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)
38 extern long not_a_user_address;
39 #define check_user_ptr(x) \
40 (void) ({ void __user * __userptr = (__typeof__(*(x)) *)¬_a_user_address; __userptr; })
43 * movsl can be slow when source and dest are not both 8-byte aligned
45 #ifdef CONFIG_X86_INTEL_USERCOPY
46 extern struct movsl_mask {
48 } ____cacheline_aligned_in_smp movsl_mask;
51 #define __addr_ok(addr) ((unsigned long __force)(addr) < (current_thread_info()->addr_limit.seg))
54 * Test whether a block of memory is a valid user space address.
55 * Returns 0 if the range is valid, nonzero otherwise.
57 * This is equivalent to the following test:
58 * (u33)addr + (u33)size >= (u33)current->addr_limit.seg
60 * This needs 33-bit arithmetic. We have a carry...
62 #define __range_ok(addr,size) ({ \
63 unsigned long flag,sum; \
64 check_user_ptr(addr); \
65 asm("addl %3,%1 ; sbbl %0,%0; cmpl %1,%4; sbbl $0,%0" \
66 :"=&r" (flag), "=r" (sum) \
67 :"1" (addr),"g" ((int)(size)),"g" (current_thread_info()->addr_limit.seg)); \
71 * access_ok: - Checks if a user space pointer is valid
72 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
73 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
74 * to write to a block, it is always safe to read from it.
75 * @addr: User space pointer to start of block to check
76 * @size: Size of block to check
78 * Context: User context only. This function may sleep.
80 * Checks if a pointer to a block of memory in user space is valid.
82 * Returns true (nonzero) if the memory block may be valid, false (zero)
83 * if it is definitely invalid.
85 * Note that, depending on architecture, this function probably just
86 * checks that the pointer is in the user space range - after calling
87 * this function, memory access functions may still return -EFAULT.
89 #define access_ok(type,addr,size) (likely(__range_ok(addr,size) == 0))
92 * verify_area: - Obsolete, use access_ok()
93 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE
94 * @addr: User space pointer to start of block to check
95 * @size: Size of block to check
97 * Context: User context only. This function may sleep.
99 * This function has been replaced by access_ok().
101 * Checks if a pointer to a block of memory in user space is valid.
103 * Returns zero if the memory block may be valid, -EFAULT
104 * if it is definitely invalid.
106 * See access_ok() for more details.
108 static inline int verify_area(int type, const void __user * addr, unsigned long size)
110 return access_ok(type,addr,size) ? 0 : -EFAULT;
115 * The exception table consists of pairs of addresses: the first is the
116 * address of an instruction that is allowed to fault, and the second is
117 * the address at which the program should continue. No registers are
118 * modified, so it is entirely up to the continuation code to figure out
121 * All the routines below use bits of fixup code that are out of line
122 * with the main instruction path. This means when everything is well,
123 * we don't even have to jump over them. Further, they do not intrude
124 * on our cache or tlb entries.
127 struct exception_table_entry
129 unsigned long insn, fixup;
132 extern int fixup_exception(struct pt_regs *regs);
135 * These are the main single-value transfer routines. They automatically
136 * use the right size if we just have the right pointer type.
138 * This gets kind of ugly. We want to return _two_ values in "get_user()"
139 * and yet we don't want to do any pointers, because that is too much
140 * of a performance impact. Thus we have a few rather ugly macros here,
141 * and hide all the ugliness from the user.
143 * The "__xxx" versions of the user access functions are versions that
144 * do not verify the address space, that must have been done previously
145 * with a separate "access_ok()" call (this is used when we do multiple
146 * accesses to the same area of user memory).
149 extern void __get_user_1(void);
150 extern void __get_user_2(void);
151 extern void __get_user_4(void);
153 #define __get_user_x(size,ret,x,ptr) \
154 __asm__ __volatile__("call __get_user_" #size \
155 :"=a" (ret),"=d" (x) \
158 extern int get_user_size(unsigned int size, void *val, const void *ptr);
159 extern int put_user_size(unsigned int size, const void *val, void *ptr);
160 extern int zero_user_size(unsigned int size, void *ptr);
161 extern int copy_str_fromuser_size(unsigned int size, void *val, const void *ptr);
162 extern int strlen_fromuser_size(unsigned int size, const void *ptr);
165 # define indirect_get_user(x,ptr) \
166 ({ int __ret_gu,__val_gu; \
167 __typeof__(ptr) __ptr_gu = (ptr); \
168 __ret_gu = get_user_size(sizeof(*__ptr_gu), &__val_gu,__ptr_gu) ? -EFAULT : 0;\
169 (x) = (__typeof__(*__ptr_gu))__val_gu; \
172 #define indirect_put_user(x,ptr) \
174 __typeof__(*(ptr)) *__ptr_pu = (ptr), __x_pu = (x); \
175 put_user_size(sizeof(*__ptr_pu), &__x_pu, __ptr_pu) ? -EFAULT : 0; \
177 #define __indirect_put_user indirect_put_user
178 #define __indirect_get_user indirect_get_user
180 #define indirect_copy_from_user(to,from,n) get_user_size(n,to,from)
181 #define indirect_copy_to_user(to,from,n) put_user_size(n,from,to)
183 #define __indirect_copy_from_user indirect_copy_from_user
184 #define __indirect_copy_to_user indirect_copy_to_user
186 #define indirect_strncpy_from_user(dst, src, count) \
187 copy_str_fromuser_size(count, dst, src)
189 extern int strlen_fromuser_size(unsigned int size, const void *ptr);
190 #define indirect_strnlen_user(str, n) strlen_fromuser_size(n, str)
191 #define indirect_strlen_user(str) indirect_strnlen_user(str, ~0UL >> 1)
193 extern int zero_user_size(unsigned int size, void *ptr);
195 #define indirect_clear_user(mem, len) zero_user_size(len, mem)
196 #define __indirect_clear_user clear_user
198 /* Careful: we have to cast the result to the type of the pointer for sign reasons */
200 * get_user: - Get a simple variable from user space.
201 * @x: Variable to store result.
202 * @ptr: Source address, in user space.
204 * Context: User context only. This function may sleep.
206 * This macro copies a single simple variable from user space to kernel
207 * space. It supports simple types like char and int, but not larger
208 * data types like structures or arrays.
210 * @ptr must have pointer-to-simple-variable type, and the result of
211 * dereferencing @ptr must be assignable to @x without a cast.
213 * Returns zero on success, or -EFAULT on error.
214 * On error, the variable @x is set to zero.
216 #define direct_get_user(x,ptr) \
217 ({ int __ret_gu,__val_gu; \
218 check_user_ptr(ptr); \
219 switch(sizeof (*(ptr))) { \
220 case 1: __get_user_x(1,__ret_gu,__val_gu,ptr); break; \
221 case 2: __get_user_x(2,__ret_gu,__val_gu,ptr); break; \
222 case 4: __get_user_x(4,__ret_gu,__val_gu,ptr); break; \
223 default: __get_user_x(X,__ret_gu,__val_gu,ptr); break; \
225 (x) = (__typeof__(*(ptr)))__val_gu; \
229 extern void __put_user_bad(void);
232 * put_user: - Write a simple value into user space.
233 * @x: Value to copy to user space.
234 * @ptr: Destination address, in user space.
236 * Context: User context only. This function may sleep.
238 * This macro copies a single simple value from kernel space to user
239 * space. It supports simple types like char and int, but not larger
240 * data types like structures or arrays.
242 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
243 * to the result of dereferencing @ptr.
245 * Returns zero on success, or -EFAULT on error.
247 #define direct_put_user(x,ptr) \
248 __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
252 * __get_user: - Get a simple variable from user space, with less checking.
253 * @x: Variable to store result.
254 * @ptr: Source address, in user space.
256 * Context: User context only. This function may sleep.
258 * This macro copies a single simple variable from user space to kernel
259 * space. It supports simple types like char and int, but not larger
260 * data types like structures or arrays.
262 * @ptr must have pointer-to-simple-variable type, and the result of
263 * dereferencing @ptr must be assignable to @x without a cast.
265 * Caller must check the pointer with access_ok() before calling this
268 * Returns zero on success, or -EFAULT on error.
269 * On error, the variable @x is set to zero.
271 #define __direct_get_user(x,ptr) \
272 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
276 * __put_user: - Write a simple value into user space, with less checking.
277 * @x: Value to copy to user space.
278 * @ptr: Destination address, in user space.
280 * Context: User context only. This function may sleep.
282 * This macro copies a single simple value from kernel space to user
283 * space. It supports simple types like char and int, but not larger
284 * data types like structures or arrays.
286 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
287 * to the result of dereferencing @ptr.
289 * Caller must check the pointer with access_ok() before calling this
292 * Returns zero on success, or -EFAULT on error.
294 #define __direct_put_user(x,ptr) \
295 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
297 #define __put_user_nocheck(x,ptr,size) \
300 __put_user_size((x),(ptr),(size),__pu_err,-EFAULT); \
305 #define __put_user_check(x,ptr,size) \
307 long __pu_err = -EFAULT; \
308 __typeof__(*(ptr)) *__pu_addr = (ptr); \
310 if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
311 __put_user_size((x),__pu_addr,(size),__pu_err,-EFAULT); \
315 #define __put_user_u64(x, addr, err) \
316 __asm__ __volatile__( \
317 "1: movl %%eax,0(%2)\n" \
318 "2: movl %%edx,4(%2)\n" \
320 ".section .fixup,\"ax\"\n" \
324 ".section __ex_table,\"a\"\n" \
330 : "A" (x), "r" (addr), "i"(-EFAULT), "0"(err))
332 #ifdef CONFIG_X86_WP_WORKS_OK
334 #define __put_user_size(x,ptr,size,retval,errret) \
337 check_user_ptr(ptr); \
339 case 1: __put_user_asm(x,ptr,retval,"b","b","iq",errret);break; \
340 case 2: __put_user_asm(x,ptr,retval,"w","w","ir",errret);break; \
341 case 4: __put_user_asm(x,ptr,retval,"l","","ir",errret); break; \
342 case 8: __put_user_u64((__typeof__(*ptr))(x),ptr,retval); break;\
343 default: __put_user_bad(); \
349 #define __put_user_size(x,ptr,size,retval,errret) \
351 __typeof__(*(ptr)) __pus_tmp = x; \
354 if(unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \
359 struct __large_struct { unsigned long buf[100]; };
360 #define __m(x) (*(struct __large_struct *)(x))
363 * Tell gcc we read from memory instead of writing: this is because
364 * we do not write to any memory gcc knows about, so there are no
367 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \
368 __asm__ __volatile__( \
369 "1: mov"itype" %"rtype"1,%2\n" \
371 ".section .fixup,\"ax\"\n" \
375 ".section __ex_table,\"a\"\n" \
380 : ltype (x), "m"(__m(addr)), "i"(errret), "0"(err))
383 #define __get_user_nocheck(x,ptr,size) \
385 long __gu_err, __gu_val; \
386 __get_user_size(__gu_val,(ptr),(size),__gu_err,-EFAULT);\
387 (x) = (__typeof__(*(ptr)))__gu_val; \
391 extern long __get_user_bad(void);
393 #define __get_user_size(x,ptr,size,retval,errret) \
396 check_user_ptr(ptr); \
398 case 1: __get_user_asm(x,ptr,retval,"b","b","=q",errret);break; \
399 case 2: __get_user_asm(x,ptr,retval,"w","w","=r",errret);break; \
400 case 4: __get_user_asm(x,ptr,retval,"l","","=r",errret);break; \
401 default: (x) = __get_user_bad(); \
405 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \
406 __asm__ __volatile__( \
407 "1: mov"itype" %2,%"rtype"1\n" \
409 ".section .fixup,\"ax\"\n" \
411 " xor"itype" %"rtype"1,%"rtype"1\n" \
414 ".section __ex_table,\"a\"\n" \
418 : "=r"(err), ltype (x) \
419 : "m"(__m(addr)), "i"(errret), "0"(err))
422 unsigned long __must_check __copy_to_user_ll(void __user *to, const void *from, unsigned long n);
423 unsigned long __must_check __copy_from_user_ll(void *to, const void __user *from, unsigned long n);
426 * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault
427 * we return the initial request size (1, 2 or 4), as copy_*_user should do.
428 * If a store crosses a page boundary and gets a fault, the x86 will not write
429 * anything, so this is accurate.
433 * __copy_to_user: - Copy a block of data into user space, with less checking.
434 * @to: Destination address, in user space.
435 * @from: Source address, in kernel space.
436 * @n: Number of bytes to copy.
438 * Context: User context only. This function may sleep.
440 * Copy data from kernel space to user space. Caller must check
441 * the specified block with access_ok() before calling this function.
443 * Returns number of bytes that could not be copied.
444 * On success, this will be zero.
446 static inline unsigned long __must_check
447 __direct_copy_to_user(void __user *to, const void *from, unsigned long n)
449 if (__builtin_constant_p(n)) {
454 __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret, 1);
457 __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret, 2);
460 __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret, 4);
464 return __copy_to_user_ll(to, from, n);
468 * __copy_from_user: - Copy a block of data from user space, with less checking.
469 * @to: Destination address, in kernel space.
470 * @from: Source address, in user space.
471 * @n: Number of bytes to copy.
473 * Context: User context only. This function may sleep.
475 * Copy data from user space to kernel space. Caller must check
476 * the specified block with access_ok() before calling this function.
478 * Returns number of bytes that could not be copied.
479 * On success, this will be zero.
481 * If some data could not be copied, this function will pad the copied
482 * data to the requested size using zero bytes.
484 static inline unsigned long __must_check
485 __direct_copy_from_user(void *to, const void __user *from, unsigned long n)
487 if (__builtin_constant_p(n)) {
492 __get_user_size(*(u8 *)to, from, 1, ret, 1);
495 __get_user_size(*(u16 *)to, from, 2, ret, 2);
498 __get_user_size(*(u32 *)to, from, 4, ret, 4);
502 return __copy_from_user_ll(to, from, n);
506 * copy_to_user: - Copy a block of data into user space.
507 * @to: Destination address, in user space.
508 * @from: Source address, in kernel space.
509 * @n: Number of bytes to copy.
511 * Context: User context only. This function may sleep.
513 * Copy data from kernel space to user space.
515 * Returns number of bytes that could not be copied.
516 * On success, this will be zero.
518 static inline unsigned long __must_check
519 direct_copy_to_user(void __user *to, const void *from, unsigned long n)
522 if (access_ok(VERIFY_WRITE, to, n))
523 n = __direct_copy_to_user(to, from, n);
528 * copy_from_user: - Copy a block of data from user space.
529 * @to: Destination address, in kernel space.
530 * @from: Source address, in user space.
531 * @n: Number of bytes to copy.
533 * Context: User context only. This function may sleep.
535 * Copy data from user space to kernel space.
537 * Returns number of bytes that could not be copied.
538 * On success, this will be zero.
540 * If some data could not be copied, this function will pad the copied
541 * data to the requested size using zero bytes.
543 static inline unsigned long __must_check
544 direct_copy_from_user(void *to, const void __user *from, unsigned long n)
547 if (access_ok(VERIFY_READ, from, n))
548 n = __direct_copy_from_user(to, from, n);
554 long strncpy_from_user(char *dst, const char __user *src, long count);
555 long __strncpy_from_user(char *dst, const char __user *src, long count);
558 * strlen_user: - Get the size of a string in user space.
559 * @str: The string to measure.
561 * Context: User context only. This function may sleep.
563 * Get the size of a NUL-terminated string in user space.
565 * Returns the size of the string INCLUDING the terminating NUL.
566 * On exception, returns 0.
568 * If there is a limit on the length of a valid string, you may wish to
569 * consider using strnlen_user() instead.
572 long direct_strncpy_from_user(char *dst, const char *src, long count);
573 long __direct_strncpy_from_user(char *dst, const char *src, long count);
574 #define direct_strlen_user(str) direct_strnlen_user(str, ~0UL >> 1)
575 long direct_strnlen_user(const char *str, long n);
576 unsigned long direct_clear_user(void *mem, unsigned long len);
577 unsigned long __direct_clear_user(void *mem, unsigned long len);
579 extern int indirect_uaccess;
581 #ifdef CONFIG_X86_UACCESS_INDIRECT
584 * Return code and zeroing semantics:
586 __clear_user 0 <-> bytes not done
587 clear_user 0 <-> bytes not done
588 __copy_to_user 0 <-> bytes not done
589 copy_to_user 0 <-> bytes not done
590 __copy_from_user 0 <-> bytes not done, zero rest
591 copy_from_user 0 <-> bytes not done, zero rest
592 __get_user 0 <-> -EFAULT
593 get_user 0 <-> -EFAULT
594 __put_user 0 <-> -EFAULT
595 put_user 0 <-> -EFAULT
596 strlen_user strlen + 1 <-> 0
597 strnlen_user strlen + 1 (or n+1) <-> 0
598 strncpy_from_user strlen (or n) <-> -EFAULT
602 #define __clear_user(mem,len) __indirect_clear_user(mem,len)
603 #define clear_user(mem,len) indirect_clear_user(mem,len)
604 #define __copy_to_user(to,from,n) __indirect_copy_to_user(to,from,n)
605 #define copy_to_user(to,from,n) indirect_copy_to_user(to,from,n)
606 #define __copy_from_user(to,from,n) __indirect_copy_from_user(to,from,n)
607 #define copy_from_user(to,from,n) indirect_copy_from_user(to,from,n)
608 #define __get_user(val,ptr) __indirect_get_user(val,ptr)
609 #define get_user(val,ptr) indirect_get_user(val,ptr)
610 #define __put_user(val,ptr) __indirect_put_user(val,ptr)
611 #define put_user(val,ptr) indirect_put_user(val,ptr)
612 #define strlen_user(str) indirect_strlen_user(str)
613 #define strnlen_user(src,count) indirect_strnlen_user(src,count)
614 #define strncpy_from_user(dst,src,count) \
615 indirect_strncpy_from_user(dst,src,count)
619 #define __clear_user __direct_clear_user
620 #define clear_user direct_clear_user
621 #define __copy_to_user __direct_copy_to_user
622 #define copy_to_user direct_copy_to_user
623 #define __copy_from_user __direct_copy_from_user
624 #define copy_from_user direct_copy_from_user
625 #define __get_user __direct_get_user
626 #define get_user direct_get_user
627 #define __put_user __direct_put_user
628 #define put_user direct_put_user
629 #define strlen_user direct_strlen_user
630 #define strnlen_user direct_strnlen_user
631 #define strncpy_from_user direct_strncpy_from_user
633 #endif /* CONFIG_X86_UACCESS_INDIRECT */
635 #endif /* __i386_UACCESS_H */