1#ifndef __METAG_UACCESS_H
2#define __METAG_UACCESS_H
3
4/*
5 * User space memory access functions
6 */
7#include <linux/sched.h>
8
9#define VERIFY_READ	0
10#define VERIFY_WRITE	1
11
12/*
13 * The fs value determines whether argument validity checking should be
14 * performed or not.  If get_fs() == USER_DS, checking is performed, with
15 * get_fs() == KERNEL_DS, checking is bypassed.
16 *
17 * For historical reasons, these macros are grossly misnamed.
18 */
19
20#define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
21
22#define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
23#define USER_DS		MAKE_MM_SEG(PAGE_OFFSET)
24
25#define get_ds()	(KERNEL_DS)
26#define get_fs()        (current_thread_info()->addr_limit)
27#define set_fs(x)       (current_thread_info()->addr_limit = (x))
28
29#define segment_eq(a, b)	((a).seg == (b).seg)
30
31#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
32/*
33 * Explicitly allow NULL pointers here. Parts of the kernel such
34 * as readv/writev use access_ok to validate pointers, but want
35 * to allow NULL pointers for various reasons. NULL pointers are
36 * safe to allow through because the first page is not mappable on
37 * Meta.
38 *
39 * We also wish to avoid letting user code access the system area
40 * and the kernel half of the address space.
41 */
42#define __user_bad(addr, size) (((addr) > 0 && (addr) < META_MEMORY_BASE) || \
43				((addr) > PAGE_OFFSET &&		\
44				 (addr) < LINCORE_BASE))
45
46static inline int __access_ok(unsigned long addr, unsigned long size)
47{
48	return __kernel_ok || !__user_bad(addr, size);
49}
50
51#define access_ok(type, addr, size) __access_ok((unsigned long)(addr),	\
52						(unsigned long)(size))
53
54static inline int verify_area(int type, const void *addr, unsigned long size)
55{
56	return access_ok(type, addr, size) ? 0 : -EFAULT;
57}
58
59/*
60 * The exception table consists of pairs of addresses: the first is the
61 * address of an instruction that is allowed to fault, and the second is
62 * the address at which the program should continue.  No registers are
63 * modified, so it is entirely up to the continuation code to figure out
64 * what to do.
65 *
66 * All the routines below use bits of fixup code that are out of line
67 * with the main instruction path.  This means when everything is well,
68 * we don't even have to jump over them.  Further, they do not intrude
69 * on our cache or tlb entries.
70 */
71struct exception_table_entry {
72	unsigned long insn, fixup;
73};
74
75extern int fixup_exception(struct pt_regs *regs);
76
77/*
78 * These are the main single-value transfer routines.  They automatically
79 * use the right size if we just have the right pointer type.
80 */
81
82#define put_user(x, ptr) \
83	__put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
84#define __put_user(x, ptr) \
85	__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
86
87extern void __put_user_bad(void);
88
89#define __put_user_nocheck(x, ptr, size)		\
90({                                                      \
91	long __pu_err;                                  \
92	__put_user_size((x), (ptr), (size), __pu_err);	\
93	__pu_err;                                       \
94})
95
96#define __put_user_check(x, ptr, size)				\
97({                                                              \
98	long __pu_err = -EFAULT;                                \
99	__typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
100	if (access_ok(VERIFY_WRITE, __pu_addr, size))		\
101		__put_user_size((x), __pu_addr, (size), __pu_err);	\
102	__pu_err;                                               \
103})
104
105extern long __put_user_asm_b(unsigned int x, void __user *addr);
106extern long __put_user_asm_w(unsigned int x, void __user *addr);
107extern long __put_user_asm_d(unsigned int x, void __user *addr);
108extern long __put_user_asm_l(unsigned long long x, void __user *addr);
109
110#define __put_user_size(x, ptr, size, retval)				\
111do {                                                                    \
112	retval = 0;                                                     \
113	switch (size) {                                                 \
114	case 1:								\
115		retval = __put_user_asm_b((__force unsigned int)x, ptr);\
116		break;							\
117	case 2:								\
118		retval = __put_user_asm_w((__force unsigned int)x, ptr);\
119		break;							\
120	case 4:								\
121		retval = __put_user_asm_d((__force unsigned int)x, ptr);\
122		break;							\
123	case 8:								\
124		retval = __put_user_asm_l((__force unsigned long long)x,\
125					  ptr);				\
126		break;							\
127	default:							\
128		__put_user_bad();					\
129	}								\
130} while (0)
131
132#define get_user(x, ptr) \
133	__get_user_check((x), (ptr), sizeof(*(ptr)))
134#define __get_user(x, ptr) \
135	__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
136
137extern long __get_user_bad(void);
138
139#define __get_user_nocheck(x, ptr, size)			\
140({                                                              \
141	long __gu_err, __gu_val;                                \
142	__get_user_size(__gu_val, (ptr), (size), __gu_err);	\
143	(x) = (__force __typeof__(*(ptr)))__gu_val;             \
144	__gu_err;                                               \
145})
146
147#define __get_user_check(x, ptr, size)					\
148({                                                                      \
149	long __gu_err = -EFAULT, __gu_val = 0;                          \
150	const __typeof__(*(ptr)) __user *__gu_addr = (ptr);		\
151	if (access_ok(VERIFY_READ, __gu_addr, size))			\
152		__get_user_size(__gu_val, __gu_addr, (size), __gu_err);	\
153	(x) = (__force __typeof__(*(ptr)))__gu_val;                     \
154	__gu_err;                                                       \
155})
156
157extern unsigned char __get_user_asm_b(const void __user *addr, long *err);
158extern unsigned short __get_user_asm_w(const void __user *addr, long *err);
159extern unsigned int __get_user_asm_d(const void __user *addr, long *err);
160
161#define __get_user_size(x, ptr, size, retval)			\
162do {                                                            \
163	retval = 0;                                             \
164	switch (size) {                                         \
165	case 1:							\
166		x = __get_user_asm_b(ptr, &retval); break;	\
167	case 2:							\
168		x = __get_user_asm_w(ptr, &retval); break;	\
169	case 4:							\
170		x = __get_user_asm_d(ptr, &retval); break;	\
171	default:						\
172		(x) = __get_user_bad();				\
173	}                                                       \
174} while (0)
175
176/*
177 * Copy a null terminated string from userspace.
178 *
179 * Must return:
180 * -EFAULT		for an exception
181 * count		if we hit the buffer limit
182 * bytes copied		if we hit a null byte
183 * (without the null byte)
184 */
185
186extern long __must_check __strncpy_from_user(char *dst, const char __user *src,
187					     long count);
188
189#define strncpy_from_user(dst, src, count) __strncpy_from_user(dst, src, count)
190
191/*
192 * Return the size of a string (including the ending 0)
193 *
194 * Return 0 on exception, a value greater than N if too long
195 */
196extern long __must_check strnlen_user(const char __user *src, long count);
197
198#define strlen_user(str) strnlen_user(str, 32767)
199
200extern unsigned long __must_check __copy_user_zeroing(void *to,
201						      const void __user *from,
202						      unsigned long n);
203
204static inline unsigned long
205copy_from_user(void *to, const void __user *from, unsigned long n)
206{
207	if (access_ok(VERIFY_READ, from, n))
208		return __copy_user_zeroing(to, from, n);
209	return n;
210}
211
212#define __copy_from_user(to, from, n) __copy_user_zeroing(to, from, n)
213#define __copy_from_user_inatomic __copy_from_user
214
215extern unsigned long __must_check __copy_user(void __user *to,
216					      const void *from,
217					      unsigned long n);
218
219static inline unsigned long copy_to_user(void __user *to, const void *from,
220					 unsigned long n)
221{
222	if (access_ok(VERIFY_WRITE, to, n))
223		return __copy_user(to, from, n);
224	return n;
225}
226
227#define __copy_to_user(to, from, n) __copy_user(to, from, n)
228#define __copy_to_user_inatomic __copy_to_user
229
230/*
231 * Zero Userspace
232 */
233
234extern unsigned long __must_check __do_clear_user(void __user *to,
235						  unsigned long n);
236
237static inline unsigned long clear_user(void __user *to, unsigned long n)
238{
239	if (access_ok(VERIFY_WRITE, to, n))
240		return __do_clear_user(to, n);
241	return n;
242}
243
244#define __clear_user(to, n)            __do_clear_user(to, n)
245
246#endif /* _METAG_UACCESS_H */
247