aboutsummaryrefslogtreecommitdiffstats
path: root/arch/m68knommu/include/asm/uaccess.h
blob: 68bbe9b312f149e5286068a90bbe59310176747b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
#ifndef __M68KNOMMU_UACCESS_H
#define __M68KNOMMU_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/string.h>

#include <asm/segment.h>

#define VERIFY_READ	0
#define VERIFY_WRITE	1

#define access_ok(type,addr,size)	_access_ok((unsigned long)(addr),(size))

/*
 * It is not enough to just have access_ok check for a real RAM address.
 * This would disallow the case of code/ro-data running XIP in flash/rom.
 * Ideally we would check the possible flash ranges too, but that is
 * currently not so easy.
 */
static inline int _access_ok(unsigned long addr, unsigned long size)
{
	return 1;
}

/*
 * The exception table consists of pairs of addresses: the first is the
 * address of an instruction that is allowed to fault, and the second is
 * the address at which the program should continue.  No registers are
 * modified, so it is entirely up to the continuation code to figure out
 * what to do.
 *
 * All the routines below use bits of fixup code that are out of line
 * with the main instruction path.  This means when everything is well,
 * we don't even have to jump over them.  Further, they do not intrude
 * on our cache or tlb entries.
 */

struct exception_table_entry
{
	unsigned long insn, fixup;
};

/* Returns 0 if exception not found and fixup otherwise.  */
extern unsigned long search_exception_table(unsigned long);


/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 */

#define put_user(x, ptr)				\
({							\
    int __pu_err = 0;					\
    typeof(*(ptr)) __pu_val = (x);			\
    switch (sizeof (*(ptr))) {				\
    case 1:						\
	__put_user_asm(__pu_err, __pu_val, ptr, b);	\
	break;						\
    case 2:						\
	__put_user_asm(__pu_err, __pu_val, ptr, w);	\
	break;						\
    case 4:						\
	__put_user_asm(__pu_err, __pu_val, ptr, l);	\
	break;						\
    case 8:						\
	memcpy(ptr, &__pu_val, sizeof (*(ptr))); \
	break;						\
    default:						\
	__pu_err = __put_user_bad();			\
	break;						\
    }							\
    __pu_err;						\
})
#define __put_user(x, ptr) put_user(x, ptr)

extern int __put_user_bad(void);

/*
 * Tell gcc we read from memory instead of writing: this is because
 * we do not write to any memory gcc knows about, so there are no
 * aliasing issues.
 */

#define __ptr(x) ((unsigned long *)(x))

#define __put_user_asm(err,x,ptr,bwl)				\
	__asm__ ("move" #bwl " %0,%1"				\
		: /* no outputs */						\
		:"d" (x),"m" (*__ptr(ptr)) : "memory")

#define get_user(x, ptr)					\
({								\
    int __gu_err = 0;						\
    typeof(x) __gu_val = 0;					\
    switch (sizeof(*(ptr))) {					\
    case 1:							\
	__get_user_asm(__gu_err, __gu_val, ptr, b, "=d");	\
	break;							\
    case 2:							\
	__get_user_asm(__gu_err, __gu_val, ptr, w, "=r");	\
	break;							\
    case 4:							\
	__get_user_asm(__gu_err, __gu_val, ptr, l, "=r");	\
	break;							\
    case 8:							\
	memcpy((void *) &__gu_val, ptr, sizeof (*(ptr)));	\
	break;							\
    default:							\
	__gu_val = 0;						\
	__gu_err = __get_user_bad();				\
	break;							\
    }								\
    (x) = (typeof(*(ptr))) __gu_val;				\
    __gu_err;							\
})
#define __get_user(x, ptr) get_user(x, ptr)

extern int __get_user_bad(void);

#define __get_user_asm(err,x,ptr,bwl,reg)			\
	__asm__ ("move" #bwl " %1,%0"				\
		 : "=d" (x)					\
		 : "m" (*__ptr(ptr)))

#define copy_from_user(to, from, n)		(memcpy(to, from, n), 0)
#define copy_to_user(to, from, n)		(memcpy(to, from, n), 0)

#define __copy_from_user(to, from, n) copy_from_user(to, from, n)
#define __copy_to_user(to, from, n) copy_to_user(to, from, n)
#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user

#define copy_to_user_ret(to,from,n,retval) ({ if (copy_to_user(to,from,n)) return retval; })

#define copy_from_user_ret(to,from,n,retval) ({ if (copy_from_user(to,from,n)) return retval; })

/*
 * Copy a null terminated string from userspace.
 */

static inline long
strncpy_from_user(char *dst, const char *src, long count)
{
	char *tmp;
	strncpy(dst, src, count);
	for (tmp = dst; *tmp && count > 0; tmp++, count--)
		;
	return(tmp - dst); /* DAVIDM should we count a NUL ?  check getname */
}

/*
 * Return the size of a string (including the ending 0)
 *
 * Return 0 on exception, a value greater than N if too long
 */
static inline long strnlen_user(const char *src, long n)
{
	return(strlen(src) + 1); /* DAVIDM make safer */
}

#define strlen_user(str) strnlen_user(str, 32767)

/*
 * Zero Userspace
 */

static inline unsigned long
__clear_user(void *to, unsigned long n)
{
	memset(to, 0, n);
	return 0;
}

#define	clear_user(to,n)	__clear_user(to,n)

#endif /* _M68KNOMMU_UACCESS_H */