1 #ifndef __i386_UACCESS_H
2 #define __i386_UACCESS_H
5 * User space memory access functions
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 <linux/compiler.h>
16 #define VERIFY_WRITE 1
19 * The fs value determines whether argument validity checking should be
20 * performed or not. If get_fs() == USER_DS, checking is performed, with
21 * get_fs() == KERNEL_DS, checking is bypassed.
23 * For historical reasons, these macros are grossly misnamed.
26 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
29 #define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFUL)
30 #define USER_DS MAKE_MM_SEG(TASK_SIZE)
32 #define get_ds() (KERNEL_DS)
33 #define get_fs() (current_thread_info()->addr_limit)
34 #define set_fs(x) (current_thread_info()->addr_limit = (x))
36 #define segment_eq(a,b) ((a).seg == (b).seg)
39 * movsl can be slow when source and dest are not both 8-byte aligned
41 #ifdef CONFIG_X86_INTEL_USERCOPY
42 extern struct movsl_mask {
44 } ____cacheline_aligned_in_smp movsl_mask;
47 #define __addr_ok(addr) ((unsigned long __force)(addr) < (current_thread_info()->addr_limit.seg))
50 * Test whether a block of memory is a valid user space address.
51 * Returns 0 if the range is valid, nonzero otherwise.
53 * This is equivalent to the following test:
54 * (u33)addr + (u33)size >= (u33)current->addr_limit.seg
56 * This needs 33-bit arithmetic. We have a carry...
58 #define __range_ok(addr,size) ({ \
59 unsigned long flag,sum; \
60 __chk_user_ptr(addr); \
61 asm("addl %3,%1 ; sbbl %0,%0; cmpl %1,%4; sbbl $0,%0" \
62 :"=&r" (flag), "=r" (sum) \
63 :"1" (addr),"g" ((int)(size)),"g" (current_thread_info()->addr_limit.seg)); \
67 * access_ok: - Checks if a user space pointer is valid
68 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
69 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
70 * to write to a block, it is always safe to read from it.
71 * @addr: User space pointer to start of block to check
72 * @size: Size of block to check
74 * Context: User context only. This function may sleep.
76 * Checks if a pointer to a block of memory in user space is valid.
78 * Returns true (nonzero) if the memory block may be valid, false (zero)
79 * if it is definitely invalid.
81 * Note that, depending on architecture, this function probably just
82 * checks that the pointer is in the user space range - after calling
83 * this function, memory access functions may still return -EFAULT.
85 #define access_ok(type,addr,size) (likely(__range_ok(addr,size) == 0))
88 * verify_area: - Obsolete, use access_ok()
89 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE
90 * @addr: User space pointer to start of block to check
91 * @size: Size of block to check
93 * Context: User context only. This function may sleep.
95 * This function has been replaced by access_ok().
97 * Checks if a pointer to a block of memory in user space is valid.
99 * Returns zero if the memory block may be valid, -EFAULT
100 * if it is definitely invalid.
102 * See access_ok() for more details.
104 static inline int verify_area(int type, const void __user * addr, unsigned long size)
106 return access_ok(type,addr,size) ? 0 : -EFAULT;
111 * The exception table consists of pairs of addresses: the first is the
112 * address of an instruction that is allowed to fault, and the second is
113 * the address at which the program should continue. No registers are
114 * modified, so it is entirely up to the continuation code to figure out
117 * All the routines below use bits of fixup code that are out of line
118 * with the main instruction path. This means when everything is well,
119 * we don't even have to jump over them. Further, they do not intrude
120 * on our cache or tlb entries.
123 struct exception_table_entry
125 unsigned long insn, fixup;
128 extern int fixup_exception(struct pt_regs *regs);
131 * These are the main single-value transfer routines. They automatically
132 * use the right size if we just have the right pointer type.
134 * This gets kind of ugly. We want to return _two_ values in "get_user()"
135 * and yet we don't want to do any pointers, because that is too much
136 * of a performance impact. Thus we have a few rather ugly macros here,
137 * and hide all the ugliness from the user.
139 * The "__xxx" versions of the user access functions are versions that
140 * do not verify the address space, that must have been done previously
141 * with a separate "access_ok()" call (this is used when we do multiple
142 * accesses to the same area of user memory).
145 extern void __get_user_1(void);
146 extern void __get_user_2(void);
147 extern void __get_user_4(void);
149 #define __get_user_x(size,ret,x,ptr) \
150 __asm__ __volatile__("call __get_user_" #size \
151 :"=a" (ret),"=d" (x) \
154 extern int get_user_size(unsigned int size, void *val, const void *ptr);
155 extern int put_user_size(unsigned int size, const void *val, void *ptr);
156 extern int zero_user_size(unsigned int size, void *ptr);
157 extern int copy_str_fromuser_size(unsigned int size, void *val, const void *ptr);
158 extern int strlen_fromuser_size(unsigned int size, const void *ptr);
161 # define indirect_get_user(x,ptr) \
162 ({ int __ret_gu,__val_gu; \
163 __typeof__(ptr) __ptr_gu = (ptr); \
164 __ret_gu = get_user_size(sizeof(*__ptr_gu), &__val_gu,__ptr_gu) ? -EFAULT : 0;\
165 (x) = (__typeof__(*__ptr_gu))__val_gu; \
168 #define indirect_put_user(x,ptr) \
170 __typeof__(*(ptr)) *__ptr_pu = (ptr), __x_pu = (x); \
171 put_user_size(sizeof(*__ptr_pu), &__x_pu, __ptr_pu) ? -EFAULT : 0; \
173 #define __indirect_put_user indirect_put_user
174 #define __indirect_get_user indirect_get_user
176 #define indirect_copy_from_user(to,from,n) get_user_size(n,to,from)
177 #define indirect_copy_to_user(to,from,n) put_user_size(n,from,to)
179 #define __indirect_copy_from_user indirect_copy_from_user
180 #define __indirect_copy_to_user indirect_copy_to_user
182 #define indirect_strncpy_from_user(dst, src, count) \
183 copy_str_fromuser_size(count, dst, src)
185 extern int strlen_fromuser_size(unsigned int size, const void *ptr);
186 #define indirect_strnlen_user(str, n) strlen_fromuser_size(n, str)
187 #define indirect_strlen_user(str) indirect_strnlen_user(str, ~0UL >> 1)
189 extern int zero_user_size(unsigned int size, void *ptr);
191 #define indirect_clear_user(mem, len) zero_user_size(len, mem)
192 #define __indirect_clear_user clear_user
194 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
196 * get_user: - Get a simple variable from user space.
197 * @x: Variable to store result.
198 * @ptr: Source address, in user space.
200 * Context: User context only. This function may sleep.
202 * This macro copies a single simple variable from user space to kernel
203 * space. It supports simple types like char and int, but not larger
204 * data types like structures or arrays.
206 * @ptr must have pointer-to-simple-variable type, and the result of
207 * dereferencing @ptr must be assignable to @x without a cast.
209 * Returns zero on success, or -EFAULT on error.
210 * On error, the variable @x is set to zero.
212 #define direct_get_user(x,ptr) \
213 ({ int __ret_gu,__val_gu; \
214 __chk_user_ptr(ptr); \
215 switch(sizeof (*(ptr))) { \
216 case 1: __get_user_x(1,__ret_gu,__val_gu,ptr); break; \
217 case 2: __get_user_x(2,__ret_gu,__val_gu,ptr); break; \
218 case 4: __get_user_x(4,__ret_gu,__val_gu,ptr); break; \
219 default: __get_user_x(X,__ret_gu,__val_gu,ptr); break; \
221 (x) = (__typeof__(*(ptr)))__val_gu; \
225 extern void __put_user_bad(void);
228 * put_user: - Write a simple value into user space.
229 * @x: Value to copy to user space.
230 * @ptr: Destination address, in user space.
232 * Context: User context only. This function may sleep.
234 * This macro copies a single simple value from kernel space to user
235 * space. It supports simple types like char and int, but not larger
236 * data types like structures or arrays.
238 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
239 * to the result of dereferencing @ptr.
241 * Returns zero on success, or -EFAULT on error.
243 #define direct_put_user(x,ptr) \
244 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
248 * __get_user: - Get a simple variable from user space, with less checking.
249 * @x: Variable to store result.
250 * @ptr: Source address, in user space.
252 * Context: User context only. This function may sleep.
254 * This macro copies a single simple variable from user space to kernel
255 * space. It supports simple types like char and int, but not larger
256 * data types like structures or arrays.
258 * @ptr must have pointer-to-simple-variable type, and the result of
259 * dereferencing @ptr must be assignable to @x without a cast.
261 * Caller must check the pointer with access_ok() before calling this
264 * Returns zero on success, or -EFAULT on error.
265 * On error, the variable @x is set to zero.
267 #define __direct_get_user(x,ptr) \
268 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
272 * __put_user: - Write a simple value into user space, with less checking.
273 * @x: Value to copy to user space.
274 * @ptr: Destination address, in user space.
276 * Context: User context only. This function may sleep.
278 * This macro copies a single simple value from kernel space to user
279 * space. It supports simple types like char and int, but not larger
280 * data types like structures or arrays.
282 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
283 * to the result of dereferencing @ptr.
285 * Caller must check the pointer with access_ok() before calling this
288 * Returns zero on success, or -EFAULT on error.
290 #define __direct_put_user(x,ptr) \
291 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
293 #define __put_user_nocheck(x,ptr,size) \
296 __put_user_size((x),(ptr),(size),__pu_err,-EFAULT); \
301 #define __put_user_check(x,ptr,size) \
303 long __pu_err = -EFAULT; \
304 __typeof__(*(ptr)) *__pu_addr = (ptr); \
306 if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
307 __put_user_size((x),__pu_addr,(size),__pu_err,-EFAULT); \
311 #define __put_user_u64(x, addr, err) \
312 __asm__ __volatile__( \
313 "1: movl %%eax,0(%2)\n" \
314 "2: movl %%edx,4(%2)\n" \
316 ".section .fixup,\"ax\"\n" \
320 ".section __ex_table,\"a\"\n" \
326 : "A" (x), "r" (addr), "i"(-EFAULT), "0"(err))
328 #ifdef CONFIG_X86_WP_WORKS_OK
330 #define __put_user_size(x,ptr,size,retval,errret) \
333 __chk_user_ptr(ptr); \
335 case 1: __put_user_asm(x,ptr,retval,"b","b","iq",errret);break; \
336 case 2: __put_user_asm(x,ptr,retval,"w","w","ir",errret);break; \
337 case 4: __put_user_asm(x,ptr,retval,"l","","ir",errret); break; \
338 case 8: __put_user_u64((__typeof__(*ptr))(x),ptr,retval); break;\
339 default: __put_user_bad(); \
345 #define __put_user_size(x,ptr,size,retval,errret) \
347 __typeof__(*(ptr)) __pus_tmp = x; \
350 if(unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \
355 struct __large_struct { unsigned long buf[100]; };
356 #define __m(x) (*(struct __large_struct *)(x))
359 * Tell gcc we read from memory instead of writing: this is because
360 * we do not write to any memory gcc knows about, so there are no
363 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \
364 __asm__ __volatile__( \
365 "1: mov"itype" %"rtype"1,%2\n" \
367 ".section .fixup,\"ax\"\n" \
371 ".section __ex_table,\"a\"\n" \
376 : ltype (x), "m"(__m(addr)), "i"(errret), "0"(err))
379 #define __get_user_nocheck(x,ptr,size) \
381 long __gu_err, __gu_val; \
382 __get_user_size(__gu_val,(ptr),(size),__gu_err,-EFAULT);\
383 (x) = (__typeof__(*(ptr)))__gu_val; \
387 extern long __get_user_bad(void);
389 #define __get_user_size(x,ptr,size,retval,errret) \
392 __chk_user_ptr(ptr); \
394 case 1: __get_user_asm(x,ptr,retval,"b","b","=q",errret);break; \
395 case 2: __get_user_asm(x,ptr,retval,"w","w","=r",errret);break; \
396 case 4: __get_user_asm(x,ptr,retval,"l","","=r",errret);break; \
397 default: (x) = __get_user_bad(); \
401 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \
402 __asm__ __volatile__( \
403 "1: mov"itype" %2,%"rtype"1\n" \
405 ".section .fixup,\"ax\"\n" \
407 " xor"itype" %"rtype"1,%"rtype"1\n" \
410 ".section __ex_table,\"a\"\n" \
414 : "=r"(err), ltype (x) \
415 : "m"(__m(addr)), "i"(errret), "0"(err))
418 unsigned long __must_check __copy_to_user_ll(void __user *to, const void *from, unsigned long n);
419 unsigned long __must_check __copy_from_user_ll(void *to, const void __user *from, unsigned long n);
422 * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault
423 * we return the initial request size (1, 2 or 4), as copy_*_user should do.
424 * If a store crosses a page boundary and gets a fault, the x86 will not write
425 * anything, so this is accurate.
429 * __copy_to_user: - Copy a block of data into user space, with less checking.
430 * @to: Destination address, in user space.
431 * @from: Source address, in kernel space.
432 * @n: Number of bytes to copy.
434 * Context: User context only. This function may sleep.
436 * Copy data from kernel space to user space. Caller must check
437 * the specified block with access_ok() before calling this function.
439 * Returns number of bytes that could not be copied.
440 * On success, this will be zero.
442 static inline unsigned long __must_check
443 __direct_copy_to_user(void __user *to, const void *from, unsigned long n)
445 if (__builtin_constant_p(n)) {
450 __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret, 1);
453 __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret, 2);
456 __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret, 4);
460 return __copy_to_user_ll(to, from, n);
464 * __copy_from_user: - Copy a block of data from user space, with less checking.
465 * @to: Destination address, in kernel space.
466 * @from: Source address, in user space.
467 * @n: Number of bytes to copy.
469 * Context: User context only. This function may sleep.
471 * Copy data from user space to kernel space. Caller must check
472 * the specified block with access_ok() before calling this function.
474 * Returns number of bytes that could not be copied.
475 * On success, this will be zero.
477 * If some data could not be copied, this function will pad the copied
478 * data to the requested size using zero bytes.
480 static inline unsigned long __must_check
481 __direct_copy_from_user(void *to, const void __user *from, unsigned long n)
483 if (__builtin_constant_p(n)) {
488 __get_user_size(*(u8 *)to, from, 1, ret, 1);
491 __get_user_size(*(u16 *)to, from, 2, ret, 2);
494 __get_user_size(*(u32 *)to, from, 4, ret, 4);
498 return __copy_from_user_ll(to, from, n);
502 * copy_to_user: - Copy a block of data into user space.
503 * @to: Destination address, in user space.
504 * @from: Source address, in kernel space.
505 * @n: Number of bytes to copy.
507 * Context: User context only. This function may sleep.
509 * Copy data from kernel space to user space.
511 * Returns number of bytes that could not be copied.
512 * On success, this will be zero.
514 static inline unsigned long __must_check
515 direct_copy_to_user(void __user *to, const void *from, unsigned long n)
518 if (access_ok(VERIFY_WRITE, to, n))
519 n = __direct_copy_to_user(to, from, n);
524 * copy_from_user: - Copy a block of data from user space.
525 * @to: Destination address, in kernel space.
526 * @from: Source address, in user space.
527 * @n: Number of bytes to copy.
529 * Context: User context only. This function may sleep.
531 * Copy data from user space to kernel space.
533 * Returns number of bytes that could not be copied.
534 * On success, this will be zero.
536 * If some data could not be copied, this function will pad the copied
537 * data to the requested size using zero bytes.
539 static inline unsigned long __must_check
540 direct_copy_from_user(void *to, const void __user *from, unsigned long n)
543 if (access_ok(VERIFY_READ, from, n))
544 n = __direct_copy_from_user(to, from, n);
550 long strncpy_from_user(char *dst, const char __user *src, long count);
551 long __strncpy_from_user(char *dst, const char __user *src, long count);
554 * strlen_user: - Get the size of a string in user space.
555 * @str: The string to measure.
557 * Context: User context only. This function may sleep.
559 * Get the size of a NUL-terminated string in user space.
561 * Returns the size of the string INCLUDING the terminating NUL.
562 * On exception, returns 0.
564 * If there is a limit on the length of a valid string, you may wish to
565 * consider using strnlen_user() instead.
568 long direct_strncpy_from_user(char *dst, const char *src, long count);
569 long __direct_strncpy_from_user(char *dst, const char *src, long count);
570 #define direct_strlen_user(str) direct_strnlen_user(str, ~0UL >> 1)
571 long direct_strnlen_user(const char *str, long n);
572 unsigned long direct_clear_user(void *mem, unsigned long len);
573 unsigned long __direct_clear_user(void *mem, unsigned long len);
575 extern int indirect_uaccess;
577 #ifdef CONFIG_X86_UACCESS_INDIRECT
580 * Return code and zeroing semantics:
582 __clear_user 0 <-> bytes not done
583 clear_user 0 <-> bytes not done
584 __copy_to_user 0 <-> bytes not done
585 copy_to_user 0 <-> bytes not done
586 __copy_from_user 0 <-> bytes not done, zero rest
587 copy_from_user 0 <-> bytes not done, zero rest
588 __get_user 0 <-> -EFAULT
589 get_user 0 <-> -EFAULT
590 __put_user 0 <-> -EFAULT
591 put_user 0 <-> -EFAULT
592 strlen_user strlen + 1 <-> 0
593 strnlen_user strlen + 1 (or n+1) <-> 0
594 strncpy_from_user strlen (or n) <-> -EFAULT
598 #define __clear_user(mem,len) __indirect_clear_user(mem,len)
599 #define clear_user(mem,len) indirect_clear_user(mem,len)
600 #define __copy_to_user(to,from,n) __indirect_copy_to_user(to,from,n)
601 #define copy_to_user(to,from,n) indirect_copy_to_user(to,from,n)
602 #define __copy_from_user(to,from,n) __indirect_copy_from_user(to,from,n)
603 #define copy_from_user(to,from,n) indirect_copy_from_user(to,from,n)
604 #define __get_user(val,ptr) __indirect_get_user(val,ptr)
605 #define get_user(val,ptr) indirect_get_user(val,ptr)
606 #define __put_user(val,ptr) __indirect_put_user(val,ptr)
607 #define put_user(val,ptr) indirect_put_user(val,ptr)
608 #define strlen_user(str) indirect_strlen_user(str)
609 #define strnlen_user(src,count) indirect_strnlen_user(src,count)
610 #define strncpy_from_user(dst,src,count) \
611 indirect_strncpy_from_user(dst,src,count)
615 #define __clear_user __direct_clear_user
616 #define clear_user direct_clear_user
617 #define __copy_to_user __direct_copy_to_user
618 #define copy_to_user direct_copy_to_user
619 #define __copy_from_user __direct_copy_from_user
620 #define copy_from_user direct_copy_from_user
621 #define __get_user __direct_get_user
622 #define get_user direct_get_user
623 #define __put_user __direct_put_user
624 #define put_user direct_put_user
625 #define strlen_user direct_strlen_user
626 #define strnlen_user direct_strnlen_user
627 #define strncpy_from_user direct_strncpy_from_user
629 #endif /* CONFIG_X86_UACCESS_INDIRECT */
630 #define __copy_to_user_inatomic __copy_to_user
631 #define __copy_from_user_inatomic __copy_from_user
634 #endif /* __i386_UACCESS_H */