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[mirror_ubuntu-bionic-kernel.git] / include / asm-alpha / uaccess.h
1 #ifndef __ALPHA_UACCESS_H
2 #define __ALPHA_UACCESS_H
3
4 #include <linux/errno.h>
5 #include <linux/sched.h>
6
7
8 /*
9 * The fs value determines whether argument validity checking should be
10 * performed or not. If get_fs() == USER_DS, checking is performed, with
11 * get_fs() == KERNEL_DS, checking is bypassed.
12 *
13 * Or at least it did once upon a time. Nowadays it is a mask that
14 * defines which bits of the address space are off limits. This is a
15 * wee bit faster than the above.
16 *
17 * For historical reasons, these macros are grossly misnamed.
18 */
19
20 #define KERNEL_DS ((mm_segment_t) { 0UL })
21 #define USER_DS ((mm_segment_t) { -0x40000000000UL })
22
23 #define VERIFY_READ 0
24 #define VERIFY_WRITE 1
25
26 #define get_fs() (current_thread_info()->addr_limit)
27 #define get_ds() (KERNEL_DS)
28 #define set_fs(x) (current_thread_info()->addr_limit = (x))
29
30 #define segment_eq(a,b) ((a).seg == (b).seg)
31
32 /*
33 * Is a address valid? This does a straightforward calculation rather
34 * than tests.
35 *
36 * Address valid if:
37 * - "addr" doesn't have any high-bits set
38 * - AND "size" doesn't have any high-bits set
39 * - AND "addr+size" doesn't have any high-bits set
40 * - OR we are in kernel mode.
41 */
42 #define __access_ok(addr,size,segment) \
43 (((segment).seg & (addr | size | (addr+size))) == 0)
44
45 #define access_ok(type,addr,size) \
46 ({ \
47 __chk_user_ptr(addr); \
48 __access_ok(((unsigned long)(addr)),(size),get_fs()); \
49 })
50
51 /* this function will go away soon - use access_ok() instead */
52 extern inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size)
53 {
54 return access_ok(type,addr,size) ? 0 : -EFAULT;
55 }
56
57 /*
58 * These are the main single-value transfer routines. They automatically
59 * use the right size if we just have the right pointer type.
60 *
61 * As the alpha uses the same address space for kernel and user
62 * data, we can just do these as direct assignments. (Of course, the
63 * exception handling means that it's no longer "just"...)
64 *
65 * Careful to not
66 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
67 * (b) require any knowledge of processes at this stage
68 */
69 #define put_user(x,ptr) \
70 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)),get_fs())
71 #define get_user(x,ptr) \
72 __get_user_check((x),(ptr),sizeof(*(ptr)),get_fs())
73
74 /*
75 * The "__xxx" versions do not do address space checking, useful when
76 * doing multiple accesses to the same area (the programmer has to do the
77 * checks by hand with "access_ok()")
78 */
79 #define __put_user(x,ptr) \
80 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
81 #define __get_user(x,ptr) \
82 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
83
84 /*
85 * The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to
86 * encode the bits we need for resolving the exception. See the
87 * more extensive comments with fixup_inline_exception below for
88 * more information.
89 */
90
91 extern void __get_user_unknown(void);
92
93 #define __get_user_nocheck(x,ptr,size) \
94 ({ \
95 long __gu_err = 0; \
96 unsigned long __gu_val; \
97 __chk_user_ptr(ptr); \
98 switch (size) { \
99 case 1: __get_user_8(ptr); break; \
100 case 2: __get_user_16(ptr); break; \
101 case 4: __get_user_32(ptr); break; \
102 case 8: __get_user_64(ptr); break; \
103 default: __get_user_unknown(); break; \
104 } \
105 (x) = (__typeof__(*(ptr))) __gu_val; \
106 __gu_err; \
107 })
108
109 #define __get_user_check(x,ptr,size,segment) \
110 ({ \
111 long __gu_err = -EFAULT; \
112 unsigned long __gu_val = 0; \
113 const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
114 if (__access_ok((unsigned long)__gu_addr,size,segment)) { \
115 __gu_err = 0; \
116 switch (size) { \
117 case 1: __get_user_8(__gu_addr); break; \
118 case 2: __get_user_16(__gu_addr); break; \
119 case 4: __get_user_32(__gu_addr); break; \
120 case 8: __get_user_64(__gu_addr); break; \
121 default: __get_user_unknown(); break; \
122 } \
123 } \
124 (x) = (__typeof__(*(ptr))) __gu_val; \
125 __gu_err; \
126 })
127
128 struct __large_struct { unsigned long buf[100]; };
129 #define __m(x) (*(struct __large_struct __user *)(x))
130
131 #define __get_user_64(addr) \
132 __asm__("1: ldq %0,%2\n" \
133 "2:\n" \
134 ".section __ex_table,\"a\"\n" \
135 " .long 1b - .\n" \
136 " lda %0, 2b-1b(%1)\n" \
137 ".previous" \
138 : "=r"(__gu_val), "=r"(__gu_err) \
139 : "m"(__m(addr)), "1"(__gu_err))
140
141 #define __get_user_32(addr) \
142 __asm__("1: ldl %0,%2\n" \
143 "2:\n" \
144 ".section __ex_table,\"a\"\n" \
145 " .long 1b - .\n" \
146 " lda %0, 2b-1b(%1)\n" \
147 ".previous" \
148 : "=r"(__gu_val), "=r"(__gu_err) \
149 : "m"(__m(addr)), "1"(__gu_err))
150
151 #ifdef __alpha_bwx__
152 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves. */
153
154 #define __get_user_16(addr) \
155 __asm__("1: ldwu %0,%2\n" \
156 "2:\n" \
157 ".section __ex_table,\"a\"\n" \
158 " .long 1b - .\n" \
159 " lda %0, 2b-1b(%1)\n" \
160 ".previous" \
161 : "=r"(__gu_val), "=r"(__gu_err) \
162 : "m"(__m(addr)), "1"(__gu_err))
163
164 #define __get_user_8(addr) \
165 __asm__("1: ldbu %0,%2\n" \
166 "2:\n" \
167 ".section __ex_table,\"a\"\n" \
168 " .long 1b - .\n" \
169 " lda %0, 2b-1b(%1)\n" \
170 ".previous" \
171 : "=r"(__gu_val), "=r"(__gu_err) \
172 : "m"(__m(addr)), "1"(__gu_err))
173 #else
174 /* Unfortunately, we can't get an unaligned access trap for the sub-word
175 load, so we have to do a general unaligned operation. */
176
177 #define __get_user_16(addr) \
178 { \
179 long __gu_tmp; \
180 __asm__("1: ldq_u %0,0(%3)\n" \
181 "2: ldq_u %1,1(%3)\n" \
182 " extwl %0,%3,%0\n" \
183 " extwh %1,%3,%1\n" \
184 " or %0,%1,%0\n" \
185 "3:\n" \
186 ".section __ex_table,\"a\"\n" \
187 " .long 1b - .\n" \
188 " lda %0, 3b-1b(%2)\n" \
189 " .long 2b - .\n" \
190 " lda %0, 3b-2b(%2)\n" \
191 ".previous" \
192 : "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err) \
193 : "r"(addr), "2"(__gu_err)); \
194 }
195
196 #define __get_user_8(addr) \
197 __asm__("1: ldq_u %0,0(%2)\n" \
198 " extbl %0,%2,%0\n" \
199 "2:\n" \
200 ".section __ex_table,\"a\"\n" \
201 " .long 1b - .\n" \
202 " lda %0, 2b-1b(%1)\n" \
203 ".previous" \
204 : "=&r"(__gu_val), "=r"(__gu_err) \
205 : "r"(addr), "1"(__gu_err))
206 #endif
207
208 extern void __put_user_unknown(void);
209
210 #define __put_user_nocheck(x,ptr,size) \
211 ({ \
212 long __pu_err = 0; \
213 __chk_user_ptr(ptr); \
214 switch (size) { \
215 case 1: __put_user_8(x,ptr); break; \
216 case 2: __put_user_16(x,ptr); break; \
217 case 4: __put_user_32(x,ptr); break; \
218 case 8: __put_user_64(x,ptr); break; \
219 default: __put_user_unknown(); break; \
220 } \
221 __pu_err; \
222 })
223
224 #define __put_user_check(x,ptr,size,segment) \
225 ({ \
226 long __pu_err = -EFAULT; \
227 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
228 if (__access_ok((unsigned long)__pu_addr,size,segment)) { \
229 __pu_err = 0; \
230 switch (size) { \
231 case 1: __put_user_8(x,__pu_addr); break; \
232 case 2: __put_user_16(x,__pu_addr); break; \
233 case 4: __put_user_32(x,__pu_addr); break; \
234 case 8: __put_user_64(x,__pu_addr); break; \
235 default: __put_user_unknown(); break; \
236 } \
237 } \
238 __pu_err; \
239 })
240
241 /*
242 * The "__put_user_xx()" macros tell gcc they read from memory
243 * instead of writing: this is because they do not write to
244 * any memory gcc knows about, so there are no aliasing issues
245 */
246 #define __put_user_64(x,addr) \
247 __asm__ __volatile__("1: stq %r2,%1\n" \
248 "2:\n" \
249 ".section __ex_table,\"a\"\n" \
250 " .long 1b - .\n" \
251 " lda $31,2b-1b(%0)\n" \
252 ".previous" \
253 : "=r"(__pu_err) \
254 : "m" (__m(addr)), "rJ" (x), "0"(__pu_err))
255
256 #define __put_user_32(x,addr) \
257 __asm__ __volatile__("1: stl %r2,%1\n" \
258 "2:\n" \
259 ".section __ex_table,\"a\"\n" \
260 " .long 1b - .\n" \
261 " lda $31,2b-1b(%0)\n" \
262 ".previous" \
263 : "=r"(__pu_err) \
264 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
265
266 #ifdef __alpha_bwx__
267 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves. */
268
269 #define __put_user_16(x,addr) \
270 __asm__ __volatile__("1: stw %r2,%1\n" \
271 "2:\n" \
272 ".section __ex_table,\"a\"\n" \
273 " .long 1b - .\n" \
274 " lda $31,2b-1b(%0)\n" \
275 ".previous" \
276 : "=r"(__pu_err) \
277 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
278
279 #define __put_user_8(x,addr) \
280 __asm__ __volatile__("1: stb %r2,%1\n" \
281 "2:\n" \
282 ".section __ex_table,\"a\"\n" \
283 " .long 1b - .\n" \
284 " lda $31,2b-1b(%0)\n" \
285 ".previous" \
286 : "=r"(__pu_err) \
287 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
288 #else
289 /* Unfortunately, we can't get an unaligned access trap for the sub-word
290 write, so we have to do a general unaligned operation. */
291
292 #define __put_user_16(x,addr) \
293 { \
294 long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4; \
295 __asm__ __volatile__( \
296 "1: ldq_u %2,1(%5)\n" \
297 "2: ldq_u %1,0(%5)\n" \
298 " inswh %6,%5,%4\n" \
299 " inswl %6,%5,%3\n" \
300 " mskwh %2,%5,%2\n" \
301 " mskwl %1,%5,%1\n" \
302 " or %2,%4,%2\n" \
303 " or %1,%3,%1\n" \
304 "3: stq_u %2,1(%5)\n" \
305 "4: stq_u %1,0(%5)\n" \
306 "5:\n" \
307 ".section __ex_table,\"a\"\n" \
308 " .long 1b - .\n" \
309 " lda $31, 5b-1b(%0)\n" \
310 " .long 2b - .\n" \
311 " lda $31, 5b-2b(%0)\n" \
312 " .long 3b - .\n" \
313 " lda $31, 5b-3b(%0)\n" \
314 " .long 4b - .\n" \
315 " lda $31, 5b-4b(%0)\n" \
316 ".previous" \
317 : "=r"(__pu_err), "=&r"(__pu_tmp1), \
318 "=&r"(__pu_tmp2), "=&r"(__pu_tmp3), \
319 "=&r"(__pu_tmp4) \
320 : "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
321 }
322
323 #define __put_user_8(x,addr) \
324 { \
325 long __pu_tmp1, __pu_tmp2; \
326 __asm__ __volatile__( \
327 "1: ldq_u %1,0(%4)\n" \
328 " insbl %3,%4,%2\n" \
329 " mskbl %1,%4,%1\n" \
330 " or %1,%2,%1\n" \
331 "2: stq_u %1,0(%4)\n" \
332 "3:\n" \
333 ".section __ex_table,\"a\"\n" \
334 " .long 1b - .\n" \
335 " lda $31, 3b-1b(%0)\n" \
336 " .long 2b - .\n" \
337 " lda $31, 3b-2b(%0)\n" \
338 ".previous" \
339 : "=r"(__pu_err), \
340 "=&r"(__pu_tmp1), "=&r"(__pu_tmp2) \
341 : "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
342 }
343 #endif
344
345
346 /*
347 * Complex access routines
348 */
349
350 /* This little bit of silliness is to get the GP loaded for a function
351 that ordinarily wouldn't. Otherwise we could have it done by the macro
352 directly, which can be optimized the linker. */
353 #ifdef MODULE
354 #define __module_address(sym) "r"(sym),
355 #define __module_call(ra, arg, sym) "jsr $" #ra ",(%" #arg ")," #sym
356 #else
357 #define __module_address(sym)
358 #define __module_call(ra, arg, sym) "bsr $" #ra "," #sym " !samegp"
359 #endif
360
361 extern void __copy_user(void);
362
363 extern inline long
364 __copy_tofrom_user_nocheck(void *to, const void *from, long len)
365 {
366 register void * __cu_to __asm__("$6") = to;
367 register const void * __cu_from __asm__("$7") = from;
368 register long __cu_len __asm__("$0") = len;
369
370 __asm__ __volatile__(
371 __module_call(28, 3, __copy_user)
372 : "=r" (__cu_len), "=r" (__cu_from), "=r" (__cu_to)
373 : __module_address(__copy_user)
374 "0" (__cu_len), "1" (__cu_from), "2" (__cu_to)
375 : "$1","$2","$3","$4","$5","$28","memory");
376
377 return __cu_len;
378 }
379
380 extern inline long
381 __copy_tofrom_user(void *to, const void *from, long len, const void __user *validate)
382 {
383 if (__access_ok((unsigned long)validate, len, get_fs()))
384 len = __copy_tofrom_user_nocheck(to, from, len);
385 return len;
386 }
387
388 #define __copy_to_user(to,from,n) \
389 ({ \
390 __chk_user_ptr(to); \
391 __copy_tofrom_user_nocheck((__force void *)(to),(from),(n)); \
392 })
393 #define __copy_from_user(to,from,n) \
394 ({ \
395 __chk_user_ptr(from); \
396 __copy_tofrom_user_nocheck((to),(__force void *)(from),(n)); \
397 })
398
399 #define __copy_to_user_inatomic __copy_to_user
400 #define __copy_from_user_inatomic __copy_from_user
401
402
403 extern inline long
404 copy_to_user(void __user *to, const void *from, long n)
405 {
406 return __copy_tofrom_user((__force void *)to, from, n, to);
407 }
408
409 extern inline long
410 copy_from_user(void *to, const void __user *from, long n)
411 {
412 return __copy_tofrom_user(to, (__force void *)from, n, from);
413 }
414
415 extern void __do_clear_user(void);
416
417 extern inline long
418 __clear_user(void __user *to, long len)
419 {
420 register void __user * __cl_to __asm__("$6") = to;
421 register long __cl_len __asm__("$0") = len;
422 __asm__ __volatile__(
423 __module_call(28, 2, __do_clear_user)
424 : "=r"(__cl_len), "=r"(__cl_to)
425 : __module_address(__do_clear_user)
426 "0"(__cl_len), "1"(__cl_to)
427 : "$1","$2","$3","$4","$5","$28","memory");
428 return __cl_len;
429 }
430
431 extern inline long
432 clear_user(void __user *to, long len)
433 {
434 if (__access_ok((unsigned long)to, len, get_fs()))
435 len = __clear_user(to, len);
436 return len;
437 }
438
439 #undef __module_address
440 #undef __module_call
441
442 /* Returns: -EFAULT if exception before terminator, N if the entire
443 buffer filled, else strlen. */
444
445 extern long __strncpy_from_user(char *__to, const char __user *__from, long __to_len);
446
447 extern inline long
448 strncpy_from_user(char *to, const char __user *from, long n)
449 {
450 long ret = -EFAULT;
451 if (__access_ok((unsigned long)from, 0, get_fs()))
452 ret = __strncpy_from_user(to, from, n);
453 return ret;
454 }
455
456 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
457 extern long __strlen_user(const char __user *);
458
459 extern inline long strlen_user(const char __user *str)
460 {
461 return access_ok(VERIFY_READ,str,0) ? __strlen_user(str) : 0;
462 }
463
464 /* Returns: 0 if exception before NUL or reaching the supplied limit (N),
465 * a value greater than N if the limit would be exceeded, else strlen. */
466 extern long __strnlen_user(const char __user *, long);
467
468 extern inline long strnlen_user(const char __user *str, long n)
469 {
470 return access_ok(VERIFY_READ,str,0) ? __strnlen_user(str, n) : 0;
471 }
472
473 /*
474 * About the exception table:
475 *
476 * - insn is a 32-bit pc-relative offset from the faulting insn.
477 * - nextinsn is a 16-bit offset off of the faulting instruction
478 * (not off of the *next* instruction as branches are).
479 * - errreg is the register in which to place -EFAULT.
480 * - valreg is the final target register for the load sequence
481 * and will be zeroed.
482 *
483 * Either errreg or valreg may be $31, in which case nothing happens.
484 *
485 * The exception fixup information "just so happens" to be arranged
486 * as in a MEM format instruction. This lets us emit our three
487 * values like so:
488 *
489 * lda valreg, nextinsn(errreg)
490 *
491 */
492
493 struct exception_table_entry
494 {
495 signed int insn;
496 union exception_fixup {
497 unsigned unit;
498 struct {
499 signed int nextinsn : 16;
500 unsigned int errreg : 5;
501 unsigned int valreg : 5;
502 } bits;
503 } fixup;
504 };
505
506 /* Returns the new pc */
507 #define fixup_exception(map_reg, fixup, pc) \
508 ({ \
509 if ((fixup)->fixup.bits.valreg != 31) \
510 map_reg((fixup)->fixup.bits.valreg) = 0; \
511 if ((fixup)->fixup.bits.errreg != 31) \
512 map_reg((fixup)->fixup.bits.errreg) = -EFAULT; \
513 (pc) + (fixup)->fixup.bits.nextinsn; \
514 })
515
516
517 #endif /* __ALPHA_UACCESS_H */
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