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#include <asm-generic/access_ok.h>
22
23# define __EX_TABLE_SECTION	".section __ex_table,\"a\"\n"
24
25/*
26 * Zero Userspace
27 */
28
29static inline unsigned long __must_check __clear_user(void __user *to,
30						      unsigned long n)
31{
32	__asm__ __volatile__ (
33		"1:     stb     zero, 0(%1)\n"
34		"       addi    %0, %0, -1\n"
35		"       addi    %1, %1, 1\n"
36		"       bne     %0, zero, 1b\n"
37		"2:\n"
38		__EX_TABLE_SECTION
39		".word  1b, 2b\n"
40		".previous\n"
41		: "=r" (n), "=r" (to)
42		: "0" (n), "1" (to)
43	);
44
45	return n;
46}
47
48static inline unsigned long __must_check clear_user(void __user *to,
49						    unsigned long n)
50{
51	if (!access_ok(to, n))
52		return n;
53	return __clear_user(to, n);
54}
55
56extern unsigned long
57raw_copy_from_user(void *to, const void __user *from, unsigned long n);
58extern unsigned long
59raw_copy_to_user(void __user *to, const void *from, unsigned long n);
60#define INLINE_COPY_FROM_USER
61#define INLINE_COPY_TO_USER
62
63extern long strncpy_from_user(char *__to, const char __user *__from,
64			      long __len);
65extern __must_check long strnlen_user(const char __user *s, long n);
66
67/* Optimized macros */
68#define __get_user_asm(val, insn, addr, err)				\
69{									\
70	unsigned long __gu_val;						\
71	__asm__ __volatile__(						\
72	"       movi    %0, %3\n"					\
73	"1:   " insn " %1, 0(%2)\n"					\
74	"       movi     %0, 0\n"					\
75	"2:\n"								\
76	"       .section __ex_table,\"a\"\n"				\
77	"       .word 1b, 2b\n"						\
78	"       .previous"						\
79	: "=&r" (err), "=r" (__gu_val)					\
80	: "r" (addr), "i" (-EFAULT));					\
81	val = (__force __typeof__(*(addr)))__gu_val;			\
82}
83
84extern void __get_user_unknown(void);
85
86#define __get_user_8(val, ptr, err) do {				\
87	u64 __val = 0;							\
88	err = 0;							\
89	if (raw_copy_from_user(&(__val), ptr, sizeof(val))) {		\
90		err = -EFAULT;						\
91	} else {							\
92		val = (typeof(val))(typeof((val) - (val)))__val;	\
93	}								\
94	} while (0)
95
96#define __get_user_common(val, size, ptr, err)				\
97do {									\
98	switch (size) {							\
99	case 1:								\
100		__get_user_asm(val, "ldbu", ptr, err);			\
101		break;							\
102	case 2:								\
103		__get_user_asm(val, "ldhu", ptr, err);			\
104		break;							\
105	case 4:								\
106		__get_user_asm(val, "ldw", ptr, err);			\
107		break;							\
108	case 8:								\
109		__get_user_8(val, ptr, err);				\
110		break;							\
111	default:							\
112		__get_user_unknown();					\
113		break;							\
114	}								\
115} while (0)
116
117#define __get_user(x, ptr)						\
118	({								\
119	long __gu_err = -EFAULT;					\
120	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
121	__get_user_common(x, sizeof(*(ptr)), __gu_ptr, __gu_err);	\
122	__gu_err;							\
123	})
124
125#define get_user(x, ptr)						\
126({									\
127	long __gu_err = -EFAULT;					\
128	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
129	if (access_ok( __gu_ptr, sizeof(*__gu_ptr)))	\
130		__get_user_common(x, sizeof(*__gu_ptr),			\
131			__gu_ptr, __gu_err);				\
132	__gu_err;							\
133})
134
135#define __put_user_asm(val, insn, ptr, err)				\
136{									\
137	__asm__ __volatile__(						\
138	"       movi    %0, %3\n"					\
139	"1:   " insn " %1, 0(%2)\n"					\
140	"       movi     %0, 0\n"					\
141	"2:\n"								\
142	"       .section __ex_table,\"a\"\n"				\
143	"       .word 1b, 2b\n"						\
144	"       .previous\n"						\
145	: "=&r" (err)							\
146	: "r" (val), "r" (ptr), "i" (-EFAULT));				\
147}
148
149#define __put_user_common(__pu_val, __pu_ptr)				\
150({									\
151	long __pu_err = -EFAULT;					\
152	switch (sizeof(*__pu_ptr)) {					\
153	case 1:								\
154		__put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err);	\
155		break;							\
156	case 2:								\
157		__put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err);	\
158		break;							\
159	case 4:								\
160		__put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err);	\
161		break;							\
162	default:							\
163		/* XXX: This looks wrong... */				\
164		__pu_err = 0;						\
165		if (__copy_to_user(__pu_ptr, &(__pu_val),		\
166			sizeof(*__pu_ptr)))				\
167			__pu_err = -EFAULT;				\
168		break;							\
169	}								\
170	__pu_err;							\
171})
172
173#define __put_user(x, ptr)						\
174({									\
175	__auto_type __pu_ptr = (ptr);					\
176	typeof(*__pu_ptr) __pu_val = (typeof(*__pu_ptr))(x);		\
177	__put_user_common(__pu_val, __pu_ptr);				\
178})
179
180#define put_user(x, ptr)						\
181({									\
182	__auto_type __pu_ptr = (ptr);					\
183	typeof(*__pu_ptr) __pu_val = (typeof(*__pu_ptr))(x);		\
184	access_ok(__pu_ptr, sizeof(*__pu_ptr)) ?			\
185		__put_user_common(__pu_val, __pu_ptr) :			\
186		-EFAULT;						\
187})
188
189#endif /* _ASM_NIOS2_UACCESS_H */
190