xref: /freebsd/sys/dev/mem/memdev.c (revision 009a196247b29caa5eb892e3ff23f8dacef6c537)
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("$FreeBSD$");
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 
51 static struct cdev *memdev, *kmemdev;
52 
53 static struct cdevsw mem_cdevsw = {
54 	.d_version =	D_VERSION,
55 	.d_flags =	D_MEM|D_NEEDGIANT,
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 */
65 int
66 memopen(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 */
84 static int
85 mem_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 
115 DEV_MODULE(mem, mem_modevent, NULL);
116 MODULE_VERSION(mem, 1);
117