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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _ASM_M32R_UACCESS_H |
3 | #define _ASM_M32R_UACCESS_H | |
4 | ||
5 | /* | |
6 | * linux/include/asm-m32r/uaccess.h | |
7 | * | |
8 | * M32R version. | |
04dfd0de | 9 | * Copyright (C) 2004, 2006 Hirokazu Takata <takata at linux-m32r.org> |
1da177e4 LT |
10 | */ |
11 | ||
1da177e4 LT |
12 | /* |
13 | * User space memory access functions | |
14 | */ | |
1da177e4 | 15 | #include <asm/page.h> |
ec0ced15 | 16 | #include <asm/setup.h> |
9a677341 | 17 | #include <linux/prefetch.h> |
1da177e4 | 18 | |
1da177e4 LT |
19 | /* |
20 | * The fs value determines whether argument validity checking should be | |
21 | * performed or not. If get_fs() == USER_DS, checking is performed, with | |
22 | * get_fs() == KERNEL_DS, checking is bypassed. | |
23 | * | |
24 | * For historical reasons, these macros are grossly misnamed. | |
25 | */ | |
26 | ||
27 | #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) | |
28 | ||
29 | #ifdef CONFIG_MMU | |
04dfd0de | 30 | |
1da177e4 LT |
31 | #define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF) |
32 | #define USER_DS MAKE_MM_SEG(PAGE_OFFSET) | |
1da177e4 | 33 | #define get_ds() (KERNEL_DS) |
1da177e4 LT |
34 | #define get_fs() (current_thread_info()->addr_limit) |
35 | #define set_fs(x) (current_thread_info()->addr_limit = (x)) | |
04dfd0de HT |
36 | |
37 | #else /* not CONFIG_MMU */ | |
38 | ||
39 | #define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF) | |
40 | #define USER_DS MAKE_MM_SEG(0xFFFFFFFF) | |
41 | #define get_ds() (KERNEL_DS) | |
42 | ||
1da177e4 LT |
43 | static inline mm_segment_t get_fs(void) |
44 | { | |
04dfd0de | 45 | return USER_DS; |
1da177e4 LT |
46 | } |
47 | ||
48 | static inline void set_fs(mm_segment_t s) | |
49 | { | |
50 | } | |
04dfd0de HT |
51 | |
52 | #endif /* not CONFIG_MMU */ | |
1da177e4 | 53 | |
0ab06604 | 54 | #define segment_eq(a, b) ((a).seg == (b).seg) |
1da177e4 LT |
55 | |
56 | #define __addr_ok(addr) \ | |
57 | ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg)) | |
58 | ||
59 | /* | |
60 | * Test whether a block of memory is a valid user space address. | |
61 | * Returns 0 if the range is valid, nonzero otherwise. | |
62 | * | |
63 | * This is equivalent to the following test: | |
64 | * (u33)addr + (u33)size >= (u33)current->addr_limit.seg | |
65 | * | |
66 | * This needs 33-bit arithmetic. We have a carry... | |
67 | */ | |
0ab06604 | 68 | #define __range_ok(addr, size) ({ \ |
16cf5b39 | 69 | unsigned long flag, roksum; \ |
1da177e4 LT |
70 | __chk_user_ptr(addr); \ |
71 | asm ( \ | |
72 | " cmpu %1, %1 ; clear cbit\n" \ | |
73 | " addx %1, %3 ; set cbit if overflow\n" \ | |
74 | " subx %0, %0\n" \ | |
75 | " cmpu %4, %1\n" \ | |
76 | " subx %0, %5\n" \ | |
16cf5b39 | 77 | : "=&r" (flag), "=r" (roksum) \ |
04dfd0de HT |
78 | : "1" (addr), "r" ((int)(size)), \ |
79 | "r" (current_thread_info()->addr_limit.seg), "r" (0) \ | |
1da177e4 LT |
80 | : "cbit" ); \ |
81 | flag; }) | |
82 | ||
83 | /** | |
84 | * access_ok: - Checks if a user space pointer is valid | |
85 | * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that | |
86 | * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe | |
87 | * to write to a block, it is always safe to read from it. | |
88 | * @addr: User space pointer to start of block to check | |
89 | * @size: Size of block to check | |
90 | * | |
b3c395ef DH |
91 | * Context: User context only. This function may sleep if pagefaults are |
92 | * enabled. | |
1da177e4 LT |
93 | * |
94 | * Checks if a pointer to a block of memory in user space is valid. | |
95 | * | |
96 | * Returns true (nonzero) if the memory block may be valid, false (zero) | |
97 | * if it is definitely invalid. | |
98 | * | |
99 | * Note that, depending on architecture, this function probably just | |
100 | * checks that the pointer is in the user space range - after calling | |
101 | * this function, memory access functions may still return -EFAULT. | |
102 | */ | |
103 | #ifdef CONFIG_MMU | |
0ab06604 | 104 | #define access_ok(type, addr, size) (likely(__range_ok(addr, size) == 0)) |
1da177e4 LT |
105 | #else |
106 | static inline int access_ok(int type, const void *addr, unsigned long size) | |
107 | { | |
04dfd0de | 108 | unsigned long val = (unsigned long)addr; |
1da177e4 | 109 | |
04dfd0de | 110 | return ((val >= memory_start) && ((val + size) < memory_end)); |
1da177e4 LT |
111 | } |
112 | #endif /* CONFIG_MMU */ | |
113 | ||
35f8acd5 | 114 | #include <asm/extable.h> |
1da177e4 LT |
115 | |
116 | /* | |
117 | * These are the main single-value transfer routines. They automatically | |
118 | * use the right size if we just have the right pointer type. | |
119 | * | |
120 | * This gets kind of ugly. We want to return _two_ values in "get_user()" | |
121 | * and yet we don't want to do any pointers, because that is too much | |
122 | * of a performance impact. Thus we have a few rather ugly macros here, | |
123 | * and hide all the uglyness from the user. | |
124 | * | |
125 | * The "__xxx" versions of the user access functions are versions that | |
126 | * do not verify the address space, that must have been done previously | |
127 | * with a separate "access_ok()" call (this is used when we do multiple | |
128 | * accesses to the same area of user memory). | |
129 | */ | |
130 | ||
1da177e4 LT |
131 | /* Careful: we have to cast the result to the type of the pointer for sign |
132 | reasons */ | |
133 | /** | |
134 | * get_user: - Get a simple variable from user space. | |
135 | * @x: Variable to store result. | |
136 | * @ptr: Source address, in user space. | |
137 | * | |
b3c395ef DH |
138 | * Context: User context only. This function may sleep if pagefaults are |
139 | * enabled. | |
1da177e4 LT |
140 | * |
141 | * This macro copies a single simple variable from user space to kernel | |
142 | * space. It supports simple types like char and int, but not larger | |
143 | * data types like structures or arrays. | |
144 | * | |
145 | * @ptr must have pointer-to-simple-variable type, and the result of | |
146 | * dereferencing @ptr must be assignable to @x without a cast. | |
147 | * | |
148 | * Returns zero on success, or -EFAULT on error. | |
149 | * On error, the variable @x is set to zero. | |
150 | */ | |
0ab06604 MT |
151 | #define get_user(x, ptr) \ |
152 | __get_user_check((x), (ptr), sizeof(*(ptr))) | |
1da177e4 LT |
153 | |
154 | /** | |
155 | * put_user: - Write a simple value into user space. | |
156 | * @x: Value to copy to user space. | |
157 | * @ptr: Destination address, in user space. | |
158 | * | |
b3c395ef DH |
159 | * Context: User context only. This function may sleep if pagefaults are |
160 | * enabled. | |
1da177e4 LT |
161 | * |
162 | * This macro copies a single simple value from kernel space to user | |
163 | * space. It supports simple types like char and int, but not larger | |
164 | * data types like structures or arrays. | |
165 | * | |
166 | * @ptr must have pointer-to-simple-variable type, and @x must be assignable | |
167 | * to the result of dereferencing @ptr. | |
168 | * | |
169 | * Returns zero on success, or -EFAULT on error. | |
170 | */ | |
0ab06604 MT |
171 | #define put_user(x, ptr) \ |
172 | __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) | |
1da177e4 LT |
173 | |
174 | /** | |
175 | * __get_user: - Get a simple variable from user space, with less checking. | |
176 | * @x: Variable to store result. | |
177 | * @ptr: Source address, in user space. | |
178 | * | |
b3c395ef DH |
179 | * Context: User context only. This function may sleep if pagefaults are |
180 | * enabled. | |
1da177e4 LT |
181 | * |
182 | * This macro copies a single simple variable from user space to kernel | |
183 | * space. It supports simple types like char and int, but not larger | |
184 | * data types like structures or arrays. | |
185 | * | |
186 | * @ptr must have pointer-to-simple-variable type, and the result of | |
187 | * dereferencing @ptr must be assignable to @x without a cast. | |
188 | * | |
189 | * Caller must check the pointer with access_ok() before calling this | |
190 | * function. | |
191 | * | |
192 | * Returns zero on success, or -EFAULT on error. | |
193 | * On error, the variable @x is set to zero. | |
194 | */ | |
0ab06604 MT |
195 | #define __get_user(x, ptr) \ |
196 | __get_user_nocheck((x), (ptr), sizeof(*(ptr))) | |
1da177e4 | 197 | |
0ab06604 | 198 | #define __get_user_nocheck(x, ptr, size) \ |
04dfd0de HT |
199 | ({ \ |
200 | long __gu_err = 0; \ | |
c90a3bc5 | 201 | unsigned long __gu_val = 0; \ |
01682576 | 202 | might_fault(); \ |
0ab06604 | 203 | __get_user_size(__gu_val, (ptr), (size), __gu_err); \ |
a618337e | 204 | (x) = (__force __typeof__(*(ptr)))__gu_val; \ |
04dfd0de HT |
205 | __gu_err; \ |
206 | }) | |
207 | ||
0ab06604 | 208 | #define __get_user_check(x, ptr, size) \ |
04dfd0de HT |
209 | ({ \ |
210 | long __gu_err = -EFAULT; \ | |
211 | unsigned long __gu_val = 0; \ | |
212 | const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ | |
01682576 | 213 | might_fault(); \ |
0ab06604 MT |
214 | if (access_ok(VERIFY_READ, __gu_addr, size)) \ |
215 | __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ | |
a618337e | 216 | (x) = (__force __typeof__(*(ptr)))__gu_val; \ |
04dfd0de HT |
217 | __gu_err; \ |
218 | }) | |
219 | ||
220 | extern long __get_user_bad(void); | |
221 | ||
0ab06604 | 222 | #define __get_user_size(x, ptr, size, retval) \ |
04dfd0de HT |
223 | do { \ |
224 | retval = 0; \ | |
225 | __chk_user_ptr(ptr); \ | |
226 | switch (size) { \ | |
0ab06604 MT |
227 | case 1: __get_user_asm(x, ptr, retval, "ub"); break; \ |
228 | case 2: __get_user_asm(x, ptr, retval, "uh"); break; \ | |
229 | case 4: __get_user_asm(x, ptr, retval, ""); break; \ | |
04dfd0de HT |
230 | default: (x) = __get_user_bad(); \ |
231 | } \ | |
232 | } while (0) | |
233 | ||
234 | #define __get_user_asm(x, addr, err, itype) \ | |
235 | __asm__ __volatile__( \ | |
236 | " .fillinsn\n" \ | |
237 | "1: ld"itype" %1,@%2\n" \ | |
238 | " .fillinsn\n" \ | |
239 | "2:\n" \ | |
240 | ".section .fixup,\"ax\"\n" \ | |
241 | " .balign 4\n" \ | |
242 | "3: ldi %0,%3\n" \ | |
243 | " seth r14,#high(2b)\n" \ | |
244 | " or3 r14,r14,#low(2b)\n" \ | |
245 | " jmp r14\n" \ | |
246 | ".previous\n" \ | |
247 | ".section __ex_table,\"a\"\n" \ | |
248 | " .balign 4\n" \ | |
249 | " .long 1b,3b\n" \ | |
250 | ".previous" \ | |
251 | : "=&r" (err), "=&r" (x) \ | |
252 | : "r" (addr), "i" (-EFAULT), "0" (err) \ | |
253 | : "r14", "memory") | |
1da177e4 LT |
254 | |
255 | /** | |
256 | * __put_user: - Write a simple value into user space, with less checking. | |
257 | * @x: Value to copy to user space. | |
258 | * @ptr: Destination address, in user space. | |
259 | * | |
b3c395ef DH |
260 | * Context: User context only. This function may sleep if pagefaults are |
261 | * enabled. | |
1da177e4 LT |
262 | * |
263 | * This macro copies a single simple value from kernel space to user | |
264 | * space. It supports simple types like char and int, but not larger | |
265 | * data types like structures or arrays. | |
266 | * | |
267 | * @ptr must have pointer-to-simple-variable type, and @x must be assignable | |
268 | * to the result of dereferencing @ptr. | |
269 | * | |
270 | * Caller must check the pointer with access_ok() before calling this | |
271 | * function. | |
272 | * | |
273 | * Returns zero on success, or -EFAULT on error. | |
274 | */ | |
0ab06604 MT |
275 | #define __put_user(x, ptr) \ |
276 | __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) | |
04dfd0de | 277 | |
1da177e4 | 278 | |
0ab06604 | 279 | #define __put_user_nocheck(x, ptr, size) \ |
1da177e4 LT |
280 | ({ \ |
281 | long __pu_err; \ | |
01682576 | 282 | might_fault(); \ |
0ab06604 | 283 | __put_user_size((x), (ptr), (size), __pu_err); \ |
1da177e4 LT |
284 | __pu_err; \ |
285 | }) | |
286 | ||
287 | ||
0ab06604 | 288 | #define __put_user_check(x, ptr, size) \ |
1da177e4 LT |
289 | ({ \ |
290 | long __pu_err = -EFAULT; \ | |
291 | __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ | |
01682576 | 292 | might_fault(); \ |
0ab06604 MT |
293 | if (access_ok(VERIFY_WRITE, __pu_addr, size)) \ |
294 | __put_user_size((x), __pu_addr, (size), __pu_err); \ | |
1da177e4 LT |
295 | __pu_err; \ |
296 | }) | |
297 | ||
298 | #if defined(__LITTLE_ENDIAN__) | |
04dfd0de HT |
299 | #define __put_user_u64(x, addr, err) \ |
300 | __asm__ __volatile__( \ | |
301 | " .fillinsn\n" \ | |
302 | "1: st %L1,@%2\n" \ | |
303 | " .fillinsn\n" \ | |
304 | "2: st %H1,@(4,%2)\n" \ | |
305 | " .fillinsn\n" \ | |
306 | "3:\n" \ | |
307 | ".section .fixup,\"ax\"\n" \ | |
308 | " .balign 4\n" \ | |
309 | "4: ldi %0,%3\n" \ | |
310 | " seth r14,#high(3b)\n" \ | |
311 | " or3 r14,r14,#low(3b)\n" \ | |
312 | " jmp r14\n" \ | |
313 | ".previous\n" \ | |
314 | ".section __ex_table,\"a\"\n" \ | |
315 | " .balign 4\n" \ | |
316 | " .long 1b,4b\n" \ | |
317 | " .long 2b,4b\n" \ | |
318 | ".previous" \ | |
319 | : "=&r" (err) \ | |
320 | : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err) \ | |
1da177e4 LT |
321 | : "r14", "memory") |
322 | ||
323 | #elif defined(__BIG_ENDIAN__) | |
324 | #define __put_user_u64(x, addr, err) \ | |
325 | __asm__ __volatile__( \ | |
326 | " .fillinsn\n" \ | |
327 | "1: st %H1,@%2\n" \ | |
328 | " .fillinsn\n" \ | |
329 | "2: st %L1,@(4,%2)\n" \ | |
330 | " .fillinsn\n" \ | |
331 | "3:\n" \ | |
332 | ".section .fixup,\"ax\"\n" \ | |
333 | " .balign 4\n" \ | |
334 | "4: ldi %0,%3\n" \ | |
335 | " seth r14,#high(3b)\n" \ | |
336 | " or3 r14,r14,#low(3b)\n" \ | |
337 | " jmp r14\n" \ | |
338 | ".previous\n" \ | |
339 | ".section __ex_table,\"a\"\n" \ | |
340 | " .balign 4\n" \ | |
341 | " .long 1b,4b\n" \ | |
342 | " .long 2b,4b\n" \ | |
343 | ".previous" \ | |
04dfd0de HT |
344 | : "=&r" (err) \ |
345 | : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err) \ | |
1da177e4 LT |
346 | : "r14", "memory") |
347 | #else | |
348 | #error no endian defined | |
349 | #endif | |
350 | ||
04dfd0de HT |
351 | extern void __put_user_bad(void); |
352 | ||
0ab06604 | 353 | #define __put_user_size(x, ptr, size, retval) \ |
1da177e4 LT |
354 | do { \ |
355 | retval = 0; \ | |
356 | __chk_user_ptr(ptr); \ | |
357 | switch (size) { \ | |
0ab06604 MT |
358 | case 1: __put_user_asm(x, ptr, retval, "b"); break; \ |
359 | case 2: __put_user_asm(x, ptr, retval, "h"); break; \ | |
360 | case 4: __put_user_asm(x, ptr, retval, ""); break; \ | |
361 | case 8: __put_user_u64((__typeof__(*ptr))(x), ptr, retval); break;\ | |
1da177e4 LT |
362 | default: __put_user_bad(); \ |
363 | } \ | |
364 | } while (0) | |
365 | ||
366 | struct __large_struct { unsigned long buf[100]; }; | |
367 | #define __m(x) (*(struct __large_struct *)(x)) | |
368 | ||
369 | /* | |
370 | * Tell gcc we read from memory instead of writing: this is because | |
371 | * we do not write to any memory gcc knows about, so there are no | |
372 | * aliasing issues. | |
373 | */ | |
374 | #define __put_user_asm(x, addr, err, itype) \ | |
375 | __asm__ __volatile__( \ | |
376 | " .fillinsn\n" \ | |
377 | "1: st"itype" %1,@%2\n" \ | |
378 | " .fillinsn\n" \ | |
379 | "2:\n" \ | |
380 | ".section .fixup,\"ax\"\n" \ | |
381 | " .balign 4\n" \ | |
382 | "3: ldi %0,%3\n" \ | |
383 | " seth r14,#high(2b)\n" \ | |
384 | " or3 r14,r14,#low(2b)\n" \ | |
385 | " jmp r14\n" \ | |
386 | ".previous\n" \ | |
387 | ".section __ex_table,\"a\"\n" \ | |
388 | " .balign 4\n" \ | |
389 | " .long 1b,3b\n" \ | |
390 | ".previous" \ | |
04dfd0de HT |
391 | : "=&r" (err) \ |
392 | : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err) \ | |
1da177e4 LT |
393 | : "r14", "memory") |
394 | ||
395 | /* | |
396 | * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault | |
397 | * we return the initial request size (1, 2 or 4), as copy_*_user should do. | |
398 | * If a store crosses a page boundary and gets a fault, the m32r will not write | |
399 | * anything, so this is accurate. | |
400 | */ | |
401 | ||
1da177e4 LT |
402 | /* |
403 | * Copy To/From Userspace | |
404 | */ | |
405 | ||
406 | /* Generic arbitrary sized copy. */ | |
407 | /* Return the number of bytes NOT copied. */ | |
0ab06604 | 408 | #define __copy_user(to, from, size) \ |
1da177e4 LT |
409 | do { \ |
410 | unsigned long __dst, __src, __c; \ | |
411 | __asm__ __volatile__ ( \ | |
412 | " mv r14, %0\n" \ | |
413 | " or r14, %1\n" \ | |
414 | " beq %0, %1, 9f\n" \ | |
415 | " beqz %2, 9f\n" \ | |
416 | " and3 r14, r14, #3\n" \ | |
417 | " bnez r14, 2f\n" \ | |
418 | " and3 %2, %2, #3\n" \ | |
419 | " beqz %3, 2f\n" \ | |
420 | " addi %0, #-4 ; word_copy \n" \ | |
421 | " .fillinsn\n" \ | |
422 | "0: ld r14, @%1+\n" \ | |
423 | " addi %3, #-1\n" \ | |
424 | " .fillinsn\n" \ | |
425 | "1: st r14, @+%0\n" \ | |
426 | " bnez %3, 0b\n" \ | |
427 | " beqz %2, 9f\n" \ | |
428 | " addi %0, #4\n" \ | |
429 | " .fillinsn\n" \ | |
430 | "2: ldb r14, @%1 ; byte_copy \n" \ | |
431 | " .fillinsn\n" \ | |
432 | "3: stb r14, @%0\n" \ | |
433 | " addi %1, #1\n" \ | |
434 | " addi %2, #-1\n" \ | |
435 | " addi %0, #1\n" \ | |
436 | " bnez %2, 2b\n" \ | |
437 | " .fillinsn\n" \ | |
438 | "9:\n" \ | |
439 | ".section .fixup,\"ax\"\n" \ | |
440 | " .balign 4\n" \ | |
441 | "5: addi %3, #1\n" \ | |
442 | " addi %1, #-4\n" \ | |
443 | " .fillinsn\n" \ | |
444 | "6: slli %3, #2\n" \ | |
445 | " add %2, %3\n" \ | |
446 | " addi %0, #4\n" \ | |
447 | " .fillinsn\n" \ | |
448 | "7: seth r14, #high(9b)\n" \ | |
449 | " or3 r14, r14, #low(9b)\n" \ | |
450 | " jmp r14\n" \ | |
451 | ".previous\n" \ | |
452 | ".section __ex_table,\"a\"\n" \ | |
453 | " .balign 4\n" \ | |
454 | " .long 0b,6b\n" \ | |
455 | " .long 1b,5b\n" \ | |
456 | " .long 2b,9b\n" \ | |
457 | " .long 3b,9b\n" \ | |
458 | ".previous\n" \ | |
04dfd0de HT |
459 | : "=&r" (__dst), "=&r" (__src), "=&r" (size), \ |
460 | "=&r" (__c) \ | |
461 | : "0" (to), "1" (from), "2" (size), "3" (size / 4) \ | |
1da177e4 LT |
462 | : "r14", "memory"); \ |
463 | } while (0) | |
464 | ||
1da177e4 LT |
465 | /* We let the __ versions of copy_from/to_user inline, because they're often |
466 | * used in fast paths and have only a small space overhead. | |
467 | */ | |
9a677341 AV |
468 | static inline unsigned long |
469 | raw_copy_from_user(void *to, const void __user *from, unsigned long n) | |
1da177e4 | 470 | { |
9a677341 | 471 | prefetchw(to); |
8cd920f2 | 472 | __copy_user(to, from, n); |
1da177e4 LT |
473 | return n; |
474 | } | |
475 | ||
9a677341 AV |
476 | static inline unsigned long |
477 | raw_copy_to_user(void __user *to, const void *from, unsigned long n) | |
1da177e4 | 478 | { |
9a677341 | 479 | prefetch(from); |
0ab06604 | 480 | __copy_user(to, from, n); |
1da177e4 LT |
481 | return n; |
482 | } | |
483 | ||
1da177e4 LT |
484 | long __must_check strncpy_from_user(char *dst, const char __user *src, |
485 | long count); | |
1da177e4 LT |
486 | |
487 | /** | |
488 | * __clear_user: - Zero a block of memory in user space, with less checking. | |
489 | * @to: Destination address, in user space. | |
490 | * @n: Number of bytes to zero. | |
491 | * | |
492 | * Zero a block of memory in user space. Caller must check | |
493 | * the specified block with access_ok() before calling this function. | |
494 | * | |
495 | * Returns number of bytes that could not be cleared. | |
496 | * On success, this will be zero. | |
497 | */ | |
498 | unsigned long __clear_user(void __user *mem, unsigned long len); | |
499 | ||
500 | /** | |
501 | * clear_user: - Zero a block of memory in user space. | |
502 | * @to: Destination address, in user space. | |
503 | * @n: Number of bytes to zero. | |
504 | * | |
505 | * Zero a block of memory in user space. Caller must check | |
506 | * the specified block with access_ok() before calling this function. | |
507 | * | |
508 | * Returns number of bytes that could not be cleared. | |
509 | * On success, this will be zero. | |
510 | */ | |
511 | unsigned long clear_user(void __user *mem, unsigned long len); | |
512 | ||
1da177e4 LT |
513 | long strnlen_user(const char __user *str, long n); |
514 | ||
515 | #endif /* _ASM_M32R_UACCESS_H */ |