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	__asm__ __volatile__(						\
 93	"       movi    %0, %3\n"					\
 94	"1:   " insn " %1, 0(%2)\n"					\
 95	"       movi     %0, 0\n"					\
 96	"2:\n"								\
 97	"       .section __ex_table,\"a\"\n"				\
 98	"       .word 1b, 2b\n"						\
 99	"       .previous"						\
100	: "=&r" (err), "=r" (val)					\
101	: "r" (addr), "i" (-EFAULT));					\
102}
103
104#define __get_user_unknown(val, size, ptr, err) do {			\
105	err = 0;							\
106	if (__copy_from_user(&(val), ptr, size)) {			\
107		err = -EFAULT;						\
108	}								\
109	} while (0)
110
111#define __get_user_common(val, size, ptr, err)				\
112do {									\
113	switch (size) {							\
114	case 1:								\
115		__get_user_asm(val, "ldbu", ptr, err);			\
116		break;							\
117	case 2:								\
118		__get_user_asm(val, "ldhu", ptr, err);			\
119		break;							\
120	case 4:								\
121		__get_user_asm(val, "ldw", ptr, err);			\
122		break;							\
123	default:							\
124		__get_user_unknown(val, size, ptr, err);		\
125		break;							\
126	}								\
127} while (0)
128
129#define __get_user(x, ptr)						\
130	({								\
131	long __gu_err = -EFAULT;					\
132	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
133	unsigned long __gu_val = 0;					\
134	__get_user_common(__gu_val, sizeof(*(ptr)), __gu_ptr, __gu_err);\
135	(x) = (__force __typeof__(x))__gu_val;				\
136	__gu_err;							\
137	})
138
139#define get_user(x, ptr)						\
140({									\
141	long __gu_err = -EFAULT;					\
142	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
143	unsigned long __gu_val = 0;					\
144	if (access_ok( __gu_ptr, sizeof(*__gu_ptr)))	\
145		__get_user_common(__gu_val, sizeof(*__gu_ptr),		\
146			__gu_ptr, __gu_err);				\
147	(x) = (__force __typeof__(x))__gu_val;				\
148	__gu_err;							\
149})
150
151#define __put_user_asm(val, insn, ptr, err)				\
152{									\
153	__asm__ __volatile__(						\
154	"       movi    %0, %3\n"					\
155	"1:   " insn " %1, 0(%2)\n"					\
156	"       movi     %0, 0\n"					\
157	"2:\n"								\
158	"       .section __ex_table,\"a\"\n"				\
159	"       .word 1b, 2b\n"						\
160	"       .previous\n"						\
161	: "=&r" (err)							\
162	: "r" (val), "r" (ptr), "i" (-EFAULT));				\
163}
164
165#define put_user(x, ptr)						\
166({									\
167	long __pu_err = -EFAULT;					\
168	__typeof__(*(ptr)) __user *__pu_ptr = (ptr);			\
169	__typeof__(*(ptr)) __pu_val = (__typeof(*ptr))(x);		\
170	if (access_ok(__pu_ptr, sizeof(*__pu_ptr))) {	\
171		switch (sizeof(*__pu_ptr)) {				\
172		case 1:							\
173			__put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \
174			break;						\
175		case 2:							\
176			__put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \
177			break;						\
178		case 4:							\
179			__put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \
180			break;						\
181		default:						\
182			/* XXX: This looks wrong... */			\
183			__pu_err = 0;					\
184			if (copy_to_user(__pu_ptr, &(__pu_val),		\
185				sizeof(*__pu_ptr)))			\
186				__pu_err = -EFAULT;			\
187			break;						\
188		}							\
189	}								\
190	__pu_err;							\
191})
192
193#define __put_user(x, ptr) put_user(x, ptr)
194
195#endif /* _ASM_NIOS2_UACCESS_H */