1 #ifdef __KERNEL__
2 #ifndef _PPC_UACCESS_H
3 #define _PPC_UACCESS_H
4
5 #ifndef __ASSEMBLY__
6 #include <linux/sched.h>
7 #include <linux/errno.h>
8 #include <asm/processor.h>
9
10 #define VERIFY_READ 0
11 #define VERIFY_WRITE 1
12
13 /*
14 * The fs value determines whether argument validity checking should be
15 * performed or not. If get_fs() == USER_DS, checking is performed, with
16 * get_fs() == KERNEL_DS, checking is bypassed.
17 *
18 * For historical reasons, these macros are grossly misnamed.
19 */
20
21 #define KERNEL_DS ((mm_segment_t) { 0 })
22 #define USER_DS ((mm_segment_t) { 1 })
23
24 #define get_ds() (KERNEL_DS)
25 #define get_fs() (current->thread.fs)
26 #define set_fs(val) (current->thread.fs = (val))
27
28 #define segment_eq(a,b) ((a).seg == (b).seg)
29
30 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
31 #define __user_ok(addr,size) (((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size)))
32 #define __access_ok(addr,size) (__kernel_ok || __user_ok((addr),(size)))
33 #define access_ok(type,addr,size) __access_ok((unsigned long)(addr),(size))
34
verify_area(int type,const void * addr,unsigned long size)35 extern inline int verify_area(int type, const void * addr, unsigned long size)
36 {
37 return access_ok(type,addr,size) ? 0 : -EFAULT;
38 }
39
40
41 /*
42 * The exception table consists of pairs of addresses: the first is the
43 * address of an instruction that is allowed to fault, and the second is
44 * the address at which the program should continue. No registers are
45 * modified, so it is entirely up to the continuation code to figure out
46 * what to do.
47 *
48 * All the routines below use bits of fixup code that are out of line
49 * with the main instruction path. This means when everything is well,
50 * we don't even have to jump over them. Further, they do not intrude
51 * on our cache or tlb entries.
52 */
53
54 struct exception_table_entry
55 {
56 unsigned long insn, fixup;
57 };
58
59 /* Returns 0 if exception not found and fixup otherwise. */
60 extern unsigned long search_exception_table(unsigned long);
61 extern void sort_exception_table(void);
62
63 /*
64 * These are the main single-value transfer routines. They automatically
65 * use the right size if we just have the right pointer type.
66 *
67 * This gets kind of ugly. We want to return _two_ values in "get_user()"
68 * and yet we don't want to do any pointers, because that is too much
69 * of a performance impact. Thus we have a few rather ugly macros here,
70 * and hide all the uglyness from the user.
71 *
72 * The "__xxx" versions of the user access functions are versions that
73 * do not verify the address space, that must have been done previously
74 * with a separate "access_ok()" call (this is used when we do multiple
75 * accesses to the same area of user memory).
76 *
77 * As we use the same address space for kernel and user data on the
78 * PowerPC, we can just do these as direct assignments. (Of course, the
79 * exception handling means that it's no longer "just"...)
80 *
81 * The "user64" versions of the user access functions are versions that
82 * allow access of 64-bit data. The "get_user" functions do not
83 * properly handle 64-bit data because the value gets down cast to a long.
84 * The "put_user" functions already handle 64-bit data properly but we add
85 * "user64" versions for completeness
86 */
87 #define get_user(x,ptr) \
88 __get_user_check((x),(ptr),sizeof(*(ptr)))
89 #define get_user64(x,ptr) \
90 __get_user64_check((x),(ptr),sizeof(*(ptr)))
91 #define put_user(x,ptr) \
92 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
93 #define put_user64(x,ptr) put_user(x,ptr)
94
95 #define __get_user(x,ptr) \
96 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
97 #define __get_user64(x,ptr) \
98 __get_user64_nocheck((x),(ptr),sizeof(*(ptr)))
99 #define __put_user(x,ptr) \
100 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
101 #define __put_user64(x,ptr) __put_user(x,ptr)
102
103 extern long __put_user_bad(void);
104
105 #define __put_user_nocheck(x,ptr,size) \
106 ({ \
107 long __pu_err; \
108 __put_user_size((x),(ptr),(size),__pu_err); \
109 __pu_err; \
110 })
111
112 #define __put_user_check(x,ptr,size) \
113 ({ \
114 long __pu_err = -EFAULT; \
115 __typeof__(*(ptr)) *__pu_addr = (ptr); \
116 if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
117 __put_user_size((x),__pu_addr,(size),__pu_err); \
118 __pu_err; \
119 })
120
121 #define __put_user_size(x,ptr,size,retval) \
122 do { \
123 retval = 0; \
124 switch (size) { \
125 case 1: __put_user_asm(x,ptr,retval,"stb"); break; \
126 case 2: __put_user_asm(x,ptr,retval,"sth"); break; \
127 case 4: __put_user_asm(x,ptr,retval,"stw"); break; \
128 case 8: __put_user_asm2(x,ptr,retval); break; \
129 default: __put_user_bad(); \
130 } \
131 } while (0)
132
133 struct __large_struct { unsigned long buf[100]; };
134 #define __m(x) (*(struct __large_struct *)(x))
135
136 /*
137 * We don't tell gcc that we are accessing memory, but this is OK
138 * because we do not write to any memory gcc knows about, so there
139 * are no aliasing issues.
140 */
141 #define __put_user_asm(x, addr, err, op) \
142 __asm__ __volatile__( \
143 "1: "op" %1,0(%2)\n" \
144 "2:\n" \
145 ".section .fixup,\"ax\"\n" \
146 "3: li %0,%3\n" \
147 " b 2b\n" \
148 ".previous\n" \
149 ".section __ex_table,\"a\"\n" \
150 " .align 2\n" \
151 " .long 1b,3b\n" \
152 ".previous" \
153 : "=r"(err) \
154 : "r"(x), "b"(addr), "i"(-EFAULT), "0"(err))
155
156 #define __put_user_asm2(x, addr, err) \
157 __asm__ __volatile__( \
158 "1: stw %1,0(%2)\n" \
159 "2: stw %1+1,4(%2)\n" \
160 "3:\n" \
161 ".section .fixup,\"ax\"\n" \
162 "4: li %0,%3\n" \
163 " b 3b\n" \
164 ".previous\n" \
165 ".section __ex_table,\"a\"\n" \
166 " .align 2\n" \
167 " .long 1b,4b\n" \
168 " .long 2b,4b\n" \
169 ".previous" \
170 : "=r"(err) \
171 : "r"(x), "b"(addr), "i"(-EFAULT), "0"(err))
172
173 #define __get_user_nocheck(x,ptr,size) \
174 ({ \
175 long __gu_err, __gu_val; \
176 __get_user_size(__gu_val,(ptr),(size),__gu_err); \
177 (x) = (__typeof__(*(ptr)))__gu_val; \
178 __gu_err; \
179 })
180
181 #define __get_user64_nocheck(x,ptr,size) \
182 ({ \
183 long __gu_err; \
184 long long __gu_val; \
185 __get_user_size64(__gu_val,(ptr),(size),__gu_err); \
186 (x) = (__typeof__(*(ptr)))__gu_val; \
187 __gu_err; \
188 })
189
190 #define __get_user_check(x,ptr,size) \
191 ({ \
192 long __gu_err = -EFAULT, __gu_val = 0; \
193 const __typeof__(*(ptr)) *__gu_addr = (ptr); \
194 if (access_ok(VERIFY_READ,__gu_addr,size)) \
195 __get_user_size(__gu_val,__gu_addr,(size),__gu_err); \
196 (x) = (__typeof__(*(ptr)))__gu_val; \
197 __gu_err; \
198 })
199
200 #define __get_user64_check(x,ptr,size) \
201 ({ \
202 long __gu_err = -EFAULT; \
203 long long __gu_val = 0; \
204 const __typeof__(*(ptr)) *__gu_addr = (ptr); \
205 if (access_ok(VERIFY_READ,__gu_addr,size)) \
206 __get_user_size64(__gu_val,__gu_addr,(size),__gu_err); \
207 (x) = (__typeof__(*(ptr)))__gu_val; \
208 __gu_err; \
209 })
210
211 extern long __get_user_bad(void);
212
213 #define __get_user_size(x,ptr,size,retval) \
214 do { \
215 retval = 0; \
216 switch (size) { \
217 case 1: __get_user_asm(x,ptr,retval,"lbz"); break; \
218 case 2: __get_user_asm(x,ptr,retval,"lhz"); break; \
219 case 4: __get_user_asm(x,ptr,retval,"lwz"); break; \
220 default: (x) = __get_user_bad(); \
221 } \
222 } while (0)
223
224 #define __get_user_size64(x,ptr,size,retval) \
225 do { \
226 retval = 0; \
227 switch (size) { \
228 case 1: __get_user_asm(x,ptr,retval,"lbz"); break; \
229 case 2: __get_user_asm(x,ptr,retval,"lhz"); break; \
230 case 4: __get_user_asm(x,ptr,retval,"lwz"); break; \
231 case 8: __get_user_asm2(x, ptr, retval); break; \
232 default: (x) = __get_user_bad(); \
233 } \
234 } while (0)
235
236 #define __get_user_asm(x, addr, err, op) \
237 __asm__ __volatile__( \
238 "1: "op" %1,0(%2)\n" \
239 "2:\n" \
240 ".section .fixup,\"ax\"\n" \
241 "3: li %0,%3\n" \
242 " li %1,0\n" \
243 " b 2b\n" \
244 ".previous\n" \
245 ".section __ex_table,\"a\"\n" \
246 " .align 2\n" \
247 " .long 1b,3b\n" \
248 ".previous" \
249 : "=r"(err), "=r"(x) \
250 : "b"(addr), "i"(-EFAULT), "0"(err))
251
252 #define __get_user_asm2(x, addr, err) \
253 __asm__ __volatile__( \
254 "1: lwz %1,0(%2)\n" \
255 "2: lwz %1+1,4(%2)\n" \
256 "3:\n" \
257 ".section .fixup,\"ax\"\n" \
258 "4: li %0,%3\n" \
259 " li %1,0\n" \
260 " li %1+1,0\n" \
261 " b 3b\n" \
262 ".previous\n" \
263 ".section __ex_table,\"a\"\n" \
264 " .align 2\n" \
265 " .long 1b,4b\n" \
266 " .long 2b,4b\n" \
267 ".previous" \
268 : "=r"(err), "=&r"(x) \
269 : "b"(addr), "i"(-EFAULT), "0"(err))
270
271 /* more complex routines */
272
273 extern int __copy_tofrom_user(void *to, const void *from, unsigned long size);
274
275 extern inline unsigned long
copy_from_user(void * to,const void * from,unsigned long n)276 copy_from_user(void *to, const void *from, unsigned long n)
277 {
278 unsigned long over;
279
280 if (access_ok(VERIFY_READ, from, n))
281 return __copy_tofrom_user(to, from, n);
282 if ((unsigned long)from < TASK_SIZE) {
283 over = (unsigned long)from + n - TASK_SIZE;
284 return __copy_tofrom_user(to, from, n - over) + over;
285 }
286 return n;
287 }
288
289 extern inline unsigned long
copy_to_user(void * to,const void * from,unsigned long n)290 copy_to_user(void *to, const void *from, unsigned long n)
291 {
292 unsigned long over;
293
294 if (access_ok(VERIFY_WRITE, to, n))
295 return __copy_tofrom_user(to, from, n);
296 if ((unsigned long)to < TASK_SIZE) {
297 over = (unsigned long)to + n - TASK_SIZE;
298 return __copy_tofrom_user(to, from, n - over) + over;
299 }
300 return n;
301 }
302
303 #define __copy_from_user(to, from, size) \
304 __copy_tofrom_user((to), (from), (size))
305 #define __copy_to_user(to, from, size) \
306 __copy_tofrom_user((to), (from), (size))
307
308 extern unsigned long __clear_user(void *addr, unsigned long size);
309
310 extern inline unsigned long
clear_user(void * addr,unsigned long size)311 clear_user(void *addr, unsigned long size)
312 {
313 if (access_ok(VERIFY_WRITE, addr, size))
314 return __clear_user(addr, size);
315 if ((unsigned long)addr < TASK_SIZE) {
316 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
317 return __clear_user(addr, size - over) + over;
318 }
319 return size;
320 }
321
322 extern int __strncpy_from_user(char *dst, const char *src, long count);
323
324 extern inline long
strncpy_from_user(char * dst,const char * src,long count)325 strncpy_from_user(char *dst, const char *src, long count)
326 {
327 if (access_ok(VERIFY_READ, src, 1))
328 return __strncpy_from_user(dst, src, count);
329 return -EFAULT;
330 }
331
332 /*
333 * Return the size of a string (including the ending 0)
334 *
335 * Return 0 for error
336 */
337
338 extern int __strnlen_user(const char *str, long len, unsigned long top);
339
340 /*
341 * Returns the length of the string at str (including the null byte),
342 * or 0 if we hit a page we can't access,
343 * or something > len if we didn't find a null byte.
344 *
345 * The `top' parameter to __strnlen_user is to make sure that
346 * we can never overflow from the user area into kernel space.
347 */
strnlen_user(const char * str,long len)348 extern __inline__ int strnlen_user(const char *str, long len)
349 {
350 unsigned long top = __kernel_ok? ~0UL: TASK_SIZE - 1;
351
352 if ((unsigned long)str > top)
353 return 0;
354 return __strnlen_user(str, len, top);
355 }
356
357 #define strlen_user(str) strnlen_user((str), 0x7ffffffe)
358
359 #endif /* __ASSEMBLY__ */
360
361 #endif /* _PPC_UACCESS_H */
362 #endif /* __KERNEL__ */
363