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 * Note that using this definition ignores is_arch_mappable_range(),
69 * so on tilepro code that uses user_addr_max() is constrained not
70 * to reference the tilepro user-interrupt region.
71 */
72 #define user_addr_max() (current_thread_info()->addr_limit.seg)
73
74 /*
75 * Test whether a block of memory is a valid user space address.
76 * Returns 0 if the range is valid, nonzero otherwise.
77 */
78 int __range_ok(unsigned long addr, unsigned long size);
79
80 /**
81 * access_ok: - Checks if a user space pointer is valid
82 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
83 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
84 * to write to a block, it is always safe to read from it.
85 * @addr: User space pointer to start of block to check
86 * @size: Size of block to check
87 *
88 * Context: User context only. This function may sleep.
89 *
90 * Checks if a pointer to a block of memory in user space is valid.
91 *
92 * Returns true (nonzero) if the memory block may be valid, false (zero)
93 * if it is definitely invalid.
94 *
95 * Note that, depending on architecture, this function probably just
96 * checks that the pointer is in the user space range - after calling
97 * this function, memory access functions may still return -EFAULT.
98 */
99 #define access_ok(type, addr, size) ({ \
100 __chk_user_ptr(addr); \
101 likely(__range_ok((unsigned long)(addr), (size)) == 0); \
102 })
103
104 /*
105 * The exception table consists of pairs of addresses: the first is the
106 * address of an instruction that is allowed to fault, and the second is
107 * the address at which the program should continue. No registers are
108 * modified, so it is entirely up to the continuation code to figure out
109 * what to do.
110 *
111 * All the routines below use bits of fixup code that are out of line
112 * with the main instruction path. This means when everything is well,
113 * we don't even have to jump over them. Further, they do not intrude
114 * on our cache or tlb entries.
115 */
116
117 struct exception_table_entry {
118 unsigned long insn, fixup;
119 };
120
121 extern int fixup_exception(struct pt_regs *regs);
122
123 /*
124 * Support macros for __get_user().
125 *
126 * Implementation note: The "case 8" logic of casting to the type of
127 * the result of subtracting the value from itself is basically a way
128 * of keeping all integer types the same, but casting any pointers to
129 * ptrdiff_t, i.e. also an integer type. This way there are no
130 * questionable casts seen by the compiler on an ILP32 platform.
131 *
132 * Note that __get_user() and __put_user() assume proper alignment.
133 */
134
135 #ifdef __LP64__
136 #define _ASM_PTR ".quad"
137 #define _ASM_ALIGN ".align 8"
138 #else
139 #define _ASM_PTR ".long"
140 #define _ASM_ALIGN ".align 4"
141 #endif
142
143 #define __get_user_asm(OP, x, ptr, ret) \
144 asm volatile("1: {" #OP " %1, %2; movei %0, 0 }\n" \
145 ".pushsection .fixup,\"ax\"\n" \
146 "0: { movei %1, 0; movei %0, %3 }\n" \
147 "j 9f\n" \
148 ".section __ex_table,\"a\"\n" \
149 _ASM_ALIGN "\n" \
150 _ASM_PTR " 1b, 0b\n" \
151 ".popsection\n" \
152 "9:" \
153 : "=r" (ret), "=r" (x) \
154 : "r" (ptr), "i" (-EFAULT))
155
156 #ifdef __tilegx__
157 #define __get_user_1(x, ptr, ret) __get_user_asm(ld1u, x, ptr, ret)
158 #define __get_user_2(x, ptr, ret) __get_user_asm(ld2u, x, ptr, ret)
159 #define __get_user_4(x, ptr, ret) __get_user_asm(ld4s, x, ptr, ret)
160 #define __get_user_8(x, ptr, ret) __get_user_asm(ld, x, ptr, ret)
161 #else
162 #define __get_user_1(x, ptr, ret) __get_user_asm(lb_u, x, ptr, ret)
163 #define __get_user_2(x, ptr, ret) __get_user_asm(lh_u, x, ptr, ret)
164 #define __get_user_4(x, ptr, ret) __get_user_asm(lw, x, ptr, ret)
165 #ifdef __LITTLE_ENDIAN
166 #define __lo32(a, b) a
167 #define __hi32(a, b) b
168 #else
169 #define __lo32(a, b) b
170 #define __hi32(a, b) a
171 #endif
172 #define __get_user_8(x, ptr, ret) \
173 ({ \
174 unsigned int __a, __b; \
175 asm volatile("1: { lw %1, %3; addi %2, %3, 4 }\n" \
176 "2: { lw %2, %2; movei %0, 0 }\n" \
177 ".pushsection .fixup,\"ax\"\n" \
178 "0: { movei %1, 0; movei %2, 0 }\n" \
179 "{ movei %0, %4; j 9f }\n" \
180 ".section __ex_table,\"a\"\n" \
181 ".align 4\n" \
182 ".word 1b, 0b\n" \
183 ".word 2b, 0b\n" \
184 ".popsection\n" \
185 "9:" \
186 : "=r" (ret), "=r" (__a), "=&r" (__b) \
187 : "r" (ptr), "i" (-EFAULT)); \
188 (x) = (__typeof(x))(__typeof((x)-(x))) \
189 (((u64)__hi32(__a, __b) << 32) | \
190 __lo32(__a, __b)); \
191 })
192 #endif
193
194 extern int __get_user_bad(void)
195 __attribute__((warning("sizeof __get_user argument not 1, 2, 4 or 8")));
196
197 /**
198 * __get_user: - Get a simple variable from user space, with less checking.
199 * @x: Variable to store result.
200 * @ptr: Source address, in user space.
201 *
202 * Context: User context only. This function may sleep.
203 *
204 * This macro copies a single simple variable from user space to kernel
205 * space. It supports simple types like char and int, but not larger
206 * data types like structures or arrays.
207 *
208 * @ptr must have pointer-to-simple-variable type, and the result of
209 * dereferencing @ptr must be assignable to @x without a cast.
210 *
211 * Returns zero on success, or -EFAULT on error.
212 * On error, the variable @x is set to zero.
213 *
214 * Caller must check the pointer with access_ok() before calling this
215 * function.
216 */
217 #define __get_user(x, ptr) \
218 ({ \
219 int __ret; \
220 __chk_user_ptr(ptr); \
221 switch (sizeof(*(ptr))) { \
222 case 1: __get_user_1(x, ptr, __ret); break; \
223 case 2: __get_user_2(x, ptr, __ret); break; \
224 case 4: __get_user_4(x, ptr, __ret); break; \
225 case 8: __get_user_8(x, ptr, __ret); break; \
226 default: __ret = __get_user_bad(); break; \
227 } \
228 __ret; \
229 })
230
231 /* Support macros for __put_user(). */
232
233 #define __put_user_asm(OP, x, ptr, ret) \
234 asm volatile("1: {" #OP " %1, %2; movei %0, 0 }\n" \
235 ".pushsection .fixup,\"ax\"\n" \
236 "0: { movei %0, %3; j 9f }\n" \
237 ".section __ex_table,\"a\"\n" \
238 _ASM_ALIGN "\n" \
239 _ASM_PTR " 1b, 0b\n" \
240 ".popsection\n" \
241 "9:" \
242 : "=r" (ret) \
243 : "r" (ptr), "r" (x), "i" (-EFAULT))
244
245 #ifdef __tilegx__
246 #define __put_user_1(x, ptr, ret) __put_user_asm(st1, x, ptr, ret)
247 #define __put_user_2(x, ptr, ret) __put_user_asm(st2, x, ptr, ret)
248 #define __put_user_4(x, ptr, ret) __put_user_asm(st4, x, ptr, ret)
249 #define __put_user_8(x, ptr, ret) __put_user_asm(st, x, ptr, ret)
250 #else
251 #define __put_user_1(x, ptr, ret) __put_user_asm(sb, x, ptr, ret)
252 #define __put_user_2(x, ptr, ret) __put_user_asm(sh, x, ptr, ret)
253 #define __put_user_4(x, ptr, ret) __put_user_asm(sw, x, ptr, ret)
254 #define __put_user_8(x, ptr, ret) \
255 ({ \
256 u64 __x = (__typeof((x)-(x)))(x); \
257 int __lo = (int) __x, __hi = (int) (__x >> 32); \
258 asm volatile("1: { sw %1, %2; addi %0, %1, 4 }\n" \
259 "2: { sw %0, %3; movei %0, 0 }\n" \
260 ".pushsection .fixup,\"ax\"\n" \
261 "0: { movei %0, %4; j 9f }\n" \
262 ".section __ex_table,\"a\"\n" \
263 ".align 4\n" \
264 ".word 1b, 0b\n" \
265 ".word 2b, 0b\n" \
266 ".popsection\n" \
267 "9:" \
268 : "=&r" (ret) \
269 : "r" (ptr), "r" (__lo32(__lo, __hi)), \
270 "r" (__hi32(__lo, __hi)), "i" (-EFAULT)); \
271 })
272 #endif
273
274 extern int __put_user_bad(void)
275 __attribute__((warning("sizeof __put_user argument not 1, 2, 4 or 8")));
276
277 /**
278 * __put_user: - Write a simple value into user space, with less checking.
279 * @x: Value to copy to user space.
280 * @ptr: Destination address, in user space.
281 *
282 * Context: User context only. This function may sleep.
283 *
284 * This macro copies a single simple value from kernel space to user
285 * space. It supports simple types like char and int, but not larger
286 * data types like structures or arrays.
287 *
288 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
289 * to the result of dereferencing @ptr.
290 *
291 * Caller must check the pointer with access_ok() before calling this
292 * function.
293 *
294 * Returns zero on success, or -EFAULT on error.
295 */
296 #define __put_user(x, ptr) \
297 ({ \
298 int __ret; \
299 __chk_user_ptr(ptr); \
300 switch (sizeof(*(ptr))) { \
301 case 1: __put_user_1(x, ptr, __ret); break; \
302 case 2: __put_user_2(x, ptr, __ret); break; \
303 case 4: __put_user_4(x, ptr, __ret); break; \
304 case 8: __put_user_8(x, ptr, __ret); break; \
305 default: __ret = __put_user_bad(); break; \
306 } \
307 __ret; \
308 })
309
310 /*
311 * The versions of get_user and put_user without initial underscores
312 * check the address of their arguments to make sure they are not
313 * in kernel space.
314 */
315 #define put_user(x, ptr) \
316 ({ \
317 __typeof__(*(ptr)) __user *__Pu_addr = (ptr); \
318 access_ok(VERIFY_WRITE, (__Pu_addr), sizeof(*(__Pu_addr))) ? \
319 __put_user((x), (__Pu_addr)) : \
320 -EFAULT; \
321 })
322
323 #define get_user(x, ptr) \
324 ({ \
325 __typeof__(*(ptr)) const __user *__Gu_addr = (ptr); \
326 access_ok(VERIFY_READ, (__Gu_addr), sizeof(*(__Gu_addr))) ? \
327 __get_user((x), (__Gu_addr)) : \
328 ((x) = 0, -EFAULT); \
329 })
330
331 /**
332 * __copy_to_user() - copy data into user space, with less checking.
333 * @to: Destination address, in user space.
334 * @from: Source address, in kernel space.
335 * @n: Number of bytes to copy.
336 *
337 * Context: User context only. This function may sleep.
338 *
339 * Copy data from kernel space to user space. Caller must check
340 * the specified block with access_ok() before calling this function.
341 *
342 * Returns number of bytes that could not be copied.
343 * On success, this will be zero.
344 *
345 * An alternate version - __copy_to_user_inatomic() - is designed
346 * to be called from atomic context, typically bracketed by calls
347 * to pagefault_disable() and pagefault_enable().
348 */
349 extern unsigned long __must_check __copy_to_user_inatomic(
350 void __user *to, const void *from, unsigned long n);
351
352 static inline unsigned long __must_check
__copy_to_user(void __user * to,const void * from,unsigned long n)353 __copy_to_user(void __user *to, const void *from, unsigned long n)
354 {
355 might_fault();
356 return __copy_to_user_inatomic(to, from, n);
357 }
358
359 static inline unsigned long __must_check
copy_to_user(void __user * to,const void * from,unsigned long n)360 copy_to_user(void __user *to, const void *from, unsigned long n)
361 {
362 if (access_ok(VERIFY_WRITE, to, n))
363 n = __copy_to_user(to, from, n);
364 return n;
365 }
366
367 /**
368 * __copy_from_user() - copy data from user space, with less checking.
369 * @to: Destination address, in kernel space.
370 * @from: Source address, in user space.
371 * @n: Number of bytes to copy.
372 *
373 * Context: User context only. This function may sleep.
374 *
375 * Copy data from user space to kernel space. Caller must check
376 * the specified block with access_ok() before calling this function.
377 *
378 * Returns number of bytes that could not be copied.
379 * On success, this will be zero.
380 *
381 * If some data could not be copied, this function will pad the copied
382 * data to the requested size using zero bytes.
383 *
384 * An alternate version - __copy_from_user_inatomic() - is designed
385 * to be called from atomic context, typically bracketed by calls
386 * to pagefault_disable() and pagefault_enable(). This version
387 * does *NOT* pad with zeros.
388 */
389 extern unsigned long __must_check __copy_from_user_inatomic(
390 void *to, const void __user *from, unsigned long n);
391 extern unsigned long __must_check __copy_from_user_zeroing(
392 void *to, const void __user *from, unsigned long n);
393
394 static inline unsigned long __must_check
__copy_from_user(void * to,const void __user * from,unsigned long n)395 __copy_from_user(void *to, const void __user *from, unsigned long n)
396 {
397 might_fault();
398 return __copy_from_user_zeroing(to, from, n);
399 }
400
401 static inline unsigned long __must_check
_copy_from_user(void * to,const void __user * from,unsigned long n)402 _copy_from_user(void *to, const void __user *from, unsigned long n)
403 {
404 if (access_ok(VERIFY_READ, from, n))
405 n = __copy_from_user(to, from, n);
406 else
407 memset(to, 0, n);
408 return n;
409 }
410
411 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
412 /*
413 * There are still unprovable places in the generic code as of 2.6.34, so this
414 * option is not really compatible with -Werror, which is more useful in
415 * general.
416 */
417 extern void copy_from_user_overflow(void)
418 __compiletime_warning("copy_from_user() size is not provably correct");
419
copy_from_user(void * to,const void __user * from,unsigned long n)420 static inline unsigned long __must_check copy_from_user(void *to,
421 const void __user *from,
422 unsigned long n)
423 {
424 int sz = __compiletime_object_size(to);
425
426 if (likely(sz == -1 || sz >= n))
427 n = _copy_from_user(to, from, n);
428 else
429 copy_from_user_overflow();
430
431 return n;
432 }
433 #else
434 #define copy_from_user _copy_from_user
435 #endif
436
437 #ifdef __tilegx__
438 /**
439 * __copy_in_user() - copy data within user space, with less checking.
440 * @to: Destination address, in user space.
441 * @from: Source address, in user space.
442 * @n: Number of bytes to copy.
443 *
444 * Context: User context only. This function may sleep.
445 *
446 * Copy data from user space to user space. Caller must check
447 * the specified blocks with access_ok() before calling this function.
448 *
449 * Returns number of bytes that could not be copied.
450 * On success, this will be zero.
451 */
452 extern unsigned long __copy_in_user_inatomic(
453 void __user *to, const void __user *from, unsigned long n);
454
455 static inline unsigned long __must_check
__copy_in_user(void __user * to,const void __user * from,unsigned long n)456 __copy_in_user(void __user *to, const void __user *from, unsigned long n)
457 {
458 might_fault();
459 return __copy_in_user_inatomic(to, from, n);
460 }
461
462 static inline unsigned long __must_check
copy_in_user(void __user * to,const void __user * from,unsigned long n)463 copy_in_user(void __user *to, const void __user *from, unsigned long n)
464 {
465 if (access_ok(VERIFY_WRITE, to, n) && access_ok(VERIFY_READ, from, n))
466 n = __copy_in_user(to, from, n);
467 return n;
468 }
469 #endif
470
471
472 extern long strnlen_user(const char __user *str, long n);
473 extern long strlen_user(const char __user *str);
474 extern long strncpy_from_user(char *dst, const char __user *src, long);
475
476 /**
477 * clear_user: - Zero a block of memory in user space.
478 * @mem: Destination address, in user space.
479 * @len: Number of bytes to zero.
480 *
481 * Zero a block of memory in user space.
482 *
483 * Returns number of bytes that could not be cleared.
484 * On success, this will be zero.
485 */
486 extern unsigned long clear_user_asm(void __user *mem, unsigned long len);
__clear_user(void __user * mem,unsigned long len)487 static inline unsigned long __must_check __clear_user(
488 void __user *mem, unsigned long len)
489 {
490 might_fault();
491 return clear_user_asm(mem, len);
492 }
clear_user(void __user * mem,unsigned long len)493 static inline unsigned long __must_check clear_user(
494 void __user *mem, unsigned long len)
495 {
496 if (access_ok(VERIFY_WRITE, mem, len))
497 return __clear_user(mem, len);
498 return len;
499 }
500
501 /**
502 * flush_user: - Flush a block of memory in user space from cache.
503 * @mem: Destination address, in user space.
504 * @len: Number of bytes to flush.
505 *
506 * Returns number of bytes that could not be flushed.
507 * On success, this will be zero.
508 */
509 extern unsigned long flush_user_asm(void __user *mem, unsigned long len);
__flush_user(void __user * mem,unsigned long len)510 static inline unsigned long __must_check __flush_user(
511 void __user *mem, unsigned long len)
512 {
513 int retval;
514
515 might_fault();
516 retval = flush_user_asm(mem, len);
517 mb_incoherent();
518 return retval;
519 }
520
flush_user(void __user * mem,unsigned long len)521 static inline unsigned long __must_check flush_user(
522 void __user *mem, unsigned long len)
523 {
524 if (access_ok(VERIFY_WRITE, mem, len))
525 return __flush_user(mem, len);
526 return len;
527 }
528
529 /**
530 * finv_user: - Flush-inval a block of memory in user space from cache.
531 * @mem: Destination address, in user space.
532 * @len: Number of bytes to invalidate.
533 *
534 * Returns number of bytes that could not be flush-invalidated.
535 * On success, this will be zero.
536 */
537 extern unsigned long finv_user_asm(void __user *mem, unsigned long len);
__finv_user(void __user * mem,unsigned long len)538 static inline unsigned long __must_check __finv_user(
539 void __user *mem, unsigned long len)
540 {
541 int retval;
542
543 might_fault();
544 retval = finv_user_asm(mem, len);
545 mb_incoherent();
546 return retval;
547 }
finv_user(void __user * mem,unsigned long len)548 static inline unsigned long __must_check finv_user(
549 void __user *mem, unsigned long len)
550 {
551 if (access_ok(VERIFY_WRITE, mem, len))
552 return __finv_user(mem, len);
553 return len;
554 }
555
556 #endif /* _ASM_TILE_UACCESS_H */
557