1 /* uaccess.h: userspace accessor functions
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #ifndef _ASM_UACCESS_H
13 #define _ASM_UACCESS_H
16 * User space memory access functions
18 #include <linux/sched.h>
20 #include <asm/segment.h>
21 #include <asm/sections.h>
23 #define __ptr(x) ((unsigned long __force *)(x))
26 #define VERIFY_WRITE 1
29 * check that a range of addresses falls within the current address limit
31 static inline int ___range_ok(unsigned long addr, unsigned long size)
34 int flag = -EFAULT, tmp;
37 " addcc %3,%2,%1,icc0 \n" /* set C-flag if addr+size>4GB */
38 " subcc.p %1,%4,gr0,icc1 \n" /* jump if addr+size>limit */
41 " setlos #0,%0 \n" /* mark okay */
43 : "=r"(flag), "=&r"(tmp)
44 : "r"(addr), "r"(size), "r"(get_addr_limit()), "0"(flag)
51 if (addr < memory_start ||
53 size > memory_end - memory_start ||
54 addr + size > memory_end)
61 #define __range_ok(addr,size) ___range_ok((unsigned long) (addr), (unsigned long) (size))
63 #define access_ok(type,addr,size) (__range_ok((void __user *)(addr), (size)) == 0)
64 #define __access_ok(addr,size) (__range_ok((addr), (size)) == 0)
67 * The exception table consists of pairs of addresses: the first is the
68 * address of an instruction that is allowed to fault, and the second is
69 * the address at which the program should continue. No registers are
70 * modified, so it is entirely up to the continuation code to figure out
73 * All the routines below use bits of fixup code that are out of line
74 * with the main instruction path. This means when everything is well,
75 * we don't even have to jump over them. Further, they do not intrude
76 * on our cache or tlb entries.
78 struct exception_table_entry
80 unsigned long insn, fixup;
83 /* Returns 0 if exception not found and fixup otherwise. */
84 extern unsigned long search_exception_table(unsigned long);
88 * These are the main single-value transfer routines. They automatically
89 * use the right size if we just have the right pointer type.
91 #define __put_user(x, ptr) \
95 typeof(*(ptr)) __pu_val = (x); \
96 __chk_user_ptr(ptr); \
98 switch (sizeof (*(ptr))) { \
100 __put_user_asm(__pu_err, __pu_val, ptr, "b", "r"); \
103 __put_user_asm(__pu_err, __pu_val, ptr, "h", "r"); \
106 __put_user_asm(__pu_err, __pu_val, ptr, "", "r"); \
109 __put_user_asm(__pu_err, __pu_val, ptr, "d", "e"); \
112 __pu_err = __put_user_bad(); \
118 #define put_user(x, ptr) \
120 typeof(*(ptr)) __user *_p = (ptr); \
123 _e = __range_ok(_p, sizeof(*_p)); \
125 _e = __put_user((x), _p); \
129 extern int __put_user_bad(void);
132 * Tell gcc we read from memory instead of writing: this is because
133 * we do not write to any memory gcc knows about, so there are no
139 #define __put_user_asm(err,x,ptr,dsize,constraint) \
141 asm volatile("1: st"dsize"%I1 %2,%M1 \n" \
144 "3: setlos %3,%0 \n" \
147 ".section __ex_table,\"a\" \n" \
152 : "m" (*__ptr(ptr)), constraint (x), "i"(-EFAULT), "0"(err) \
158 #define __put_user_asm(err,x,ptr,bwl,con) \
160 asm(" st"bwl"%I0 %1,%M0 \n" \
163 : "m" (*__ptr(ptr)), con (x) \
169 /*****************************************************************************/
173 #define __get_user(x, ptr) \
176 __chk_user_ptr(ptr); \
178 switch (sizeof(*(ptr))) { \
180 unsigned char __gu_val; \
181 __get_user_asm(__gu_err, __gu_val, ptr, "ub", "=r"); \
182 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
186 unsigned short __gu_val; \
187 __get_user_asm(__gu_err, __gu_val, ptr, "uh", "=r"); \
188 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
192 unsigned int __gu_val; \
193 __get_user_asm(__gu_err, __gu_val, ptr, "", "=r"); \
194 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
198 unsigned long long __gu_val; \
199 __get_user_asm(__gu_err, __gu_val, ptr, "d", "=e"); \
200 (x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
204 __gu_err = __get_user_bad(); \
210 #define get_user(x, ptr) \
212 const typeof(*(ptr)) __user *_p = (ptr);\
215 _e = __range_ok(_p, sizeof(*_p)); \
216 if (likely(_e == 0)) \
217 _e = __get_user((x), _p); \
219 (x) = (typeof(x)) 0; \
223 extern int __get_user_bad(void);
227 #define __get_user_asm(err,x,ptr,dtype,constraint) \
229 asm("1: ld"dtype"%I2 %M2,%1 \n" \
232 "3: setlos %3,%0 \n" \
236 ".section __ex_table,\"a\" \n" \
240 : "=r" (err), constraint (x) \
241 : "m" (*__ptr(ptr)), "i"(-EFAULT), "0"(err) \
247 #define __get_user_asm(err,x,ptr,bwl,con) \
248 asm(" ld"bwl"%I1 %M1,%0 \n" \
255 /*****************************************************************************/
259 #define ____force(x) (__force void *)(void __user *)(x)
261 extern long __memset_user(void *dst, unsigned long count);
262 extern long __memcpy_user(void *dst, const void *src, unsigned long count);
264 #define __clear_user(dst,count) __memset_user(____force(dst), (count))
265 #define __copy_from_user_inatomic(to, from, n) __memcpy_user((to), ____force(from), (n))
266 #define __copy_to_user_inatomic(to, from, n) __memcpy_user(____force(to), (from), (n))
270 #define __clear_user(dst,count) (memset(____force(dst), 0, (count)), 0)
271 #define __copy_from_user_inatomic(to, from, n) (memcpy((to), ____force(from), (n)), 0)
272 #define __copy_to_user_inatomic(to, from, n) (memcpy(____force(to), (from), (n)), 0)
276 static inline unsigned long __must_check
277 clear_user(void __user *to, unsigned long n)
279 if (likely(__access_ok(to, n)))
280 n = __clear_user(to, n);
284 static inline unsigned long __must_check
285 __copy_to_user(void __user *to, const void *from, unsigned long n)
288 return __copy_to_user_inatomic(to, from, n);
291 static inline unsigned long
292 __copy_from_user(void *to, const void __user *from, unsigned long n)
295 return __copy_from_user_inatomic(to, from, n);
298 static inline long copy_from_user(void *to, const void __user *from, unsigned long n)
300 unsigned long ret = n;
302 if (likely(__access_ok(from, n)))
303 ret = __copy_from_user(to, from, n);
305 if (unlikely(ret != 0))
306 memset(to + (n - ret), 0, ret);
311 static inline long copy_to_user(void __user *to, const void *from, unsigned long n)
313 return likely(__access_ok(to, n)) ? __copy_to_user(to, from, n) : n;
316 extern long strncpy_from_user(char *dst, const char __user *src, long count);
317 extern long strnlen_user(const char __user *src, long count);
319 #define strlen_user(str) strnlen_user(str, 32767)
321 extern unsigned long search_exception_table(unsigned long addr);
323 #endif /* _ASM_UACCESS_H */