst, src, count);
522 return -EFAULT;
523 }
524
525 /**
526 * clear_user: - Zero a block of memory in user space.
527 * @mem: Destination address, in user space.
528 * @len: Number of bytes to zero.
529 *
530 * Zero a block of memory in user space.
531 *
532 * Returns number of bytes that could not be cleared.
533 * On success, this will be zero.
534 */
535 extern unsigned long clear_user_asm(void __user *mem, unsigned long len);
__clear_user(void __user * mem,unsigned long len)536 static inline unsigned long __must_check __clear_user(
537 void __user *mem, unsigned long len)
538 {
539 might_fault();
540 return clear_user_asm(mem, len);
541 }
clear_user(void __user * mem,unsigned long len)542 static inline unsigned long __must_check clear_user(
543 void __user *mem, unsigned long len)
544 {
545 if (access_ok(VERIFY_WRITE, mem, len))
546 return __clear_user(mem, len);
547 return len;
548 }
549
550 /**
551 * flush_user: - Flush a block of memory in user space from cache.
552 * @mem: Destination address, in user space.
553 * @len: Number of bytes to flush.
554 *
555 * Returns number of bytes that could not be flushed.
556 * On success, this will be zero.
557 */
558 extern unsigned long flush_user_asm(void __user *mem, unsigned long len);
__flush_user(void __user * mem,unsigned long len)559 static inline unsigned long __must_check __flush_user(
560 void __user *mem, unsigned long len)
561 {
562 int retval;
563
564 might_fault();
565 retval = flush_user_asm(mem, len);
566 mb_incoherent();
567 return retval;
568 }
569
flush_user(void __user * mem,unsigned long len)570 static inline unsigned long __must_check flush_user(
571 void __user *mem, unsigned long len)
572 {
573 if (access_ok(VERIFY_WRITE, mem, len))
574 return __flush_user(mem, len);
575 return len;
576 }
577
578 /**
579 * finv_user: - Flush-inval a block of memory in user space from cache.
580 * @mem: Destination address, in user space.
581 * @len: Number of bytes to invalidate.
582 *
583 * Returns number of bytes that could not be flush-invalidated.
584 * On success, this will be zero.
585 */
586 extern unsigned long finv_user_asm(void __user *mem, unsigned long len);
__finv_user(void __user * mem,unsigned long len)587 static inline unsigned long __must_check __finv_user(
588 void __user *mem, unsigned long len)
589 {
590 int retval;
591
592 might_fault();
593 retval = finv_user_asm(mem, len);
594 mb_incoherent();
595 return retval;
596 }
finv_user(void __user * mem,unsigned long len)597 static inline unsigned long __must_check finv_user(
598 void __user *mem, unsigned long len)
599 {
600 if (access_ok(VERIFY_WRITE, mem, len))
601 return __finv_user(mem, len);
602 return len;
603 }
604
605 #endif /* _ASM_TILE_UACCESS_H */
606