1/*
2 * Copyright (c) 2000-2016 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/*-
29 * Copyright (c) 1988 University of Utah.
30 * Copyright (c) 1982, 1986, 1990, 1993
31 * The Regents of the University of California. All rights reserved.
32 *
33 * This code is derived from software contributed to Berkeley by
34 * the Systems Programming Group of the University of Utah Computer
35 * Science Department, and code derived from software contributed to
36 * Berkeley by William Jolitz.
37 *
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
40 * are met:
41 * 1. Redistributions of source code must retain the above copyright
42 * notice, this list of conditions and the following disclaimer.
43 * 2. Redistributions in binary form must reproduce the above copyright
44 * notice, this list of conditions and the following disclaimer in the
45 * documentation and/or other materials provided with the distribution.
46 * 3. All advertising materials mentioning features or use of this software
47 * must display the following acknowledgement:
48 * This product includes software developed by the University of
49 * California, Berkeley and its contributors.
50 * 4. Neither the name of the University nor the names of its contributors
51 * may be used to endorse or promote products derived from this software
52 * without specific prior written permission.
53 *
54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64 * SUCH DAMAGE.
65 *
66 * from: Utah $Hdr: mem.c 1.13 89/10/08$
67 * @(#)mem.c 8.1 (Berkeley) 6/11/93
68 */
69
70/*
71 * Memory special file
72 */
73
74#include <sys/param.h>
75#include <sys/dir.h>
76#include <sys/proc.h>
77#include <sys/systm.h>
78#include <sys/conf.h>
79#include <sys/vm.h>
80#include <sys/uio_internal.h>
81#include <sys/malloc.h>
82
83#include <mach/vm_types.h>
84#include <mach/vm_param.h>
85#include <vm/vm_kern.h> /* for kernel_map */
86
87#include <pexpert/pexpert.h> /* for PE_parse_boot_argn */
88
89boolean_t iskmemdev(dev_t dev);
90
91#if CONFIG_DEV_KMEM
92boolean_t dev_kmem_enabled;
93boolean_t dev_kmem_mask_top_bit;
94
95void dev_kmem_init(void);
96
97#if defined(__x86_64__)
98extern addr64_t kvtophys(vm_offset_t va);
99#else
100#error need kvtophys prototype
101#endif
102extern boolean_t kernacc(off_t, size_t );
103
104#endif
105
106static caddr_t devzerobuf;
107
108int mmread(dev_t dev, struct uio *uio);
109int mmwrite(dev_t dev, struct uio *uio);
110int mmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p);
111int mmrw(dev_t dev, struct uio *uio, enum uio_rw rw);
112
113int
114mmread(dev_t dev, struct uio *uio)
115{
116 return (mmrw(dev, uio, UIO_READ));
117}
118
119int
120mmwrite(dev_t dev, struct uio *uio)
121{
122 return (mmrw(dev, uio, UIO_WRITE));
123}
124
125int
126mmioctl(dev_t dev, u_long cmd, __unused caddr_t data,
127 __unused int flag, __unused struct proc *p)
128{
129 int minnum = minor(dev);
130
131 if (0 == minnum || 1 == minnum) {
132 /* /dev/mem and /dev/kmem */
133#if CONFIG_DEV_KMEM
134 if (!dev_kmem_enabled)
135 return (ENODEV);
136#else
137 return (ENODEV);
138#endif
139 }
140
141 switch (cmd) {
142 case FIONBIO:
143 case FIOASYNC:
144 /* OK to do nothing: we always return immediately */
145 break;
146 default:
147 return ENODEV;
148 }
149
150 return (0);
151}
152
153int
154mmrw(dev_t dev, struct uio *uio, enum uio_rw rw)
155{
156 unsigned int c;
157 int error = 0;
158
159 while (uio_resid(uio) > 0) {
160 uio_update(uio, 0);
161
162 switch (minor(dev)) {
163
164 /* minor device 0 is physical memory */
165 case 0:
166 return (ENODEV);
167
168 /* minor device 1 is kernel memory */
169 case 1:
170#if !CONFIG_DEV_KMEM
171 return (ENODEV);
172#else /* CONFIG_DEV_KMEM */
173 if (!dev_kmem_enabled)
174 return (ENODEV);
175
176 vm_address_t kaddr = (vm_address_t)uio->uio_offset;
177 if (dev_kmem_mask_top_bit) {
178 /*
179 * KVA addresses of the form 0xFFFFFF80AABBCCDD can't be
180 * represented as a signed off_t correctly. In these cases,
181 * 0x7FFFFF80AABBCCDD is passed in, and the top bit OR-ed
182 * on.
183 */
184 const vm_address_t top_bit = (~((vm_address_t)0)) ^ (~((vm_address_t)0) >> 1UL);
185 if (kaddr & top_bit) {
186 /* top bit should not be set already */
187 return (EFAULT);
188 }
189 kaddr |= top_bit;
190 }
191
192 c = uio_curriovlen(uio);
193
194 /* Do some sanity checking */
195 if ((kaddr > (VM_MAX_KERNEL_ADDRESS - c)) ||
196 (kaddr <= VM_MIN_KERNEL_AND_KEXT_ADDRESS))
197 goto fault;
198 if (!kernacc(kaddr, c))
199 goto fault;
200 error = uiomove((const char *)(uintptr_t)kaddr,
201 (int)c, uio);
202 if (error)
203 break;
204
205 continue; /* Keep going until UIO is done */
206#endif /* CONFIG_DEV_KMEM */
207
208 /* minor device 2 is EOF/RATHOLE */
209 case 2:
210 if (rw == UIO_READ)
211 return (0);
212 c = uio_curriovlen(uio);
213
214 error = 0; /* Always succeeds, always consumes all input */
215 break;
216 case 3:
217 if(devzerobuf == NULL) {
218 MALLOC(devzerobuf, caddr_t,PAGE_SIZE, M_TEMP, M_WAITOK);
219 bzero(devzerobuf, PAGE_SIZE);
220 }
221 if(uio->uio_rw == UIO_WRITE) {
222 c = uio_curriovlen(uio);
223
224 error = 0; /* Always succeeds, always consumes all input */
225 break;
226 }
227
228 c = min(uio_curriovlen(uio), PAGE_SIZE);
229 error = uiomove(devzerobuf, (int)c, uio);
230 if (error)
231 break;
232
233 continue; /* Keep going until UIO is done */
234 default:
235 return (ENODEV);
236 }
237
238 if (error)
239 break;
240
241 uio_update(uio, c);
242 }
243 return (error);
244#if CONFIG_DEV_KMEM
245fault:
246 return (EFAULT);
247#endif
248}
249
250#if CONFIG_DEV_KMEM
251void dev_kmem_init(void)
252{
253 uint32_t kmem;
254
255 if (PE_i_can_has_debugger(NULL) &&
256 PE_parse_boot_argn("kmem", &kmem, sizeof (kmem))) {
257 if (kmem & 0x1) {
258 dev_kmem_enabled = TRUE;
259 }
260 if (kmem & 0x2) {
261 dev_kmem_mask_top_bit = TRUE;
262 }
263 }
264}
265
266boolean_t
267kernacc(
268 off_t start,
269 size_t len
270)
271{
272 off_t base;
273 off_t end;
274
275 base = trunc_page(start);
276 end = start + len;
277
278 while (base < end) {
279 if(kvtophys((vm_offset_t)base) == 0ULL)
280 return(FALSE);
281 base += page_size;
282 }
283
284 return (TRUE);
285}
286
287#endif /* CONFIG_DEV_KMEM */
288
289/*
290 * Returns true if dev is /dev/mem or /dev/kmem.
291 */
292boolean_t iskmemdev(dev_t dev)
293{
294 return (major(dev) == 3 && minor(dev) < 2);
295}
296