1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ALPHA_UACCESS_H
3 #define __ALPHA_UACCESS_H
4
5 /*
6 * The fs value determines whether argument validity checking should be
7 * performed or not. If get_fs() == USER_DS, checking is performed, with
8 * get_fs() == KERNEL_DS, checking is bypassed.
9 *
10 * Or at least it did once upon a time. Nowadays it is a mask that
11 * defines which bits of the address space are off limits. This is a
12 * wee bit faster than the above.
13 *
14 * For historical reasons, these macros are grossly misnamed.
15 */
16
17 #define KERNEL_DS ((mm_segment_t) { 0UL })
18 #define USER_DS ((mm_segment_t) { -0x40000000000UL })
19
20 #define get_fs() (current_thread_info()->addr_limit)
21 #define set_fs(x) (current_thread_info()->addr_limit = (x))
22
23 #define segment_eq(a, b) ((a).seg == (b).seg)
24
25 /*
26 * Is a address valid? This does a straightforward calculation rather
27 * than tests.
28 *
29 * Address valid if:
30 * - "addr" doesn't have any high-bits set
31 * - AND "size" doesn't have any high-bits set
32 * - AND "addr+size-(size != 0)" doesn't have any high-bits set
33 * - OR we are in kernel mode.
34 */
35 #define __access_ok(addr, size) ({ \
36 unsigned long __ao_a = (addr), __ao_b = (size); \
37 unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b; \
38 (get_fs().seg & (__ao_a | __ao_b | __ao_end)) == 0; })
39
40 #define access_ok(addr, size) \
41 ({ \
42 __chk_user_ptr(addr); \
43 __access_ok(((unsigned long)(addr)), (size)); \
44 })
45
46 /*
47 * These are the main single-value transfer routines. They automatically
48 * use the right size if we just have the right pointer type.
49 *
50 * As the alpha uses the same address space for kernel and user
51 * data, we can just do these as direct assignments. (Of course, the
52 * exception handling means that it's no longer "just"...)
53 *
54 * Careful to not
55 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
56 * (b) require any knowledge of processes at this stage
57 */
58 #define put_user(x, ptr) \
59 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
60 #define get_user(x, ptr) \
61 __get_user_check((x), (ptr), sizeof(*(ptr)))
62
63 /*
64 * The "__xxx" versions do not do address space checking, useful when
65 * doing multiple accesses to the same area (the programmer has to do the
66 * checks by hand with "access_ok()")
67 */
68 #define __put_user(x, ptr) \
69 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
70 #define __get_user(x, ptr) \
71 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
72
73 /*
74 * The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to
75 * encode the bits we need for resolving the exception. See the
76 * more extensive comments with fixup_inline_exception below for
77 * more information.
78 */
79 #define EXC(label,cont,res,err) \
80 ".section __ex_table,\"a\"\n" \
81 " .long "#label"-.\n" \
82 " lda "#res","#cont"-"#label"("#err")\n" \
83 ".previous\n"
84
85 extern void __get_user_unknown(void);
86
87 #define __get_user_nocheck(x, ptr, size) \
88 ({ \
89 long __gu_err = 0; \
90 unsigned long __gu_val; \
91 __chk_user_ptr(ptr); \
92 switch (size) { \
93 case 1: __get_user_8(ptr); break; \
94 case 2: __get_user_16(ptr); break; \
95 case 4: __get_user_32(ptr); break; \
96 case 8: __get_user_64(ptr); break; \
97 default: __get_user_unknown(); break; \
98 } \
99 (x) = (__force __typeof__(*(ptr))) __gu_val; \
100 __gu_err; \
101 })
102
103 #define __get_user_check(x, ptr, size) \
104 ({ \
105 long __gu_err = -EFAULT; \
106 unsigned long __gu_val = 0; \
107 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
108 if (__access_ok((unsigned long)__gu_addr, size)) { \
109 __gu_err = 0; \
110 switch (size) { \
111 case 1: __get_user_8(__gu_addr); break; \
112 case 2: __get_user_16(__gu_addr); break; \
113 case 4: __get_user_32(__gu_addr); break; \
114 case 8: __get_user_64(__gu_addr); break; \
115 default: __get_user_unknown(); break; \
116 } \
117 } \
118 (x) = (__force __typeof__(*(ptr))) __gu_val; \
119 __gu_err; \
120 })
121
122 struct __large_struct { unsigned long buf[100]; };
123 #define __m(x) (*(struct __large_struct __user *)(x))
124
125 #define __get_user_64(addr) \
126 __asm__("1: ldq %0,%2\n" \
127 "2:\n" \
128 EXC(1b,2b,%0,%1) \
129 : "=r"(__gu_val), "=r"(__gu_err) \
130 : "m"(__m(addr)), "1"(__gu_err))
131
132 #define __get_user_32(addr) \
133 __asm__("1: ldl %0,%2\n" \
134 "2:\n" \
135 EXC(1b,2b,%0,%1) \
136 : "=r"(__gu_val), "=r"(__gu_err) \
137 : "m"(__m(addr)), "1"(__gu_err))
138
139 #ifdef __alpha_bwx__
140 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves. */
141
142 #define __get_user_16(addr) \
143 __asm__("1: ldwu %0,%2\n" \
144 "2:\n" \
145 EXC(1b,2b,%0,%1) \
146 : "=r"(__gu_val), "=r"(__gu_err) \
147 : "m"(__m(addr)), "1"(__gu_err))
148
149 #define __get_user_8(addr) \
150 __asm__("1: ldbu %0,%2\n" \
151 "2:\n" \
152 EXC(1b,2b,%0,%1) \
153 : "=r"(__gu_val), "=r"(__gu_err) \
154 : "m"(__m(addr)), "1"(__gu_err))
155 #else
156 /* Unfortunately, we can't get an unaligned access trap for the sub-word
157 load, so we have to do a general unaligned operation. */
158
159 #define __get_user_16(addr) \
160 { \
161 long __gu_tmp; \
162 __asm__("1: ldq_u %0,0(%3)\n" \
163 "2: ldq_u %1,1(%3)\n" \
164 " extwl %0,%3,%0\n" \
165 " extwh %1,%3,%1\n" \
166 " or %0,%1,%0\n" \
167 "3:\n" \
168 EXC(1b,3b,%0,%2) \
169 EXC(2b,3b,%0,%2) \
170 : "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err) \
171 : "r"(addr), "2"(__gu_err)); \
172 }
173
174 #define __get_user_8(addr) \
175 __asm__("1: ldq_u %0,0(%2)\n" \
176 " extbl %0,%2,%0\n" \
177 "2:\n" \
178 EXC(1b,2b,%0,%1) \
179 : "=&r"(__gu_val), "=r"(__gu_err) \
180 : "r"(addr), "1"(__gu_err))
181 #endif
182
183 extern void __put_user_unknown(void);
184
185 #define __put_user_nocheck(x, ptr, size) \
186 ({ \
187 long __pu_err = 0; \
188 __chk_user_ptr(ptr); \
189 switch (size) { \
190 case 1: __put_user_8(x, ptr); break; \
191 case 2: __put_user_16(x, ptr); break; \
192 case 4: __put_user_32(x, ptr); break; \
193 case 8: __put_user_64(x, ptr); break; \
194 default: __put_user_unknown(); break; \
195 } \
196 __pu_err; \
197 })
198
199 #define __put_user_check(x, ptr, size) \
200 ({ \
201 long __pu_err = -EFAULT; \
202 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
203 if (__access_ok((unsigned long)__pu_addr, size)) { \
204 __pu_err = 0; \
205 switch (size) { \
206 case 1: __put_user_8(x, __pu_addr); break; \
207 case 2: __put_user_16(x, __pu_addr); break; \
208 case 4: __put_user_32(x, __pu_addr); break; \
209 case 8: __put_user_64(x, __pu_addr); break; \
210 default: __put_user_unknown(); break; \
211 } \
212 } \
213 __pu_err; \
214 })
215
216 /*
217 * The "__put_user_xx()" macros tell gcc they read from memory
218 * instead of writing: this is because they do not write to
219 * any memory gcc knows about, so there are no aliasing issues
220 */
221 #define __put_user_64(x, addr) \
222 __asm__ __volatile__("1: stq %r2,%1\n" \
223 "2:\n" \
224 EXC(1b,2b,$31,%0) \
225 : "=r"(__pu_err) \
226 : "m" (__m(addr)), "rJ" (x), "0"(__pu_err))
227
228 #define __put_user_32(x, addr) \
229 __asm__ __volatile__("1: stl %r2,%1\n" \
230 "2:\n" \
231 EXC(1b,2b,$31,%0) \
232 : "=r"(__pu_err) \
233 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
234
235 #ifdef __alpha_bwx__
236 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves. */
237
238 #define __put_user_16(x, addr) \
239 __asm__ __volatile__("1: stw %r2,%1\n" \
240 "2:\n" \
241 EXC(1b,2b,$31,%0) \
242 : "=r"(__pu_err) \
243 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
244
245 #define __put_user_8(x, addr) \
246 __asm__ __volatile__("1: stb %r2,%1\n" \
247 "2:\n" \
248 EXC(1b,2b,$31,%0) \
249 : "=r"(__pu_err) \
250 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
251 #else
252 /* Unfortunately, we can't get an unaligned access trap for the sub-word
253 write, so we have to do a general unaligned operation. */
254
255 #define __put_user_16(x, addr) \
256 { \
257 long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4; \
258 __asm__ __volatile__( \
259 "1: ldq_u %2,1(%5)\n" \
260 "2: ldq_u %1,0(%5)\n" \
261 " inswh %6,%5,%4\n" \
262 " inswl %6,%5,%3\n" \
263 " mskwh %2,%5,%2\n" \
264 " mskwl %1,%5,%1\n" \
265 " or %2,%4,%2\n" \
266 " or %1,%3,%1\n" \
267 "3: stq_u %2,1(%5)\n" \
268 "4: stq_u %1,0(%5)\n" \
269 "5:\n" \
270 EXC(1b,5b,$31,%0) \
271 EXC(2b,5b,$31,%0) \
272 EXC(3b,5b,$31,%0) \
273 EXC(4b,5b,$31,%0) \
274 : "=r"(__pu_err), "=&r"(__pu_tmp1), \
275 "=&r"(__pu_tmp2), "=&r"(__pu_tmp3), \
276 "=&r"(__pu_tmp4) \
277 : "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
278 }
279
280 #define __put_user_8(x, addr) \
281 { \
282 long __pu_tmp1, __pu_tmp2; \
283 __asm__ __volatile__( \
284 "1: ldq_u %1,0(%4)\n" \
285 " insbl %3,%4,%2\n" \
286 " mskbl %1,%4,%1\n" \
287 " or %1,%2,%1\n" \
288 "2: stq_u %1,0(%4)\n" \
289 "3:\n" \
290 EXC(1b,3b,$31,%0) \
291 EXC(2b,3b,$31,%0) \
292 : "=r"(__pu_err), \
293 "=&r"(__pu_tmp1), "=&r"(__pu_tmp2) \
294 : "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
295 }
296 #endif
297
298
299 /*
300 * Complex access routines
301 */
302
303 extern long __copy_user(void *to, const void *from, long len);
304
305 static inline unsigned long
raw_copy_from_user(void * to,const void __user * from,unsigned long len)306 raw_copy_from_user(void *to, const void __user *from, unsigned long len)
307 {
308 return __copy_user(to, (__force const void *)from, len);
309 }
310
311 static inline unsigned long
raw_copy_to_user(void __user * to,const void * from,unsigned long len)312 raw_copy_to_user(void __user *to, const void *from, unsigned long len)
313 {
314 return __copy_user((__force void *)to, from, len);
315 }
316
317 extern long __clear_user(void __user *to, long len);
318
319 extern inline long
clear_user(void __user * to,long len)320 clear_user(void __user *to, long len)
321 {
322 if (__access_ok((unsigned long)to, len))
323 len = __clear_user(to, len);
324 return len;
325 }
326
327 #define user_addr_max() \
328 (uaccess_kernel() ? ~0UL : TASK_SIZE)
329
330 extern long strncpy_from_user(char *dest, const char __user *src, long count);
331 extern __must_check long strnlen_user(const char __user *str, long n);
332
333 #include <asm/extable.h>
334
335 #endif /* __ALPHA_UACCESS_H */
336
