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      1 /*	$NetBSD: uaccess.h,v 1.11 2022/10/25 23:38:33 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _ASM_UACCESS_H_
     33 #define _ASM_UACCESS_H_
     34 
     35 #include <sys/types.h>
     36 #include <sys/errno.h>
     37 #include <sys/systm.h>
     38 
     39 #include <linux/compiler.h>
     40 
     41 /* XXX This is a cop-out.  */
     42 #define	VERIFY_READ	0
     43 #define	VERIFY_WRITE	1
     44 static inline bool
     45 access_ok(const void *uaddr __unused, size_t nbytes __unused)
     46 {
     47 	return true;
     48 }
     49 
     50 #define	__copy_from_user	copy_from_user
     51 #define	__copy_to_user		copy_to_user
     52 
     53 static inline int
     54 copy_from_user(void *kernel_addr, const void *user_addr, size_t len)
     55 {
     56 	/* XXX errno NetBSD->Linux */
     57 	return -copyin(user_addr, kernel_addr, len);
     58 }
     59 
     60 static inline long
     61 strncpy_from_user(char *kernel_addr, const void *user_addr, long len)
     62 {
     63 	size_t done;
     64 	int error;
     65 
     66 	if (len <= 0)
     67 		return 0;
     68 	error = copyinstr(user_addr, kernel_addr, len, &done);
     69 	if (error)
     70 		return error;
     71 	KASSERT(done <= (size_t)len);
     72 	KASSERT(done >= 1);
     73 	return done - 1;
     74 }
     75 
     76 static inline int
     77 copy_to_user(void *user_addr, const void *kernel_addr, size_t len)
     78 {
     79 	/* XXX errno NetBSD->Linux */
     80 	return -copyout(kernel_addr, user_addr, len);
     81 }
     82 
     83 #define	get_user(KERNEL_LVAL, USER_PTR)					      \
     84 	copy_from_user(&(KERNEL_LVAL), (USER_PTR), sizeof(*(USER_PTR)) +      \
     85 	    0*sizeof(&(KERNEL_LVAL) - (USER_PTR)))
     86 
     87 #define	put_user(KERNEL_RVAL, USER_PTR)	({				      \
     88 	const typeof(*(USER_PTR)) __put_user_tmp = (KERNEL_RVAL);	      \
     89 	copy_to_user((USER_PTR), &__put_user_tmp, sizeof(__put_user_tmp));    \
     90 })
     91 
     92 #define	__get_user	get_user
     93 #define	__put_user	put_user
     94 
     95 #define	user_access_begin(P,N)	access_ok(P,N)
     96 #define	user_access_end()	__nothing
     97 
     98 #define	unsafe_put_user(KERNEL_RVAL, USER_PTR, LABEL)	do {		      \
     99 	if (__put_user(KERNEL_RVAL, USER_PTR))				      \
    100 		goto LABEL;						      \
    101 } while (0)
    102 
    103 static inline size_t
    104 clear_user(void __user *user_ptr, size_t size)
    105 {
    106 	char __user *p = user_ptr;
    107 	size_t n = size;
    108 
    109 	/*
    110 	 * This loop which sets up a fault handler on every iteration
    111 	 * is not going to win any speed records, but it'll do to copy
    112 	 * out an int.
    113 	 */
    114 	while (n --> 0) {
    115 		if (ustore_char(p, 0) != 0)
    116 			return ++n;
    117 	}
    118 
    119 	return 0;
    120 }
    121 
    122 #if 0
    123 /*
    124  * XXX These `inatomic' versions are a cop out, but they should do for
    125  * now -- they are used only in fast paths which can't fault but which
    126  * can fall back to slower paths that arrange things so faulting is OK.
    127  */
    128 
    129 static inline int
    130 __copy_from_user_inatomic(void *kernel_addr __unused,
    131     const void *user_addr __unused, size_t len __unused)
    132 {
    133 	return -EFAULT;
    134 }
    135 
    136 static inline int
    137 __copy_to_user_inatomic(void *user_addr __unused,
    138     const void *kernel_addr __unused, size_t len __unused)
    139 {
    140 	return -EFAULT;
    141 }
    142 #endif	/* 0 */
    143 
    144 static inline int
    145 __copy_from_user_inatomic_nocache(void *kernel_addr __unused,
    146     const void *user_addr __unused, size_t len __unused)
    147 {
    148 	return -EFAULT;
    149 }
    150 
    151 #endif  /* _ASM_UACCESS_H_ */
    152