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uaccess.h
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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 static inline int is_in_rom(unsigned long addr)
38 {
39  /*
40  * What we are really trying to do is determine if addr is
41  * in an allocated kernel memory region. If not then assume
42  * we cannot free it or otherwise de-allocate it. Ideally
43  * we could restrict this to really being in a ROM or flash,
44  * but that would need to be done on a board by board basis,
45  * not globally.
46  */
47  if ((addr < _ramstart) || (addr >= _ramend))
48  return (1);
49 
50  /* Default case, not in ROM */
51  return (0);
52 }
53 
54 /*
55  * The fs value determines whether argument validity checking should be
56  * performed or not. If get_fs() == USER_DS, checking is performed, with
57  * get_fs() == KERNEL_DS, checking is bypassed.
58  */
59 
60 #ifndef CONFIG_ACCESS_CHECK
61 static inline int _access_ok(unsigned long addr, unsigned long size) { return 1; }
62 #else
63 extern int _access_ok(unsigned long addr, unsigned long size);
64 #endif
65 
66 /*
67  * The exception table consists of pairs of addresses: the first is the
68  * address of an instruction that is allowed to fault, and the second is
69  * the address at which the program should continue. No registers are
70  * modified, so it is entirely up to the continuation code to figure out
71  * what to do.
72  *
73  * All the routines below use bits of fixup code that are out of line
74  * with the main instruction path. This means when everything is well,
75  * we don't even have to jump over them. Further, they do not intrude
76  * on our cache or tlb entries.
77  */
78 
79 struct exception_table_entry {
80  unsigned long insn, fixup;
81 };
82 
83 /*
84  * These are the main single-value transfer routines. They automatically
85  * use the right size if we just have the right pointer type.
86  */
87 
88 #define put_user(x,p) \
89  ({ \
90  int _err = 0; \
91  typeof(*(p)) _x = (x); \
92  typeof(*(p)) *_p = (p); \
93  if (!access_ok(VERIFY_WRITE, _p, sizeof(*(_p)))) {\
94  _err = -EFAULT; \
95  } \
96  else { \
97  switch (sizeof (*(_p))) { \
98  case 1: \
99  __put_user_asm(_x, _p, B); \
100  break; \
101  case 2: \
102  __put_user_asm(_x, _p, W); \
103  break; \
104  case 4: \
105  __put_user_asm(_x, _p, ); \
106  break; \
107  case 8: { \
108  long _xl, _xh; \
109  _xl = ((long *)&_x)[0]; \
110  _xh = ((long *)&_x)[1]; \
111  __put_user_asm(_xl, ((long *)_p)+0, ); \
112  __put_user_asm(_xh, ((long *)_p)+1, ); \
113  } break; \
114  default: \
115  _err = __put_user_bad(); \
116  break; \
117  } \
118  } \
119  _err; \
120  })
121 
122 #define __put_user(x,p) put_user(x,p)
123 static inline int bad_user_access_length(void)
124 {
125  panic("bad_user_access_length");
126  return -1;
127 }
128 
129 #define __put_user_bad() (printk(KERN_INFO "put_user_bad %s:%d %s\n",\
130  __FILE__, __LINE__, __func__),\
131  bad_user_access_length(), (-EFAULT))
132 
133 /*
134  * Tell gcc we read from memory instead of writing: this is because
135  * we do not write to any memory gcc knows about, so there are no
136  * aliasing issues.
137  */
138 
139 #define __ptr(x) ((unsigned long *)(x))
140 
141 #define __put_user_asm(x,p,bhw) \
142  __asm__ (#bhw"[%1] = %0;\n\t" \
143  : /* no outputs */ \
144  :"d" (x),"a" (__ptr(p)) : "memory")
145 
146 #define get_user(x, ptr) \
147 ({ \
148  int _err = 0; \
149  unsigned long _val = 0; \
150  const typeof(*(ptr)) __user *_p = (ptr); \
151  const size_t ptr_size = sizeof(*(_p)); \
152  if (likely(access_ok(VERIFY_READ, _p, ptr_size))) { \
153  BUILD_BUG_ON(ptr_size >= 8); \
154  switch (ptr_size) { \
155  case 1: \
156  __get_user_asm(_val, _p, B,(Z)); \
157  break; \
158  case 2: \
159  __get_user_asm(_val, _p, W,(Z)); \
160  break; \
161  case 4: \
162  __get_user_asm(_val, _p, , ); \
163  break; \
164  } \
165  } else \
166  _err = -EFAULT; \
167  x = (typeof(*(ptr)))_val; \
168  _err; \
169 })
170 
171 #define __get_user(x,p) get_user(x,p)
172 
173 #define __get_user_bad() (bad_user_access_length(), (-EFAULT))
174 
175 #define __get_user_asm(x, ptr, bhw, option) \
176 ({ \
177  __asm__ __volatile__ ( \
178  "%0 =" #bhw "[%1]" #option ";" \
179  : "=d" (x) \
180  : "a" (__ptr(ptr))); \
181 })
182 
183 #define __copy_from_user(to, from, n) copy_from_user(to, from, n)
184 #define __copy_to_user(to, from, n) copy_to_user(to, from, n)
185 #define __copy_to_user_inatomic __copy_to_user
186 #define __copy_from_user_inatomic __copy_from_user
187 
188 #define copy_to_user_ret(to,from,n,retval) ({ if (copy_to_user(to,from,n))\
189  return retval; })
190 
191 #define copy_from_user_ret(to,from,n,retval) ({ if (copy_from_user(to,from,n))\
192  return retval; })
193 
194 static inline unsigned long __must_check
195 copy_from_user(void *to, const void __user *from, unsigned long n)
196 {
197  if (access_ok(VERIFY_READ, from, n))
198  memcpy(to, (const void __force *)from, n);
199  else
200  return n;
201  return 0;
202 }
203 
204 static inline unsigned long __must_check
205 copy_to_user(void __user *to, const void *from, unsigned long n)
206 {
207  if (access_ok(VERIFY_WRITE, to, n))
208  memcpy((void __force *)to, from, n);
209  else
210  return n;
211  return 0;
212 }
213 
214 /*
215  * Copy a null terminated string from userspace.
216  */
217 
218 static inline long __must_check
219 strncpy_from_user(char *dst, const char *src, long count)
220 {
221  char *tmp;
222  if (!access_ok(VERIFY_READ, src, 1))
223  return -EFAULT;
224  strncpy(dst, src, count);
225  for (tmp = dst; *tmp && count > 0; tmp++, count--) ;
226  return (tmp - dst);
227 }
228 
229 /*
230  * Get the size of a string in user space.
231  * src: The string to measure
232  * n: The maximum valid length
233  *
234  * Get the size of a NUL-terminated string in user space.
235  *
236  * Returns the size of the string INCLUDING the terminating NUL.
237  * On exception, returns 0.
238  * If the string is too long, returns a value greater than n.
239  */
240 static inline long __must_check strnlen_user(const char *src, long n)
241 {
242  if (!access_ok(VERIFY_READ, src, 1))
243  return 0;
244  return strnlen(src, n) + 1;
245 }
246 
247 static inline long __must_check strlen_user(const char *src)
248 {
249  if (!access_ok(VERIFY_READ, src, 1))
250  return 0;
251  return strlen(src) + 1;
252 }
253 
254 /*
255  * Zero Userspace
256  */
257 
258 static inline unsigned long __must_check
259 __clear_user(void *to, unsigned long n)
260 {
261  if (!access_ok(VERIFY_WRITE, to, n))
262  return n;
263  memset(to, 0, n);
264  return 0;
265 }
266 
267 #define clear_user(to, n) __clear_user(to, n)
268 
269 /* How to interpret these return values:
270  * CORE: can be accessed by core load or dma memcpy
271  * CORE_ONLY: can only be accessed by core load
272  * DMA: can only be accessed by dma memcpy
273  * IDMA: can only be accessed by interprocessor dma memcpy (BF561)
274  * ITEST: can be accessed by isram memcpy or dma memcpy
275  */
276 enum {
282 };
289 int bfin_mem_access_type(unsigned long addr, unsigned long size);
290 
291 #endif /* _BLACKFIN_UACCESS_H */