1#ifndef __M68KNOMMU_UACCESS_H
2#define __M68KNOMMU_UACCESS_H
3
4/*
5 * User space memory access functions
6 */
7#include <linux/sched.h>
8#include <linux/mm.h>
9#include <linux/string.h>
10
11#include <asm/segment.h>
12
13#define VERIFY_READ	0
14#define VERIFY_WRITE	1
15
16#define access_ok(type,addr,size)	_access_ok((unsigned long)(addr),(size))
17
18/*
19 * It is not enough to just have access_ok check for a real RAM address.
20 * This would disallow the case of code/ro-data running XIP in flash/rom.
21 * Ideally we would check the possible flash ranges too, but that is
22 * currently not so easy.
23 */
24static inline int _access_ok(unsigned long addr, unsigned long size)
25{
26	return 1;
27}
28
29/*
30 * The exception table consists of pairs of addresses: the first is the
31 * address of an instruction that is allowed to fault, and the second is
32 * the address at which the program should continue.  No registers are
33 * modified, so it is entirely up to the continuation code to figure out
34 * what to do.
35 *
36 * All the routines below use bits of fixup code that are out of line
37 * with the main instruction path.  This means when everything is well,
38 * we don't even have to jump over them.  Further, they do not intrude
39 * on our cache or tlb entries.
40 */
41
42struct exception_table_entry
43{
44	unsigned long insn, fixup;
45};
46
47/* Returns 0 if exception not found and fixup otherwise.  */
48extern unsigned long search_exception_table(unsigned long);
49
50
51/*
52 * These are the main single-value transfer routines.  They automatically
53 * use the right size if we just have the right pointer type.
54 */
55
56#define put_user(x, ptr)				\
57({							\
58    int __pu_err = 0;					\
59    typeof(*(ptr)) __pu_val = (x);			\
60    switch (sizeof (*(ptr))) {				\
61    case 1:						\
62	__put_user_asm(__pu_err, __pu_val, ptr, b);	\
63	break;						\
64    case 2:						\
65	__put_user_asm(__pu_err, __pu_val, ptr, w);	\
66	break;						\
67    case 4:						\
68	__put_user_asm(__pu_err, __pu_val, ptr, l);	\
69	break;						\
70    case 8:						\
71	memcpy(ptr, &__pu_val, sizeof (*(ptr))); \
72	break;						\
73    default:						\
74	__pu_err = __put_user_bad();			\
75	break;						\
76    }							\
77    __pu_err;						\
78})
79#define __put_user(x, ptr) put_user(x, ptr)
80
81extern int __put_user_bad(void);
82
83/*
84 * Tell gcc we read from memory instead of writing: this is because
85 * we do not write to any memory gcc knows about, so there are no
86 * aliasing issues.
87 */
88
89#define __ptr(x) ((unsigned long *)(x))
90
91#define __put_user_asm(err,x,ptr,bwl)				\
92	__asm__ ("move" #bwl " %0,%1"				\
93		: /* no outputs */						\
94		:"d" (x),"m" (*__ptr(ptr)) : "memory")
95
96#define get_user(x, ptr)					\
97({								\
98    int __gu_err = 0;						\
99    typeof(x) __gu_val = 0;					\
100    switch (sizeof(*(ptr))) {					\
101    case 1:							\
102	__get_user_asm(__gu_err, __gu_val, ptr, b, "=d");	\
103	break;							\
104    case 2:							\
105	__get_user_asm(__gu_err, __gu_val, ptr, w, "=r");	\
106	break;							\
107    case 4:							\
108	__get_user_asm(__gu_err, __gu_val, ptr, l, "=r");	\
109	break;							\
110    case 8:							\
111	memcpy((void *) &__gu_val, ptr, sizeof (*(ptr)));	\
112	break;							\
113    default:							\
114	__gu_val = 0;						\
115	__gu_err = __get_user_bad();				\
116	break;							\
117    }								\
118    (x) = (typeof(*(ptr))) __gu_val;				\
119    __gu_err;							\
120})
121#define __get_user(x, ptr) get_user(x, ptr)
122
123extern int __get_user_bad(void);
124
125#define __get_user_asm(err,x,ptr,bwl,reg)			\
126	__asm__ ("move" #bwl " %1,%0"				\
127		 : "=d" (x)					\
128		 : "m" (*__ptr(ptr)))
129
130#define copy_from_user(to, from, n)		(memcpy(to, from, n), 0)
131#define copy_to_user(to, from, n)		(memcpy(to, from, n), 0)
132
133#define __copy_from_user(to, from, n) copy_from_user(to, from, n)
134#define __copy_to_user(to, from, n) copy_to_user(to, from, n)
135#define __copy_to_user_inatomic __copy_to_user
136#define __copy_from_user_inatomic __copy_from_user
137
138#define copy_to_user_ret(to,from,n,retval) ({ if (copy_to_user(to,from,n)) return retval; })
139
140#define copy_from_user_ret(to,from,n,retval) ({ if (copy_from_user(to,from,n)) return retval; })
141
142/*
143 * Copy a null terminated string from userspace.
144 */
145
146static inline long
147strncpy_from_user(char *dst, const char *src, long count)
148{
149	char *tmp;
150	strncpy(dst, src, count);
151	for (tmp = dst; *tmp && count > 0; tmp++, count--)
152		;
153	return(tmp - dst); /* DAVIDM should we count a NUL ?  check getname */
154}
155
156/*
157 * Return the size of a string (including the ending 0)
158 *
159 * Return 0 on exception, a value greater than N if too long
160 */
161static inline long strnlen_user(const char *src, long n)
162{
163	return(strlen(src) + 1); /* DAVIDM make safer */
164}
165
166#define strlen_user(str) strnlen_user(str, 32767)
167
168/*
169 * Zero Userspace
170 */
171
172static inline unsigned long
173__clear_user(void *to, unsigned long n)
174{
175	memset(to, 0, n);
176	return 0;
177}
178
179#define	clear_user(to,n)	__clear_user(to,n)
180
181#endif /* _M68KNOMMU_UACCESS_H */
182