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
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 #define get_user(x,ptr) \
82 __get_user_check((x),(ptr),sizeof(*(ptr)))
83 #define put_user(x,ptr) \
84 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
85
86 #define __get_user(x,ptr) \
87 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
88 #define __put_user(x,ptr) \
89 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
90
91 extern long __put_user_bad(void);
92
93 #define __put_user_nocheck(x,ptr,size) \
94 ({ \
95 long __pu_err; \
96 __put_user_size((x),(ptr),(size),__pu_err); \
97 __pu_err; \
98 })
99
100 #define __put_user_check(x,ptr,size) \
101 ({ \
102 long __pu_err = -EFAULT; \
103 __typeof__(*(ptr)) *__pu_addr = (ptr); \
104 if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
105 __put_user_size((x),__pu_addr,(size),__pu_err); \
106 __pu_err; \
107 })
108
109 #define __put_user_size(x,ptr,size,retval) \
110 do { \
111 retval = 0; \
112 switch (size) { \
113 case 1: __put_user_asm(x,ptr,retval,"stb"); break; \
114 case 2: __put_user_asm(x,ptr,retval,"sth"); break; \
115 case 4: __put_user_asm(x,ptr,retval,"stw"); break; \
116 default: __put_user_bad(); \
117 } \
118 } while (0)
119
120 struct __large_struct { unsigned long buf[100]; };
121 #define __m(x) (*(struct __large_struct *)(x))
122
123 /*
124 * We don't tell gcc that we are accessing memory, but this is OK
125 * because we do not write to any memory gcc knows about, so there
126 * are no aliasing issues.
127 */
128 #define __put_user_asm(x, addr, err, op) \
129 __asm__ __volatile__( \
130 "1: "op" %1,0(%2)\n" \
131 "2:\n" \
132 ".section .fixup,\"ax\"\n" \
133 "3: li %0,%3\n" \
134 " b 2b\n" \
135 ".previous\n" \
136 ".section __ex_table,\"a\"\n" \
137 " .align 2\n" \
138 " .long 1b,3b\n" \
139 ".previous" \
140 : "=r"(err) \
141 : "r"(x), "b"(addr), "i"(-EFAULT), ""(err))
142
143
144 #define __get_user_nocheck(x,ptr,size) \
145 ({ \
146 long __gu_err, __gu_val; \
147 __get_user_size(__gu_val,(ptr),(size),__gu_err); \
148 (x) = (__typeof__(*(ptr)))__gu_val; \
149 __gu_err; \
150 })
151
152 #define __get_user_check(x,ptr,size) \
153 ({ \
154 long __gu_err = -EFAULT, __gu_val = 0; \
155 const __typeof__(*(ptr)) *__gu_addr = (ptr); \
156 if (access_ok(VERIFY_READ,__gu_addr,size)) \
157 __get_user_size(__gu_val,__gu_addr,(size),__gu_err); \
158 (x) = (__typeof__(*(ptr)))__gu_val; \
159 __gu_err; \
160 })
161
162 extern long __get_user_bad(void);
163
164 #define __get_user_size(x,ptr,size,retval) \
165 do { \
166 retval = 0; \
167 switch (size) { \
168 case 1: __get_user_asm(x,ptr,retval,"lbz"); break; \
169 case 2: __get_user_asm(x,ptr,retval,"lhz"); break; \
170 case 4: __get_user_asm(x,ptr,retval,"lwz"); break; \
171 default: (x) = __get_user_bad(); \
172 } \
173 } while (0)
174
175 #define __get_user_asm(x, addr, err, op) \
176 __asm__ __volatile__( \
177 "1: "op" %1,0(%2)\n" \
178 "2:\n" \
179 ".section .fixup,\"ax\"\n" \
180 "3: li %0,%3\n" \
181 " li %1,0\n" \
182 " b 2b\n" \
183 ".previous\n" \
184 ".section __ex_table,\"a\"\n" \
185 " .align 2\n" \
186 " .long 1b,3b\n" \
187 ".previous" \
188 : "=r"(err), "=r"(x) \
189 : "b"(addr), "i"(-EFAULT), ""(err))
190
191 /* more complex routines */
192
193 extern int __copy_tofrom_user(void *to, const void *from, unsigned long size);
194
195 extern inline unsigned long
196 copy_from_user(void *to, const void *from, unsigned long n)
197 {
198 unsigned long over;
199
200 if (access_ok(VERIFY_READ, from, n))
201 return __copy_tofrom_user(to, from, n);
202 if ((unsigned long)from < TASK_SIZE) {
203 over = (unsigned long)from + n - TASK_SIZE;
204 return __copy_tofrom_user(to, from, n - over) + over;
205 }
206 return n;
207 }
208
209 extern inline unsigned long
210 copy_to_user(void *to, const void *from, unsigned long n)
211 {
212 unsigned long over;
213
214 if (access_ok(VERIFY_WRITE, to, n))
215 return __copy_tofrom_user(to, from, n);
216 if ((unsigned long)to < TASK_SIZE) {
217 over = (unsigned long)to + n - TASK_SIZE;
218 return __copy_tofrom_user(to, from, n - over) + over;
219 }
220 return n;
221 }
222
223 #define __copy_from_user(to, from, size) \
224 __copy_tofrom_user((to), (from), (size))
225 #define __copy_to_user(to, from, size) \
226 __copy_tofrom_user((to), (from), (size))
227
228 extern unsigned long __clear_user(void *addr, unsigned long size);
229
230 extern inline unsigned long
231 clear_user(void *addr, unsigned long size)
232 {
233 if (access_ok(VERIFY_WRITE, addr, size))
234 return __clear_user(addr, size);
235 return size? -EFAULT: 0;
236 }
237
238 extern int __strncpy_from_user(char *dst, const char *src, long count);
239
240 extern inline long
241 strncpy_from_user(char *dst, const char *src, long count)
242 {
243 if (access_ok(VERIFY_READ, src, 1))
244 return __strncpy_from_user(dst, src, count);
245 return -EFAULT;
246 }
247
248 /*
249 * Return the size of a string (including the ending 0)
250 *
251 * Return 0 for error
252 */
253
254 extern int __strnlen_user(const char *str, long len, unsigned long top);
255
256 /*
257 * Returns the length of the string at str (including the null byte),
258 * or 0 if we hit a page we can't access,
259 * or something > len if we didn't find a null byte.
260 *
261 * The `top' parameter to __strnlen_user is to make sure that
262 * we can never overflow from the user area into kernel space.
263 */
264 extern __inline__ int strnlen_user(const char *str, long len)
265 {
266 unsigned long top = __kernel_ok? ~0UL: TASK_SIZE - 1;
267
268 if ((unsigned long)str > top)
269 return 0;
270 return __strnlen_user(str, len, top);
271 }
272
273 #define strlen_user(str) strnlen_user((str), 0x7ffffffe)
274
275 #endif /* __ASSEMBLY__ */
276
277 #endif /* _PPC_UACCESS_H */
278 #endif /* __KERNEL__ */
279
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