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Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / include / asm-powerpc / uaccess.h
blob8e798e3758bc38137ca15d2f0e23c954e0339c26
1 #ifndef _ARCH_POWERPC_UACCESS_H
2 #define _ARCH_POWERPC_UACCESS_H
3
4 #ifdef __KERNEL__
5 #ifndef __ASSEMBLY__
6
7 #include <linux/sched.h>
8 #include <linux/errno.h>
9 #include <asm/processor.h>
10 #include <asm/page.h>
11
12 #define VERIFY_READ 0
13 #define VERIFY_WRITE 1
14
15 /*
16 * The fs value determines whether argument validity checking should be
17 * performed or not. If get_fs() == USER_DS, checking is performed, with
18 * get_fs() == KERNEL_DS, checking is bypassed.
19 *
20 * For historical reasons, these macros are grossly misnamed.
21 *
22 * The fs/ds values are now the highest legal address in the "segment".
23 * This simplifies the checking in the routines below.
24 */
25
26 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
27
28 #define KERNEL_DS MAKE_MM_SEG(~0UL)
29 #ifdef __powerpc64__
30 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
31 #define USER_DS MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
32 #else
33 #define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
34 #endif
35
36 #define get_ds() (KERNEL_DS)
37 #define get_fs() (current->thread.fs)
38 #define set_fs(val) (current->thread.fs = (val))
39
40 #define segment_eq(a, b) ((a).seg == (b).seg)
41
42 #ifdef __powerpc64__
43 /*
44 * This check is sufficient because there is a large enough
45 * gap between user addresses and the kernel addresses
46 */
47 #define __access_ok(addr, size, segment) \
48 (((addr) <= (segment).seg) && ((size) <= (segment).seg))
49
50 #else
51
52 #define __access_ok(addr, size, segment) \
53 (((addr) <= (segment).seg) && \
54 (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
55
56 #endif
57
58 #define access_ok(type, addr, size) \
59 (__chk_user_ptr(addr), \
60 __access_ok((__force unsigned long)(addr), (size), get_fs()))
61
62 /*
63 * The exception table consists of pairs of addresses: the first is the
64 * address of an instruction that is allowed to fault, and the second is
65 * the address at which the program should continue. No registers are
66 * modified, so it is entirely up to the continuation code to figure out
67 * what to do.
68 *
69 * All the routines below use bits of fixup code that are out of line
70 * with the main instruction path. This means when everything is well,
71 * we don't even have to jump over them. Further, they do not intrude
72 * on our cache or tlb entries.
73 */
74
75 struct exception_table_entry {
76 unsigned long insn;
77 unsigned long fixup;
78 };
79
80 /*
81 * These are the main single-value transfer routines. They automatically
82 * use the right size if we just have the right pointer type.
83 *
84 * This gets kind of ugly. We want to return _two_ values in "get_user()"
85 * and yet we don't want to do any pointers, because that is too much
86 * of a performance impact. Thus we have a few rather ugly macros here,
87 * and hide all the ugliness from the user.
88 *
89 * The "__xxx" versions of the user access functions are versions that
90 * do not verify the address space, that must have been done previously
91 * with a separate "access_ok()" call (this is used when we do multiple
92 * accesses to the same area of user memory).
93 *
94 * As we use the same address space for kernel and user data on the
95 * PowerPC, we can just do these as direct assignments. (Of course, the
96 * exception handling means that it's no longer "just"...)
97 *
98 * The "user64" versions of the user access functions are versions that
99 * allow access of 64-bit data. The "get_user" functions do not
100 * properly handle 64-bit data because the value gets down cast to a long.
101 * The "put_user" functions already handle 64-bit data properly but we add
102 * "user64" versions for completeness
103 */
104 #define get_user(x, ptr) \
105 __get_user_check((x), (ptr), sizeof(*(ptr)))
106 #define put_user(x, ptr) \
107 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
108
109 #define __get_user(x, ptr) \
110 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
111 #define __put_user(x, ptr) \
112 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
113
114 #ifndef __powerpc64__
115 #define __get_user64(x, ptr) \
116 __get_user64_nocheck((x), (ptr), sizeof(*(ptr)))
117 #define __put_user64(x, ptr) __put_user(x, ptr)
118 #endif
119
120 #define __get_user_inatomic(x, ptr) \
121 __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
122 #define __put_user_inatomic(x, ptr) \
123 __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
124
125 #define __get_user_unaligned __get_user
126 #define __put_user_unaligned __put_user
127
128 extern long __put_user_bad(void);
129
130 /*
131 * We don't tell gcc that we are accessing memory, but this is OK
132 * because we do not write to any memory gcc knows about, so there
133 * are no aliasing issues.
134 */
135 #define __put_user_asm(x, addr, err, op) \
136 __asm__ __volatile__( \
137 "1: " op " %1,0(%2) # put_user\n" \
138 "2:\n" \
139 ".section .fixup,\"ax\"\n" \
140 "3: li %0,%3\n" \
141 " b 2b\n" \
142 ".previous\n" \
143 ".section __ex_table,\"a\"\n" \
144 " .balign %5\n" \
145 PPC_LONG "1b,3b\n" \
146 ".previous" \
147 : "=r" (err) \
148 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err),\
149 "i"(sizeof(unsigned long)))
150
151 #ifdef __powerpc64__
152 #define __put_user_asm2(x, ptr, retval) \
153 __put_user_asm(x, ptr, retval, "std")
154 #else /* __powerpc64__ */
155 #define __put_user_asm2(x, addr, err) \
156 __asm__ __volatile__( \
157 "1: stw %1,0(%2)\n" \
158 "2: stw %1+1,4(%2)\n" \
159 "3:\n" \
160 ".section .fixup,\"ax\"\n" \
161 "4: li %0,%3\n" \
162 " b 3b\n" \
163 ".previous\n" \
164 ".section __ex_table,\"a\"\n" \
165 " .balign %5\n" \
166 PPC_LONG "1b,4b\n" \
167 PPC_LONG "2b,4b\n" \
168 ".previous" \
169 : "=r" (err) \
170 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err),\
171 "i"(sizeof(unsigned long)))
172 #endif /* __powerpc64__ */
173
174 #define __put_user_size(x, ptr, size, retval) \
175 do { \
176 retval = 0; \
177 switch (size) { \
178 case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
179 case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
180 case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
181 case 8: __put_user_asm2(x, ptr, retval); break; \
182 default: __put_user_bad(); \
183 } \
184 } while (0)
185
186 #define __put_user_nocheck(x, ptr, size) \
187 ({ \
188 long __pu_err; \
189 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
190 if (!is_kernel_addr((unsigned long)__pu_addr)) \
191 might_sleep(); \
192 __chk_user_ptr(ptr); \
193 __put_user_size((x), __pu_addr, (size), __pu_err); \
194 __pu_err; \
195 })
196
197 #define __put_user_check(x, ptr, size) \
198 ({ \
199 long __pu_err = -EFAULT; \
200 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
201 might_sleep(); \
202 if (access_ok(VERIFY_WRITE, __pu_addr, size)) \
203 __put_user_size((x), __pu_addr, (size), __pu_err); \
204 __pu_err; \
205 })
206
207 #define __put_user_nosleep(x, ptr, size) \
208 ({ \
209 long __pu_err; \
210 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
211 __chk_user_ptr(ptr); \
212 __put_user_size((x), __pu_addr, (size), __pu_err); \
213 __pu_err; \
214 })
215
216
217 extern long __get_user_bad(void);
218
219 #define __get_user_asm(x, addr, err, op) \
220 __asm__ __volatile__( \
221 "1: "op" %1,0(%2) # get_user\n" \
222 "2:\n" \
223 ".section .fixup,\"ax\"\n" \
224 "3: li %0,%3\n" \
225 " li %1,0\n" \
226 " b 2b\n" \
227 ".previous\n" \
228 ".section __ex_table,\"a\"\n" \
229 " .balign %5\n" \
230 PPC_LONG "1b,3b\n" \
231 ".previous" \
232 : "=r" (err), "=r" (x) \
233 : "b" (addr), "i" (-EFAULT), "0" (err), \
234 "i"(sizeof(unsigned long)))
235
236 #ifdef __powerpc64__
237 #define __get_user_asm2(x, addr, err) \
238 __get_user_asm(x, addr, err, "ld")
239 #else /* __powerpc64__ */
240 #define __get_user_asm2(x, addr, err) \
241 __asm__ __volatile__( \
242 "1: lwz %1,0(%2)\n" \
243 "2: lwz %1+1,4(%2)\n" \
244 "3:\n" \
245 ".section .fixup,\"ax\"\n" \
246 "4: li %0,%3\n" \
247 " li %1,0\n" \
248 " li %1+1,0\n" \
249 " b 3b\n" \
250 ".previous\n" \
251 ".section __ex_table,\"a\"\n" \
252 " .balign %5\n" \
253 PPC_LONG "1b,4b\n" \
254 PPC_LONG "2b,4b\n" \
255 ".previous" \
256 : "=r" (err), "=&r" (x) \
257 : "b" (addr), "i" (-EFAULT), "0" (err), \
258 "i"(sizeof(unsigned long)))
259 #endif /* __powerpc64__ */
260
261 #define __get_user_size(x, ptr, size, retval) \
262 do { \
263 retval = 0; \
264 __chk_user_ptr(ptr); \
265 if (size > sizeof(x)) \
266 (x) = __get_user_bad(); \
267 switch (size) { \
268 case 1: __get_user_asm(x, ptr, retval, "lbz"); break; \
269 case 2: __get_user_asm(x, ptr, retval, "lhz"); break; \
270 case 4: __get_user_asm(x, ptr, retval, "lwz"); break; \
271 case 8: __get_user_asm2(x, ptr, retval); break; \
272 default: (x) = __get_user_bad(); \
273 } \
274 } while (0)
275
276 #define __get_user_nocheck(x, ptr, size) \
277 ({ \
278 long __gu_err; \
279 unsigned long __gu_val; \
280 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
281 __chk_user_ptr(ptr); \
282 if (!is_kernel_addr((unsigned long)__gu_addr)) \
283 might_sleep(); \
284 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
285 (x) = (__typeof__(*(ptr)))__gu_val; \
286 __gu_err; \
287 })
288
289 #ifndef __powerpc64__
290 #define __get_user64_nocheck(x, ptr, size) \
291 ({ \
292 long __gu_err; \
293 long long __gu_val; \
294 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
295 __chk_user_ptr(ptr); \
296 if (!is_kernel_addr((unsigned long)__gu_addr)) \
297 might_sleep(); \
298 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
299 (x) = (__typeof__(*(ptr)))__gu_val; \
300 __gu_err; \
301 })
302 #endif /* __powerpc64__ */
303
304 #define __get_user_check(x, ptr, size) \
305 ({ \
306 long __gu_err = -EFAULT; \
307 unsigned long __gu_val = 0; \
308 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
309 might_sleep(); \
310 if (access_ok(VERIFY_READ, __gu_addr, (size))) \
311 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
312 (x) = (__typeof__(*(ptr)))__gu_val; \
313 __gu_err; \
314 })
315
316 #define __get_user_nosleep(x, ptr, size) \
317 ({ \
318 long __gu_err; \
319 unsigned long __gu_val; \
320 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
321 __chk_user_ptr(ptr); \
322 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
323 (x) = (__typeof__(*(ptr)))__gu_val; \
324 __gu_err; \
325 })
326
327
328 /* more complex routines */
329
330 extern unsigned long __copy_tofrom_user(void __user *to,
331 const void __user *from, unsigned long size);
332
333 #ifndef __powerpc64__
334
335 static inline unsigned long copy_from_user(void *to,
336 const void __user *from, unsigned long n)
337 {
338 unsigned long over;
339
340 if (access_ok(VERIFY_READ, from, n))
341 return __copy_tofrom_user((__force void __user *)to, from, n);
342 if ((unsigned long)from < TASK_SIZE) {
343 over = (unsigned long)from + n - TASK_SIZE;
344 return __copy_tofrom_user((__force void __user *)to, from,
345 n - over) + over;
346 }
347 return n;
348 }
349
350 static inline unsigned long copy_to_user(void __user *to,
351 const void *from, unsigned long n)
352 {
353 unsigned long over;
354
355 if (access_ok(VERIFY_WRITE, to, n))
356 return __copy_tofrom_user(to, (__force void __user *)from, n);
357 if ((unsigned long)to < TASK_SIZE) {
358 over = (unsigned long)to + n - TASK_SIZE;
359 return __copy_tofrom_user(to, (__force void __user *)from,
360 n - over) + over;
361 }
362 return n;
363 }
364
365 #else /* __powerpc64__ */
366
367 #define __copy_in_user(to, from, size) \
368 __copy_tofrom_user((to), (from), (size))
369
370 extern unsigned long copy_from_user(void *to, const void __user *from,
371 unsigned long n);
372 extern unsigned long copy_to_user(void __user *to, const void *from,
373 unsigned long n);
374 extern unsigned long copy_in_user(void __user *to, const void __user *from,
375 unsigned long n);
376
377 #endif /* __powerpc64__ */
378
379 static inline unsigned long __copy_from_user_inatomic(void *to,
380 const void __user *from, unsigned long n)
381 {
382 if (__builtin_constant_p(n) && (n <= 8)) {
383 unsigned long ret;
384
385 switch (n) {
386 case 1:
387 __get_user_size(*(u8 *)to, from, 1, ret);
388 break;
389 case 2:
390 __get_user_size(*(u16 *)to, from, 2, ret);
391 break;
392 case 4:
393 __get_user_size(*(u32 *)to, from, 4, ret);
394 break;
395 case 8:
396 __get_user_size(*(u64 *)to, from, 8, ret);
397 break;
398 }
399 if (ret == 0)
400 return 0;
401 }
402 return __copy_tofrom_user((__force void __user *)to, from, n);
403 }
404
405 static inline unsigned long __copy_to_user_inatomic(void __user *to,
406 const void *from, unsigned long n)
407 {
408 if (__builtin_constant_p(n) && (n <= 8)) {
409 unsigned long ret;
410
411 switch (n) {
412 case 1:
413 __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
414 break;
415 case 2:
416 __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
417 break;
418 case 4:
419 __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
420 break;
421 case 8:
422 __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
423 break;
424 }
425 if (ret == 0)
426 return 0;
427 }
428 return __copy_tofrom_user(to, (__force const void __user *)from, n);
429 }
430
431 static inline unsigned long __copy_from_user(void *to,
432 const void __user *from, unsigned long size)
433 {
434 might_sleep();
435 return __copy_from_user_inatomic(to, from, size);
436 }
437
438 static inline unsigned long __copy_to_user(void __user *to,
439 const void *from, unsigned long size)
440 {
441 might_sleep();
442 return __copy_to_user_inatomic(to, from, size);
443 }
444
445 extern unsigned long __clear_user(void __user *addr, unsigned long size);
446
447 static inline unsigned long clear_user(void __user *addr, unsigned long size)
448 {
449 might_sleep();
450 if (likely(access_ok(VERIFY_WRITE, addr, size)))
451 return __clear_user(addr, size);
452 if ((unsigned long)addr < TASK_SIZE) {
453 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
454 return __clear_user(addr, size - over) + over;
455 }
456 return size;
457 }
458
459 extern int __strncpy_from_user(char *dst, const char __user *src, long count);
460
461 static inline long strncpy_from_user(char *dst, const char __user *src,
462 long count)
463 {
464 might_sleep();
465 if (likely(access_ok(VERIFY_READ, src, 1)))
466 return __strncpy_from_user(dst, src, count);
467 return -EFAULT;
468 }
469
470 /*
471 * Return the size of a string (including the ending 0)
472 *
473 * Return 0 for error
474 */
475 extern int __strnlen_user(const char __user *str, long len, unsigned long top);
476
477 /*
478 * Returns the length of the string at str (including the null byte),
479 * or 0 if we hit a page we can't access,
480 * or something > len if we didn't find a null byte.
481 *
482 * The `top' parameter to __strnlen_user is to make sure that
483 * we can never overflow from the user area into kernel space.
484 */
485 static inline int strnlen_user(const char __user *str, long len)
486 {
487 unsigned long top = current->thread.fs.seg;
488
489 if ((unsigned long)str > top)
490 return 0;
491 return __strnlen_user(str, len, top);
492 }
493
494 #define strlen_user(str) strnlen_user((str), 0x7ffffffe)
495
496 #endif /* __ASSEMBLY__ */
497 #endif /* __KERNEL__ */
498
499 #endif /* _ARCH_POWERPC_UACCESS_H */
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