memdev.c revision 331722 
1/*-
2 * Copyright (c) 2004 Mark R V Murray
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: stable/11/sys/dev/mem/memdev.c 331722 2018-03-29 02:50:57Z eadler $");
30
31#include <sys/param.h>
32#include <sys/conf.h>
33#include <sys/fcntl.h>
34#include <sys/kernel.h>
35#include <sys/lock.h>
36#include <sys/malloc.h>
37#include <sys/memrange.h>
38#include <sys/module.h>
39#include <sys/mutex.h>
40#include <sys/priv.h>
41#include <sys/proc.h>
42#include <sys/signalvar.h>
43#include <sys/systm.h>
44#include <sys/uio.h>
45
46#include <vm/vm.h>
47#include <vm/pmap.h>
48
49#include <machine/memdev.h>
50
51static struct cdev *memdev, *kmemdev;
52
53static struct cdevsw mem_cdevsw = {
54	.d_version =	D_VERSION,
55	.d_flags =	D_MEM,
56	.d_open =	memopen,
57	.d_read =	memrw,
58	.d_write =	memrw,
59	.d_ioctl =	memioctl,
60	.d_mmap =	memmmap,
61	.d_name =	"mem",
62};
63
64/* ARGSUSED */
65int
66memopen(struct cdev *dev __unused, int flags, int fmt __unused,
67    struct thread *td)
68{
69	int error = 0;
70
71	if (flags & FREAD)
72		error = priv_check(td, PRIV_KMEM_READ);
73	if (flags & FWRITE) {
74		if (error == 0)
75			error = priv_check(td, PRIV_KMEM_WRITE);
76		if (error == 0)
77			error = securelevel_gt(td->td_ucred, 0);
78	}
79
80	return (error);
81}
82
83/* ARGSUSED */
84static int
85mem_modevent(module_t mod __unused, int type, void *data __unused)
86{
87	switch(type) {
88	case MOD_LOAD:
89		if (bootverbose)
90			printf("mem: <memory>\n");
91		mem_range_init();
92		memdev = make_dev(&mem_cdevsw, CDEV_MINOR_MEM,
93			UID_ROOT, GID_KMEM, 0640, "mem");
94		kmemdev = make_dev(&mem_cdevsw, CDEV_MINOR_KMEM,
95			UID_ROOT, GID_KMEM, 0640, "kmem");
96		break;
97
98	case MOD_UNLOAD:
99		mem_range_destroy();
100		destroy_dev(memdev);
101		destroy_dev(kmemdev);
102		break;
103
104	case MOD_SHUTDOWN:
105		break;
106
107	default:
108		return(EOPNOTSUPP);
109
110	}
111
112	return (0);
113}
114
115DEV_MODULE(mem, mem_modevent, NULL);
116MODULE_VERSION(mem, 1);
117