xref: /freebsd/sys/dev/mem/memdev.c (revision ba3c1f5972d7b90feb6e6da47905ff2757e0fe57)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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("$FreeBSD$");
32 
33 #include <sys/param.h>
34 #include <sys/conf.h>
35 #include <sys/fcntl.h>
36 #include <sys/ioccom.h>
37 #include <sys/kernel.h>
38 #include <sys/kerneldump.h>
39 #include <sys/lock.h>
40 #include <sys/malloc.h>
41 #include <sys/memrange.h>
42 #include <sys/module.h>
43 #include <sys/mutex.h>
44 #include <sys/priv.h>
45 #include <sys/proc.h>
46 #include <sys/signalvar.h>
47 #include <sys/systm.h>
48 #include <sys/uio.h>
49 
50 #include <vm/vm.h>
51 #include <vm/vm_param.h>
52 #include <vm/pmap.h>
53 #include <vm/vm_map.h>
54 #include <vm/vm_object.h>
55 #include <vm/vm_page.h>
56 #include <vm/vm_phys.h>
57 
58 #include <machine/memdev.h>
59 
60 static struct cdev *memdev, *kmemdev;
61 
62 static d_ioctl_t memioctl;
63 
64 static struct cdevsw mem_cdevsw = {
65 	.d_version =	D_VERSION,
66 	.d_flags =	D_MEM,
67 	.d_open =	memopen,
68 	.d_read =	memrw,
69 	.d_write =	memrw,
70 	.d_ioctl =	memioctl,
71 	.d_mmap =	memmmap,
72 	.d_name =	"mem",
73 };
74 
75 /* ARGSUSED */
76 int
77 memopen(struct cdev *dev __unused, int flags, int fmt __unused,
78     struct thread *td)
79 {
80 	int error = 0;
81 
82 	if (flags & FREAD)
83 		error = priv_check(td, PRIV_KMEM_READ);
84 	if (flags & FWRITE) {
85 		if (error == 0)
86 			error = priv_check(td, PRIV_KMEM_WRITE);
87 		if (error == 0)
88 			error = securelevel_gt(td->td_ucred, 0);
89 	}
90 
91 	return (error);
92 }
93 
94 static int
95 memioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags,
96     struct thread *td)
97 {
98 	vm_map_t map;
99 	vm_map_entry_t entry;
100 	const struct mem_livedump_arg *marg;
101 	struct mem_extract *me;
102 	int error;
103 
104 	error = 0;
105 	switch (cmd) {
106 	case MEM_EXTRACT_PADDR:
107 		me = (struct mem_extract *)data;
108 
109 		map = &td->td_proc->p_vmspace->vm_map;
110 		vm_map_lock_read(map);
111 		if (vm_map_lookup_entry(map, me->me_vaddr, &entry)) {
112 			me->me_paddr = pmap_extract(
113 			    &td->td_proc->p_vmspace->vm_pmap, me->me_vaddr);
114 			if (me->me_paddr != 0) {
115 				me->me_state = ME_STATE_MAPPED;
116 				me->me_domain = vm_phys_domain(me->me_paddr);
117 			} else {
118 				me->me_state = ME_STATE_VALID;
119 			}
120 		} else {
121 			me->me_state = ME_STATE_INVALID;
122 		}
123 		vm_map_unlock_read(map);
124 		break;
125 	case MEM_KERNELDUMP:
126 		marg = (const struct mem_livedump_arg *)data;
127 		error = livedump_start(marg->fd, marg->flags, marg->compression);
128 		break;
129 	default:
130 		error = memioctl_md(dev, cmd, data, flags, td);
131 		break;
132 	}
133 	return (error);
134 }
135 
136 /* ARGSUSED */
137 static int
138 mem_modevent(module_t mod __unused, int type, void *data __unused)
139 {
140 	switch(type) {
141 	case MOD_LOAD:
142 		if (bootverbose)
143 			printf("mem: <memory>\n");
144 		mem_range_init();
145 		memdev = make_dev(&mem_cdevsw, CDEV_MINOR_MEM,
146 			UID_ROOT, GID_KMEM, 0640, "mem");
147 		kmemdev = make_dev(&mem_cdevsw, CDEV_MINOR_KMEM,
148 			UID_ROOT, GID_KMEM, 0640, "kmem");
149 		break;
150 
151 	case MOD_UNLOAD:
152 		mem_range_destroy();
153 		destroy_dev(memdev);
154 		destroy_dev(kmemdev);
155 		break;
156 
157 	case MOD_SHUTDOWN:
158 		break;
159 
160 	default:
161 		return(EOPNOTSUPP);
162 	}
163 
164 	return (0);
165 }
166 
167 DEV_MODULE(mem, mem_modevent, NULL);
168 MODULE_VERSION(mem, 1);
169