1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ARCH_POWERPC_UACCESS_H
3 #define _ARCH_POWERPC_UACCESS_H
4
5 #include <asm/ppc_asm.h>
6 #include <asm/processor.h>
7 #include <asm/page.h>
8 #include <asm/extable.h>
9 #include <asm/kup.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_fs() (current->thread.addr_limit)
33
set_fs(mm_segment_t fs)34 static inline void set_fs(mm_segment_t fs)
35 {
36 current->thread.addr_limit = fs;
37 /* On user-mode return check addr_limit (fs) is correct */
38 set_thread_flag(TIF_FSCHECK);
39 }
40
41 #define segment_eq(a, b) ((a).seg == (b).seg)
42
43 #define user_addr_max() (get_fs().seg)
44
45 #ifdef __powerpc64__
46 /*
47 * This check is sufficient because there is a large enough
48 * gap between user addresses and the kernel addresses
49 */
50 #define __access_ok(addr, size, segment) \
51 (((addr) <= (segment).seg) && ((size) <= (segment).seg))
52
53 #else
54
__access_ok(unsigned long addr,unsigned long size,mm_segment_t seg)55 static inline int __access_ok(unsigned long addr, unsigned long size,
56 mm_segment_t seg)
57 {
58 if (addr > seg.seg)
59 return 0;
60 return (size == 0 || size - 1 <= seg.seg - addr);
61 }
62
63 #endif
64
65 #define access_ok(addr, size) \
66 (__chk_user_ptr(addr), \
67 __access_ok((__force unsigned long)(addr), (size), get_fs()))
68
69 /*
70 * These are the main single-value transfer routines. They automatically
71 * use the right size if we just have the right pointer type.
72 *
73 * This gets kind of ugly. We want to return _two_ values in "get_user()"
74 * and yet we don't want to do any pointers, because that is too much
75 * of a performance impact. Thus we have a few rather ugly macros here,
76 * and hide all the ugliness from the user.
77 *
78 * The "__xxx" versions of the user access functions are versions that
79 * do not verify the address space, that must have been done previously
80 * with a separate "access_ok()" call (this is used when we do multiple
81 * accesses to the same area of user memory).
82 *
83 * As we use the same address space for kernel and user data on the
84 * PowerPC, we can just do these as direct assignments. (Of course, the
85 * exception handling means that it's no longer "just"...)
86 *
87 */
88 #define get_user(x, ptr) \
89 __get_user_check((x), (ptr), sizeof(*(ptr)))
90 #define put_user(x, ptr) \
91 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
92
93 #define __get_user(x, ptr) \
94 __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
95 #define __put_user(x, ptr) \
96 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
97
98 #define __get_user_inatomic(x, ptr) \
99 __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
100 #define __put_user_inatomic(x, ptr) \
101 __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
102
103 extern long __put_user_bad(void);
104
105 /*
106 * We don't tell gcc that we are accessing memory, but this is OK
107 * because we do not write to any memory gcc knows about, so there
108 * are no aliasing issues.
109 */
110 #define __put_user_asm(x, addr, err, op) \
111 __asm__ __volatile__( \
112 "1: " op " %1,0(%2) # put_user\n" \
113 "2:\n" \
114 ".section .fixup,\"ax\"\n" \
115 "3: li %0,%3\n" \
116 " b 2b\n" \
117 ".previous\n" \
118 EX_TABLE(1b, 3b) \
119 : "=r" (err) \
120 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
121
122 #ifdef __powerpc64__
123 #define __put_user_asm2(x, ptr, retval) \
124 __put_user_asm(x, ptr, retval, "std")
125 #else /* __powerpc64__ */
126 #define __put_user_asm2(x, addr, err) \
127 __asm__ __volatile__( \
128 "1: stw %1,0(%2)\n" \
129 "2: stw %1+1,4(%2)\n" \
130 "3:\n" \
131 ".section .fixup,\"ax\"\n" \
132 "4: li %0,%3\n" \
133 " b 3b\n" \
134 ".previous\n" \
135 EX_TABLE(1b, 4b) \
136 EX_TABLE(2b, 4b) \
137 : "=r" (err) \
138 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
139 #endif /* __powerpc64__ */
140
141 #define __put_user_size(x, ptr, size, retval) \
142 do { \
143 retval = 0; \
144 allow_write_to_user(ptr, size); \
145 switch (size) { \
146 case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
147 case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
148 case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
149 case 8: __put_user_asm2(x, ptr, retval); break; \
150 default: __put_user_bad(); \
151 } \
152 prevent_write_to_user(ptr, size); \
153 } while (0)
154
155 #define __put_user_nocheck(x, ptr, size) \
156 ({ \
157 long __pu_err; \
158 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
159 if (!is_kernel_addr((unsigned long)__pu_addr)) \
160 might_fault(); \
161 __chk_user_ptr(ptr); \
162 __put_user_size((x), __pu_addr, (size), __pu_err); \
163 __pu_err; \
164 })
165
166 #define __put_user_check(x, ptr, size) \
167 ({ \
168 long __pu_err = -EFAULT; \
169 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
170 might_fault(); \
171 if (access_ok(__pu_addr, size)) \
172 __put_user_size((x), __pu_addr, (size), __pu_err); \
173 __pu_err; \
174 })
175
176 #define __put_user_nosleep(x, ptr, size) \
177 ({ \
178 long __pu_err; \
179 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
180 __chk_user_ptr(ptr); \
181 __put_user_size((x), __pu_addr, (size), __pu_err); \
182 __pu_err; \
183 })
184
185
186 extern long __get_user_bad(void);
187
188 /*
189 * This does an atomic 128 byte aligned load from userspace.
190 * Upto caller to do enable_kernel_vmx() before calling!
191 */
192 #define __get_user_atomic_128_aligned(kaddr, uaddr, err) \
193 __asm__ __volatile__( \
194 "1: lvx 0,0,%1 # get user\n" \
195 " stvx 0,0,%2 # put kernel\n" \
196 "2:\n" \
197 ".section .fixup,\"ax\"\n" \
198 "3: li %0,%3\n" \
199 " b 2b\n" \
200 ".previous\n" \
201 EX_TABLE(1b, 3b) \
202 : "=r" (err) \
203 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
204
205 #define __get_user_asm(x, addr, err, op) \
206 __asm__ __volatile__( \
207 "1: "op" %1,0(%2) # get_user\n" \
208 "2:\n" \
209 ".section .fixup,\"ax\"\n" \
210 "3: li %0,%3\n" \
211 " li %1,0\n" \
212 " b 2b\n" \
213 ".previous\n" \
214 EX_TABLE(1b, 3b) \
215 : "=r" (err), "=r" (x) \
216 : "b" (addr), "i" (-EFAULT), "0" (err))
217
218 #ifdef __powerpc64__
219 #define __get_user_asm2(x, addr, err) \
220 __get_user_asm(x, addr, err, "ld")
221 #else /* __powerpc64__ */
222 #define __get_user_asm2(x, addr, err) \
223 __asm__ __volatile__( \
224 "1: lwz %1,0(%2)\n" \
225 "2: lwz %1+1,4(%2)\n" \
226 "3:\n" \
227 ".section .fixup,\"ax\"\n" \
228 "4: li %0,%3\n" \
229 " li %1,0\n" \
230 " li %1+1,0\n" \
231 " b 3b\n" \
232 ".previous\n" \
233 EX_TABLE(1b, 4b) \
234 EX_TABLE(2b, 4b) \
235 : "=r" (err), "=&r" (x) \
236 : "b" (addr), "i" (-EFAULT), "0" (err))
237 #endif /* __powerpc64__ */
238
239 #define __get_user_size(x, ptr, size, retval) \
240 do { \
241 retval = 0; \
242 __chk_user_ptr(ptr); \
243 if (size > sizeof(x)) \
244 (x) = __get_user_bad(); \
245 allow_read_from_user(ptr, size); \
246 switch (size) { \
247 case 1: __get_user_asm(x, ptr, retval, "lbz"); break; \
248 case 2: __get_user_asm(x, ptr, retval, "lhz"); break; \
249 case 4: __get_user_asm(x, ptr, retval, "lwz"); break; \
250 case 8: __get_user_asm2(x, ptr, retval); break; \
251 default: (x) = __get_user_bad(); \
252 } \
253 prevent_read_from_user(ptr, size); \
254 } while (0)
255
256 /*
257 * This is a type: either unsigned long, if the argument fits into
258 * that type, or otherwise unsigned long long.
259 */
260 #define __long_type(x) \
261 __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
262
263 #define __get_user_nocheck(x, ptr, size) \
264 ({ \
265 long __gu_err; \
266 __long_type(*(ptr)) __gu_val; \
267 __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
268 __chk_user_ptr(ptr); \
269 if (!is_kernel_addr((unsigned long)__gu_addr)) \
270 might_fault(); \
271 barrier_nospec(); \
272 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
273 (x) = (__typeof__(*(ptr)))__gu_val; \
274 __gu_err; \
275 })
276
277 #define __get_user_check(x, ptr, size) \
278 ({ \
279 long __gu_err = -EFAULT; \
280 __long_type(*(ptr)) __gu_val = 0; \
281 __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
282 might_fault(); \
283 if (access_ok(__gu_addr, (size))) { \
284 barrier_nospec(); \
285 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
286 } \
287 (x) = (__force __typeof__(*(ptr)))__gu_val; \
288 __gu_err; \
289 })
290
291 #define __get_user_nosleep(x, ptr, size) \
292 ({ \
293 long __gu_err; \
294 __long_type(*(ptr)) __gu_val; \
295 __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
296 __chk_user_ptr(ptr); \
297 barrier_nospec(); \
298 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
299 (x) = (__force __typeof__(*(ptr)))__gu_val; \
300 __gu_err; \
301 })
302
303
304 /* more complex routines */
305
306 extern unsigned long __copy_tofrom_user(void __user *to,
307 const void __user *from, unsigned long size);
308
309 #ifdef __powerpc64__
310 static inline unsigned long
raw_copy_in_user(void __user * to,const void __user * from,unsigned long n)311 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
312 {
313 unsigned long ret;
314
315 barrier_nospec();
316 allow_user_access(to, from, n);
317 ret = __copy_tofrom_user(to, from, n);
318 prevent_user_access(to, from, n);
319 return ret;
320 }
321 #endif /* __powerpc64__ */
322
raw_copy_from_user(void * to,const void __user * from,unsigned long n)323 static inline unsigned long raw_copy_from_user(void *to,
324 const void __user *from, unsigned long n)
325 {
326 unsigned long ret;
327 if (__builtin_constant_p(n) && (n <= 8)) {
328 ret = 1;
329
330 switch (n) {
331 case 1:
332 barrier_nospec();
333 __get_user_size(*(u8 *)to, from, 1, ret);
334 break;
335 case 2:
336 barrier_nospec();
337 __get_user_size(*(u16 *)to, from, 2, ret);
338 break;
339 case 4:
340 barrier_nospec();
341 __get_user_size(*(u32 *)to, from, 4, ret);
342 break;
343 case 8:
344 barrier_nospec();
345 __get_user_size(*(u64 *)to, from, 8, ret);
346 break;
347 }
348 if (ret == 0)
349 return 0;
350 }
351
352 barrier_nospec();
353 allow_read_from_user(from, n);
354 ret = __copy_tofrom_user((__force void __user *)to, from, n);
355 prevent_read_from_user(from, n);
356 return ret;
357 }
358
raw_copy_to_user(void __user * to,const void * from,unsigned long n)359 static inline unsigned long raw_copy_to_user(void __user *to,
360 const void *from, unsigned long n)
361 {
362 unsigned long ret;
363 if (__builtin_constant_p(n) && (n <= 8)) {
364 ret = 1;
365
366 switch (n) {
367 case 1:
368 __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
369 break;
370 case 2:
371 __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
372 break;
373 case 4:
374 __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
375 break;
376 case 8:
377 __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
378 break;
379 }
380 if (ret == 0)
381 return 0;
382 }
383
384 allow_write_to_user(to, n);
385 ret = __copy_tofrom_user(to, (__force const void __user *)from, n);
386 prevent_write_to_user(to, n);
387 return ret;
388 }
389
390 static __always_inline unsigned long __must_check
copy_to_user_mcsafe(void __user * to,const void * from,unsigned long n)391 copy_to_user_mcsafe(void __user *to, const void *from, unsigned long n)
392 {
393 if (likely(check_copy_size(from, n, true))) {
394 if (access_ok(to, n)) {
395 allow_write_to_user(to, n);
396 n = memcpy_mcsafe((void *)to, from, n);
397 prevent_write_to_user(to, n);
398 }
399 }
400
401 return n;
402 }
403
404 extern unsigned long __clear_user(void __user *addr, unsigned long size);
405
clear_user(void __user * addr,unsigned long size)406 static inline unsigned long clear_user(void __user *addr, unsigned long size)
407 {
408 unsigned long ret = size;
409 might_fault();
410 if (likely(access_ok(addr, size))) {
411 allow_write_to_user(addr, size);
412 ret = __clear_user(addr, size);
413 prevent_write_to_user(addr, size);
414 }
415 return ret;
416 }
417
418 extern long strncpy_from_user(char *dst, const char __user *src, long count);
419 extern __must_check long strnlen_user(const char __user *str, long n);
420
421 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
422 unsigned size);
423 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
424 size_t len);
425
426 #endif /* _ARCH_POWERPC_UACCESS_H */
427
