blackfin: no access_ok() for __copy_{to,from}_user()
[sfrench/cifs-2.6.git] / arch / blackfin / include / asm / uaccess.h
1 /*
2  * Copyright 2004-2009 Analog Devices Inc.
3  *
4  * Licensed under the GPL-2 or later.
5  *
6  * Based on: include/asm-m68knommu/uaccess.h
7  */
8
9 #ifndef __BLACKFIN_UACCESS_H
10 #define __BLACKFIN_UACCESS_H
11
12 /*
13  * User space memory access functions
14  */
15 #include <linux/sched.h>
16 #include <linux/mm.h>
17 #include <linux/string.h>
18
19 #include <asm/segment.h>
20 #include <asm/sections.h>
21
22 #define get_ds()        (KERNEL_DS)
23 #define get_fs()        (current_thread_info()->addr_limit)
24
25 static inline void set_fs(mm_segment_t fs)
26 {
27         current_thread_info()->addr_limit = fs;
28 }
29
30 #define segment_eq(a, b) ((a) == (b))
31
32 #define VERIFY_READ     0
33 #define VERIFY_WRITE    1
34
35 #define access_ok(type, addr, size) _access_ok((unsigned long)(addr), (size))
36
37 /*
38  * The fs value determines whether argument validity checking should be
39  * performed or not.  If get_fs() == USER_DS, checking is performed, with
40  * get_fs() == KERNEL_DS, checking is bypassed.
41  */
42
43 #ifndef CONFIG_ACCESS_CHECK
44 static inline int _access_ok(unsigned long addr, unsigned long size) { return 1; }
45 #else
46 extern int _access_ok(unsigned long addr, unsigned long size);
47 #endif
48
49 /*
50  * The exception table consists of pairs of addresses: the first is the
51  * address of an instruction that is allowed to fault, and the second is
52  * the address at which the program should continue.  No registers are
53  * modified, so it is entirely up to the continuation code to figure out
54  * what to do.
55  *
56  * All the routines below use bits of fixup code that are out of line
57  * with the main instruction path.  This means when everything is well,
58  * we don't even have to jump over them.  Further, they do not intrude
59  * on our cache or tlb entries.
60  */
61
62 struct exception_table_entry {
63         unsigned long insn, fixup;
64 };
65
66 /*
67  * These are the main single-value transfer routines.  They automatically
68  * use the right size if we just have the right pointer type.
69  */
70
71 #define put_user(x, p)                                          \
72         ({                                                      \
73                 int _err = 0;                                   \
74                 typeof(*(p)) _x = (x);                          \
75                 typeof(*(p)) __user *_p = (p);                  \
76                 if (!access_ok(VERIFY_WRITE, _p, sizeof(*(_p)))) {\
77                         _err = -EFAULT;                         \
78                 }                                               \
79                 else {                                          \
80                 switch (sizeof (*(_p))) {                       \
81                 case 1:                                         \
82                         __put_user_asm(_x, _p, B);              \
83                         break;                                  \
84                 case 2:                                         \
85                         __put_user_asm(_x, _p, W);              \
86                         break;                                  \
87                 case 4:                                         \
88                         __put_user_asm(_x, _p,  );              \
89                         break;                                  \
90                 case 8: {                                       \
91                         long _xl, _xh;                          \
92                         _xl = ((__force long *)&_x)[0];         \
93                         _xh = ((__force long *)&_x)[1];         \
94                         __put_user_asm(_xl, ((__force long __user *)_p)+0, );\
95                         __put_user_asm(_xh, ((__force long __user *)_p)+1, );\
96                 } break;                                        \
97                 default:                                        \
98                         _err = __put_user_bad();                \
99                         break;                                  \
100                 }                                               \
101                 }                                               \
102                 _err;                                           \
103         })
104
105 #define __put_user(x, p) put_user(x, p)
106 static inline int bad_user_access_length(void)
107 {
108         panic("bad_user_access_length");
109         return -1;
110 }
111
112 #define __put_user_bad() (printk(KERN_INFO "put_user_bad %s:%d %s\n",\
113                            __FILE__, __LINE__, __func__),\
114                            bad_user_access_length(), (-EFAULT))
115
116 /*
117  * Tell gcc we read from memory instead of writing: this is because
118  * we do not write to any memory gcc knows about, so there are no
119  * aliasing issues.
120  */
121
122 #define __ptr(x) ((unsigned long __force *)(x))
123
124 #define __put_user_asm(x, p, bhw)                       \
125         __asm__ (#bhw"[%1] = %0;\n\t"                   \
126                  : /* no outputs */                     \
127                  :"d" (x), "a" (__ptr(p)) : "memory")
128
129 #define get_user(x, ptr)                                        \
130 ({                                                              \
131         int _err = 0;                                           \
132         unsigned long _val = 0;                                 \
133         const typeof(*(ptr)) __user *_p = (ptr);                \
134         const size_t ptr_size = sizeof(*(_p));                  \
135         if (likely(access_ok(VERIFY_READ, _p, ptr_size))) {     \
136                 BUILD_BUG_ON(ptr_size >= 8);                    \
137                 switch (ptr_size) {                             \
138                 case 1:                                         \
139                         __get_user_asm(_val, _p, B, (Z));       \
140                         break;                                  \
141                 case 2:                                         \
142                         __get_user_asm(_val, _p, W, (Z));       \
143                         break;                                  \
144                 case 4:                                         \
145                         __get_user_asm(_val, _p,  , );          \
146                         break;                                  \
147                 }                                               \
148         } else                                                  \
149                 _err = -EFAULT;                                 \
150         x = (__force typeof(*(ptr)))_val;                       \
151         _err;                                                   \
152 })
153
154 #define __get_user(x, p) get_user(x, p)
155
156 #define __get_user_bad() (bad_user_access_length(), (-EFAULT))
157
158 #define __get_user_asm(x, ptr, bhw, option)     \
159 ({                                              \
160         __asm__ __volatile__ (                  \
161                 "%0 =" #bhw "[%1]" #option ";"  \
162                 : "=d" (x)                      \
163                 : "a" (__ptr(ptr)));            \
164 })
165
166 #define __copy_to_user_inatomic __copy_to_user
167 #define __copy_from_user_inatomic __copy_from_user
168
169 static inline unsigned long __must_check
170 __copy_from_user(void *to, const void __user *from, unsigned long n)
171 {
172         memcpy(to, (const void __force *)from, n);
173         return 0;
174 }
175
176 static inline unsigned long __must_check
177 __copy_to_user(void __user *to, const void *from, unsigned long n)
178 {
179         memcpy((void __force *)to, from, n);
180         SSYNC();
181         return 0;
182 }
183
184 static inline unsigned long __must_check
185 copy_from_user(void *to, const void __user *from, unsigned long n)
186 {
187         if (likely(access_ok(VERIFY_READ, from, n)))
188                 return __copy_from_user(to, from, n);
189         memset(to, 0, n);
190         return n;
191 }
192
193 static inline unsigned long __must_check
194 copy_to_user(void __user *to, const void *from, unsigned long n)
195 {
196         if (likely(access_ok(VERIFY_WRITE, to, n)))
197                 return __copy_to_user(to, from, n);
198         return n;
199 }
200
201 /*
202  * Copy a null terminated string from userspace.
203  */
204
205 static inline long __must_check
206 strncpy_from_user(char *dst, const char __user *src, long count)
207 {
208         char *tmp;
209         if (!access_ok(VERIFY_READ, src, 1))
210                 return -EFAULT;
211         strncpy(dst, (const char __force *)src, count);
212         for (tmp = dst; *tmp && count > 0; tmp++, count--) ;
213         return (tmp - dst);
214 }
215
216 /*
217  * Get the size of a string in user space.
218  *   src: The string to measure
219  *     n: The maximum valid length
220  *
221  * Get the size of a NUL-terminated string in user space.
222  *
223  * Returns the size of the string INCLUDING the terminating NUL.
224  * On exception, returns 0.
225  * If the string is too long, returns a value greater than n.
226  */
227 static inline long __must_check strnlen_user(const char __user *src, long n)
228 {
229         if (!access_ok(VERIFY_READ, src, 1))
230                 return 0;
231         return strnlen((const char __force *)src, n) + 1;
232 }
233
234 static inline long __must_check strlen_user(const char __user *src)
235 {
236         if (!access_ok(VERIFY_READ, src, 1))
237                 return 0;
238         return strlen((const char __force *)src) + 1;
239 }
240
241 /*
242  * Zero Userspace
243  */
244
245 static inline unsigned long __must_check
246 __clear_user(void __user *to, unsigned long n)
247 {
248         if (!access_ok(VERIFY_WRITE, to, n))
249                 return n;
250         memset((void __force *)to, 0, n);
251         return 0;
252 }
253
254 #define clear_user(to, n) __clear_user(to, n)
255
256 /* How to interpret these return values:
257  *      CORE:      can be accessed by core load or dma memcpy
258  *      CORE_ONLY: can only be accessed by core load
259  *      DMA:       can only be accessed by dma memcpy
260  *      IDMA:      can only be accessed by interprocessor dma memcpy (BF561)
261  *      ITEST:     can be accessed by isram memcpy or dma memcpy
262  */
263 enum {
264         BFIN_MEM_ACCESS_CORE = 0,
265         BFIN_MEM_ACCESS_CORE_ONLY,
266         BFIN_MEM_ACCESS_DMA,
267         BFIN_MEM_ACCESS_IDMA,
268         BFIN_MEM_ACCESS_ITEST,
269 };
270 /**
271  *      bfin_mem_access_type() - what kind of memory access is required
272  *      @addr:   the address to check
273  *      @size:   number of bytes needed
274  *      @return: <0 is error, >=0 is BFIN_MEM_ACCESS_xxx enum (see above)
275  */
276 int bfin_mem_access_type(unsigned long addr, unsigned long size);
277
278 #endif                          /* _BLACKFIN_UACCESS_H */