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>
15 #define VERIFY_WRITE 1
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.
22 * For historical reasons, these macros are grossly misnamed.
25 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
28 #define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFUL)
29 #define USER_DS MAKE_MM_SEG(TASK_SIZE)
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))
35 #define segment_eq(a,b) ((a).seg == (b).seg)
38 * movsl can be slow when source and dest are not both 8-byte aligned
40 #ifdef CONFIG_X86_INTEL_USERCOPY
41 extern struct movsl_mask {
43 } ____cacheline_aligned_in_smp movsl_mask;
46 #define __addr_ok(addr) ((unsigned long __force)(addr) < (current_thread_info()->addr_limit.seg))
49 * Test whether a block of memory is a valid user space address.
50 * Returns 0 if the range is valid, nonzero otherwise.
52 * This is equivalent to the following test:
53 * (u33)addr + (u33)size >= (u33)current->addr_limit.seg
55 * This needs 33-bit arithmetic. We have a carry...
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)); \
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
73 * Context: User context only. This function may sleep.
75 * Checks if a pointer to a block of memory in user space is valid.
77 * Returns true (nonzero) if the memory block may be valid, false (zero)
78 * if it is definitely invalid.
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.
84 #define access_ok(type,addr,size) (likely(__range_ok(addr,size) == 0))
87 * verify_area: - Obsolete, use access_ok()
88 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE
89 * @addr: User space pointer to start of block to check
90 * @size: Size of block to check
92 * Context: User context only. This function may sleep.
94 * This function has been replaced by access_ok().
96 * Checks if a pointer to a block of memory in user space is valid.
98 * Returns zero if the memory block may be valid, -EFAULT
99 * if it is definitely invalid.
101 * See access_ok() for more details.
103 static inline int verify_area(int type, const void __user * addr, unsigned long size)
105 return access_ok(type,addr,size) ? 0 : -EFAULT;
110 * The exception table consists of pairs of addresses: the first is the
111 * address of an instruction that is allowed to fault, and the second is
112 * the address at which the program should continue. No registers are
113 * modified, so it is entirely up to the continuation code to figure out
116 * All the routines below use bits of fixup code that are out of line
117 * with the main instruction path. This means when everything is well,
118 * we don't even have to jump over them. Further, they do not intrude
119 * on our cache or tlb entries.
122 struct exception_table_entry
124 unsigned long insn, fixup;
127 extern int fixup_exception(struct pt_regs *regs);
130 * These are the main single-value transfer routines. They automatically
131 * use the right size if we just have the right pointer type.
133 * This gets kind of ugly. We want to return _two_ values in "get_user()"
134 * and yet we don't want to do any pointers, because that is too much
135 * of a performance impact. Thus we have a few rather ugly macros here,
136 * and hide all the ugliness from the user.
138 * The "__xxx" versions of the user access functions are versions that
139 * do not verify the address space, that must have been done previously
140 * with a separate "access_ok()" call (this is used when we do multiple
141 * accesses to the same area of user memory).
144 extern void __get_user_1(void);
145 extern void __get_user_2(void);
146 extern void __get_user_4(void);
148 #define __get_user_x(size,ret,x,ptr) \
149 __asm__ __volatile__("call __get_user_" #size \
150 :"=a" (ret),"=d" (x) \
153 extern int get_user_size(unsigned int size, void *val, const void *ptr);
154 extern int put_user_size(unsigned int size, const void *val, void *ptr);
155 extern int zero_user_size(unsigned int size, void *ptr);
156 extern int copy_str_fromuser_size(unsigned int size, void *val, const void *ptr);
157 extern int strlen_fromuser_size(unsigned int size, const void *ptr);
160 # define indirect_get_user(x,ptr) \
161 ({ int __ret_gu,__val_gu; \
162 __typeof__(ptr) __ptr_gu = (ptr); \
163 __ret_gu = get_user_size(sizeof(*__ptr_gu), &__val_gu,__ptr_gu) ? -EFAULT : 0;\
164 (x) = (__typeof__(*__ptr_gu))__val_gu; \
167 #define indirect_put_user(x,ptr) \
169 __typeof__(*(ptr)) *__ptr_pu = (ptr), __x_pu = (x); \
170 put_user_size(sizeof(*__ptr_pu), &__x_pu, __ptr_pu) ? -EFAULT : 0; \
172 #define __indirect_put_user indirect_put_user
173 #define __indirect_get_user indirect_get_user
175 #define indirect_copy_from_user(to,from,n) get_user_size(n,to,from)
176 #define indirect_copy_to_user(to,from,n) put_user_size(n,from,to)
178 #define __indirect_copy_from_user indirect_copy_from_user
179 #define __indirect_copy_to_user indirect_copy_to_user
181 #define indirect_strncpy_from_user(dst, src, count) \
182 copy_str_fromuser_size(count, dst, src)
184 extern int strlen_fromuser_size(unsigned int size, const void *ptr);
185 #define indirect_strnlen_user(str, n) strlen_fromuser_size(n, str)
186 #define indirect_strlen_user(str) indirect_strnlen_user(str, ~0UL >> 1)
188 extern int zero_user_size(unsigned int size, void *ptr);
190 #define indirect_clear_user(mem, len) zero_user_size(len, mem)
191 #define __indirect_clear_user clear_user
193 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
195 * get_user: - Get a simple variable from user space.
196 * @x: Variable to store result.
197 * @ptr: Source address, in user space.
199 * Context: User context only. This function may sleep.
201 * This macro copies a single simple variable from user space to kernel
202 * space. It supports simple types like char and int, but not larger
203 * data types like structures or arrays.
205 * @ptr must have pointer-to-simple-variable type, and the result of
206 * dereferencing @ptr must be assignable to @x without a cast.
208 * Returns zero on success, or -EFAULT on error.
209 * On error, the variable @x is set to zero.
211 #define direct_get_user(x,ptr) \
212 ({ int __ret_gu,__val_gu; \
213 __chk_user_ptr(ptr); \
214 switch(sizeof (*(ptr))) { \
215 case 1: __get_user_x(1,__ret_gu,__val_gu,ptr); break; \
216 case 2: __get_user_x(2,__ret_gu,__val_gu,ptr); break; \
217 case 4: __get_user_x(4,__ret_gu,__val_gu,ptr); break; \
218 default: __get_user_x(X,__ret_gu,__val_gu,ptr); break; \
220 (x) = (__typeof__(*(ptr)))__val_gu; \
224 extern void __put_user_bad(void);
227 * put_user: - Write a simple value into user space.
228 * @x: Value to copy to user space.
229 * @ptr: Destination address, in user space.
231 * Context: User context only. This function may sleep.
233 * This macro copies a single simple value from kernel space to user
234 * space. It supports simple types like char and int, but not larger
235 * data types like structures or arrays.
237 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
238 * to the result of dereferencing @ptr.
240 * Returns zero on success, or -EFAULT on error.
242 #define direct_put_user(x,ptr) \
243 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
247 * __get_user: - Get a simple variable from user space, with less checking.
248 * @x: Variable to store result.
249 * @ptr: Source address, in user space.
251 * Context: User context only. This function may sleep.
253 * This macro copies a single simple variable from user space to kernel
254 * space. It supports simple types like char and int, but not larger
255 * data types like structures or arrays.
257 * @ptr must have pointer-to-simple-variable type, and the result of
258 * dereferencing @ptr must be assignable to @x without a cast.
260 * Caller must check the pointer with access_ok() before calling this
263 * Returns zero on success, or -EFAULT on error.
264 * On error, the variable @x is set to zero.
266 #define __direct_get_user(x,ptr) \
267 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
271 * __put_user: - Write a simple value into user space, with less checking.
272 * @x: Value to copy to user space.
273 * @ptr: Destination address, in user space.
275 * Context: User context only. This function may sleep.
277 * This macro copies a single simple value from kernel space to user
278 * space. It supports simple types like char and int, but not larger
279 * data types like structures or arrays.
281 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
282 * to the result of dereferencing @ptr.
284 * Caller must check the pointer with access_ok() before calling this
287 * Returns zero on success, or -EFAULT on error.
289 #define __direct_put_user(x,ptr) \
290 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
292 #define __put_user_nocheck(x,ptr,size) \
295 __put_user_size((x),(ptr),(size),__pu_err,-EFAULT); \
300 #define __put_user_check(x,ptr,size) \
302 long __pu_err = -EFAULT; \
303 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
305 if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
306 __put_user_size((x),__pu_addr,(size),__pu_err,-EFAULT); \
310 #define __put_user_u64(x, addr, err) \
311 __asm__ __volatile__( \
312 "1: movl %%eax,0(%2)\n" \
313 "2: movl %%edx,4(%2)\n" \
315 ".section .fixup,\"ax\"\n" \
319 ".section __ex_table,\"a\"\n" \
325 : "A" (x), "r" (addr), "i"(-EFAULT), "0"(err))
327 #ifdef CONFIG_X86_WP_WORKS_OK
329 #define __put_user_size(x,ptr,size,retval,errret) \
332 __chk_user_ptr(ptr); \
334 case 1: __put_user_asm(x,ptr,retval,"b","b","iq",errret);break; \
335 case 2: __put_user_asm(x,ptr,retval,"w","w","ir",errret);break; \
336 case 4: __put_user_asm(x,ptr,retval,"l","","ir",errret); break; \
337 case 8: __put_user_u64((__typeof__(*ptr))(x),ptr,retval); break;\
338 default: __put_user_bad(); \
344 #define __put_user_size(x,ptr,size,retval,errret) \
346 __typeof__(*(ptr)) __pus_tmp = x; \
349 if(unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \
354 struct __large_struct { unsigned long buf[100]; };
355 #define __m(x) (*(struct __large_struct *)(x))
358 * Tell gcc we read from memory instead of writing: this is because
359 * we do not write to any memory gcc knows about, so there are no
362 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \
363 __asm__ __volatile__( \
364 "1: mov"itype" %"rtype"1,%2\n" \
366 ".section .fixup,\"ax\"\n" \
370 ".section __ex_table,\"a\"\n" \
375 : ltype (x), "m"(__m(addr)), "i"(errret), "0"(err))
378 #define __get_user_nocheck(x,ptr,size) \
380 long __gu_err, __gu_val; \
381 __get_user_size(__gu_val,(ptr),(size),__gu_err,-EFAULT);\
382 (x) = (__typeof__(*(ptr)))__gu_val; \
386 extern long __get_user_bad(void);
388 #define __get_user_size(x,ptr,size,retval,errret) \
391 __chk_user_ptr(ptr); \
393 case 1: __get_user_asm(x,ptr,retval,"b","b","=q",errret);break; \
394 case 2: __get_user_asm(x,ptr,retval,"w","w","=r",errret);break; \
395 case 4: __get_user_asm(x,ptr,retval,"l","","=r",errret);break; \
396 default: (x) = __get_user_bad(); \
400 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \
401 __asm__ __volatile__( \
402 "1: mov"itype" %2,%"rtype"1\n" \
404 ".section .fixup,\"ax\"\n" \
406 " xor"itype" %"rtype"1,%"rtype"1\n" \
409 ".section __ex_table,\"a\"\n" \
413 : "=r"(err), ltype (x) \
414 : "m"(__m(addr)), "i"(errret), "0"(err))
417 unsigned long __copy_to_user_ll(void __user *to, const void *from, unsigned long n);
418 unsigned long __copy_from_user_ll(void *to, const void __user *from, unsigned long n);
421 * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault
422 * we return the initial request size (1, 2 or 4), as copy_*_user should do.
423 * If a store crosses a page boundary and gets a fault, the x86 will not write
424 * anything, so this is accurate.
428 * __copy_to_user: - Copy a block of data into user space, with less checking.
429 * @to: Destination address, in user space.
430 * @from: Source address, in kernel space.
431 * @n: Number of bytes to copy.
433 * Context: User context only. This function may sleep.
435 * Copy data from kernel space to user space. Caller must check
436 * the specified block with access_ok() before calling this function.
438 * Returns number of bytes that could not be copied.
439 * On success, this will be zero.
441 static inline unsigned long
442 __direct_copy_to_user(void __user *to, const void *from, unsigned long n)
444 if (__builtin_constant_p(n)) {
449 __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret, 1);
452 __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret, 2);
455 __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret, 4);
459 return __copy_to_user_ll(to, from, n);
463 * __copy_from_user: - Copy a block of data from user space, with less checking.
464 * @to: Destination address, in kernel space.
465 * @from: Source address, in user space.
466 * @n: Number of bytes to copy.
468 * Context: User context only. This function may sleep.
470 * Copy data from user space to kernel space. Caller must check
471 * the specified block with access_ok() before calling this function.
473 * Returns number of bytes that could not be copied.
474 * On success, this will be zero.
476 * If some data could not be copied, this function will pad the copied
477 * data to the requested size using zero bytes.
479 static inline unsigned long
480 __direct_copy_from_user(void *to, const void __user *from, unsigned long n)
482 if (__builtin_constant_p(n)) {
487 __get_user_size(*(u8 *)to, from, 1, ret, 1);
490 __get_user_size(*(u16 *)to, from, 2, ret, 2);
493 __get_user_size(*(u32 *)to, from, 4, ret, 4);
497 return __copy_from_user_ll(to, from, n);
501 * copy_to_user: - Copy a block of data into user space.
502 * @to: Destination address, in user space.
503 * @from: Source address, in kernel space.
504 * @n: Number of bytes to copy.
506 * Context: User context only. This function may sleep.
508 * Copy data from kernel space to user space.
510 * Returns number of bytes that could not be copied.
511 * On success, this will be zero.
513 static inline unsigned long
514 direct_copy_to_user(void __user *to, const void *from, unsigned long n)
517 if (access_ok(VERIFY_WRITE, to, n))
518 n = __direct_copy_to_user(to, from, n);
523 * copy_from_user: - Copy a block of data from user space.
524 * @to: Destination address, in kernel space.
525 * @from: Source address, in user space.
526 * @n: Number of bytes to copy.
528 * Context: User context only. This function may sleep.
530 * Copy data from user space to kernel space.
532 * Returns number of bytes that could not be copied.
533 * On success, this will be zero.
535 * If some data could not be copied, this function will pad the copied
536 * data to the requested size using zero bytes.
538 static inline unsigned long
539 direct_copy_from_user(void *to, const void __user *from, unsigned long n)
542 if (access_ok(VERIFY_READ, from, n))
543 n = __direct_copy_from_user(to, from, n);
549 long strncpy_from_user(char *dst, const char __user *src, long count);
550 long __strncpy_from_user(char *dst, const char __user *src, long count);
553 * strlen_user: - Get the size of a string in user space.
554 * @str: The string to measure.
556 * Context: User context only. This function may sleep.
558 * Get the size of a NUL-terminated string in user space.
560 * Returns the size of the string INCLUDING the terminating NUL.
561 * On exception, returns 0.
563 * If there is a limit on the length of a valid string, you may wish to
564 * consider using strnlen_user() instead.
567 long direct_strncpy_from_user(char *dst, const char *src, long count);
568 long __direct_strncpy_from_user(char *dst, const char *src, long count);
569 #define direct_strlen_user(str) direct_strnlen_user(str, ~0UL >> 1)
570 long direct_strnlen_user(const char *str, long n);
571 unsigned long direct_clear_user(void *mem, unsigned long len);
572 unsigned long __direct_clear_user(void *mem, unsigned long len);
574 extern int indirect_uaccess;
576 #ifdef CONFIG_X86_UACCESS_INDIRECT
579 * Return code and zeroing semantics:
581 __clear_user 0 <-> bytes not done
582 clear_user 0 <-> bytes not done
583 __copy_to_user 0 <-> bytes not done
584 copy_to_user 0 <-> bytes not done
585 __copy_from_user 0 <-> bytes not done, zero rest
586 copy_from_user 0 <-> bytes not done, zero rest
587 __get_user 0 <-> -EFAULT
588 get_user 0 <-> -EFAULT
589 __put_user 0 <-> -EFAULT
590 put_user 0 <-> -EFAULT
591 strlen_user strlen + 1 <-> 0
592 strnlen_user strlen + 1 (or n+1) <-> 0
593 strncpy_from_user strlen (or n) <-> -EFAULT
597 #define __clear_user(mem,len) __indirect_clear_user(mem,len)
598 #define clear_user(mem,len) indirect_clear_user(mem,len)
599 #define __copy_to_user(to,from,n) __indirect_copy_to_user(to,from,n)
600 #define copy_to_user(to,from,n) indirect_copy_to_user(to,from,n)
601 #define __copy_from_user(to,from,n) __indirect_copy_from_user(to,from,n)
602 #define copy_from_user(to,from,n) indirect_copy_from_user(to,from,n)
603 #define __get_user(val,ptr) __indirect_get_user(val,ptr)
604 #define get_user(val,ptr) indirect_get_user(val,ptr)
605 #define __put_user(val,ptr) __indirect_put_user(val,ptr)
606 #define put_user(val,ptr) indirect_put_user(val,ptr)
607 #define strlen_user(str) indirect_strlen_user(str)
608 #define strnlen_user(src,count) indirect_strnlen_user(src,count)
609 #define strncpy_from_user(dst,src,count) \
610 indirect_strncpy_from_user(dst,src,count)
614 #define __clear_user __direct_clear_user
615 #define clear_user direct_clear_user
616 #define __copy_to_user __direct_copy_to_user
617 #define copy_to_user direct_copy_to_user
618 #define __copy_from_user __direct_copy_from_user
619 #define copy_from_user direct_copy_from_user
620 #define __get_user __direct_get_user
621 #define get_user direct_get_user
622 #define __put_user __direct_put_user
623 #define put_user direct_put_user
624 #define strlen_user direct_strlen_user
625 #define strnlen_user direct_strnlen_user
626 #define strncpy_from_user direct_strncpy_from_user
628 #endif /* CONFIG_X86_UACCESS_INDIRECT */
629 #define __copy_to_user_inatomic __copy_to_user
630 #define __copy_from_user_inatomic __copy_from_user
633 #endif /* __i386_UACCESS_H */