1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ARCH_POWERPC_UACCESS_H
3 #define _ARCH_POWERPC_UACCESS_H
4
5 #include <asm/asm-compat.h>
6 #include <asm/ppc_asm.h>
7 #include <asm/processor.h>
8 #include <asm/page.h>
9 #include <asm/extable.h>
10
11 /*
12 * The fs value determines whether argument validity checking should be
13 * performed or not. If get_fs() == USER_DS, checking is performed, with
14 * get_fs() == KERNEL_DS, checking is bypassed.
15 *
16 * For historical reasons, these macros are grossly misnamed.
17 *
18 * The fs/ds values are now the highest legal address in the "segment".
19 * This simplifies the checking in the routines below.
20 */
21
22 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
23
24 #define KERNEL_DS MAKE_MM_SEG(~0UL)
25 #ifdef __powerpc64__
26 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
27 #define USER_DS MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
28 #else
29 #define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
30 #endif
31
32 #define get_ds() (KERNEL_DS)
33 #define get_fs() (current->thread.fs)
34 #define set_fs(val) (current->thread.fs = (val))
35
36 #define segment_eq(a, b) ((a).seg == (b).seg)
37
38 #define user_addr_max() (get_fs().seg)
39
40 #ifdef __powerpc64__
41 /*
42 * This check is sufficient because there is a large enough
43 * gap between user addresses and the kernel addresses
44 */
45 #define __access_ok(addr, size, segment) \
46 (((addr) <= (segment).seg) && ((size) <= (segment).seg))
47
48 #else
49
50 #define __access_ok(addr, size, segment) \
51 (((addr) <= (segment).seg) && \
52 (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
53
54 #endif
55
56 #define access_ok(type, addr, size) \
57 (__chk_user_ptr(addr), (void)(type), \
58 __access_ok((__force unsigned long)(addr), (size), get_fs()))
59
60 /*
61 * These are the main single-value transfer routines. They automatically
62 * use the right size if we just have the right pointer type.
63 *
64 * This gets kind of ugly. We want to return _two_ values in "get_user()"
65 * and yet we don't want to do any pointers, because that is too much
66 * of a performance impact. Thus we have a few rather ugly macros here,
67 * and hide all the ugliness from the user.
68 *
69 * The "__xxx" versions of the user access functions are versions that
70 * do not verify the address space, that must have been done previously
71 * with a separate "access_ok()" call (this is used when we do multiple
72 * accesses to the same area of user memory).
73 *
74 * As we use the same address space for kernel and user data on the
75 * PowerPC, we can just do these as direct assignments. (Of course, the
76 * exception handling means that it's no longer "just"...)
77 *
78 */
79 #define get_user(x, ptr) \
80 __get_user_check((x), (ptr), sizeof(*(ptr)))
81 #define put_user(x, ptr) \
82 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
83
84 #define __get_user(x, ptr) \
85 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
86 #define __put_user(x, ptr) \
87 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
88
89 #define __get_user_inatomic(x, ptr) \
90 __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
91 #define __put_user_inatomic(x, ptr) \
92 __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
93
94 extern long __put_user_bad(void);
95
96 /*
97 * We don't tell gcc that we are accessing memory, but this is OK
98 * because we do not write to any memory gcc knows about, so there
99 * are no aliasing issues.
100 */
101 #define __put_user_asm(x, addr, err, op) \
102 __asm__ __volatile__( \
103 "1: " op " %1,0(%2) # put_user\n" \
104 "2:\n" \
105 ".section .fixup,\"ax\"\n" \
106 "3: li %0,%3\n" \
107 " b 2b\n" \
108 ".previous\n" \
109 EX_TABLE(1b, 3b) \
110 : "=r" (err) \
111 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
112
113 #ifdef __powerpc64__
114 #define __put_user_asm2(x, ptr, retval) \
115 __put_user_asm(x, ptr, retval, "std")
116 #else /* __powerpc64__ */
117 #define __put_user_asm2(x, addr, err) \
118 __asm__ __volatile__( \
119 "1: stw %1,0(%2)\n" \
120 "2: stw %1+1,4(%2)\n" \
121 "3:\n" \
122 ".section .fixup,\"ax\"\n" \
123 "4: li %0,%3\n" \
124 " b 3b\n" \
125 ".previous\n" \
126 EX_TABLE(1b, 4b) \
127 EX_TABLE(2b, 4b) \
128 : "=r" (err) \
129 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
130 #endif /* __powerpc64__ */
131
132 #define __put_user_size(x, ptr, size, retval) \
133 do { \
134 retval = 0; \
135 switch (size) { \
136 case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
137 case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
138 case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
139 case 8: __put_user_asm2(x, ptr, retval); break; \
140 default: __put_user_bad(); \
141 } \
142 } while (0)
143
144 #define __put_user_nocheck(x, ptr, size) \
145 ({ \
146 long __pu_err; \
147 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
148 if (!is_kernel_addr((unsigned long)__pu_addr)) \
149 might_fault(); \
150 __chk_user_ptr(ptr); \
151 __put_user_size((x), __pu_addr, (size), __pu_err); \
152 __pu_err; \
153 })
154
155 #define __put_user_check(x, ptr, size) \
156 ({ \
157 long __pu_err = -EFAULT; \
158 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
159 might_fault(); \
160 if (access_ok(VERIFY_WRITE, __pu_addr, size)) \
161 __put_user_size((x), __pu_addr, (size), __pu_err); \
162 __pu_err; \
163 })
164
165 #define __put_user_nosleep(x, ptr, size) \
166 ({ \
167 long __pu_err; \
168 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
169 __chk_user_ptr(ptr); \
170 __put_user_size((x), __pu_addr, (size), __pu_err); \
171 __pu_err; \
172 })
173
174
175 extern long __get_user_bad(void);
176
177 #define __get_user_asm(x, addr, err, op) \
178 __asm__ __volatile__( \
179 "1: "op" %1,0(%2) # get_user\n" \
180 "2:\n" \
181 ".section .fixup,\"ax\"\n" \
182 "3: li %0,%3\n" \
183 " li %1,0\n" \
184 " b 2b\n" \
185 ".previous\n" \
186 EX_TABLE(1b, 3b) \
187 : "=r" (err), "=r" (x) \
188 : "b" (addr), "i" (-EFAULT), "0" (err))
189
190 #ifdef __powerpc64__
191 #define __get_user_asm2(x, addr, err) \
192 __get_user_asm(x, addr, err, "ld")
193 #else /* __powerpc64__ */
194 #define __get_user_asm2(x, addr, err) \
195 __asm__ __volatile__( \
196 "1: lwz %1,0(%2)\n" \
197 "2: lwz %1+1,4(%2)\n" \
198 "3:\n" \
199 ".section .fixup,\"ax\"\n" \
200 "4: li %0,%3\n" \
201 " li %1,0\n" \
202 " li %1+1,0\n" \
203 " b 3b\n" \
204 ".previous\n" \
205 EX_TABLE(1b, 4b) \
206 EX_TABLE(2b, 4b) \
207 : "=r" (err), "=&r" (x) \
208 : "b" (addr), "i" (-EFAULT), "0" (err))
209 #endif /* __powerpc64__ */
210
211 #define __get_user_size(x, ptr, size, retval) \
212 do { \
213 retval = 0; \
214 __chk_user_ptr(ptr); \
215 if (size > sizeof(x)) \
216 (x) = __get_user_bad(); \
217 switch (size) { \
218 case 1: __get_user_asm(x, ptr, retval, "lbz"); break; \
219 case 2: __get_user_asm(x, ptr, retval, "lhz"); break; \
220 case 4: __get_user_asm(x, ptr, retval, "lwz"); break; \
221 case 8: __get_user_asm2(x, ptr, retval); break; \
222 default: (x) = __get_user_bad(); \
223 } \
224 } while (0)
225
226 /*
227 * This is a type: either unsigned long, if the argument fits into
228 * that type, or otherwise unsigned long long.
229 */
230 #define __long_type(x) \
231 __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
232
233 #define __get_user_nocheck(x, ptr, size) \
234 ({ \
235 long __gu_err; \
236 __long_type(*(ptr)) __gu_val; \
237 __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
238 __chk_user_ptr(ptr); \
239 if (!is_kernel_addr((unsigned long)__gu_addr)) \
240 might_fault(); \
241 barrier_nospec(); \
242 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
243 (x) = (__typeof__(*(ptr)))__gu_val; \
244 __gu_err; \
245 })
246
247 #define __get_user_check(x, ptr, size) \
248 ({ \
249 long __gu_err = -EFAULT; \
250 __long_type(*(ptr)) __gu_val = 0; \
251 __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
252 might_fault(); \
253 if (access_ok(VERIFY_READ, __gu_addr, (size))) { \
254 barrier_nospec(); \
255 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
256 } \
257 (x) = (__force __typeof__(*(ptr)))__gu_val; \
258 __gu_err; \
259 })
260
261 #define __get_user_nosleep(x, ptr, size) \
262 ({ \
263 long __gu_err; \
264 __long_type(*(ptr)) __gu_val; \
265 __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
266 __chk_user_ptr(ptr); \
267 barrier_nospec(); \
268 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
269 (x) = (__force __typeof__(*(ptr)))__gu_val; \
270 __gu_err; \
271 })
272
273
274 /* more complex routines */
275
276 extern unsigned long __copy_tofrom_user(void __user *to,
277 const void __user *from, unsigned long size);
278
279 #ifdef __powerpc64__
280 static inline unsigned long
raw_copy_in_user(void __user * to,const void __user * from,unsigned long n)281 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
282 {
283 barrier_nospec();
284 return __copy_tofrom_user(to, from, n);
285 }
286 #endif /* __powerpc64__ */
287
raw_copy_from_user(void * to,const void __user * from,unsigned long n)288 static inline unsigned long raw_copy_from_user(void *to,
289 const void __user *from, unsigned long n)
290 {
291 if (__builtin_constant_p(n) && (n <= 8)) {
292 unsigned long ret = 1;
293
294 switch (n) {
295 case 1:
296 barrier_nospec();
297 __get_user_size(*(u8 *)to, from, 1, ret);
298 break;
299 case 2:
300 barrier_nospec();
301 __get_user_size(*(u16 *)to, from, 2, ret);
302 break;
303 case 4:
304 barrier_nospec();
305 __get_user_size(*(u32 *)to, from, 4, ret);
306 break;
307 case 8:
308 barrier_nospec();
309 __get_user_size(*(u64 *)to, from, 8, ret);
310 break;
311 }
312 if (ret == 0)
313 return 0;
314 }
315
316 barrier_nospec();
317 return __copy_tofrom_user((__force void __user *)to, from, n);
318 }
319
raw_copy_to_user(void __user * to,const void * from,unsigned long n)320 static inline unsigned long raw_copy_to_user(void __user *to,
321 const void *from, unsigned long n)
322 {
323 if (__builtin_constant_p(n) && (n <= 8)) {
324 unsigned long ret = 1;
325
326 switch (n) {
327 case 1:
328 __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
329 break;
330 case 2:
331 __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
332 break;
333 case 4:
334 __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
335 break;
336 case 8:
337 __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
338 break;
339 }
340 if (ret == 0)
341 return 0;
342 }
343
344 return __copy_tofrom_user(to, (__force const void __user *)from, n);
345 }
346
347 extern unsigned long __clear_user(void __user *addr, unsigned long size);
348
clear_user(void __user * addr,unsigned long size)349 static inline unsigned long clear_user(void __user *addr, unsigned long size)
350 {
351 might_fault();
352 if (likely(access_ok(VERIFY_WRITE, addr, size)))
353 return __clear_user(addr, size);
354 return size;
355 }
356
357 extern long strncpy_from_user(char *dst, const char __user *src, long count);
358 extern __must_check long strnlen_user(const char __user *str, long n);
359
360 #endif /* _ARCH_POWERPC_UACCESS_H */
361