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