[PATCH] m32r: security fix of {get,put}_user macros
[linux-2.6.git] / include / asm-m32r / uaccess.h
1 #ifndef _ASM_M32R_UACCESS_H
2 #define _ASM_M32R_UACCESS_H
3
4 /*
5  *  linux/include/asm-m32r/uaccess.h
6  *
7  *  M32R version.
8  *    Copyright (C) 2004, 2006  Hirokazu Takata <takata at linux-m32r.org>
9  */
10
11 /*
12  * User space memory access functions
13  */
14 #include <linux/config.h>
15 #include <linux/errno.h>
16 #include <linux/thread_info.h>
17 #include <asm/page.h>
18
19 #define VERIFY_READ 0
20 #define VERIFY_WRITE 1
21
22 /*
23  * The fs value determines whether argument validity checking should be
24  * performed or not.  If get_fs() == USER_DS, checking is performed, with
25  * get_fs() == KERNEL_DS, checking is bypassed.
26  *
27  * For historical reasons, these macros are grossly misnamed.
28  */
29
30 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
31
32 #ifdef CONFIG_MMU
33
34 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
35 #define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
36 #define get_ds()        (KERNEL_DS)
37 #define get_fs()        (current_thread_info()->addr_limit)
38 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
39
40 #else /* not CONFIG_MMU */
41
42 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
43 #define USER_DS         MAKE_MM_SEG(0xFFFFFFFF)
44 #define get_ds()        (KERNEL_DS)
45
46 static inline mm_segment_t get_fs(void)
47 {
48         return USER_DS;
49 }
50
51 static inline void set_fs(mm_segment_t s)
52 {
53 }
54
55 #endif /* not CONFIG_MMU */
56
57 #define segment_eq(a,b) ((a).seg == (b).seg)
58
59 #define __addr_ok(addr) \
60         ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))
61
62 /*
63  * Test whether a block of memory is a valid user space address.
64  * Returns 0 if the range is valid, nonzero otherwise.
65  *
66  * This is equivalent to the following test:
67  * (u33)addr + (u33)size >= (u33)current->addr_limit.seg
68  *
69  * This needs 33-bit arithmetic. We have a carry...
70  */
71 #define __range_ok(addr,size) ({                                        \
72         unsigned long flag, sum;                                        \
73         __chk_user_ptr(addr);                                           \
74         asm (                                                           \
75                 "       cmpu    %1, %1    ; clear cbit\n"               \
76                 "       addx    %1, %3    ; set cbit if overflow\n"     \
77                 "       subx    %0, %0\n"                               \
78                 "       cmpu    %4, %1\n"                               \
79                 "       subx    %0, %5\n"                               \
80                 : "=&r" (flag), "=r" (sum)                              \
81                 : "1" (addr), "r" ((int)(size)),                        \
82                   "r" (current_thread_info()->addr_limit.seg), "r" (0)  \
83                 : "cbit" );                                             \
84         flag; })
85
86 /**
87  * access_ok: - Checks if a user space pointer is valid
88  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
89  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
90  *        to write to a block, it is always safe to read from it.
91  * @addr: User space pointer to start of block to check
92  * @size: Size of block to check
93  *
94  * Context: User context only.  This function may sleep.
95  *
96  * Checks if a pointer to a block of memory in user space is valid.
97  *
98  * Returns true (nonzero) if the memory block may be valid, false (zero)
99  * if it is definitely invalid.
100  *
101  * Note that, depending on architecture, this function probably just
102  * checks that the pointer is in the user space range - after calling
103  * this function, memory access functions may still return -EFAULT.
104  */
105 #ifdef CONFIG_MMU
106 #define access_ok(type,addr,size) (likely(__range_ok(addr,size) == 0))
107 #else
108 static inline int access_ok(int type, const void *addr, unsigned long size)
109 {
110         extern unsigned long memory_start, memory_end;
111         unsigned long val = (unsigned long)addr;
112
113         return ((val >= memory_start) && ((val + size) < memory_end));
114 }
115 #endif /* CONFIG_MMU */
116
117 /*
118  * The exception table consists of pairs of addresses: the first is the
119  * address of an instruction that is allowed to fault, and the second is
120  * the address at which the program should continue.  No registers are
121  * modified, so it is entirely up to the continuation code to figure out
122  * what to do.
123  *
124  * All the routines below use bits of fixup code that are out of line
125  * with the main instruction path.  This means when everything is well,
126  * we don't even have to jump over them.  Further, they do not intrude
127  * on our cache or tlb entries.
128  */
129
130 struct exception_table_entry
131 {
132         unsigned long insn, fixup;
133 };
134
135 extern int fixup_exception(struct pt_regs *regs);
136
137 /*
138  * These are the main single-value transfer routines.  They automatically
139  * use the right size if we just have the right pointer type.
140  *
141  * This gets kind of ugly. We want to return _two_ values in "get_user()"
142  * and yet we don't want to do any pointers, because that is too much
143  * of a performance impact. Thus we have a few rather ugly macros here,
144  * and hide all the uglyness from the user.
145  *
146  * The "__xxx" versions of the user access functions are versions that
147  * do not verify the address space, that must have been done previously
148  * with a separate "access_ok()" call (this is used when we do multiple
149  * accesses to the same area of user memory).
150  */
151
152 /* Careful: we have to cast the result to the type of the pointer for sign
153    reasons */
154 /**
155  * get_user: - Get a simple variable from user space.
156  * @x:   Variable to store result.
157  * @ptr: Source address, in user space.
158  *
159  * Context: User context only.  This function may sleep.
160  *
161  * This macro copies a single simple variable from user space to kernel
162  * space.  It supports simple types like char and int, but not larger
163  * data types like structures or arrays.
164  *
165  * @ptr must have pointer-to-simple-variable type, and the result of
166  * dereferencing @ptr must be assignable to @x without a cast.
167  *
168  * Returns zero on success, or -EFAULT on error.
169  * On error, the variable @x is set to zero.
170  */
171 #define get_user(x,ptr)                                                 \
172         __get_user_check((x),(ptr),sizeof(*(ptr)))
173
174 /**
175  * put_user: - Write a simple value into user space.
176  * @x:   Value to copy to user space.
177  * @ptr: Destination address, in user space.
178  *
179  * Context: User context only.  This function may sleep.
180  *
181  * This macro copies a single simple value from kernel space to user
182  * space.  It supports simple types like char and int, but not larger
183  * data types like structures or arrays.
184  *
185  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
186  * to the result of dereferencing @ptr.
187  *
188  * Returns zero on success, or -EFAULT on error.
189  */
190 #define put_user(x,ptr)                                                 \
191         __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
192
193 /**
194  * __get_user: - Get a simple variable from user space, with less checking.
195  * @x:   Variable to store result.
196  * @ptr: Source address, in user space.
197  *
198  * Context: User context only.  This function may sleep.
199  *
200  * This macro copies a single simple variable from user space to kernel
201  * space.  It supports simple types like char and int, but not larger
202  * data types like structures or arrays.
203  *
204  * @ptr must have pointer-to-simple-variable type, and the result of
205  * dereferencing @ptr must be assignable to @x without a cast.
206  *
207  * Caller must check the pointer with access_ok() before calling this
208  * function.
209  *
210  * Returns zero on success, or -EFAULT on error.
211  * On error, the variable @x is set to zero.
212  */
213 #define __get_user(x,ptr) \
214         __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
215
216 #define __get_user_nocheck(x,ptr,size)                                  \
217 ({                                                                      \
218         long __gu_err = 0;                                              \
219         unsigned long __gu_val;                                         \
220         might_sleep();                                                  \
221         __get_user_size(__gu_val,(ptr),(size),__gu_err);                \
222         (x) = (__typeof__(*(ptr)))__gu_val;                             \
223         __gu_err;                                                       \
224 })
225
226 #define __get_user_check(x,ptr,size)                                    \
227 ({                                                                      \
228         long __gu_err = -EFAULT;                                        \
229         unsigned long __gu_val = 0;                                     \
230         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
231         might_sleep();                                                  \
232         if (access_ok(VERIFY_READ,__gu_addr,size))                      \
233                 __get_user_size(__gu_val,__gu_addr,(size),__gu_err);    \
234         (x) = (__typeof__(*(ptr)))__gu_val;                             \
235         __gu_err;                                                       \
236 })
237
238 extern long __get_user_bad(void);
239
240 #define __get_user_size(x,ptr,size,retval)                              \
241 do {                                                                    \
242         retval = 0;                                                     \
243         __chk_user_ptr(ptr);                                            \
244         switch (size) {                                                 \
245           case 1: __get_user_asm(x,ptr,retval,"ub"); break;             \
246           case 2: __get_user_asm(x,ptr,retval,"uh"); break;             \
247           case 4: __get_user_asm(x,ptr,retval,""); break;               \
248           default: (x) = __get_user_bad();                              \
249         }                                                               \
250 } while (0)
251
252 #define __get_user_asm(x, addr, err, itype)                             \
253         __asm__ __volatile__(                                           \
254                 "       .fillinsn\n"                                    \
255                 "1:     ld"itype" %1,@%2\n"                             \
256                 "       .fillinsn\n"                                    \
257                 "2:\n"                                                  \
258                 ".section .fixup,\"ax\"\n"                              \
259                 "       .balign 4\n"                                    \
260                 "3:     ldi %0,%3\n"                                    \
261                 "       seth r14,#high(2b)\n"                           \
262                 "       or3 r14,r14,#low(2b)\n"                         \
263                 "       jmp r14\n"                                      \
264                 ".previous\n"                                           \
265                 ".section __ex_table,\"a\"\n"                           \
266                 "       .balign 4\n"                                    \
267                 "       .long 1b,3b\n"                                  \
268                 ".previous"                                             \
269                 : "=&r" (err), "=&r" (x)                                \
270                 : "r" (addr), "i" (-EFAULT), "0" (err)                  \
271                 : "r14", "memory")
272
273 /**
274  * __put_user: - Write a simple value into user space, with less checking.
275  * @x:   Value to copy to user space.
276  * @ptr: Destination address, in user space.
277  *
278  * Context: User context only.  This function may sleep.
279  *
280  * This macro copies a single simple value from kernel space to user
281  * space.  It supports simple types like char and int, but not larger
282  * data types like structures or arrays.
283  *
284  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
285  * to the result of dereferencing @ptr.
286  *
287  * Caller must check the pointer with access_ok() before calling this
288  * function.
289  *
290  * Returns zero on success, or -EFAULT on error.
291  */
292 #define __put_user(x,ptr) \
293         __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
294
295
296 #define __put_user_nocheck(x,ptr,size)                                  \
297 ({                                                                      \
298         long __pu_err;                                                  \
299         might_sleep();                                                  \
300         __put_user_size((x),(ptr),(size),__pu_err);                     \
301         __pu_err;                                                       \
302 })
303
304
305 #define __put_user_check(x,ptr,size)                                    \
306 ({                                                                      \
307         long __pu_err = -EFAULT;                                        \
308         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
309         might_sleep();                                                  \
310         if (access_ok(VERIFY_WRITE,__pu_addr,size))                     \
311                 __put_user_size((x),__pu_addr,(size),__pu_err);         \
312         __pu_err;                                                       \
313 })
314
315 #if defined(__LITTLE_ENDIAN__)
316 #define __put_user_u64(x, addr, err)                                    \
317         __asm__ __volatile__(                                           \
318                 "       .fillinsn\n"                                    \
319                 "1:     st %L1,@%2\n"                                   \
320                 "       .fillinsn\n"                                    \
321                 "2:     st %H1,@(4,%2)\n"                               \
322                 "       .fillinsn\n"                                    \
323                 "3:\n"                                                  \
324                 ".section .fixup,\"ax\"\n"                              \
325                 "       .balign 4\n"                                    \
326                 "4:     ldi %0,%3\n"                                    \
327                 "       seth r14,#high(3b)\n"                           \
328                 "       or3 r14,r14,#low(3b)\n"                         \
329                 "       jmp r14\n"                                      \
330                 ".previous\n"                                           \
331                 ".section __ex_table,\"a\"\n"                           \
332                 "       .balign 4\n"                                    \
333                 "       .long 1b,4b\n"                                  \
334                 "       .long 2b,4b\n"                                  \
335                 ".previous"                                             \
336                 : "=&r" (err)                                           \
337                 : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err)         \
338                 : "r14", "memory")
339
340 #elif defined(__BIG_ENDIAN__)
341 #define __put_user_u64(x, addr, err)                                    \
342         __asm__ __volatile__(                                           \
343                 "       .fillinsn\n"                                    \
344                 "1:     st %H1,@%2\n"                                   \
345                 "       .fillinsn\n"                                    \
346                 "2:     st %L1,@(4,%2)\n"                               \
347                 "       .fillinsn\n"                                    \
348                 "3:\n"                                                  \
349                 ".section .fixup,\"ax\"\n"                              \
350                 "       .balign 4\n"                                    \
351                 "4:     ldi %0,%3\n"                                    \
352                 "       seth r14,#high(3b)\n"                           \
353                 "       or3 r14,r14,#low(3b)\n"                         \
354                 "       jmp r14\n"                                      \
355                 ".previous\n"                                           \
356                 ".section __ex_table,\"a\"\n"                           \
357                 "       .balign 4\n"                                    \
358                 "       .long 1b,4b\n"                                  \
359                 "       .long 2b,4b\n"                                  \
360                 ".previous"                                             \
361                 : "=&r" (err)                                           \
362                 : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err)         \
363                 : "r14", "memory")
364 #else
365 #error no endian defined
366 #endif
367
368 extern void __put_user_bad(void);
369
370 #define __put_user_size(x,ptr,size,retval)                              \
371 do {                                                                    \
372         retval = 0;                                                     \
373         __chk_user_ptr(ptr);                                            \
374         switch (size) {                                                 \
375           case 1: __put_user_asm(x,ptr,retval,"b"); break;              \
376           case 2: __put_user_asm(x,ptr,retval,"h"); break;              \
377           case 4: __put_user_asm(x,ptr,retval,""); break;               \
378           case 8: __put_user_u64((__typeof__(*ptr))(x),ptr,retval); break;\
379           default: __put_user_bad();                                    \
380         }                                                               \
381 } while (0)
382
383 struct __large_struct { unsigned long buf[100]; };
384 #define __m(x) (*(struct __large_struct *)(x))
385
386 /*
387  * Tell gcc we read from memory instead of writing: this is because
388  * we do not write to any memory gcc knows about, so there are no
389  * aliasing issues.
390  */
391 #define __put_user_asm(x, addr, err, itype)                             \
392         __asm__ __volatile__(                                           \
393                 "       .fillinsn\n"                                    \
394                 "1:     st"itype" %1,@%2\n"                             \
395                 "       .fillinsn\n"                                    \
396                 "2:\n"                                                  \
397                 ".section .fixup,\"ax\"\n"                              \
398                 "       .balign 4\n"                                    \
399                 "3:     ldi %0,%3\n"                                    \
400                 "       seth r14,#high(2b)\n"                           \
401                 "       or3 r14,r14,#low(2b)\n"                         \
402                 "       jmp r14\n"                                      \
403                 ".previous\n"                                           \
404                 ".section __ex_table,\"a\"\n"                           \
405                 "       .balign 4\n"                                    \
406                 "       .long 1b,3b\n"                                  \
407                 ".previous"                                             \
408                 : "=&r" (err)                                           \
409                 : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err)         \
410                 : "r14", "memory")
411
412 /*
413  * Here we special-case 1, 2 and 4-byte copy_*_user invocations.  On a fault
414  * we return the initial request size (1, 2 or 4), as copy_*_user should do.
415  * If a store crosses a page boundary and gets a fault, the m32r will not write
416  * anything, so this is accurate.
417  */
418
419 /*
420  * Copy To/From Userspace
421  */
422
423 /* Generic arbitrary sized copy.  */
424 /* Return the number of bytes NOT copied.  */
425 #define __copy_user(to,from,size)                                       \
426 do {                                                                    \
427         unsigned long __dst, __src, __c;                                \
428         __asm__ __volatile__ (                                          \
429                 "       mv      r14, %0\n"                              \
430                 "       or      r14, %1\n"                              \
431                 "       beq     %0, %1, 9f\n"                           \
432                 "       beqz    %2, 9f\n"                               \
433                 "       and3    r14, r14, #3\n"                         \
434                 "       bnez    r14, 2f\n"                              \
435                 "       and3    %2, %2, #3\n"                           \
436                 "       beqz    %3, 2f\n"                               \
437                 "       addi    %0, #-4         ; word_copy \n"         \
438                 "       .fillinsn\n"                                    \
439                 "0:     ld      r14, @%1+\n"                            \
440                 "       addi    %3, #-1\n"                              \
441                 "       .fillinsn\n"                                    \
442                 "1:     st      r14, @+%0\n"                            \
443                 "       bnez    %3, 0b\n"                               \
444                 "       beqz    %2, 9f\n"                               \
445                 "       addi    %0, #4\n"                               \
446                 "       .fillinsn\n"                                    \
447                 "2:     ldb     r14, @%1        ; byte_copy \n"         \
448                 "       .fillinsn\n"                                    \
449                 "3:     stb     r14, @%0\n"                             \
450                 "       addi    %1, #1\n"                               \
451                 "       addi    %2, #-1\n"                              \
452                 "       addi    %0, #1\n"                               \
453                 "       bnez    %2, 2b\n"                               \
454                 "       .fillinsn\n"                                    \
455                 "9:\n"                                                  \
456                 ".section .fixup,\"ax\"\n"                              \
457                 "       .balign 4\n"                                    \
458                 "5:     addi    %3, #1\n"                               \
459                 "       addi    %1, #-4\n"                              \
460                 "       .fillinsn\n"                                    \
461                 "6:     slli    %3, #2\n"                               \
462                 "       add     %2, %3\n"                               \
463                 "       addi    %0, #4\n"                               \
464                 "       .fillinsn\n"                                    \
465                 "7:     seth    r14, #high(9b)\n"                       \
466                 "       or3     r14, r14, #low(9b)\n"                   \
467                 "       jmp     r14\n"                                  \
468                 ".previous\n"                                           \
469                 ".section __ex_table,\"a\"\n"                           \
470                 "       .balign 4\n"                                    \
471                 "       .long 0b,6b\n"                                  \
472                 "       .long 1b,5b\n"                                  \
473                 "       .long 2b,9b\n"                                  \
474                 "       .long 3b,9b\n"                                  \
475                 ".previous\n"                                           \
476                 : "=&r" (__dst), "=&r" (__src), "=&r" (size),           \
477                   "=&r" (__c)                                           \
478                 : "0" (to), "1" (from), "2" (size), "3" (size / 4)      \
479                 : "r14", "memory");                                     \
480 } while (0)
481
482 #define __copy_user_zeroing(to,from,size)                               \
483 do {                                                                    \
484         unsigned long __dst, __src, __c;                                \
485         __asm__ __volatile__ (                                          \
486                 "       mv      r14, %0\n"                              \
487                 "       or      r14, %1\n"                              \
488                 "       beq     %0, %1, 9f\n"                           \
489                 "       beqz    %2, 9f\n"                               \
490                 "       and3    r14, r14, #3\n"                         \
491                 "       bnez    r14, 2f\n"                              \
492                 "       and3    %2, %2, #3\n"                           \
493                 "       beqz    %3, 2f\n"                               \
494                 "       addi    %0, #-4         ; word_copy \n"         \
495                 "       .fillinsn\n"                                    \
496                 "0:     ld      r14, @%1+\n"                            \
497                 "       addi    %3, #-1\n"                              \
498                 "       .fillinsn\n"                                    \
499                 "1:     st      r14, @+%0\n"                            \
500                 "       bnez    %3, 0b\n"                               \
501                 "       beqz    %2, 9f\n"                               \
502                 "       addi    %0, #4\n"                               \
503                 "       .fillinsn\n"                                    \
504                 "2:     ldb     r14, @%1        ; byte_copy \n"         \
505                 "       .fillinsn\n"                                    \
506                 "3:     stb     r14, @%0\n"                             \
507                 "       addi    %1, #1\n"                               \
508                 "       addi    %2, #-1\n"                              \
509                 "       addi    %0, #1\n"                               \
510                 "       bnez    %2, 2b\n"                               \
511                 "       .fillinsn\n"                                    \
512                 "9:\n"                                                  \
513                 ".section .fixup,\"ax\"\n"                              \
514                 "       .balign 4\n"                                    \
515                 "5:     addi    %3, #1\n"                               \
516                 "       addi    %1, #-4\n"                              \
517                 "       .fillinsn\n"                                    \
518                 "6:     slli    %3, #2\n"                               \
519                 "       add     %2, %3\n"                               \
520                 "       addi    %0, #4\n"                               \
521                 "       .fillinsn\n"                                    \
522                 "7:     ldi     r14, #0         ; store zero \n"        \
523                 "       .fillinsn\n"                                    \
524                 "8:     addi    %2, #-1\n"                              \
525                 "       stb     r14, @%0        ; ACE? \n"              \
526                 "       addi    %0, #1\n"                               \
527                 "       bnez    %2, 8b\n"                               \
528                 "       seth    r14, #high(9b)\n"                       \
529                 "       or3     r14, r14, #low(9b)\n"                   \
530                 "       jmp     r14\n"                                  \
531                 ".previous\n"                                           \
532                 ".section __ex_table,\"a\"\n"                           \
533                 "       .balign 4\n"                                    \
534                 "       .long 0b,6b\n"                                  \
535                 "       .long 1b,5b\n"                                  \
536                 "       .long 2b,7b\n"                                  \
537                 "       .long 3b,7b\n"                                  \
538                 ".previous\n"                                           \
539                 : "=&r" (__dst), "=&r" (__src), "=&r" (size),           \
540                   "=&r" (__c)                                           \
541                 : "0" (to), "1" (from), "2" (size), "3" (size / 4)      \
542                 : "r14", "memory");                                     \
543 } while (0)
544
545
546 /* We let the __ versions of copy_from/to_user inline, because they're often
547  * used in fast paths and have only a small space overhead.
548  */
549 static inline unsigned long __generic_copy_from_user_nocheck(void *to,
550         const void __user *from, unsigned long n)
551 {
552         __copy_user_zeroing(to,from,n);
553         return n;
554 }
555
556 static inline unsigned long __generic_copy_to_user_nocheck(void __user *to,
557         const void *from, unsigned long n)
558 {
559         __copy_user(to,from,n);
560         return n;
561 }
562
563 unsigned long __generic_copy_to_user(void __user *, const void *, unsigned long);
564 unsigned long __generic_copy_from_user(void *, const void __user *, unsigned long);
565
566 /**
567  * __copy_to_user: - Copy a block of data into user space, with less checking.
568  * @to:   Destination address, in user space.
569  * @from: Source address, in kernel space.
570  * @n:    Number of bytes to copy.
571  *
572  * Context: User context only.  This function may sleep.
573  *
574  * Copy data from kernel space to user space.  Caller must check
575  * the specified block with access_ok() before calling this function.
576  *
577  * Returns number of bytes that could not be copied.
578  * On success, this will be zero.
579  */
580 #define __copy_to_user(to,from,n)                       \
581         __generic_copy_to_user_nocheck((to),(from),(n))
582
583 #define __copy_to_user_inatomic __copy_to_user
584 #define __copy_from_user_inatomic __copy_from_user
585
586 /**
587  * copy_to_user: - Copy a block of data into user space.
588  * @to:   Destination address, in user space.
589  * @from: Source address, in kernel space.
590  * @n:    Number of bytes to copy.
591  *
592  * Context: User context only.  This function may sleep.
593  *
594  * Copy data from kernel space to user space.
595  *
596  * Returns number of bytes that could not be copied.
597  * On success, this will be zero.
598  */
599 #define copy_to_user(to,from,n)                         \
600 ({                                                      \
601         might_sleep();                                  \
602         __generic_copy_to_user((to),(from),(n));        \
603 })
604
605 /**
606  * __copy_from_user: - Copy a block of data from user space, with less checking. * @to:   Destination address, in kernel space.
607  * @from: Source address, in user space.
608  * @n:    Number of bytes to copy.
609  *
610  * Context: User context only.  This function may sleep.
611  *
612  * Copy data from user space to kernel space.  Caller must check
613  * the specified block with access_ok() before calling this function.
614  *
615  * Returns number of bytes that could not be copied.
616  * On success, this will be zero.
617  *
618  * If some data could not be copied, this function will pad the copied
619  * data to the requested size using zero bytes.
620  */
621 #define __copy_from_user(to,from,n)                     \
622         __generic_copy_from_user_nocheck((to),(from),(n))
623
624 /**
625  * copy_from_user: - Copy a block of data from user space.
626  * @to:   Destination address, in kernel space.
627  * @from: Source address, in user space.
628  * @n:    Number of bytes to copy.
629  *
630  * Context: User context only.  This function may sleep.
631  *
632  * Copy data from user space to kernel space.
633  *
634  * Returns number of bytes that could not be copied.
635  * On success, this will be zero.
636  *
637  * If some data could not be copied, this function will pad the copied
638  * data to the requested size using zero bytes.
639  */
640 #define copy_from_user(to,from,n)                       \
641 ({                                                      \
642         might_sleep();                                  \
643         __generic_copy_from_user((to),(from),(n));      \
644 })
645
646 long __must_check strncpy_from_user(char *dst, const char __user *src,
647                                 long count);
648 long __must_check __strncpy_from_user(char *dst,
649                                 const char __user *src, long count);
650
651 /**
652  * __clear_user: - Zero a block of memory in user space, with less checking.
653  * @to:   Destination address, in user space.
654  * @n:    Number of bytes to zero.
655  *
656  * Zero a block of memory in user space.  Caller must check
657  * the specified block with access_ok() before calling this function.
658  *
659  * Returns number of bytes that could not be cleared.
660  * On success, this will be zero.
661  */
662 unsigned long __clear_user(void __user *mem, unsigned long len);
663
664 /**
665  * clear_user: - Zero a block of memory in user space.
666  * @to:   Destination address, in user space.
667  * @n:    Number of bytes to zero.
668  *
669  * Zero a block of memory in user space.  Caller must check
670  * the specified block with access_ok() before calling this function.
671  *
672  * Returns number of bytes that could not be cleared.
673  * On success, this will be zero.
674  */
675 unsigned long clear_user(void __user *mem, unsigned long len);
676
677 /**
678  * strlen_user: - Get the size of a string in user space.
679  * @str: The string to measure.
680  *
681  * Context: User context only.  This function may sleep.
682  *
683  * Get the size of a NUL-terminated string in user space.
684  *
685  * Returns the size of the string INCLUDING the terminating NUL.
686  * On exception, returns 0.
687  *
688  * If there is a limit on the length of a valid string, you may wish to
689  * consider using strnlen_user() instead.
690  */
691 #define strlen_user(str) strnlen_user(str, ~0UL >> 1)
692 long strnlen_user(const char __user *str, long n);
693
694 #endif /* _ASM_M32R_UACCESS_H */