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1 /* MN10300 userspace access functions
2  *
3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public Licence
8  * as published by the Free Software Foundation; either version
9  * 2 of the Licence, or (at your option) any later version.
10  */
11 #ifndef _ASM_UACCESS_H
12 #define _ASM_UACCESS_H
13
14 /*
15  * User space memory access functions
16  */
17 #include <linux/thread_info.h>
18 #include <asm/page.h>
19 #include <asm/errno.h>
20
21 #define VERIFY_READ 0
22 #define VERIFY_WRITE 1
23
24 /*
25  * The fs value determines whether argument validity checking should be
26  * performed or not.  If get_fs() == USER_DS, checking is performed, with
27  * get_fs() == KERNEL_DS, checking is bypassed.
28  *
29  * For historical reasons, these macros are grossly misnamed.
30  */
31 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
32
33 #define KERNEL_XDS      MAKE_MM_SEG(0xBFFFFFFF)
34 #define KERNEL_DS       MAKE_MM_SEG(0x9FFFFFFF)
35 #define USER_DS         MAKE_MM_SEG(TASK_SIZE)
36
37 #define get_ds()        (KERNEL_DS)
38 #define get_fs()        (current_thread_info()->addr_limit)
39 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
40 #define __kernel_ds_p() (current_thread_info()->addr_limit.seg == 0x9FFFFFFF)
41
42 #define segment_eq(a, b) ((a).seg == (b).seg)
43
44 #define __addr_ok(addr) \
45         ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))
46
47 /*
48  * check that a range of addresses falls within the current address limit
49  */
50 static inline int ___range_ok(unsigned long addr, unsigned int size)
51 {
52         int flag = 1, tmp;
53
54         asm("   add     %3,%1   \n"     /* set C-flag if addr + size > 4Gb */
55             "   bcs     0f      \n"
56             "   cmp     %4,%1   \n"     /* jump if addr+size>limit (error) */
57             "   bhi     0f      \n"
58             "   clr     %0      \n"     /* mark okay */
59             "0:                 \n"
60             : "=r"(flag), "=&r"(tmp)
61             : "1"(addr), "ir"(size),
62               "r"(current_thread_info()->addr_limit.seg), "0"(flag)
63             : "cc"
64             );
65
66         return flag;
67 }
68
69 #define __range_ok(addr, size) ___range_ok((unsigned long)(addr), (u32)(size))
70
71 #define access_ok(type, addr, size) (__range_ok((addr), (size)) == 0)
72 #define __access_ok(addr, size)     (__range_ok((addr), (size)) == 0)
73
74 static inline int verify_area(int type, const void *addr, unsigned long size)
75 {
76         return access_ok(type, addr, size) ? 0 : -EFAULT;
77 }
78
79
80 /*
81  * The exception table consists of pairs of addresses: the first is the
82  * address of an instruction that is allowed to fault, and the second is
83  * the address at which the program should continue.  No registers are
84  * modified, so it is entirely up to the continuation code to figure out
85  * what to do.
86  *
87  * All the routines below use bits of fixup code that are out of line
88  * with the main instruction path.  This means when everything is well,
89  * we don't even have to jump over them.  Further, they do not intrude
90  * on our cache or tlb entries.
91  */
92
93 struct exception_table_entry
94 {
95         unsigned long insn, fixup;
96 };
97
98 /* Returns 0 if exception not found and fixup otherwise.  */
99 extern int fixup_exception(struct pt_regs *regs);
100
101 #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
102 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
103
104 /*
105  * The "__xxx" versions do not do address space checking, useful when
106  * doing multiple accesses to the same area (the user has to do the
107  * checks by hand with "access_ok()")
108  */
109 #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
110 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
111
112 /*
113  * The "xxx_ret" versions return constant specified in third argument, if
114  * something bad happens. These macros can be optimized for the
115  * case of just returning from the function xxx_ret is used.
116  */
117
118 #define put_user_ret(x, ptr, ret) \
119         ({ if (put_user((x), (ptr)))    return (ret); })
120 #define get_user_ret(x, ptr, ret) \
121         ({ if (get_user((x), (ptr)))    return (ret); })
122 #define __put_user_ret(x, ptr, ret) \
123         ({ if (__put_user((x), (ptr)))  return (ret); })
124 #define __get_user_ret(x, ptr, ret) \
125         ({ if (__get_user((x), (ptr)))  return (ret); })
126
127 struct __large_struct { unsigned long buf[100]; };
128 #define __m(x) (*(struct __large_struct *)(x))
129
130 #define __get_user_nocheck(x, ptr, size)                                \
131 ({                                                                      \
132         unsigned long __gu_addr;                                        \
133         int __gu_err;                                                   \
134         __gu_addr = (unsigned long) (ptr);                              \
135         switch (size) {                                                 \
136         case 1: {                                                       \
137                 unsigned char __gu_val;                                 \
138                 __get_user_asm("bu");                                   \
139                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
140                 break;                                                  \
141         }                                                               \
142         case 2: {                                                       \
143                 unsigned short __gu_val;                                \
144                 __get_user_asm("hu");                                   \
145                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
146                 break;                                                  \
147         }                                                               \
148         case 4: {                                                       \
149                 unsigned int __gu_val;                                  \
150                 __get_user_asm("");                                     \
151                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
152                 break;                                                  \
153         }                                                               \
154         default:                                                        \
155                 __get_user_unknown();                                   \
156                 break;                                                  \
157         }                                                               \
158         __gu_err;                                                       \
159 })
160
161 #define __get_user_check(x, ptr, size)                                  \
162 ({                                                                      \
163         int _e;                                                         \
164         if (likely(__access_ok((unsigned long) (ptr), (size))))         \
165                 _e = __get_user_nocheck((x), (ptr), (size));            \
166         else {                                                          \
167                 _e = -EFAULT;                                           \
168                 (x) = (__typeof__(x))0;                                 \
169         }                                                               \
170         _e;                                                             \
171 })
172
173 #define __get_user_asm(INSN)                                    \
174 ({                                                              \
175         asm volatile(                                   \
176                 "1:\n"                                          \
177                 "       mov"INSN"       %2,%1\n"                \
178                 "       mov             0,%0\n"                 \
179                 "2:\n"                                          \
180                 "       .section        .fixup,\"ax\"\n"        \
181                 "3:\n\t"                                        \
182                 "       mov             %3,%0\n"                \
183                 "       jmp             2b\n"                   \
184                 "       .previous\n"                            \
185                 "       .section        __ex_table,\"a\"\n"     \
186                 "       .balign         4\n"                    \
187                 "       .long           1b, 3b\n"               \
188                 "       .previous"                              \
189                 : "=&r" (__gu_err), "=&r" (__gu_val)            \
190                 : "m" (__m(__gu_addr)), "i" (-EFAULT));         \
191 })
192
193 extern int __get_user_unknown(void);
194
195 #define __put_user_nocheck(x, ptr, size)                        \
196 ({                                                              \
197         union {                                                 \
198                 __typeof__(*(ptr)) val;                         \
199                 u32 bits[2];                                    \
200         } __pu_val;                                             \
201         unsigned long __pu_addr;                                \
202         int __pu_err;                                           \
203         __pu_val.val = (x);                                     \
204         __pu_addr = (unsigned long) (ptr);                      \
205         switch (size) {                                         \
206         case 1:  __put_user_asm("bu"); break;                   \
207         case 2:  __put_user_asm("hu"); break;                   \
208         case 4:  __put_user_asm(""  ); break;                   \
209         case 8:  __put_user_asm8();    break;                   \
210         default: __pu_err = __put_user_unknown(); break;        \
211         }                                                       \
212         __pu_err;                                               \
213 })
214
215 #define __put_user_check(x, ptr, size)                                  \
216 ({                                                                      \
217         union {                                                         \
218                 __typeof__(*(ptr)) val;                                 \
219                 u32 bits[2];                                            \
220         } __pu_val;                                                     \
221         unsigned long __pu_addr;                                        \
222         int __pu_err;                                                   \
223         __pu_val.val = (x);                                             \
224         __pu_addr = (unsigned long) (ptr);                              \
225         if (likely(__access_ok(__pu_addr, size))) {                     \
226                 switch (size) {                                         \
227                 case 1:  __put_user_asm("bu"); break;                   \
228                 case 2:  __put_user_asm("hu"); break;                   \
229                 case 4:  __put_user_asm(""  ); break;                   \
230                 case 8:  __put_user_asm8();    break;                   \
231                 default: __pu_err = __put_user_unknown(); break;        \
232                 }                                                       \
233         }                                                               \
234         else {                                                          \
235                 __pu_err = -EFAULT;                                     \
236         }                                                               \
237         __pu_err;                                                       \
238 })
239
240 #define __put_user_asm(INSN)                                    \
241 ({                                                              \
242         asm volatile(                                           \
243                 "1:\n"                                          \
244                 "       mov"INSN"       %1,%2\n"                \
245                 "       mov             0,%0\n"                 \
246                 "2:\n"                                          \
247                 "       .section        .fixup,\"ax\"\n"        \
248                 "3:\n"                                          \
249                 "       mov             %3,%0\n"                \
250                 "       jmp             2b\n"                   \
251                 "       .previous\n"                            \
252                 "       .section        __ex_table,\"a\"\n"     \
253                 "       .balign         4\n"                    \
254                 "       .long           1b, 3b\n"               \
255                 "       .previous"                              \
256                 : "=&r" (__pu_err)                              \
257                 : "r" (__pu_val.val), "m" (__m(__pu_addr)),     \
258                   "i" (-EFAULT)                                 \
259                 );                                              \
260 })
261
262 #define __put_user_asm8()                                               \
263 ({                                                                      \
264         asm volatile(                                                   \
265                 "1:     mov             %1,%3           \n"             \
266                 "2:     mov             %2,%4           \n"             \
267                 "       mov             0,%0            \n"             \
268                 "3:                                     \n"             \
269                 "       .section        .fixup,\"ax\"   \n"             \
270                 "4:                                     \n"             \
271                 "       mov             %5,%0           \n"             \
272                 "       jmp             3b              \n"             \
273                 "       .previous                       \n"             \
274                 "       .section        __ex_table,\"a\"\n"             \
275                 "       .balign         4               \n"             \
276                 "       .long           1b, 4b          \n"             \
277                 "       .long           2b, 4b          \n"             \
278                 "       .previous                       \n"             \
279                 : "=&r" (__pu_err)                                      \
280                 : "r" (__pu_val.bits[0]), "r" (__pu_val.bits[1]),       \
281                   "m" (__m(__pu_addr)), "m" (__m(__pu_addr+4)),         \
282                   "i" (-EFAULT)                                         \
283                 );                                                      \
284 })
285
286 extern int __put_user_unknown(void);
287
288
289 /*
290  * Copy To/From Userspace
291  */
292 /* Generic arbitrary sized copy.  */
293 #define __copy_user(to, from, size)                                     \
294 do {                                                                    \
295         if (size) {                                                     \
296                 void *__to = to;                                        \
297                 const void *__from = from;                              \
298                 int w;                                                  \
299                 asm volatile(                                           \
300                         "0:     movbu   (%0),%3;\n"                     \
301                         "1:     movbu   %3,(%1);\n"                     \
302                         "       inc     %0;\n"                          \
303                         "       inc     %1;\n"                          \
304                         "       add     -1,%2;\n"                       \
305                         "       bne     0b;\n"                          \
306                         "2:\n"                                          \
307                         "       .section .fixup,\"ax\"\n"               \
308                         "3:     jmp     2b\n"                           \
309                         "       .previous\n"                            \
310                         "       .section __ex_table,\"a\"\n"            \
311                         "       .balign 4\n"                            \
312                         "       .long   0b,3b\n"                        \
313                         "       .long   1b,3b\n"                        \
314                         "       .previous\n"                            \
315                         : "=a"(__from), "=a"(__to), "=r"(size), "=&r"(w)\
316                         : "0"(__from), "1"(__to), "2"(size)             \
317                         : "cc", "memory");                              \
318         }                                                               \
319 } while (0)
320
321 #define __copy_user_zeroing(to, from, size)                             \
322 do {                                                                    \
323         if (size) {                                                     \
324                 void *__to = to;                                        \
325                 const void *__from = from;                              \
326                 int w;                                                  \
327                 asm volatile(                                           \
328                         "0:     movbu   (%0),%3;\n"                     \
329                         "1:     movbu   %3,(%1);\n"                     \
330                         "       inc     %0;\n"                          \
331                         "       inc     %1;\n"                          \
332                         "       add     -1,%2;\n"                       \
333                         "       bne     0b;\n"                          \
334                         "2:\n"                                          \
335                         "       .section .fixup,\"ax\"\n"               \
336                         "3:\n"                                          \
337                         "       mov     %2,%0\n"                        \
338                         "       clr     %3\n"                           \
339                         "4:     movbu   %3,(%1);\n"                     \
340                         "       inc     %1;\n"                          \
341                         "       add     -1,%2;\n"                       \
342                         "       bne     4b;\n"                          \
343                         "       mov     %0,%2\n"                        \
344                         "       jmp     2b\n"                           \
345                         "       .previous\n"                            \
346                         "       .section __ex_table,\"a\"\n"            \
347                         "       .balign 4\n"                            \
348                         "       .long   0b,3b\n"                        \
349                         "       .long   1b,3b\n"                        \
350                         "       .previous\n"                            \
351                         : "=a"(__from), "=a"(__to), "=r"(size), "=&r"(w)\
352                         : "0"(__from), "1"(__to), "2"(size)             \
353                         : "cc", "memory");                              \
354         }                                                               \
355 } while (0)
356
357 /* We let the __ versions of copy_from/to_user inline, because they're often
358  * used in fast paths and have only a small space overhead.
359  */
360 static inline
361 unsigned long __generic_copy_from_user_nocheck(void *to, const void *from,
362                                                unsigned long n)
363 {
364         __copy_user_zeroing(to, from, n);
365         return n;
366 }
367
368 static inline
369 unsigned long __generic_copy_to_user_nocheck(void *to, const void *from,
370                                              unsigned long n)
371 {
372         __copy_user(to, from, n);
373         return n;
374 }
375
376
377 #if 0
378 #error "don't use - these macros don't increment to & from pointers"
379 /* Optimize just a little bit when we know the size of the move. */
380 #define __constant_copy_user(to, from, size)    \
381 do {                                            \
382         asm volatile(                           \
383                 "       mov %0,a0;\n"           \
384                 "0:     movbu (%1),d3;\n"       \
385                 "1:     movbu d3,(%2);\n"       \
386                 "       add -1,a0;\n"           \
387                 "       bne 0b;\n"              \
388                 "2:;"                           \
389                 ".section .fixup,\"ax\"\n"      \
390                 "3:     jmp 2b\n"               \
391                 ".previous\n"                   \
392                 ".section __ex_table,\"a\"\n"   \
393                 "       .balign 4\n"            \
394                 "       .long 0b,3b\n"          \
395                 "       .long 1b,3b\n"          \
396                 ".previous"                     \
397                 :                               \
398                 : "d"(size), "d"(to), "d"(from) \
399                 : "d3", "a0");                  \
400 } while (0)
401
402 /* Optimize just a little bit when we know the size of the move. */
403 #define __constant_copy_user_zeroing(to, from, size)    \
404 do {                                                    \
405         asm volatile(                                   \
406                 "       mov %0,a0;\n"                   \
407                 "0:     movbu (%1),d3;\n"               \
408                 "1:     movbu d3,(%2);\n"               \
409                 "       add -1,a0;\n"                   \
410                 "       bne 0b;\n"                      \
411                 "2:;"                                   \
412                 ".section .fixup,\"ax\"\n"              \
413                 "3:     jmp 2b\n"                       \
414                 ".previous\n"                           \
415                 ".section __ex_table,\"a\"\n"           \
416                 "       .balign 4\n"                    \
417                 "       .long 0b,3b\n"                  \
418                 "       .long 1b,3b\n"                  \
419                 ".previous"                             \
420                 :                                       \
421                 : "d"(size), "d"(to), "d"(from)         \
422                 : "d3", "a0");                          \
423 } while (0)
424
425 static inline
426 unsigned long __constant_copy_to_user(void *to, const void *from,
427                                       unsigned long n)
428 {
429         if (access_ok(VERIFY_WRITE, to, n))
430                 __constant_copy_user(to, from, n);
431         return n;
432 }
433
434 static inline
435 unsigned long __constant_copy_from_user(void *to, const void *from,
436                                         unsigned long n)
437 {
438         if (access_ok(VERIFY_READ, from, n))
439                 __constant_copy_user_zeroing(to, from, n);
440         return n;
441 }
442
443 static inline
444 unsigned long __constant_copy_to_user_nocheck(void *to, const void *from,
445                                               unsigned long n)
446 {
447         __constant_copy_user(to, from, n);
448         return n;
449 }
450
451 static inline
452 unsigned long __constant_copy_from_user_nocheck(void *to, const void *from,
453                                                 unsigned long n)
454 {
455         __constant_copy_user_zeroing(to, from, n);
456         return n;
457 }
458 #endif
459
460 extern unsigned long __generic_copy_to_user(void __user *, const void *,
461                                             unsigned long);
462 extern unsigned long __generic_copy_from_user(void *, const void __user *,
463                                               unsigned long);
464
465 #define __copy_to_user_inatomic(to, from, n) \
466         __generic_copy_to_user_nocheck((to), (from), (n))
467 #define __copy_from_user_inatomic(to, from, n) \
468         __generic_copy_from_user_nocheck((to), (from), (n))
469
470 #define __copy_to_user(to, from, n)                     \
471 ({                                                      \
472         might_sleep();                                  \
473         __copy_to_user_inatomic((to), (from), (n));     \
474 })
475
476 #define __copy_from_user(to, from, n)                   \
477 ({                                                      \
478         might_sleep();                                  \
479         __copy_from_user_inatomic((to), (from), (n));   \
480 })
481
482
483 #define copy_to_user(to, from, n)   __generic_copy_to_user((to), (from), (n))
484 #define copy_from_user(to, from, n) __generic_copy_from_user((to), (from), (n))
485
486 extern long strncpy_from_user(char *dst, const char __user *src, long count);
487 extern long __strncpy_from_user(char *dst, const char __user *src, long count);
488 extern long strnlen_user(const char __user *str, long n);
489 #define strlen_user(str) strnlen_user(str, ~0UL >> 1)
490 extern unsigned long clear_user(void __user *mem, unsigned long len);
491 extern unsigned long __clear_user(void __user *mem, unsigned long len);
492
493 #endif /* _ASM_UACCESS_H */