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Linux/arch/powerpc/include/asm/uaccess.h

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  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 
 10 /*
 11  * The fs value determines whether argument validity checking should be
 12  * performed or not.  If get_fs() == USER_DS, checking is performed, with
 13  * get_fs() == KERNEL_DS, checking is bypassed.
 14  *
 15  * For historical reasons, these macros are grossly misnamed.
 16  *
 17  * The fs/ds values are now the highest legal address in the "segment".
 18  * This simplifies the checking in the routines below.
 19  */
 20 
 21 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
 22 
 23 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
 24 #ifdef __powerpc64__
 25 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
 26 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
 27 #else
 28 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
 29 #endif
 30 
 31 #define get_fs()        (current->thread.addr_limit)
 32 
 33 static inline void set_fs(mm_segment_t fs)
 34 {
 35         current->thread.addr_limit = fs;
 36         /* On user-mode return check addr_limit (fs) is correct */
 37         set_thread_flag(TIF_FSCHECK);
 38 }
 39 
 40 #define segment_eq(a, b)        ((a).seg == (b).seg)
 41 
 42 #define user_addr_max() (get_fs().seg)
 43 
 44 #ifdef __powerpc64__
 45 /*
 46  * This check is sufficient because there is a large enough
 47  * gap between user addresses and the kernel addresses
 48  */
 49 #define __access_ok(addr, size, segment)        \
 50         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
 51 
 52 #else
 53 
 54 static inline int __access_ok(unsigned long addr, unsigned long size,
 55                         mm_segment_t seg)
 56 {
 57         if (addr > seg.seg)
 58                 return 0;
 59         return (size == 0 || size - 1 <= seg.seg - addr);
 60 }
 61 
 62 #endif
 63 
 64 #define access_ok(addr, size)           \
 65         (__chk_user_ptr(addr),          \
 66          __access_ok((__force unsigned long)(addr), (size), get_fs()))
 67 
 68 /*
 69  * These are the main single-value transfer routines.  They automatically
 70  * use the right size if we just have the right pointer type.
 71  *
 72  * This gets kind of ugly. We want to return _two_ values in "get_user()"
 73  * and yet we don't want to do any pointers, because that is too much
 74  * of a performance impact. Thus we have a few rather ugly macros here,
 75  * and hide all the ugliness from the user.
 76  *
 77  * The "__xxx" versions of the user access functions are versions that
 78  * do not verify the address space, that must have been done previously
 79  * with a separate "access_ok()" call (this is used when we do multiple
 80  * accesses to the same area of user memory).
 81  *
 82  * As we use the same address space for kernel and user data on the
 83  * PowerPC, we can just do these as direct assignments.  (Of course, the
 84  * exception handling means that it's no longer "just"...)
 85  *
 86  */
 87 #define get_user(x, ptr) \
 88         __get_user_check((x), (ptr), sizeof(*(ptr)))
 89 #define put_user(x, ptr) \
 90         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 91 
 92 #define __get_user(x, ptr) \
 93         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 94 #define __put_user(x, ptr) \
 95         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 96 
 97 #define __get_user_inatomic(x, ptr) \
 98         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
 99 #define __put_user_inatomic(x, ptr) \
100         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
101 
102 extern long __put_user_bad(void);
103 
104 /*
105  * We don't tell gcc that we are accessing memory, but this is OK
106  * because we do not write to any memory gcc knows about, so there
107  * are no aliasing issues.
108  */
109 #define __put_user_asm(x, addr, err, op)                        \
110         __asm__ __volatile__(                                   \
111                 "1:     " op " %1,0(%2) # put_user\n"           \
112                 "2:\n"                                          \
113                 ".section .fixup,\"ax\"\n"                      \
114                 "3:     li %0,%3\n"                             \
115                 "       b 2b\n"                                 \
116                 ".previous\n"                                   \
117                 EX_TABLE(1b, 3b)                                \
118                 : "=r" (err)                                    \
119                 : "r" (x), "b" (addr), "i" (-EFAULT), "" (err))
120 
121 #ifdef __powerpc64__
122 #define __put_user_asm2(x, ptr, retval)                         \
123           __put_user_asm(x, ptr, retval, "std")
124 #else /* __powerpc64__ */
125 #define __put_user_asm2(x, addr, err)                           \
126         __asm__ __volatile__(                                   \
127                 "1:     stw %1,0(%2)\n"                         \
128                 "2:     stw %1+1,4(%2)\n"                       \
129                 "3:\n"                                          \
130                 ".section .fixup,\"ax\"\n"                      \
131                 "4:     li %0,%3\n"                             \
132                 "       b 3b\n"                                 \
133                 ".previous\n"                                   \
134                 EX_TABLE(1b, 4b)                                \
135                 EX_TABLE(2b, 4b)                                \
136                 : "=r" (err)                                    \
137                 : "r" (x), "b" (addr), "i" (-EFAULT), "" (err))
138 #endif /* __powerpc64__ */
139 
140 #define __put_user_size(x, ptr, size, retval)                   \
141 do {                                                            \
142         retval = 0;                                             \
143         switch (size) {                                         \
144           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
145           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
146           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
147           case 8: __put_user_asm2(x, ptr, retval); break;       \
148           default: __put_user_bad();                            \
149         }                                                       \
150 } while (0)
151 
152 #define __put_user_nocheck(x, ptr, size)                        \
153 ({                                                              \
154         long __pu_err;                                          \
155         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
156         if (!is_kernel_addr((unsigned long)__pu_addr))          \
157                 might_fault();                                  \
158         __chk_user_ptr(ptr);                                    \
159         __put_user_size((x), __pu_addr, (size), __pu_err);      \
160         __pu_err;                                               \
161 })
162 
163 #define __put_user_check(x, ptr, size)                                  \
164 ({                                                                      \
165         long __pu_err = -EFAULT;                                        \
166         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
167         might_fault();                                                  \
168         if (access_ok(__pu_addr, size))                 \
169                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
170         __pu_err;                                                       \
171 })
172 
173 #define __put_user_nosleep(x, ptr, size)                        \
174 ({                                                              \
175         long __pu_err;                                          \
176         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
177         __chk_user_ptr(ptr);                                    \
178         __put_user_size((x), __pu_addr, (size), __pu_err);      \
179         __pu_err;                                               \
180 })
181 
182 
183 extern long __get_user_bad(void);
184 
185 /*
186  * This does an atomic 128 byte aligned load from userspace.
187  * Upto caller to do enable_kernel_vmx() before calling!
188  */
189 #define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
190         __asm__ __volatile__(                           \
191                 "1:     lvx  0,0,%1     # get user\n"   \
192                 "       stvx 0,0,%2     # put kernel\n" \
193                 "2:\n"                                  \
194                 ".section .fixup,\"ax\"\n"              \
195                 "3:     li %0,%3\n"                     \
196                 "       b 2b\n"                         \
197                 ".previous\n"                           \
198                 EX_TABLE(1b, 3b)                        \
199                 : "=r" (err)                    \
200                 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "" (err))
201 
202 #define __get_user_asm(x, addr, err, op)                \
203         __asm__ __volatile__(                           \
204                 "1:     "op" %1,0(%2)   # get_user\n"   \
205                 "2:\n"                                  \
206                 ".section .fixup,\"ax\"\n"              \
207                 "3:     li %0,%3\n"                     \
208                 "       li %1,0\n"                      \
209                 "       b 2b\n"                         \
210                 ".previous\n"                           \
211                 EX_TABLE(1b, 3b)                        \
212                 : "=r" (err), "=r" (x)                  \
213                 : "b" (addr), "i" (-EFAULT), "" (err))
214 
215 #ifdef __powerpc64__
216 #define __get_user_asm2(x, addr, err)                   \
217         __get_user_asm(x, addr, err, "ld")
218 #else /* __powerpc64__ */
219 #define __get_user_asm2(x, addr, err)                   \
220         __asm__ __volatile__(                           \
221                 "1:     lwz %1,0(%2)\n"                 \
222                 "2:     lwz %1+1,4(%2)\n"               \
223                 "3:\n"                                  \
224                 ".section .fixup,\"ax\"\n"              \
225                 "4:     li %0,%3\n"                     \
226                 "       li %1,0\n"                      \
227                 "       li %1+1,0\n"                    \
228                 "       b 3b\n"                         \
229                 ".previous\n"                           \
230                 EX_TABLE(1b, 4b)                        \
231                 EX_TABLE(2b, 4b)                        \
232                 : "=r" (err), "=&r" (x)                 \
233                 : "b" (addr), "i" (-EFAULT), "" (err))
234 #endif /* __powerpc64__ */
235 
236 #define __get_user_size(x, ptr, size, retval)                   \
237 do {                                                            \
238         retval = 0;                                             \
239         __chk_user_ptr(ptr);                                    \
240         if (size > sizeof(x))                                   \
241                 (x) = __get_user_bad();                         \
242         switch (size) {                                         \
243         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
244         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
245         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
246         case 8: __get_user_asm2(x, ptr, retval);  break;        \
247         default: (x) = __get_user_bad();                        \
248         }                                                       \
249 } while (0)
250 
251 /*
252  * This is a type: either unsigned long, if the argument fits into
253  * that type, or otherwise unsigned long long.
254  */
255 #define __long_type(x) \
256         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
257 
258 #define __get_user_nocheck(x, ptr, size)                        \
259 ({                                                              \
260         long __gu_err;                                          \
261         __long_type(*(ptr)) __gu_val;                           \
262         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
263         __chk_user_ptr(ptr);                                    \
264         if (!is_kernel_addr((unsigned long)__gu_addr))          \
265                 might_fault();                                  \
266         barrier_nospec();                                       \
267         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
268         (x) = (__typeof__(*(ptr)))__gu_val;                     \
269         __gu_err;                                               \
270 })
271 
272 #define __get_user_check(x, ptr, size)                                  \
273 ({                                                                      \
274         long __gu_err = -EFAULT;                                        \
275         __long_type(*(ptr)) __gu_val = 0;                               \
276         __typeof__(*(ptr)) __user *__gu_addr = (ptr);           \
277         might_fault();                                                  \
278         if (access_ok(__gu_addr, (size))) {             \
279                 barrier_nospec();                                       \
280                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
281         }                                                               \
282         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
283         __gu_err;                                                       \
284 })
285 
286 #define __get_user_nosleep(x, ptr, size)                        \
287 ({                                                              \
288         long __gu_err;                                          \
289         __long_type(*(ptr)) __gu_val;                           \
290         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
291         __chk_user_ptr(ptr);                                    \
292         barrier_nospec();                                       \
293         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
294         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
295         __gu_err;                                               \
296 })
297 
298 
299 /* more complex routines */
300 
301 extern unsigned long __copy_tofrom_user(void __user *to,
302                 const void __user *from, unsigned long size);
303 
304 #ifdef __powerpc64__
305 static inline unsigned long
306 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
307 {
308         return __copy_tofrom_user(to, from, n);
309 }
310 #endif /* __powerpc64__ */
311 
312 static inline unsigned long raw_copy_from_user(void *to,
313                 const void __user *from, unsigned long n)
314 {
315         if (__builtin_constant_p(n) && (n <= 8)) {
316                 unsigned long ret = 1;
317 
318                 switch (n) {
319                 case 1:
320                         barrier_nospec();
321                         __get_user_size(*(u8 *)to, from, 1, ret);
322                         break;
323                 case 2:
324                         barrier_nospec();
325                         __get_user_size(*(u16 *)to, from, 2, ret);
326                         break;
327                 case 4:
328                         barrier_nospec();
329                         __get_user_size(*(u32 *)to, from, 4, ret);
330                         break;
331                 case 8:
332                         barrier_nospec();
333                         __get_user_size(*(u64 *)to, from, 8, ret);
334                         break;
335                 }
336                 if (ret == 0)
337                         return 0;
338         }
339 
340         barrier_nospec();
341         return __copy_tofrom_user((__force void __user *)to, from, n);
342 }
343 
344 static inline unsigned long raw_copy_to_user(void __user *to,
345                 const void *from, unsigned long n)
346 {
347         if (__builtin_constant_p(n) && (n <= 8)) {
348                 unsigned long ret = 1;
349 
350                 switch (n) {
351                 case 1:
352                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
353                         break;
354                 case 2:
355                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
356                         break;
357                 case 4:
358                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
359                         break;
360                 case 8:
361                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
362                         break;
363                 }
364                 if (ret == 0)
365                         return 0;
366         }
367 
368         return __copy_tofrom_user(to, (__force const void __user *)from, n);
369 }
370 
371 extern unsigned long __clear_user(void __user *addr, unsigned long size);
372 
373 static inline unsigned long clear_user(void __user *addr, unsigned long size)
374 {
375         might_fault();
376         if (likely(access_ok(addr, size)))
377                 return __clear_user(addr, size);
378         return size;
379 }
380 
381 extern long strncpy_from_user(char *dst, const char __user *src, long count);
382 extern __must_check long strnlen_user(const char __user *str, long n);
383 
384 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
385                 unsigned size);
386 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
387                            size_t len);
388 
389 #endif  /* _ARCH_POWERPC_UACCESS_H */
390 

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