memdev.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2004 Mark R V Murray
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer
12 *    in this position and unchanged.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: stable/11/sys/dev/mem/memdev.c 330897 2018-03-14 03:19:51Z eadler $");
32
33#include <sys/param.h>
34#include <sys/conf.h>
35#include <sys/fcntl.h>
36#include <sys/kernel.h>
37#include <sys/lock.h>
38#include <sys/malloc.h>
39#include <sys/memrange.h>
40#include <sys/module.h>
41#include <sys/mutex.h>
42#include <sys/priv.h>
43#include <sys/proc.h>
44#include <sys/signalvar.h>
45#include <sys/systm.h>
46#include <sys/uio.h>
47
48#include <vm/vm.h>
49#include <vm/pmap.h>
50
51#include <machine/memdev.h>
52
53static struct cdev *memdev, *kmemdev;
54
55static struct cdevsw mem_cdevsw = {
56	.d_version =	D_VERSION,
57	.d_flags =	D_MEM,
58	.d_open =	memopen,
59	.d_read =	memrw,
60	.d_write =	memrw,
61	.d_ioctl =	memioctl,
62	.d_mmap =	memmmap,
63	.d_name =	"mem",
64};
65
66/* ARGSUSED */
67int
68memopen(struct cdev *dev __unused, int flags, int fmt __unused,
69    struct thread *td)
70{
71	int error = 0;
72
73	if (flags & FREAD)
74		error = priv_check(td, PRIV_KMEM_READ);
75	if (flags & FWRITE) {
76		if (error == 0)
77			error = priv_check(td, PRIV_KMEM_WRITE);
78		if (error == 0)
79			error = securelevel_gt(td->td_ucred, 0);
80	}
81
82	return (error);
83}
84
85/* ARGSUSED */
86static int
87mem_modevent(module_t mod __unused, int type, void *data __unused)
88{
89	switch(type) {
90	case MOD_LOAD:
91		if (bootverbose)
92			printf("mem: <memory>\n");
93		mem_range_init();
94		memdev = make_dev(&mem_cdevsw, CDEV_MINOR_MEM,
95			UID_ROOT, GID_KMEM, 0640, "mem");
96		kmemdev = make_dev(&mem_cdevsw, CDEV_MINOR_KMEM,
97			UID_ROOT, GID_KMEM, 0640, "kmem");
98		break;
99
100	case MOD_UNLOAD:
101		mem_range_destroy();
102		destroy_dev(memdev);
103		destroy_dev(kmemdev);
104		break;
105
106	case MOD_SHUTDOWN:
107		break;
108
109	default:
110		return(EOPNOTSUPP);
111
112	}
113
114	return (0);
115}
116
117DEV_MODULE(mem, mem_modevent, NULL);
118MODULE_VERSION(mem, 1);
119