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-rw-r--r--include/asm-powerpc/uaccess.h468
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diff --git a/include/asm-powerpc/uaccess.h b/include/asm-powerpc/uaccess.h
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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
11#define VERIFY_READ 0
12#define VERIFY_WRITE 1
13
14/*
15 * The fs value determines whether argument validity checking should be
16 * performed or not. If get_fs() == USER_DS, checking is performed, with
17 * get_fs() == KERNEL_DS, checking is bypassed.
18 *
19 * For historical reasons, these macros are grossly misnamed.
20 *
21 * The fs/ds values are now the highest legal address in the "segment".
22 * This simplifies the checking in the routines below.
23 */
24
25#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
26
27#define KERNEL_DS MAKE_MM_SEG(~0UL)
28#ifdef __powerpc64__
29/* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
30#define USER_DS MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
31#else
32#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
33#endif
34
35#define get_ds() (KERNEL_DS)
36#define get_fs() (current->thread.fs)
37#define set_fs(val) (current->thread.fs = (val))
38
39#define segment_eq(a, b) ((a).seg == (b).seg)
40
41#ifdef __powerpc64__
42/*
43 * This check is sufficient because there is a large enough
44 * gap between user addresses and the kernel addresses
45 */
46#define __access_ok(addr, size, segment) \
47 (((addr) <= (segment).seg) && ((size) <= (segment).seg))
48
49#else
50
51#define __access_ok(addr, size, segment) \
52 (((addr) <= (segment).seg) && \
53 (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
54
55#endif
56
57#define access_ok(type, addr, size) \
58 (__chk_user_ptr(addr), \
59 __access_ok((__force unsigned long)(addr), (size), get_fs()))
60
61/*
62 * The exception table consists of pairs of addresses: the first is the
63 * address of an instruction that is allowed to fault, and the second is
64 * the address at which the program should continue. No registers are
65 * modified, so it is entirely up to the continuation code to figure out
66 * what to do.
67 *
68 * All the routines below use bits of fixup code that are out of line
69 * with the main instruction path. This means when everything is well,
70 * we don't even have to jump over them. Further, they do not intrude
71 * on our cache or tlb entries.
72 */
73
74struct exception_table_entry {
75 unsigned long insn;
76 unsigned long fixup;
77};
78
79/*
80 * These are the main single-value transfer routines. They automatically
81 * use the right size if we just have the right pointer type.
82 *
83 * This gets kind of ugly. We want to return _two_ values in "get_user()"
84 * and yet we don't want to do any pointers, because that is too much
85 * of a performance impact. Thus we have a few rather ugly macros here,
86 * and hide all the ugliness from the user.
87 *
88 * The "__xxx" versions of the user access functions are versions that
89 * do not verify the address space, that must have been done previously
90 * with a separate "access_ok()" call (this is used when we do multiple
91 * accesses to the same area of user memory).
92 *
93 * As we use the same address space for kernel and user data on the
94 * PowerPC, we can just do these as direct assignments. (Of course, the
95 * exception handling means that it's no longer "just"...)
96 *
97 * The "user64" versions of the user access functions are versions that
98 * allow access of 64-bit data. The "get_user" functions do not
99 * properly handle 64-bit data because the value gets down cast to a long.
100 * The "put_user" functions already handle 64-bit data properly but we add
101 * "user64" versions for completeness
102 */
103#define get_user(x, ptr) \
104 __get_user_check((x), (ptr), sizeof(*(ptr)))
105#define put_user(x, ptr) \
106 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
107
108#define __get_user(x, ptr) \
109 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
110#define __put_user(x, ptr) \
111 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
112#ifndef __powerpc64__
113#define __get_user64(x, ptr) \
114 __get_user64_nocheck((x), (ptr), sizeof(*(ptr)))
115#define __put_user64(x, ptr) __put_user(x, ptr)
116#endif
117
118#define __get_user_unaligned __get_user
119#define __put_user_unaligned __put_user
120
121extern long __put_user_bad(void);
122
123#ifdef __powerpc64__
124#define __EX_TABLE_ALIGN "3"
125#define __EX_TABLE_TYPE "llong"
126#else
127#define __EX_TABLE_ALIGN "2"
128#define __EX_TABLE_TYPE "long"
129#endif
130
131/*
132 * We don't tell gcc that we are accessing memory, but this is OK
133 * because we do not write to any memory gcc knows about, so there
134 * are no aliasing issues.
135 */
136#define __put_user_asm(x, addr, err, op) \
137 __asm__ __volatile__( \
138 "1: " op " %1,0(%2) # put_user\n" \
139 "2:\n" \
140 ".section .fixup,\"ax\"\n" \
141 "3: li %0,%3\n" \
142 " b 2b\n" \
143 ".previous\n" \
144 ".section __ex_table,\"a\"\n" \
145 " .align " __EX_TABLE_ALIGN "\n" \
146 " ."__EX_TABLE_TYPE" 1b,3b\n" \
147 ".previous" \
148 : "=r" (err) \
149 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
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 " .align " __EX_TABLE_ALIGN "\n" \
166 " ." __EX_TABLE_TYPE " 1b,4b\n" \
167 " ." __EX_TABLE_TYPE " 2b,4b\n" \
168 ".previous" \
169 : "=r" (err) \
170 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
171#endif /* __powerpc64__ */
172
173#define __put_user_size(x, ptr, size, retval) \
174do { \
175 retval = 0; \
176 switch (size) { \
177 case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
178 case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
179 case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
180 case 8: __put_user_asm2(x, ptr, retval); break; \
181 default: __put_user_bad(); \
182 } \
183} while (0)
184
185#define __put_user_nocheck(x, ptr, size) \
186({ \
187 long __pu_err; \
188 might_sleep(); \
189 __chk_user_ptr(ptr); \
190 __put_user_size((x), (ptr), (size), __pu_err); \
191 __pu_err; \
192})
193
194#define __put_user_check(x, ptr, size) \
195({ \
196 long __pu_err = -EFAULT; \
197 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
198 might_sleep(); \
199 if (access_ok(VERIFY_WRITE, __pu_addr, size)) \
200 __put_user_size((x), __pu_addr, (size), __pu_err); \
201 __pu_err; \
202})
203
204extern long __get_user_bad(void);
205
206#define __get_user_asm(x, addr, err, op) \
207 __asm__ __volatile__( \
208 "1: "op" %1,0(%2) # get_user\n" \
209 "2:\n" \
210 ".section .fixup,\"ax\"\n" \
211 "3: li %0,%3\n" \
212 " li %1,0\n" \
213 " b 2b\n" \
214 ".previous\n" \
215 ".section __ex_table,\"a\"\n" \
216 " .align "__EX_TABLE_ALIGN "\n" \
217 " ." __EX_TABLE_TYPE " 1b,3b\n" \
218 ".previous" \
219 : "=r" (err), "=r" (x) \
220 : "b" (addr), "i" (-EFAULT), "0" (err))
221
222#ifdef __powerpc64__
223#define __get_user_asm2(x, addr, err) \
224 __get_user_asm(x, addr, err, "ld")
225#else /* __powerpc64__ */
226#define __get_user_asm2(x, addr, err) \
227 __asm__ __volatile__( \
228 "1: lwz %1,0(%2)\n" \
229 "2: lwz %1+1,4(%2)\n" \
230 "3:\n" \
231 ".section .fixup,\"ax\"\n" \
232 "4: li %0,%3\n" \
233 " li %1,0\n" \
234 " li %1+1,0\n" \
235 " b 3b\n" \
236 ".previous\n" \
237 ".section __ex_table,\"a\"\n" \
238 " .align " __EX_TABLE_ALIGN "\n" \
239 " ." __EX_TABLE_TYPE " 1b,4b\n" \
240 " ." __EX_TABLE_TYPE " 2b,4b\n" \
241 ".previous" \
242 : "=r" (err), "=&r" (x) \
243 : "b" (addr), "i" (-EFAULT), "0" (err))
244#endif /* __powerpc64__ */
245
246#define __get_user_size(x, ptr, size, retval) \
247do { \
248 retval = 0; \
249 __chk_user_ptr(ptr); \
250 if (size > sizeof(x)) \
251 (x) = __get_user_bad(); \
252 switch (size) { \
253 case 1: __get_user_asm(x, ptr, retval, "lbz"); break; \
254 case 2: __get_user_asm(x, ptr, retval, "lhz"); break; \
255 case 4: __get_user_asm(x, ptr, retval, "lwz"); break; \
256 case 8: __get_user_asm2(x, ptr, retval); break; \
257 default: (x) = __get_user_bad(); \
258 } \
259} while (0)
260
261#define __get_user_nocheck(x, ptr, size) \
262({ \
263 long __gu_err; \
264 unsigned long __gu_val; \
265 __chk_user_ptr(ptr); \
266 might_sleep(); \
267 __get_user_size(__gu_val, (ptr), (size), __gu_err); \
268 (x) = (__typeof__(*(ptr)))__gu_val; \
269 __gu_err; \
270})
271
272#ifndef __powerpc64__
273#define __get_user64_nocheck(x, ptr, size) \
274({ \
275 long __gu_err; \
276 long long __gu_val; \
277 __chk_user_ptr(ptr); \
278 might_sleep(); \
279 __get_user_size(__gu_val, (ptr), (size), __gu_err); \
280 (x) = (__typeof__(*(ptr)))__gu_val; \
281 __gu_err; \
282})
283#endif /* __powerpc64__ */
284
285#define __get_user_check(x, ptr, size) \
286({ \
287 long __gu_err = -EFAULT; \
288 unsigned long __gu_val = 0; \
289 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
290 might_sleep(); \
291 if (access_ok(VERIFY_READ, __gu_addr, (size))) \
292 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
293 (x) = (__typeof__(*(ptr)))__gu_val; \
294 __gu_err; \
295})
296
297/* more complex routines */
298
299extern unsigned long __copy_tofrom_user(void __user *to,
300 const void __user *from, unsigned long size);
301
302#ifndef __powerpc64__
303
304extern inline unsigned long copy_from_user(void *to,
305 const void __user *from, unsigned long n)
306{
307 unsigned long over;
308
309 if (access_ok(VERIFY_READ, from, n))
310 return __copy_tofrom_user((__force void __user *)to, from, n);
311 if ((unsigned long)from < TASK_SIZE) {
312 over = (unsigned long)from + n - TASK_SIZE;
313 return __copy_tofrom_user((__force void __user *)to, from,
314 n - over) + over;
315 }
316 return n;
317}
318
319extern inline unsigned long copy_to_user(void __user *to,
320 const void *from, unsigned long n)
321{
322 unsigned long over;
323
324 if (access_ok(VERIFY_WRITE, to, n))
325 return __copy_tofrom_user(to, (__force void __user *)from, n);
326 if ((unsigned long)to < TASK_SIZE) {
327 over = (unsigned long)to + n - TASK_SIZE;
328 return __copy_tofrom_user(to, (__force void __user *)from,
329 n - over) + over;
330 }
331 return n;
332}
333
334#else /* __powerpc64__ */
335
336#define __copy_in_user(to, from, size) \
337 __copy_tofrom_user((to), (from), (size))
338
339extern unsigned long copy_from_user(void *to, const void __user *from,
340 unsigned long n);
341extern unsigned long copy_to_user(void __user *to, const void *from,
342 unsigned long n);
343extern unsigned long copy_in_user(void __user *to, const void __user *from,
344 unsigned long n);
345
346#endif /* __powerpc64__ */
347
348static inline unsigned long __copy_from_user_inatomic(void *to,
349 const void __user *from, unsigned long n)
350{
351 if (__builtin_constant_p(n) && (n <= 8)) {
352 unsigned long ret;
353
354 switch (n) {
355 case 1:
356 __get_user_size(*(u8 *)to, from, 1, ret);
357 break;
358 case 2:
359 __get_user_size(*(u16 *)to, from, 2, ret);
360 break;
361 case 4:
362 __get_user_size(*(u32 *)to, from, 4, ret);
363 break;
364 case 8:
365 __get_user_size(*(u64 *)to, from, 8, ret);
366 break;
367 }
368 if (ret == 0)
369 return 0;
370 }
371 return __copy_tofrom_user((__force void __user *)to, from, n);
372}
373
374static inline unsigned long __copy_to_user_inatomic(void __user *to,
375 const void *from, unsigned long n)
376{
377 if (__builtin_constant_p(n) && (n <= 8)) {
378 unsigned long ret;
379
380 switch (n) {
381 case 1:
382 __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
383 break;
384 case 2:
385 __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
386 break;
387 case 4:
388 __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
389 break;
390 case 8:
391 __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
392 break;
393 }
394 if (ret == 0)
395 return 0;
396 }
397 return __copy_tofrom_user(to, (__force const void __user *)from, n);
398}
399
400static inline unsigned long __copy_from_user(void *to,
401 const void __user *from, unsigned long size)
402{
403 might_sleep();
404 return __copy_from_user_inatomic(to, from, size);
405}
406
407static inline unsigned long __copy_to_user(void __user *to,
408 const void *from, unsigned long size)
409{
410 might_sleep();
411 return __copy_to_user_inatomic(to, from, size);
412}
413
414extern unsigned long __clear_user(void __user *addr, unsigned long size);
415
416static inline unsigned long clear_user(void __user *addr, unsigned long size)
417{
418 might_sleep();
419 if (likely(access_ok(VERIFY_WRITE, addr, size)))
420 return __clear_user(addr, size);
421 if ((unsigned long)addr < TASK_SIZE) {
422 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
423 return __clear_user(addr, size - over) + over;
424 }
425 return size;
426}
427
428extern int __strncpy_from_user(char *dst, const char __user *src, long count);
429
430static inline long strncpy_from_user(char *dst, const char __user *src,
431 long count)
432{
433 might_sleep();
434 if (likely(access_ok(VERIFY_READ, src, 1)))
435 return __strncpy_from_user(dst, src, count);
436 return -EFAULT;
437}
438
439/*
440 * Return the size of a string (including the ending 0)
441 *
442 * Return 0 for error
443 */
444extern int __strnlen_user(const char __user *str, long len, unsigned long top);
445
446/*
447 * Returns the length of the string at str (including the null byte),
448 * or 0 if we hit a page we can't access,
449 * or something > len if we didn't find a null byte.
450 *
451 * The `top' parameter to __strnlen_user is to make sure that
452 * we can never overflow from the user area into kernel space.
453 */
454static inline int strnlen_user(const char __user *str, long len)
455{
456 unsigned long top = current->thread.fs.seg;
457
458 if ((unsigned long)str > top)
459 return 0;
460 return __strnlen_user(str, len, top);
461}
462
463#define strlen_user(str) strnlen_user((str), 0x7ffffffe)
464
465#endif /* __ASSEMBLY__ */
466#endif /* __KERNEL__ */
467
468#endif /* _ARCH_POWERPC_UACCESS_H */
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