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Chris Metcalf867e3592010-05-28 23:09:12 -04001/*
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 */
55static 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 */
71int __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 */
Chris Metcalf0707ad32010-06-25 17:04:17 -040092#define access_ok(type, addr, size) ({ \
93 __chk_user_ptr(addr); \
94 likely(__range_ok((unsigned long)(addr), (size)) == 0); \
95})
Chris Metcalf867e3592010-05-28 23:09:12 -040096
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
110struct exception_table_entry {
111 unsigned long insn, fixup;
112};
113
114extern int fixup_exception(struct pt_regs *regs);
115
116/*
117 * We return the __get_user_N function results in a structure,
118 * thus in r0 and r1. If "err" is zero, "val" is the result
119 * of the read; otherwise, "err" is -EFAULT.
120 *
121 * We rarely need 8-byte values on a 32-bit architecture, but
122 * we size the structure to accommodate. In practice, for the
123 * the smaller reads, we can zero the high word for free, and
124 * the caller will ignore it by virtue of casting anyway.
125 */
126struct __get_user {
127 unsigned long long val;
128 int err;
129};
130
131/*
132 * FIXME: we should express these as inline extended assembler, since
133 * they're fundamentally just a variable dereference and some
134 * supporting exception_table gunk. Note that (a la i386) we can
135 * extend the copy_to_user and copy_from_user routines to call into
136 * such extended assembler routines, though we will have to use a
137 * different return code in that case (1, 2, or 4, rather than -EFAULT).
138 */
Chris Metcalf0707ad32010-06-25 17:04:17 -0400139extern struct __get_user __get_user_1(const void __user *);
140extern struct __get_user __get_user_2(const void __user *);
141extern struct __get_user __get_user_4(const void __user *);
142extern struct __get_user __get_user_8(const void __user *);
143extern int __put_user_1(long, void __user *);
144extern int __put_user_2(long, void __user *);
145extern int __put_user_4(long, void __user *);
146extern int __put_user_8(long long, void __user *);
Chris Metcalf867e3592010-05-28 23:09:12 -0400147
148/* Unimplemented routines to cause linker failures */
149extern struct __get_user __get_user_bad(void);
150extern int __put_user_bad(void);
151
152/*
153 * Careful: we have to cast the result to the type of the pointer
154 * for sign reasons.
155 */
156/**
157 * __get_user: - Get a simple variable from user space, with less checking.
158 * @x: Variable to store result.
159 * @ptr: Source address, in user space.
160 *
161 * Context: User context only. This function may sleep.
162 *
163 * This macro copies a single simple variable from user space to kernel
164 * space. It supports simple types like char and int, but not larger
165 * data types like structures or arrays.
166 *
167 * @ptr must have pointer-to-simple-variable type, and the result of
168 * dereferencing @ptr must be assignable to @x without a cast.
169 *
170 * Returns zero on success, or -EFAULT on error.
171 * On error, the variable @x is set to zero.
172 *
173 * Caller must check the pointer with access_ok() before calling this
174 * function.
175 */
176#define __get_user(x, ptr) \
177({ struct __get_user __ret; \
178 __typeof__(*(ptr)) const __user *__gu_addr = (ptr); \
179 __chk_user_ptr(__gu_addr); \
180 switch (sizeof(*(__gu_addr))) { \
181 case 1: \
182 __ret = __get_user_1(__gu_addr); \
183 break; \
184 case 2: \
185 __ret = __get_user_2(__gu_addr); \
186 break; \
187 case 4: \
188 __ret = __get_user_4(__gu_addr); \
189 break; \
190 case 8: \
191 __ret = __get_user_8(__gu_addr); \
192 break; \
193 default: \
194 __ret = __get_user_bad(); \
195 break; \
196 } \
197 (x) = (__typeof__(*__gu_addr)) (__typeof__(*__gu_addr - *__gu_addr)) \
198 __ret.val; \
199 __ret.err; \
200})
201
202/**
203 * __put_user: - Write a simple value into user space, with less checking.
204 * @x: Value to copy to user space.
205 * @ptr: Destination address, in user space.
206 *
207 * Context: User context only. This function may sleep.
208 *
209 * This macro copies a single simple value from kernel space to user
210 * space. It supports simple types like char and int, but not larger
211 * data types like structures or arrays.
212 *
213 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
214 * to the result of dereferencing @ptr.
215 *
216 * Caller must check the pointer with access_ok() before calling this
217 * function.
218 *
219 * Returns zero on success, or -EFAULT on error.
220 *
221 * Implementation note: The "case 8" logic of casting to the type of
222 * the result of subtracting the value from itself is basically a way
223 * of keeping all integer types the same, but casting any pointers to
224 * ptrdiff_t, i.e. also an integer type. This way there are no
225 * questionable casts seen by the compiler on an ILP32 platform.
226 */
227#define __put_user(x, ptr) \
228({ \
229 int __pu_err = 0; \
230 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
231 typeof(*__pu_addr) __pu_val = (x); \
232 __chk_user_ptr(__pu_addr); \
233 switch (sizeof(__pu_val)) { \
234 case 1: \
235 __pu_err = __put_user_1((long)__pu_val, __pu_addr); \
236 break; \
237 case 2: \
238 __pu_err = __put_user_2((long)__pu_val, __pu_addr); \
239 break; \
240 case 4: \
241 __pu_err = __put_user_4((long)__pu_val, __pu_addr); \
242 break; \
243 case 8: \
244 __pu_err = \
245 __put_user_8((__typeof__(__pu_val - __pu_val))__pu_val,\
246 __pu_addr); \
247 break; \
248 default: \
249 __pu_err = __put_user_bad(); \
250 break; \
251 } \
252 __pu_err; \
253})
254
255/*
256 * The versions of get_user and put_user without initial underscores
257 * check the address of their arguments to make sure they are not
258 * in kernel space.
259 */
260#define put_user(x, ptr) \
261({ \
262 __typeof__(*(ptr)) __user *__Pu_addr = (ptr); \
263 access_ok(VERIFY_WRITE, (__Pu_addr), sizeof(*(__Pu_addr))) ? \
264 __put_user((x), (__Pu_addr)) : \
265 -EFAULT; \
266})
267
268#define get_user(x, ptr) \
269({ \
270 __typeof__(*(ptr)) const __user *__Gu_addr = (ptr); \
271 access_ok(VERIFY_READ, (__Gu_addr), sizeof(*(__Gu_addr))) ? \
272 __get_user((x), (__Gu_addr)) : \
273 ((x) = 0, -EFAULT); \
274})
275
276/**
277 * __copy_to_user() - copy data into user space, with less checking.
278 * @to: Destination address, in user space.
279 * @from: Source address, in kernel space.
280 * @n: Number of bytes to copy.
281 *
282 * Context: User context only. This function may sleep.
283 *
284 * Copy data from kernel space to user space. Caller must check
285 * the specified block with access_ok() before calling this function.
286 *
287 * Returns number of bytes that could not be copied.
288 * On success, this will be zero.
289 *
290 * An alternate version - __copy_to_user_inatomic() - is designed
291 * to be called from atomic context, typically bracketed by calls
292 * to pagefault_disable() and pagefault_enable().
293 */
294extern unsigned long __must_check __copy_to_user_inatomic(
295 void __user *to, const void *from, unsigned long n);
296
297static inline unsigned long __must_check
298__copy_to_user(void __user *to, const void *from, unsigned long n)
299{
300 might_fault();
301 return __copy_to_user_inatomic(to, from, n);
302}
303
304static inline unsigned long __must_check
305copy_to_user(void __user *to, const void *from, unsigned long n)
306{
307 if (access_ok(VERIFY_WRITE, to, n))
308 n = __copy_to_user(to, from, n);
309 return n;
310}
311
312/**
313 * __copy_from_user() - copy data from user space, with less checking.
314 * @to: Destination address, in kernel space.
315 * @from: Source address, in user space.
316 * @n: Number of bytes to copy.
317 *
318 * Context: User context only. This function may sleep.
319 *
320 * Copy data from user space to kernel space. Caller must check
321 * the specified block with access_ok() before calling this function.
322 *
323 * Returns number of bytes that could not be copied.
324 * On success, this will be zero.
325 *
326 * If some data could not be copied, this function will pad the copied
327 * data to the requested size using zero bytes.
328 *
329 * An alternate version - __copy_from_user_inatomic() - is designed
330 * to be called from atomic context, typically bracketed by calls
331 * to pagefault_disable() and pagefault_enable(). This version
332 * does *NOT* pad with zeros.
333 */
334extern unsigned long __must_check __copy_from_user_inatomic(
335 void *to, const void __user *from, unsigned long n);
336extern unsigned long __must_check __copy_from_user_zeroing(
337 void *to, const void __user *from, unsigned long n);
338
339static inline unsigned long __must_check
340__copy_from_user(void *to, const void __user *from, unsigned long n)
341{
342 might_fault();
343 return __copy_from_user_zeroing(to, from, n);
344}
345
346static inline unsigned long __must_check
347_copy_from_user(void *to, const void __user *from, unsigned long n)
348{
349 if (access_ok(VERIFY_READ, from, n))
350 n = __copy_from_user(to, from, n);
351 else
352 memset(to, 0, n);
353 return n;
354}
355
356#ifdef CONFIG_DEBUG_COPY_FROM_USER
357extern void copy_from_user_overflow(void)
358 __compiletime_warning("copy_from_user() size is not provably correct");
359
360static inline unsigned long __must_check copy_from_user(void *to,
361 const void __user *from,
362 unsigned long n)
363{
364 int sz = __compiletime_object_size(to);
365
366 if (likely(sz == -1 || sz >= n))
367 n = _copy_from_user(to, from, n);
368 else
369 copy_from_user_overflow();
370
371 return n;
372}
373#else
374#define copy_from_user _copy_from_user
375#endif
376
377#ifdef __tilegx__
378/**
379 * __copy_in_user() - copy data within user space, with less checking.
380 * @to: Destination address, in user space.
381 * @from: Source address, in kernel space.
382 * @n: Number of bytes to copy.
383 *
384 * Context: User context only. This function may sleep.
385 *
386 * Copy data from user space to user space. Caller must check
387 * the specified blocks with access_ok() before calling this function.
388 *
389 * Returns number of bytes that could not be copied.
390 * On success, this will be zero.
391 */
392extern unsigned long __copy_in_user_asm(
393 void __user *to, const void __user *from, unsigned long n);
394
395static inline unsigned long __must_check
396__copy_in_user(void __user *to, const void __user *from, unsigned long n)
397{
398 might_sleep();
399 return __copy_in_user_asm(to, from, n);
400}
401
402static inline unsigned long __must_check
403copy_in_user(void __user *to, const void __user *from, unsigned long n)
404{
405 if (access_ok(VERIFY_WRITE, to, n) && access_ok(VERIFY_READ, from, n))
406 n = __copy_in_user(to, from, n);
407 return n;
408}
409#endif
410
411
412/**
413 * strlen_user: - Get the size of a string in user space.
414 * @str: The string to measure.
415 *
416 * Context: User context only. This function may sleep.
417 *
418 * Get the size of a NUL-terminated string in user space.
419 *
420 * Returns the size of the string INCLUDING the terminating NUL.
421 * On exception, returns 0.
422 *
423 * If there is a limit on the length of a valid string, you may wish to
424 * consider using strnlen_user() instead.
425 */
426extern long strnlen_user_asm(const char __user *str, long n);
427static inline long __must_check strnlen_user(const char __user *str, long n)
428{
429 might_fault();
430 return strnlen_user_asm(str, n);
431}
432#define strlen_user(str) strnlen_user(str, LONG_MAX)
433
434/**
435 * strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
436 * @dst: Destination address, in kernel space. This buffer must be at
437 * least @count bytes long.
438 * @src: Source address, in user space.
439 * @count: Maximum number of bytes to copy, including the trailing NUL.
440 *
441 * Copies a NUL-terminated string from userspace to kernel space.
442 * Caller must check the specified block with access_ok() before calling
443 * this function.
444 *
445 * On success, returns the length of the string (not including the trailing
446 * NUL).
447 *
448 * If access to userspace fails, returns -EFAULT (some data may have been
449 * copied).
450 *
451 * If @count is smaller than the length of the string, copies @count bytes
452 * and returns @count.
453 */
454extern long strncpy_from_user_asm(char *dst, const char __user *src, long);
455static inline long __must_check __strncpy_from_user(
456 char *dst, const char __user *src, long count)
457{
458 might_fault();
459 return strncpy_from_user_asm(dst, src, count);
460}
461static inline long __must_check strncpy_from_user(
462 char *dst, const char __user *src, long count)
463{
464 if (access_ok(VERIFY_READ, src, 1))
465 return __strncpy_from_user(dst, src, count);
466 return -EFAULT;
467}
468
469/**
470 * clear_user: - Zero a block of memory in user space.
471 * @mem: Destination address, in user space.
472 * @len: Number of bytes to zero.
473 *
474 * Zero a block of memory in user space.
475 *
476 * Returns number of bytes that could not be cleared.
477 * On success, this will be zero.
478 */
479extern unsigned long clear_user_asm(void __user *mem, unsigned long len);
480static inline unsigned long __must_check __clear_user(
481 void __user *mem, unsigned long len)
482{
483 might_fault();
484 return clear_user_asm(mem, len);
485}
486static inline unsigned long __must_check clear_user(
487 void __user *mem, unsigned long len)
488{
489 if (access_ok(VERIFY_WRITE, mem, len))
490 return __clear_user(mem, len);
491 return len;
492}
493
494/**
495 * flush_user: - Flush a block of memory in user space from cache.
496 * @mem: Destination address, in user space.
497 * @len: Number of bytes to flush.
498 *
499 * Returns number of bytes that could not be flushed.
500 * On success, this will be zero.
501 */
502extern unsigned long flush_user_asm(void __user *mem, unsigned long len);
503static inline unsigned long __must_check __flush_user(
504 void __user *mem, unsigned long len)
505{
506 int retval;
507
508 might_fault();
509 retval = flush_user_asm(mem, len);
510 mb_incoherent();
511 return retval;
512}
513
514static inline unsigned long __must_check flush_user(
515 void __user *mem, unsigned long len)
516{
517 if (access_ok(VERIFY_WRITE, mem, len))
518 return __flush_user(mem, len);
519 return len;
520}
521
522/**
523 * inv_user: - Invalidate a block of memory in user space from cache.
524 * @mem: Destination address, in user space.
525 * @len: Number of bytes to invalidate.
526 *
527 * Returns number of bytes that could not be invalidated.
528 * On success, this will be zero.
529 *
530 * Note that on Tile64, the "inv" operation is in fact a
531 * "flush and invalidate", so cache write-backs will occur prior
532 * to the cache being marked invalid.
533 */
534extern unsigned long inv_user_asm(void __user *mem, unsigned long len);
535static inline unsigned long __must_check __inv_user(
536 void __user *mem, unsigned long len)
537{
538 int retval;
539
540 might_fault();
541 retval = inv_user_asm(mem, len);
542 mb_incoherent();
543 return retval;
544}
545static inline unsigned long __must_check inv_user(
546 void __user *mem, unsigned long len)
547{
548 if (access_ok(VERIFY_WRITE, mem, len))
549 return __inv_user(mem, len);
550 return len;
551}
552
553/**
554 * finv_user: - Flush-inval a block of memory in user space from cache.
555 * @mem: Destination address, in user space.
556 * @len: Number of bytes to invalidate.
557 *
558 * Returns number of bytes that could not be flush-invalidated.
559 * On success, this will be zero.
560 */
561extern unsigned long finv_user_asm(void __user *mem, unsigned long len);
562static inline unsigned long __must_check __finv_user(
563 void __user *mem, unsigned long len)
564{
565 int retval;
566
567 might_fault();
568 retval = finv_user_asm(mem, len);
569 mb_incoherent();
570 return retval;
571}
572static inline unsigned long __must_check finv_user(
573 void __user *mem, unsigned long len)
574{
575 if (access_ok(VERIFY_WRITE, mem, len))
576 return __finv_user(mem, len);
577 return len;
578}
579
580#endif /* _ASM_TILE_UACCESS_H */