1 /* $Id: uaccess.h,v 1.11 2003/10/13 07:21:20 lethal Exp $
3 * User space memory access functions
5 * Copyright (C) 1999, 2002 Niibe Yutaka
6 * Copyright (C) 2003 Paul Mundt
9 * MIPS implementation version 1.15 by
10 * Copyright (C) 1996, 1997, 1998 by Ralf Baechle
13 #ifndef __ASM_SH_UACCESS_H
14 #define __ASM_SH_UACCESS_H
16 #include <linux/errno.h>
17 #include <linux/sched.h>
20 #define VERIFY_WRITE 1
23 * The fs value determines whether argument validity checking should be
24 * performed or not. If get_fs() == USER_DS, checking is performed, with
25 * get_fs() == KERNEL_DS, checking is bypassed.
27 * For historical reasons (Data Segment Register?), these macros are misnamed.
30 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
32 #define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFUL)
33 #define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
35 #define segment_eq(a,b) ((a).seg == (b).seg)
37 #define get_ds() (KERNEL_DS)
39 #if !defined(CONFIG_MMU)
40 /* NOMMU is always true */
41 #define __addr_ok(addr) (1)
43 static inline mm_segment_t get_fs(void)
48 static inline void set_fs(mm_segment_t s)
53 * __access_ok: Check if address with size is OK or not.
55 * If we don't have an MMU (or if its disabled) the only thing we really have
56 * to look out for is if the address resides somewhere outside of what
57 * available RAM we have.
59 * TODO: This check could probably also stand to be restricted somewhat more..
60 * though it still does the Right Thing(tm) for the time being.
62 static inline int __access_ok(unsigned long addr, unsigned long size)
64 return ((addr >= memory_start) && ((addr + size) < memory_end));
66 #else /* CONFIG_MMU */
67 #define __addr_ok(addr) \
68 ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))
70 #define get_fs() (current_thread_info()->addr_limit)
71 #define set_fs(x) (current_thread_info()->addr_limit = (x))
74 * __access_ok: Check if address with size is OK or not.
76 * Uhhuh, this needs 33-bit arithmetic. We have a carry..
78 * sum := addr + size; carry? --> flag = true;
79 * if (sum >= addr_limit) flag = true;
81 static inline int __access_ok(unsigned long addr, unsigned long size)
83 unsigned long flag, sum;
90 :"=&r" (flag), "=r" (sum)
91 :"1" (addr), "r" (size),
92 "r" (current_thread_info()->addr_limit.seg)
96 #endif /* CONFIG_MMU */
98 static inline int access_ok(int type, const void __user *p, unsigned long size)
100 unsigned long addr = (unsigned long)p;
101 return __access_ok(addr, size);
105 * Uh, these should become the main single-value transfer routines ...
106 * They automatically use the right size if we just have the right
109 * As SuperH uses the same address space for kernel and user data, we
110 * can just do these as direct assignments.
113 * (a) re-use the arguments for side effects (sizeof is ok)
114 * (b) require any knowledge of processes at this stage
116 #define put_user(x,ptr) __put_user_check((x),(ptr),sizeof(*(ptr)))
117 #define get_user(x,ptr) __get_user_check((x),(ptr),sizeof(*(ptr)))
120 * The "__xxx" versions do not do address space checking, useful when
121 * doing multiple accesses to the same area (the user has to do the
122 * checks by hand with "access_ok()")
124 #define __put_user(x,ptr) \
125 __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
126 #define __get_user(x,ptr) \
127 __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
129 struct __large_struct { unsigned long buf[100]; };
130 #define __m(x) (*(struct __large_struct __user *)(x))
132 #define __get_user_size(x,ptr,size,retval) \
135 __chk_user_ptr(ptr); \
138 __get_user_asm(x, ptr, retval, "b"); \
141 __get_user_asm(x, ptr, retval, "w"); \
144 __get_user_asm(x, ptr, retval, "l"); \
147 __get_user_unknown(); \
152 #define __get_user_nocheck(x,ptr,size) \
154 long __gu_err, __gu_val; \
155 __typeof__(*(ptr)) *__pu_addr = (ptr); \
156 __get_user_size(__gu_val, (__pu_addr), (size), __gu_err); \
157 (x) = (__typeof__(*(ptr)))__gu_val; \
161 #define __get_user_check(x,ptr,size) \
163 long __gu_err, __gu_val; \
164 __typeof__(*(ptr)) *__pu_addr = (ptr); \
165 __chk_user_ptr(__pu_addr); \
166 if (likely(__addr_ok((unsigned long)(__pu_addr)))) { \
167 __get_user_size(__gu_val, (__pu_addr), (size), __gu_err);\
169 __gu_err = -EFAULT; \
172 (x) = (__typeof__(*(ptr)))__gu_val; \
176 #define __get_user_asm(x, addr, err, insn) \
178 __asm__ __volatile__( \
180 "mov." insn " %2, %1\n\t" \
182 ".section .fixup,\"ax\"\n" \
191 ".section __ex_table,\"a\"\n\t" \
194 :"=&r" (err), "=&r" (x) \
195 :"m" (__m(addr)), "i" (-EFAULT), "0" (err)); })
197 extern void __get_user_unknown(void);
199 #define __put_user_size(x,ptr,size,retval) \
202 __chk_user_ptr(ptr); \
205 __put_user_asm(x, ptr, retval, "b"); \
208 __put_user_asm(x, ptr, retval, "w"); \
211 __put_user_asm(x, ptr, retval, "l"); \
214 __put_user_u64(x, ptr, retval); \
217 __put_user_unknown(); \
221 #define __put_user_nocheck(x,ptr,size) \
224 __put_user_size((x),(ptr),(size),__pu_err); \
228 #define __put_user_check(x,ptr,size) \
231 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
233 if (likely(__addr_ok((unsigned long)__pu_addr))) \
234 __put_user_size((x),__pu_addr,(size),__pu_err); \
236 __pu_err = -EFAULT; \
240 #define __put_user_asm(x, addr, err, insn) \
242 __asm__ __volatile__( \
244 "mov." insn " %1, %2\n\t" \
246 ".section .fixup,\"ax\"\n" \
254 ".section __ex_table,\"a\"\n\t" \
258 :"r" (x), "m" (__m(addr)), "i" (-EFAULT), "0" (err) \
261 #if defined(CONFIG_CPU_LITTLE_ENDIAN)
262 #define __put_user_u64(val,addr,retval) \
264 __asm__ __volatile__( \
267 "mov.l %S1,%T2\n\t" \
269 ".section .fixup,\"ax\"\n" \
277 ".section __ex_table,\"a\"\n\t" \
281 : "r" (val), "m" (__m(addr)), "i" (-EFAULT), "0" (retval) \
284 #define __put_user_u64(val,addr,retval) \
286 __asm__ __volatile__( \
289 "mov.l %R1,%T2\n\t" \
291 ".section .fixup,\"ax\"\n" \
299 ".section __ex_table,\"a\"\n\t" \
303 : "r" (val), "m" (__m(addr)), "i" (-EFAULT), "0" (retval) \
307 extern void __put_user_unknown(void);
309 /* Generic arbitrary sized copy. */
310 /* Return the number of bytes NOT copied */
311 __kernel_size_t __copy_user(void *to, const void *from, __kernel_size_t n);
313 #define copy_to_user(to,from,n) ({ \
314 void *__copy_to = (void *) (to); \
315 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
316 __kernel_size_t __copy_res; \
317 if(__copy_size && __access_ok((unsigned long)__copy_to, __copy_size)) { \
318 __copy_res = __copy_user(__copy_to, (void *) (from), __copy_size); \
319 } else __copy_res = __copy_size; \
322 #define copy_from_user(to,from,n) ({ \
323 void *__copy_to = (void *) (to); \
324 void *__copy_from = (void *) (from); \
325 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
326 __kernel_size_t __copy_res; \
327 if(__copy_size && __access_ok((unsigned long)__copy_from, __copy_size)) { \
328 __copy_res = __copy_user(__copy_to, __copy_from, __copy_size); \
329 } else __copy_res = __copy_size; \
332 static __always_inline unsigned long
333 __copy_from_user(void *to, const void __user *from, unsigned long n)
335 return __copy_user(to, (__force void *)from, n);
338 static __always_inline unsigned long __must_check
339 __copy_to_user(void __user *to, const void *from, unsigned long n)
341 return __copy_user((__force void *)to, from, n);
344 #define __copy_to_user_inatomic __copy_to_user
345 #define __copy_from_user_inatomic __copy_from_user
348 * Clear the area and return remaining number of bytes
349 * (on failure. Usually it's 0.)
351 extern __kernel_size_t __clear_user(void *addr, __kernel_size_t size);
353 #define clear_user(addr,n) ({ \
354 void * __cl_addr = (addr); \
355 unsigned long __cl_size = (n); \
356 if (__cl_size && __access_ok(((unsigned long)(__cl_addr)), __cl_size)) \
357 __cl_size = __clear_user(__cl_addr, __cl_size); \
360 static __inline__ int
361 __strncpy_from_user(unsigned long __dest, unsigned long __user __src, int __count)
364 unsigned long __dummy, _d, _s, _c;
366 __asm__ __volatile__(
379 ".section .fixup,\"ax\"\n"
387 ".section __ex_table,\"a\"\n"
391 : "=r" (res), "=&z" (__dummy), "=r" (_s), "=r" (_d), "=r"(_c)
392 : "0" (__count), "2" (__src), "3" (__dest), "4" (__count),
400 * strncpy_from_user: - Copy a NUL terminated string from userspace.
401 * @dst: Destination address, in kernel space. This buffer must be at
402 * least @count bytes long.
403 * @src: Source address, in user space.
404 * @count: Maximum number of bytes to copy, including the trailing NUL.
406 * Copies a NUL-terminated string from userspace to kernel space.
408 * On success, returns the length of the string (not including the trailing
411 * If access to userspace fails, returns -EFAULT (some data may have been
414 * If @count is smaller than the length of the string, copies @count bytes
415 * and returns @count.
417 #define strncpy_from_user(dest,src,count) ({ \
418 unsigned long __sfu_src = (unsigned long) (src); \
419 int __sfu_count = (int) (count); \
420 long __sfu_res = -EFAULT; \
421 if(__access_ok(__sfu_src, __sfu_count)) { \
422 __sfu_res = __strncpy_from_user((unsigned long) (dest), __sfu_src, __sfu_count); \
426 * Return the size of a string (including the ending 0 even when we have
427 * exceeded the maximum string length).
429 static __inline__ long __strnlen_user(const char __user *__s, long __n)
432 unsigned long __dummy;
434 __asm__ __volatile__(
436 "mov.b @(%0,%3), %1\n\t"
443 ".section .fixup,\"ax\"\n"
451 ".section __ex_table,\"a\"\n"
455 : "=z" (res), "=&r" (__dummy)
456 : "0" (0), "r" (__s), "r" (__n)
462 * strnlen_user: - Get the size of a string in user space.
463 * @s: The string to measure.
464 * @n: The maximum valid length
466 * Context: User context only. This function may sleep.
468 * Get the size of a NUL-terminated string in user space.
470 * Returns the size of the string INCLUDING the terminating NUL.
471 * On exception, returns 0.
472 * If the string is too long, returns a value greater than @n.
474 static __inline__ long strnlen_user(const char __user *s, long n)
479 return __strnlen_user(s, n);
483 * strlen_user: - Get the size of a string in user space.
484 * @str: The string to measure.
486 * Context: User context only. This function may sleep.
488 * Get the size of a NUL-terminated string in user space.
490 * Returns the size of the string INCLUDING the terminating NUL.
491 * On exception, returns 0.
493 * If there is a limit on the length of a valid string, you may wish to
494 * consider using strnlen_user() instead.
496 #define strlen_user(str) strnlen_user(str, ~0UL >> 1)
499 * The exception table consists of pairs of addresses: the first is the
500 * address of an instruction that is allowed to fault, and the second is
501 * the address at which the program should continue. No registers are
502 * modified, so it is entirely up to the continuation code to figure out
505 * All the routines below use bits of fixup code that are out of line
506 * with the main instruction path. This means when everything is well,
507 * we don't even have to jump over them. Further, they do not intrude
508 * on our cache or tlb entries.
511 struct exception_table_entry
513 unsigned long insn, fixup;
516 extern int fixup_exception(struct pt_regs *regs);
518 #endif /* __ASM_SH_UACCESS_H */