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