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1 | #ifndef __i386_UACCESS_H |
2 | #define __i386_UACCESS_H | |
3 | ||
4 | /* | |
5 | * User space memory access functions | |
6 | */ | |
7 | #include <linux/config.h> | |
8 | #include <linux/errno.h> | |
9 | #include <linux/thread_info.h> | |
10 | #include <linux/prefetch.h> | |
11 | #include <linux/string.h> | |
12 | #include <asm/page.h> | |
13 | ||
14 | #define VERIFY_READ 0 | |
15 | #define VERIFY_WRITE 1 | |
16 | ||
17 | /* | |
18 | * The fs value determines whether argument validity checking should be | |
19 | * performed or not. If get_fs() == USER_DS, checking is performed, with | |
20 | * get_fs() == KERNEL_DS, checking is bypassed. | |
21 | * | |
22 | * For historical reasons, these macros are grossly misnamed. | |
23 | */ | |
24 | ||
25 | #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) | |
26 | ||
27 | ||
28 | #define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFUL) | |
29 | #define USER_DS MAKE_MM_SEG(PAGE_OFFSET) | |
30 | ||
31 | #define get_ds() (KERNEL_DS) | |
32 | #define get_fs() (current_thread_info()->addr_limit) | |
33 | #define set_fs(x) (current_thread_info()->addr_limit = (x)) | |
34 | ||
35 | #define segment_eq(a,b) ((a).seg == (b).seg) | |
36 | ||
37 | /* | |
38 | * movsl can be slow when source and dest are not both 8-byte aligned | |
39 | */ | |
40 | #ifdef CONFIG_X86_INTEL_USERCOPY | |
41 | extern struct movsl_mask { | |
42 | int mask; | |
43 | } ____cacheline_aligned_in_smp movsl_mask; | |
44 | #endif | |
45 | ||
46 | #define __addr_ok(addr) ((unsigned long __force)(addr) < (current_thread_info()->addr_limit.seg)) | |
47 | ||
48 | /* | |
49 | * Test whether a block of memory is a valid user space address. | |
50 | * Returns 0 if the range is valid, nonzero otherwise. | |
51 | * | |
52 | * This is equivalent to the following test: | |
53 | * (u33)addr + (u33)size >= (u33)current->addr_limit.seg | |
54 | * | |
55 | * This needs 33-bit arithmetic. We have a carry... | |
56 | */ | |
57 | #define __range_ok(addr,size) ({ \ | |
58 | unsigned long flag,sum; \ | |
59 | __chk_user_ptr(addr); \ | |
60 | asm("addl %3,%1 ; sbbl %0,%0; cmpl %1,%4; sbbl $0,%0" \ | |
61 | :"=&r" (flag), "=r" (sum) \ | |
62 | :"1" (addr),"g" ((int)(size)),"g" (current_thread_info()->addr_limit.seg)); \ | |
63 | flag; }) | |
64 | ||
65 | /** | |
66 | * access_ok: - Checks if a user space pointer is valid | |
67 | * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that | |
68 | * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe | |
69 | * to write to a block, it is always safe to read from it. | |
70 | * @addr: User space pointer to start of block to check | |
71 | * @size: Size of block to check | |
72 | * | |
73 | * Context: User context only. This function may sleep. | |
74 | * | |
75 | * Checks if a pointer to a block of memory in user space is valid. | |
76 | * | |
77 | * Returns true (nonzero) if the memory block may be valid, false (zero) | |
78 | * if it is definitely invalid. | |
79 | * | |
80 | * Note that, depending on architecture, this function probably just | |
81 | * checks that the pointer is in the user space range - after calling | |
82 | * this function, memory access functions may still return -EFAULT. | |
83 | */ | |
84 | #define access_ok(type,addr,size) (likely(__range_ok(addr,size) == 0)) | |
85 | ||
1da177e4 LT |
86 | /* |
87 | * The exception table consists of pairs of addresses: the first is the | |
88 | * address of an instruction that is allowed to fault, and the second is | |
89 | * the address at which the program should continue. No registers are | |
90 | * modified, so it is entirely up to the continuation code to figure out | |
91 | * what to do. | |
92 | * | |
93 | * All the routines below use bits of fixup code that are out of line | |
94 | * with the main instruction path. This means when everything is well, | |
95 | * we don't even have to jump over them. Further, they do not intrude | |
96 | * on our cache or tlb entries. | |
97 | */ | |
98 | ||
99 | struct exception_table_entry | |
100 | { | |
101 | unsigned long insn, fixup; | |
102 | }; | |
103 | ||
104 | extern int fixup_exception(struct pt_regs *regs); | |
105 | ||
106 | /* | |
107 | * These are the main single-value transfer routines. They automatically | |
108 | * use the right size if we just have the right pointer type. | |
109 | * | |
110 | * This gets kind of ugly. We want to return _two_ values in "get_user()" | |
111 | * and yet we don't want to do any pointers, because that is too much | |
112 | * of a performance impact. Thus we have a few rather ugly macros here, | |
113 | * and hide all the ugliness from the user. | |
114 | * | |
115 | * The "__xxx" versions of the user access functions are versions that | |
116 | * do not verify the address space, that must have been done previously | |
117 | * with a separate "access_ok()" call (this is used when we do multiple | |
118 | * accesses to the same area of user memory). | |
119 | */ | |
120 | ||
121 | extern void __get_user_1(void); | |
122 | extern void __get_user_2(void); | |
123 | extern void __get_user_4(void); | |
124 | ||
125 | #define __get_user_x(size,ret,x,ptr) \ | |
126 | __asm__ __volatile__("call __get_user_" #size \ | |
127 | :"=a" (ret),"=d" (x) \ | |
128 | :"0" (ptr)) | |
129 | ||
130 | ||
131 | /* Careful: we have to cast the result to the type of the pointer for sign reasons */ | |
132 | /** | |
133 | * get_user: - Get a simple variable from user space. | |
134 | * @x: Variable to store result. | |
135 | * @ptr: Source address, in user space. | |
136 | * | |
137 | * Context: User context only. This function may sleep. | |
138 | * | |
139 | * This macro copies a single simple variable from user space to kernel | |
140 | * space. It supports simple types like char and int, but not larger | |
141 | * data types like structures or arrays. | |
142 | * | |
143 | * @ptr must have pointer-to-simple-variable type, and the result of | |
144 | * dereferencing @ptr must be assignable to @x without a cast. | |
145 | * | |
146 | * Returns zero on success, or -EFAULT on error. | |
147 | * On error, the variable @x is set to zero. | |
148 | */ | |
149 | #define get_user(x,ptr) \ | |
150 | ({ int __ret_gu; \ | |
151 | unsigned long __val_gu; \ | |
152 | __chk_user_ptr(ptr); \ | |
153 | switch(sizeof (*(ptr))) { \ | |
154 | case 1: __get_user_x(1,__ret_gu,__val_gu,ptr); break; \ | |
155 | case 2: __get_user_x(2,__ret_gu,__val_gu,ptr); break; \ | |
156 | case 4: __get_user_x(4,__ret_gu,__val_gu,ptr); break; \ | |
157 | default: __get_user_x(X,__ret_gu,__val_gu,ptr); break; \ | |
158 | } \ | |
159 | (x) = (__typeof__(*(ptr)))__val_gu; \ | |
160 | __ret_gu; \ | |
161 | }) | |
162 | ||
163 | extern void __put_user_bad(void); | |
164 | ||
165 | /* | |
166 | * Strange magic calling convention: pointer in %ecx, | |
167 | * value in %eax(:%edx), return value in %eax, no clobbers. | |
168 | */ | |
169 | extern void __put_user_1(void); | |
170 | extern void __put_user_2(void); | |
171 | extern void __put_user_4(void); | |
172 | extern void __put_user_8(void); | |
173 | ||
174 | #define __put_user_1(x, ptr) __asm__ __volatile__("call __put_user_1":"=a" (__ret_pu):"0" ((typeof(*(ptr)))(x)), "c" (ptr)) | |
175 | #define __put_user_2(x, ptr) __asm__ __volatile__("call __put_user_2":"=a" (__ret_pu):"0" ((typeof(*(ptr)))(x)), "c" (ptr)) | |
176 | #define __put_user_4(x, ptr) __asm__ __volatile__("call __put_user_4":"=a" (__ret_pu):"0" ((typeof(*(ptr)))(x)), "c" (ptr)) | |
177 | #define __put_user_8(x, ptr) __asm__ __volatile__("call __put_user_8":"=a" (__ret_pu):"A" ((typeof(*(ptr)))(x)), "c" (ptr)) | |
178 | #define __put_user_X(x, ptr) __asm__ __volatile__("call __put_user_X":"=a" (__ret_pu):"c" (ptr)) | |
179 | ||
180 | /** | |
181 | * put_user: - Write a simple value into user space. | |
182 | * @x: Value to copy to user space. | |
183 | * @ptr: Destination address, in user space. | |
184 | * | |
185 | * Context: User context only. This function may sleep. | |
186 | * | |
187 | * This macro copies a single simple value from kernel space to user | |
188 | * space. It supports simple types like char and int, but not larger | |
189 | * data types like structures or arrays. | |
190 | * | |
191 | * @ptr must have pointer-to-simple-variable type, and @x must be assignable | |
192 | * to the result of dereferencing @ptr. | |
193 | * | |
194 | * Returns zero on success, or -EFAULT on error. | |
195 | */ | |
196 | #ifdef CONFIG_X86_WP_WORKS_OK | |
197 | ||
198 | #define put_user(x,ptr) \ | |
199 | ({ int __ret_pu; \ | |
200 | __chk_user_ptr(ptr); \ | |
201 | switch(sizeof(*(ptr))) { \ | |
202 | case 1: __put_user_1(x, ptr); break; \ | |
203 | case 2: __put_user_2(x, ptr); break; \ | |
204 | case 4: __put_user_4(x, ptr); break; \ | |
205 | case 8: __put_user_8(x, ptr); break; \ | |
206 | default:__put_user_X(x, ptr); break; \ | |
207 | } \ | |
208 | __ret_pu; \ | |
209 | }) | |
210 | ||
211 | #else | |
212 | #define put_user(x,ptr) \ | |
213 | ({ \ | |
214 | int __ret_pu; \ | |
215 | __typeof__(*(ptr)) __pus_tmp = x; \ | |
216 | __ret_pu=0; \ | |
217 | if(unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \ | |
218 | sizeof(*(ptr))) != 0)) \ | |
219 | __ret_pu=-EFAULT; \ | |
220 | __ret_pu; \ | |
221 | }) | |
222 | ||
223 | ||
224 | #endif | |
225 | ||
226 | /** | |
227 | * __get_user: - Get a simple variable from user space, with less checking. | |
228 | * @x: Variable to store result. | |
229 | * @ptr: Source address, in user space. | |
230 | * | |
231 | * Context: User context only. This function may sleep. | |
232 | * | |
233 | * This macro copies a single simple variable from user space to kernel | |
234 | * space. It supports simple types like char and int, but not larger | |
235 | * data types like structures or arrays. | |
236 | * | |
237 | * @ptr must have pointer-to-simple-variable type, and the result of | |
238 | * dereferencing @ptr must be assignable to @x without a cast. | |
239 | * | |
240 | * Caller must check the pointer with access_ok() before calling this | |
241 | * function. | |
242 | * | |
243 | * Returns zero on success, or -EFAULT on error. | |
244 | * On error, the variable @x is set to zero. | |
245 | */ | |
246 | #define __get_user(x,ptr) \ | |
247 | __get_user_nocheck((x),(ptr),sizeof(*(ptr))) | |
248 | ||
249 | ||
250 | /** | |
251 | * __put_user: - Write a simple value into user space, with less checking. | |
252 | * @x: Value to copy to user space. | |
253 | * @ptr: Destination address, in user space. | |
254 | * | |
255 | * Context: User context only. This function may sleep. | |
256 | * | |
257 | * This macro copies a single simple value from kernel space to user | |
258 | * space. It supports simple types like char and int, but not larger | |
259 | * data types like structures or arrays. | |
260 | * | |
261 | * @ptr must have pointer-to-simple-variable type, and @x must be assignable | |
262 | * to the result of dereferencing @ptr. | |
263 | * | |
264 | * Caller must check the pointer with access_ok() before calling this | |
265 | * function. | |
266 | * | |
267 | * Returns zero on success, or -EFAULT on error. | |
268 | */ | |
269 | #define __put_user(x,ptr) \ | |
270 | __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr))) | |
271 | ||
272 | #define __put_user_nocheck(x,ptr,size) \ | |
273 | ({ \ | |
274 | long __pu_err; \ | |
275 | __put_user_size((x),(ptr),(size),__pu_err,-EFAULT); \ | |
276 | __pu_err; \ | |
277 | }) | |
278 | ||
279 | ||
280 | #define __put_user_u64(x, addr, err) \ | |
281 | __asm__ __volatile__( \ | |
282 | "1: movl %%eax,0(%2)\n" \ | |
283 | "2: movl %%edx,4(%2)\n" \ | |
284 | "3:\n" \ | |
285 | ".section .fixup,\"ax\"\n" \ | |
286 | "4: movl %3,%0\n" \ | |
287 | " jmp 3b\n" \ | |
288 | ".previous\n" \ | |
289 | ".section __ex_table,\"a\"\n" \ | |
290 | " .align 4\n" \ | |
291 | " .long 1b,4b\n" \ | |
292 | " .long 2b,4b\n" \ | |
293 | ".previous" \ | |
294 | : "=r"(err) \ | |
295 | : "A" (x), "r" (addr), "i"(-EFAULT), "0"(err)) | |
296 | ||
297 | #ifdef CONFIG_X86_WP_WORKS_OK | |
298 | ||
299 | #define __put_user_size(x,ptr,size,retval,errret) \ | |
300 | do { \ | |
301 | retval = 0; \ | |
302 | __chk_user_ptr(ptr); \ | |
303 | switch (size) { \ | |
304 | case 1: __put_user_asm(x,ptr,retval,"b","b","iq",errret);break; \ | |
305 | case 2: __put_user_asm(x,ptr,retval,"w","w","ir",errret);break; \ | |
306 | case 4: __put_user_asm(x,ptr,retval,"l","","ir",errret); break; \ | |
307 | case 8: __put_user_u64((__typeof__(*ptr))(x),ptr,retval); break;\ | |
308 | default: __put_user_bad(); \ | |
309 | } \ | |
310 | } while (0) | |
311 | ||
312 | #else | |
313 | ||
314 | #define __put_user_size(x,ptr,size,retval,errret) \ | |
315 | do { \ | |
316 | __typeof__(*(ptr)) __pus_tmp = x; \ | |
317 | retval = 0; \ | |
318 | \ | |
319 | if(unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \ | |
320 | retval = errret; \ | |
321 | } while (0) | |
322 | ||
323 | #endif | |
324 | struct __large_struct { unsigned long buf[100]; }; | |
325 | #define __m(x) (*(struct __large_struct __user *)(x)) | |
326 | ||
327 | /* | |
328 | * Tell gcc we read from memory instead of writing: this is because | |
329 | * we do not write to any memory gcc knows about, so there are no | |
330 | * aliasing issues. | |
331 | */ | |
332 | #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ | |
333 | __asm__ __volatile__( \ | |
334 | "1: mov"itype" %"rtype"1,%2\n" \ | |
335 | "2:\n" \ | |
336 | ".section .fixup,\"ax\"\n" \ | |
337 | "3: movl %3,%0\n" \ | |
338 | " jmp 2b\n" \ | |
339 | ".previous\n" \ | |
340 | ".section __ex_table,\"a\"\n" \ | |
341 | " .align 4\n" \ | |
342 | " .long 1b,3b\n" \ | |
343 | ".previous" \ | |
344 | : "=r"(err) \ | |
345 | : ltype (x), "m"(__m(addr)), "i"(errret), "0"(err)) | |
346 | ||
347 | ||
348 | #define __get_user_nocheck(x,ptr,size) \ | |
349 | ({ \ | |
350 | long __gu_err; \ | |
351 | unsigned long __gu_val; \ | |
352 | __get_user_size(__gu_val,(ptr),(size),__gu_err,-EFAULT);\ | |
353 | (x) = (__typeof__(*(ptr)))__gu_val; \ | |
354 | __gu_err; \ | |
355 | }) | |
356 | ||
357 | extern long __get_user_bad(void); | |
358 | ||
359 | #define __get_user_size(x,ptr,size,retval,errret) \ | |
360 | do { \ | |
361 | retval = 0; \ | |
362 | __chk_user_ptr(ptr); \ | |
363 | switch (size) { \ | |
364 | case 1: __get_user_asm(x,ptr,retval,"b","b","=q",errret);break; \ | |
365 | case 2: __get_user_asm(x,ptr,retval,"w","w","=r",errret);break; \ | |
366 | case 4: __get_user_asm(x,ptr,retval,"l","","=r",errret);break; \ | |
367 | default: (x) = __get_user_bad(); \ | |
368 | } \ | |
369 | } while (0) | |
370 | ||
371 | #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ | |
372 | __asm__ __volatile__( \ | |
373 | "1: mov"itype" %2,%"rtype"1\n" \ | |
374 | "2:\n" \ | |
375 | ".section .fixup,\"ax\"\n" \ | |
376 | "3: movl %3,%0\n" \ | |
377 | " xor"itype" %"rtype"1,%"rtype"1\n" \ | |
378 | " jmp 2b\n" \ | |
379 | ".previous\n" \ | |
380 | ".section __ex_table,\"a\"\n" \ | |
381 | " .align 4\n" \ | |
382 | " .long 1b,3b\n" \ | |
383 | ".previous" \ | |
384 | : "=r"(err), ltype (x) \ | |
385 | : "m"(__m(addr)), "i"(errret), "0"(err)) | |
386 | ||
387 | ||
388 | unsigned long __must_check __copy_to_user_ll(void __user *to, | |
389 | const void *from, unsigned long n); | |
390 | unsigned long __must_check __copy_from_user_ll(void *to, | |
391 | const void __user *from, unsigned long n); | |
392 | ||
393 | /* | |
394 | * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault | |
395 | * we return the initial request size (1, 2 or 4), as copy_*_user should do. | |
396 | * If a store crosses a page boundary and gets a fault, the x86 will not write | |
397 | * anything, so this is accurate. | |
398 | */ | |
399 | ||
400 | /** | |
401 | * __copy_to_user: - Copy a block of data into user space, with less checking. | |
402 | * @to: Destination address, in user space. | |
403 | * @from: Source address, in kernel space. | |
404 | * @n: Number of bytes to copy. | |
405 | * | |
406 | * Context: User context only. This function may sleep. | |
407 | * | |
408 | * Copy data from kernel space to user space. Caller must check | |
409 | * the specified block with access_ok() before calling this function. | |
410 | * | |
411 | * Returns number of bytes that could not be copied. | |
412 | * On success, this will be zero. | |
413 | */ | |
414 | static inline unsigned long __must_check | |
415 | __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n) | |
416 | { | |
417 | if (__builtin_constant_p(n)) { | |
418 | unsigned long ret; | |
419 | ||
420 | switch (n) { | |
421 | case 1: | |
422 | __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret, 1); | |
423 | return ret; | |
424 | case 2: | |
425 | __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret, 2); | |
426 | return ret; | |
427 | case 4: | |
428 | __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret, 4); | |
429 | return ret; | |
430 | } | |
431 | } | |
432 | return __copy_to_user_ll(to, from, n); | |
433 | } | |
434 | ||
435 | static inline unsigned long __must_check | |
436 | __copy_to_user(void __user *to, const void *from, unsigned long n) | |
437 | { | |
438 | might_sleep(); | |
439 | return __copy_to_user_inatomic(to, from, n); | |
440 | } | |
441 | ||
442 | /** | |
443 | * __copy_from_user: - Copy a block of data from user space, with less checking. | |
444 | * @to: Destination address, in kernel space. | |
445 | * @from: Source address, in user space. | |
446 | * @n: Number of bytes to copy. | |
447 | * | |
448 | * Context: User context only. This function may sleep. | |
449 | * | |
450 | * Copy data from user space to kernel space. Caller must check | |
451 | * the specified block with access_ok() before calling this function. | |
452 | * | |
453 | * Returns number of bytes that could not be copied. | |
454 | * On success, this will be zero. | |
455 | * | |
456 | * If some data could not be copied, this function will pad the copied | |
457 | * data to the requested size using zero bytes. | |
458 | */ | |
459 | static inline unsigned long | |
460 | __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) | |
461 | { | |
462 | if (__builtin_constant_p(n)) { | |
463 | unsigned long ret; | |
464 | ||
465 | switch (n) { | |
466 | case 1: | |
467 | __get_user_size(*(u8 *)to, from, 1, ret, 1); | |
468 | return ret; | |
469 | case 2: | |
470 | __get_user_size(*(u16 *)to, from, 2, ret, 2); | |
471 | return ret; | |
472 | case 4: | |
473 | __get_user_size(*(u32 *)to, from, 4, ret, 4); | |
474 | return ret; | |
475 | } | |
476 | } | |
477 | return __copy_from_user_ll(to, from, n); | |
478 | } | |
479 | ||
480 | static inline unsigned long | |
481 | __copy_from_user(void *to, const void __user *from, unsigned long n) | |
482 | { | |
483 | might_sleep(); | |
484 | return __copy_from_user_inatomic(to, from, n); | |
485 | } | |
486 | unsigned long __must_check copy_to_user(void __user *to, | |
487 | const void *from, unsigned long n); | |
488 | unsigned long __must_check copy_from_user(void *to, | |
489 | const void __user *from, unsigned long n); | |
490 | long __must_check strncpy_from_user(char *dst, const char __user *src, | |
491 | long count); | |
492 | long __must_check __strncpy_from_user(char *dst, | |
493 | const char __user *src, long count); | |
494 | ||
495 | /** | |
496 | * strlen_user: - Get the size of a string in user space. | |
497 | * @str: The string to measure. | |
498 | * | |
499 | * Context: User context only. This function may sleep. | |
500 | * | |
501 | * Get the size of a NUL-terminated string in user space. | |
502 | * | |
503 | * Returns the size of the string INCLUDING the terminating NUL. | |
504 | * On exception, returns 0. | |
505 | * | |
506 | * If there is a limit on the length of a valid string, you may wish to | |
507 | * consider using strnlen_user() instead. | |
508 | */ | |
509 | #define strlen_user(str) strnlen_user(str, ~0UL >> 1) | |
510 | ||
511 | long strnlen_user(const char __user *str, long n); | |
512 | unsigned long __must_check clear_user(void __user *mem, unsigned long len); | |
513 | unsigned long __must_check __clear_user(void __user *mem, unsigned long len); | |
514 | ||
515 | #endif /* __i386_UACCESS_H */ |