1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * OpenRISC Linux
4 *
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
7 * declaration.
8 *
9 * OpenRISC implementation:
10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
12 * et al.
13 */
14
15 #ifndef __ASM_OPENRISC_UACCESS_H
16 #define __ASM_OPENRISC_UACCESS_H
17
18 /*
19 * User space memory access functions
20 */
21 #include <linux/prefetch.h>
22 #include <linux/string.h>
23 #include <asm/page.h>
24 #include <asm/extable.h>
25
26 /*
27 * The fs value determines whether argument validity checking should be
28 * performed or not. If get_fs() == USER_DS, checking is performed, with
29 * get_fs() == KERNEL_DS, checking is bypassed.
30 *
31 * For historical reasons, these macros are grossly misnamed.
32 */
33
34 /* addr_limit is the maximum accessible address for the task. we misuse
35 * the KERNEL_DS and USER_DS values to both assign and compare the
36 * addr_limit values through the equally misnamed get/set_fs macros.
37 * (see above)
38 */
39
40 #define KERNEL_DS (~0UL)
41
42 #define USER_DS (TASK_SIZE)
43 #define get_fs() (current_thread_info()->addr_limit)
44 #define set_fs(x) (current_thread_info()->addr_limit = (x))
45
46 #define segment_eq(a, b) ((a) == (b))
47
48 /* Ensure that the range from addr to addr+size is all within the process'
49 * address space
50 */
51 #define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size))
52
53 /* Ensure that addr is below task's addr_limit */
54 #define __addr_ok(addr) ((unsigned long) addr < get_fs())
55
56 #define access_ok(addr, size) \
57 ({ \
58 unsigned long __ao_addr = (unsigned long)(addr); \
59 unsigned long __ao_size = (unsigned long)(size); \
60 __range_ok(__ao_addr, __ao_size); \
61 })
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(__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, "l.sb"); break; \
114 case 2: __put_user_asm(x, ptr, retval, "l.sh"); break; \
115 case 4: __put_user_asm(x, ptr, retval, "l.sw"); break; \
116 case 8: __put_user_asm2(x, ptr, retval); break; \
117 default: __put_user_bad(); \
118 } \
119 } while (0)
120
121 struct __large_struct {
122 unsigned long buf[100];
123 };
124 #define __m(x) (*(struct __large_struct *)(x))
125
126 /*
127 * We don't tell gcc that we are accessing memory, but this is OK
128 * because we do not write to any memory gcc knows about, so there
129 * are no aliasing issues.
130 */
131 #define __put_user_asm(x, addr, err, op) \
132 __asm__ __volatile__( \
133 "1: "op" 0(%2),%1\n" \
134 "2:\n" \
135 ".section .fixup,\"ax\"\n" \
136 "3: l.addi %0,r0,%3\n" \
137 " l.j 2b\n" \
138 " l.nop\n" \
139 ".previous\n" \
140 ".section __ex_table,\"a\"\n" \
141 " .align 2\n" \
142 " .long 1b,3b\n" \
143 ".previous" \
144 : "=r"(err) \
145 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
146
147 #define __put_user_asm2(x, addr, err) \
148 __asm__ __volatile__( \
149 "1: l.sw 0(%2),%1\n" \
150 "2: l.sw 4(%2),%H1\n" \
151 "3:\n" \
152 ".section .fixup,\"ax\"\n" \
153 "4: l.addi %0,r0,%3\n" \
154 " l.j 3b\n" \
155 " l.nop\n" \
156 ".previous\n" \
157 ".section __ex_table,\"a\"\n" \
158 " .align 2\n" \
159 " .long 1b,4b\n" \
160 " .long 2b,4b\n" \
161 ".previous" \
162 : "=r"(err) \
163 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
164
165 #define __get_user_nocheck(x, ptr, size) \
166 ({ \
167 long __gu_err, __gu_val; \
168 __get_user_size(__gu_val, (ptr), (size), __gu_err); \
169 (x) = (__force __typeof__(*(ptr)))__gu_val; \
170 __gu_err; \
171 })
172
173 #define __get_user_check(x, ptr, size) \
174 ({ \
175 long __gu_err = -EFAULT, __gu_val = 0; \
176 const __typeof__(*(ptr)) * __gu_addr = (ptr); \
177 if (access_ok(__gu_addr, size)) \
178 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
179 (x) = (__force __typeof__(*(ptr)))__gu_val; \
180 __gu_err; \
181 })
182
183 extern long __get_user_bad(void);
184
185 #define __get_user_size(x, ptr, size, retval) \
186 do { \
187 retval = 0; \
188 switch (size) { \
189 case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break; \
190 case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break; \
191 case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break; \
192 case 8: __get_user_asm2(x, ptr, retval); break; \
193 default: (x) = __get_user_bad(); \
194 } \
195 } while (0)
196
197 #define __get_user_asm(x, addr, err, op) \
198 __asm__ __volatile__( \
199 "1: "op" %1,0(%2)\n" \
200 "2:\n" \
201 ".section .fixup,\"ax\"\n" \
202 "3: l.addi %0,r0,%3\n" \
203 " l.addi %1,r0,0\n" \
204 " l.j 2b\n" \
205 " l.nop\n" \
206 ".previous\n" \
207 ".section __ex_table,\"a\"\n" \
208 " .align 2\n" \
209 " .long 1b,3b\n" \
210 ".previous" \
211 : "=r"(err), "=r"(x) \
212 : "r"(addr), "i"(-EFAULT), "0"(err))
213
214 #define __get_user_asm2(x, addr, err) \
215 __asm__ __volatile__( \
216 "1: l.lwz %1,0(%2)\n" \
217 "2: l.lwz %H1,4(%2)\n" \
218 "3:\n" \
219 ".section .fixup,\"ax\"\n" \
220 "4: l.addi %0,r0,%3\n" \
221 " l.addi %1,r0,0\n" \
222 " l.addi %H1,r0,0\n" \
223 " l.j 3b\n" \
224 " l.nop\n" \
225 ".previous\n" \
226 ".section __ex_table,\"a\"\n" \
227 " .align 2\n" \
228 " .long 1b,4b\n" \
229 " .long 2b,4b\n" \
230 ".previous" \
231 : "=r"(err), "=&r"(x) \
232 : "r"(addr), "i"(-EFAULT), "0"(err))
233
234 /* more complex routines */
235
236 extern unsigned long __must_check
237 __copy_tofrom_user(void *to, const void *from, unsigned long size);
238 static inline unsigned long
239 raw_copy_from_user(void *to, const void __user *from, unsigned long size)
240 {
241 return __copy_tofrom_user(to, (__force const void *)from, size);
242 }
243 static inline unsigned long
244 raw_copy_to_user(void *to, const void __user *from, unsigned long size)
245 {
246 return __copy_tofrom_user((__force void *)to, from, size);
247 }
248 #define INLINE_COPY_FROM_USER
249 #define INLINE_COPY_TO_USER
250
251 extern unsigned long __clear_user(void *addr, unsigned long size);
252
253 static inline __must_check unsigned long
254 clear_user(void *addr, unsigned long size)
255 {
256 if (likely(access_ok(addr, size)))
257 size = __clear_user(addr, size);
258 return size;
259 }
260
261 #define user_addr_max() \
262 (uaccess_kernel() ? ~0UL : TASK_SIZE)
263
264 extern long strncpy_from_user(char *dest, const char __user *src, long count);
265
266 extern __must_check long strnlen_user(const char __user *str, long n);
267
268 #endif /* __ASM_OPENRISC_UACCESS_H */