1/*
2 * User space memory access functions for Nios II
3 *
4 * Copyright (C) 2010-2011, Tobias Klauser <tklauser@distanz.ch>
5 * Copyright (C) 2009, Wind River Systems Inc
6 *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License.  See the file "COPYING" in the main directory of this archive
10 * for more details.
11 */
12
13#ifndef _ASM_NIOS2_UACCESS_H
14#define _ASM_NIOS2_UACCESS_H
15
16#include <linux/string.h>
17
18#include <asm/page.h>
19
20#include <asm/extable.h>
21
22/*
23 * Segment stuff
24 */
25#define MAKE_MM_SEG(s)		((mm_segment_t) { (s) })
26#define USER_DS			MAKE_MM_SEG(0x80000000UL)
27#define KERNEL_DS		MAKE_MM_SEG(0)
28
29
30#define get_fs()		(current_thread_info()->addr_limit)
31#define set_fs(seg)		(current_thread_info()->addr_limit = (seg))
32
33#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
34
35#define __access_ok(addr, len)			\
36	(((signed long)(((long)get_fs().seg) &	\
37		((long)(addr) | (((long)(addr)) + (len)) | (len)))) == 0)
38
39#define access_ok(addr, len)		\
40	likely(__access_ok((unsigned long)(addr), (unsigned long)(len)))
41
42# define __EX_TABLE_SECTION	".section __ex_table,\"a\"\n"
43
44#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE)
45
46/*
47 * Zero Userspace
48 */
49
50static inline unsigned long __must_check __clear_user(void __user *to,
51						      unsigned long n)
52{
53	__asm__ __volatile__ (
54		"1:     stb     zero, 0(%1)\n"
55		"       addi    %0, %0, -1\n"
56		"       addi    %1, %1, 1\n"
57		"       bne     %0, zero, 1b\n"
58		"2:\n"
59		__EX_TABLE_SECTION
60		".word  1b, 2b\n"
61		".previous\n"
62		: "=r" (n), "=r" (to)
63		: "0" (n), "1" (to)
64	);
65
66	return n;
67}
68
69static inline unsigned long __must_check clear_user(void __user *to,
70						    unsigned long n)
71{
72	if (!access_ok(to, n))
73		return n;
74	return __clear_user(to, n);
75}
76
77extern unsigned long
78raw_copy_from_user(void *to, const void __user *from, unsigned long n);
79extern unsigned long
80raw_copy_to_user(void __user *to, const void *from, unsigned long n);
81#define INLINE_COPY_FROM_USER
82#define INLINE_COPY_TO_USER
83
84extern long strncpy_from_user(char *__to, const char __user *__from,
85			      long __len);
86extern __must_check long strlen_user(const char __user *str);
87extern __must_check long strnlen_user(const char __user *s, long n);
88
89/* Optimized macros */
90#define __get_user_asm(val, insn, addr, err)				\
91{									\
92	unsigned long __gu_val;						\
93	__asm__ __volatile__(						\
94	"       movi    %0, %3\n"					\
95	"1:   " insn " %1, 0(%2)\n"					\
96	"       movi     %0, 0\n"					\
97	"2:\n"								\
98	"       .section __ex_table,\"a\"\n"				\
99	"       .word 1b, 2b\n"						\
100	"       .previous"						\
101	: "=&r" (err), "=r" (__gu_val)					\
102	: "r" (addr), "i" (-EFAULT));					\
103	val = (__force __typeof__(*(addr)))__gu_val;			\
104}
105
106extern void __get_user_unknown(void);
107
108#define __get_user_8(val, ptr, err) do {				\
109	u64 __val = 0;							\
110	err = 0;							\
111	if (raw_copy_from_user(&(__val), ptr, sizeof(val))) {		\
112		err = -EFAULT;						\
113	} else {							\
114		val = (typeof(val))(typeof((val) - (val)))__val;	\
115	}								\
116	} while (0)
117
118#define __get_user_common(val, size, ptr, err)				\
119do {									\
120	switch (size) {							\
121	case 1:								\
122		__get_user_asm(val, "ldbu", ptr, err);			\
123		break;							\
124	case 2:								\
125		__get_user_asm(val, "ldhu", ptr, err);			\
126		break;							\
127	case 4:								\
128		__get_user_asm(val, "ldw", ptr, err);			\
129		break;							\
130	case 8:								\
131		__get_user_8(val, ptr, err);				\
132		break;							\
133	default:							\
134		__get_user_unknown();					\
135		break;							\
136	}								\
137} while (0)
138
139#define __get_user(x, ptr)						\
140	({								\
141	long __gu_err = -EFAULT;					\
142	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
143	__get_user_common(x, sizeof(*(ptr)), __gu_ptr, __gu_err);	\
144	__gu_err;							\
145	})
146
147#define get_user(x, ptr)						\
148({									\
149	long __gu_err = -EFAULT;					\
150	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
151	if (access_ok( __gu_ptr, sizeof(*__gu_ptr)))	\
152		__get_user_common(x, sizeof(*__gu_ptr),			\
153			__gu_ptr, __gu_err);				\
154	__gu_err;							\
155})
156
157#define __put_user_asm(val, insn, ptr, err)				\
158{									\
159	__asm__ __volatile__(						\
160	"       movi    %0, %3\n"					\
161	"1:   " insn " %1, 0(%2)\n"					\
162	"       movi     %0, 0\n"					\
163	"2:\n"								\
164	"       .section __ex_table,\"a\"\n"				\
165	"       .word 1b, 2b\n"						\
166	"       .previous\n"						\
167	: "=&r" (err)							\
168	: "r" (val), "r" (ptr), "i" (-EFAULT));				\
169}
170
171#define put_user(x, ptr)						\
172({									\
173	long __pu_err = -EFAULT;					\
174	__typeof__(*(ptr)) __user *__pu_ptr = (ptr);			\
175	__typeof__(*(ptr)) __pu_val = (__typeof(*ptr))(x);		\
176	if (access_ok(__pu_ptr, sizeof(*__pu_ptr))) {	\
177		switch (sizeof(*__pu_ptr)) {				\
178		case 1:							\
179			__put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \
180			break;						\
181		case 2:							\
182			__put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \
183			break;						\
184		case 4:							\
185			__put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \
186			break;						\
187		default:						\
188			/* XXX: This looks wrong... */			\
189			__pu_err = 0;					\
190			if (copy_to_user(__pu_ptr, &(__pu_val),		\
191				sizeof(*__pu_ptr)))			\
192				__pu_err = -EFAULT;			\
193			break;						\
194		}							\
195	}								\
196	__pu_err;							\
197})
198
199#define __put_user(x, ptr) put_user(x, ptr)
200
201#endif /* _ASM_NIOS2_UACCESS_H */
202