1 #ifndef __METAG_UACCESS_H
2 #define __METAG_UACCESS_H
3
4 /*
5 * User space memory access functions
6 */
7 #include <linux/sched.h>
8
9 #define VERIFY_READ 0
10 #define VERIFY_WRITE 1
11
12 /*
13 * The fs value determines whether argument validity checking should be
14 * performed or not. If get_fs() == USER_DS, checking is performed, with
15 * get_fs() == KERNEL_DS, checking is bypassed.
16 *
17 * For historical reasons, these macros are grossly misnamed.
18 */
19
20 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
21
22 #define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
23 #define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
24
25 #define get_ds() (KERNEL_DS)
26 #define get_fs() (current_thread_info()->addr_limit)
27 #define set_fs(x) (current_thread_info()->addr_limit = (x))
28
29 #define segment_eq(a, b) ((a).seg == (b).seg)
30
__access_ok(unsigned long addr,unsigned long size)31 static inline int __access_ok(unsigned long addr, unsigned long size)
32 {
33 /*
34 * Allow access to the user mapped memory area, but not the system area
35 * before it. The check extends to the top of the address space when
36 * kernel access is allowed (there's no real reason to user copy to the
37 * system area in any case).
38 */
39 if (likely(addr >= META_MEMORY_BASE && addr < get_fs().seg &&
40 size <= get_fs().seg - addr))
41 return true;
42 /*
43 * Explicitly allow NULL pointers here. Parts of the kernel such
44 * as readv/writev use access_ok to validate pointers, but want
45 * to allow NULL pointers for various reasons. NULL pointers are
46 * safe to allow through because the first page is not mappable on
47 * Meta.
48 */
49 if (!addr)
50 return true;
51 /* Allow access to core code memory area... */
52 if (addr >= LINCORE_CODE_BASE && addr <= LINCORE_CODE_LIMIT &&
53 size <= LINCORE_CODE_LIMIT + 1 - addr)
54 return true;
55 /* ... but no other areas. */
56 return false;
57 }
58
59 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr), \
60 (unsigned long)(size))
61
verify_area(int type,const void * addr,unsigned long size)62 static inline int verify_area(int type, const void *addr, unsigned long size)
63 {
64 return access_ok(type, addr, size) ? 0 : -EFAULT;
65 }
66
67 /*
68 * The exception table consists of pairs of addresses: the first is the
69 * address of an instruction that is allowed to fault, and the second is
70 * the address at which the program should continue. No registers are
71 * modified, so it is entirely up to the continuation code to figure out
72 * what to do.
73 *
74 * All the routines below use bits of fixup code that are out of line
75 * with the main instruction path. This means when everything is well,
76 * we don't even have to jump over them. Further, they do not intrude
77 * on our cache or tlb entries.
78 */
79 struct exception_table_entry {
80 unsigned long insn, fixup;
81 };
82
83 extern int fixup_exception(struct pt_regs *regs);
84
85 /*
86 * These are the main single-value transfer routines. They automatically
87 * use the right size if we just have the right pointer type.
88 */
89
90 #define put_user(x, ptr) \
91 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
92 #define __put_user(x, ptr) \
93 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
94
95 extern void __put_user_bad(void);
96
97 #define __put_user_nocheck(x, ptr, size) \
98 ({ \
99 long __pu_err; \
100 __put_user_size((x), (ptr), (size), __pu_err); \
101 __pu_err; \
102 })
103
104 #define __put_user_check(x, ptr, size) \
105 ({ \
106 long __pu_err = -EFAULT; \
107 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
108 if (access_ok(VERIFY_WRITE, __pu_addr, size)) \
109 __put_user_size((x), __pu_addr, (size), __pu_err); \
110 __pu_err; \
111 })
112
113 extern long __put_user_asm_b(unsigned int x, void __user *addr);
114 extern long __put_user_asm_w(unsigned int x, void __user *addr);
115 extern long __put_user_asm_d(unsigned int x, void __user *addr);
116 extern long __put_user_asm_l(unsigned long long x, void __user *addr);
117
118 #define __put_user_size(x, ptr, size, retval) \
119 do { \
120 retval = 0; \
121 switch (size) { \
122 case 1: \
123 retval = __put_user_asm_b((__force unsigned int)x, ptr);\
124 break; \
125 case 2: \
126 retval = __put_user_asm_w((__force unsigned int)x, ptr);\
127 break; \
128 case 4: \
129 retval = __put_user_asm_d((__force unsigned int)x, ptr);\
130 break; \
131 case 8: \
132 retval = __put_user_asm_l((__force unsigned long long)x,\
133 ptr); \
134 break; \
135 default: \
136 __put_user_bad(); \
137 } \
138 } while (0)
139
140 #define get_user(x, ptr) \
141 __get_user_check((x), (ptr), sizeof(*(ptr)))
142 #define __get_user(x, ptr) \
143 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
144
145 extern long __get_user_bad(void);
146
147 #define __get_user_nocheck(x, ptr, size) \
148 ({ \
149 long __gu_err, __gu_val; \
150 __get_user_size(__gu_val, (ptr), (size), __gu_err); \
151 (x) = (__force __typeof__(*(ptr)))__gu_val; \
152 __gu_err; \
153 })
154
155 #define __get_user_check(x, ptr, size) \
156 ({ \
157 long __gu_err = -EFAULT, __gu_val = 0; \
158 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
159 if (access_ok(VERIFY_READ, __gu_addr, size)) \
160 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
161 (x) = (__force __typeof__(*(ptr)))__gu_val; \
162 __gu_err; \
163 })
164
165 extern unsigned char __get_user_asm_b(const void __user *addr, long *err);
166 extern unsigned short __get_user_asm_w(const void __user *addr, long *err);
167 extern unsigned int __get_user_asm_d(const void __user *addr, long *err);
168
169 #define __get_user_size(x, ptr, size, retval) \
170 do { \
171 retval = 0; \
172 switch (size) { \
173 case 1: \
174 x = __get_user_asm_b(ptr, &retval); break; \
175 case 2: \
176 x = __get_user_asm_w(ptr, &retval); break; \
177 case 4: \
178 x = __get_user_asm_d(ptr, &retval); break; \
179 default: \
180 (x) = __get_user_bad(); \
181 } \
182 } while (0)
183
184 /*
185 * Copy a null terminated string from userspace.
186 *
187 * Must return:
188 * -EFAULT for an exception
189 * count if we hit the buffer limit
190 * bytes copied if we hit a null byte
191 * (without the null byte)
192 */
193
194 extern long __must_check __strncpy_from_user(char *dst, const char __user *src,
195 long count);
196
197 static inline long
strncpy_from_user(char * dst,const char __user * src,long count)198 strncpy_from_user(char *dst, const char __user *src, long count)
199 {
200 if (!access_ok(VERIFY_READ, src, 1))
201 return -EFAULT;
202 return __strncpy_from_user(dst, src, count);
203 }
204 /*
205 * Return the size of a string (including the ending 0)
206 *
207 * Return 0 on exception, a value greater than N if too long
208 */
209 extern long __must_check strnlen_user(const char __user *src, long count);
210
211 #define strlen_user(str) strnlen_user(str, 32767)
212
213 extern unsigned long raw_copy_from_user(void *to, const void __user *from,
214 unsigned long n);
215
216 static inline unsigned long
copy_from_user(void * to,const void __user * from,unsigned long n)217 copy_from_user(void *to, const void __user *from, unsigned long n)
218 {
219 unsigned long res = n;
220 if (likely(access_ok(VERIFY_READ, from, n)))
221 res = raw_copy_from_user(to, from, n);
222 if (unlikely(res))
223 memset(to + (n - res), 0, res);
224 return res;
225 }
226
227 #define __copy_from_user(to, from, n) raw_copy_from_user(to, from, n)
228 #define __copy_from_user_inatomic __copy_from_user
229
230 extern unsigned long __must_check __copy_user(void __user *to,
231 const void *from,
232 unsigned long n);
233
copy_to_user(void __user * to,const void * from,unsigned long n)234 static inline unsigned long copy_to_user(void __user *to, const void *from,
235 unsigned long n)
236 {
237 if (access_ok(VERIFY_WRITE, to, n))
238 return __copy_user(to, from, n);
239 return n;
240 }
241
242 #define __copy_to_user(to, from, n) __copy_user(to, from, n)
243 #define __copy_to_user_inatomic __copy_to_user
244
245 /*
246 * Zero Userspace
247 */
248
249 extern unsigned long __must_check __do_clear_user(void __user *to,
250 unsigned long n);
251
clear_user(void __user * to,unsigned long n)252 static inline unsigned long clear_user(void __user *to, unsigned long n)
253 {
254 if (access_ok(VERIFY_WRITE, to, n))
255 return __do_clear_user(to, n);
256 return n;
257 }
258
259 #define __clear_user(to, n) __do_clear_user(to, n)
260
261 #endif /* _METAG_UACCESS_H */
262