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 | |
82 | #include <kern/zalloc.h> |
83 | |
84 | #include <mach/vm_types.h> |
85 | #include <mach/vm_param.h> |
86 | #include <vm/vm_kern.h> /* for kernel_map */ |
87 | #include <libkern/section_keywords.h> |
88 | |
89 | #include <pexpert/pexpert.h> /* for PE_parse_boot_argn */ |
90 | |
91 | boolean_t iskmemdev(dev_t dev); |
92 | |
93 | #if CONFIG_DEV_KMEM |
94 | boolean_t dev_kmem_enabled; |
95 | boolean_t dev_kmem_mask_top_bit; |
96 | |
97 | void dev_kmem_init(void); |
98 | |
99 | #if defined(__x86_64__) |
100 | extern addr64_t kvtophys(vm_offset_t va); |
101 | #else |
102 | #error need kvtophys prototype |
103 | #endif |
104 | extern boolean_t kernacc(off_t, size_t ); |
105 | |
106 | #endif |
107 | |
108 | static SECURITY_READ_ONLY_LATE(caddr_t) devzerobuf; |
109 | |
110 | int mmread(dev_t dev, struct uio *uio); |
111 | int mmwrite(dev_t dev, struct uio *uio); |
112 | int mmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p); |
113 | int mmrw(dev_t dev, struct uio *uio, enum uio_rw rw); |
114 | |
115 | int |
116 | mmread(dev_t dev, struct uio *uio) |
117 | { |
118 | return mmrw(dev, uio, rw: UIO_READ); |
119 | } |
120 | |
121 | int |
122 | mmwrite(dev_t dev, struct uio *uio) |
123 | { |
124 | return mmrw(dev, uio, rw: UIO_WRITE); |
125 | } |
126 | |
127 | int |
128 | mmioctl(dev_t dev, u_long cmd, __unused caddr_t data, |
129 | __unused int flag, __unused struct proc *p) |
130 | { |
131 | int minnum = minor(dev); |
132 | |
133 | if (0 == minnum || 1 == minnum) { |
134 | /* /dev/mem and /dev/kmem */ |
135 | #if CONFIG_DEV_KMEM |
136 | if (!dev_kmem_enabled) { |
137 | return ENODEV; |
138 | } |
139 | #else |
140 | return ENODEV; |
141 | #endif |
142 | } |
143 | |
144 | switch (cmd) { |
145 | case FIONBIO: |
146 | case FIOASYNC: |
147 | /* OK to do nothing: we always return immediately */ |
148 | break; |
149 | default: |
150 | return ENODEV; |
151 | } |
152 | |
153 | return 0; |
154 | } |
155 | |
156 | int |
157 | mmrw(dev_t dev, struct uio *uio, enum uio_rw rw) |
158 | { |
159 | user_size_t c; |
160 | int error = 0; |
161 | |
162 | while (uio_resid(a_uio: uio) > 0) { |
163 | uio_update(a_uio: uio, a_count: 0); |
164 | |
165 | switch (minor(dev)) { |
166 | /* minor device 0 is physical memory */ |
167 | case 0: |
168 | return ENODEV; |
169 | |
170 | /* minor device 1 is kernel memory */ |
171 | case 1: |
172 | #if !CONFIG_DEV_KMEM |
173 | return ENODEV; |
174 | #else /* CONFIG_DEV_KMEM */ |
175 | if (!dev_kmem_enabled) { |
176 | return ENODEV; |
177 | } |
178 | |
179 | vm_address_t kaddr = (vm_address_t)uio->uio_offset; |
180 | if (dev_kmem_mask_top_bit) { |
181 | /* |
182 | * KVA addresses of the form 0xFFFFFF80AABBCCDD can't be |
183 | * represented as a signed off_t correctly. In these cases, |
184 | * 0x7FFFFF80AABBCCDD is passed in, and the top bit OR-ed |
185 | * on. |
186 | */ |
187 | const vm_address_t top_bit = (~((vm_address_t)0)) ^ (~((vm_address_t)0) >> 1UL); |
188 | if (kaddr & top_bit) { |
189 | /* top bit should not be set already */ |
190 | return EFAULT; |
191 | } |
192 | kaddr |= top_bit; |
193 | } |
194 | |
195 | c = uio_curriovlen(uio); |
196 | |
197 | /* Do some sanity checking */ |
198 | if ((kaddr > (VM_MAX_KERNEL_ADDRESS - c)) || |
199 | (kaddr <= VM_MIN_KERNEL_AND_KEXT_ADDRESS)) { |
200 | goto fault; |
201 | } |
202 | if (!kernacc(kaddr, c)) { |
203 | goto fault; |
204 | } |
205 | error = uiomove((const char *)(uintptr_t)kaddr, |
206 | (int)c, uio); |
207 | if (error) { |
208 | break; |
209 | } |
210 | |
211 | continue; /* Keep going until UIO is done */ |
212 | #endif /* CONFIG_DEV_KMEM */ |
213 | |
214 | /* minor device 2 is EOF/RATHOLE */ |
215 | case 2: |
216 | if (rw == UIO_READ) { |
217 | return 0; |
218 | } |
219 | c = uio_curriovlen(a_uio: uio); |
220 | |
221 | error = 0; /* Always succeeds, always consumes all input */ |
222 | break; |
223 | case 3: |
224 | assert(devzerobuf != NULL); |
225 | |
226 | if (uio->uio_rw == UIO_WRITE) { |
227 | c = uio_curriovlen(a_uio: uio); |
228 | |
229 | error = 0; /* Always succeeds, always consumes all input */ |
230 | break; |
231 | } |
232 | |
233 | c = MIN(uio_curriovlen(uio), PAGE_SIZE); |
234 | error = uiomove(cp: devzerobuf, n: (int)c, uio); |
235 | if (error) { |
236 | break; |
237 | } |
238 | |
239 | continue; /* Keep going until UIO is done */ |
240 | default: |
241 | return ENODEV; |
242 | } |
243 | |
244 | if (error) { |
245 | break; |
246 | } |
247 | |
248 | uio_update(a_uio: uio, a_count: c); |
249 | } |
250 | return error; |
251 | #if CONFIG_DEV_KMEM |
252 | fault: |
253 | return EFAULT; |
254 | #endif |
255 | } |
256 | |
257 | __startup_func |
258 | static void |
259 | devzerobuf_init(void) |
260 | { |
261 | devzerobuf = zalloc_permanent(PAGE_SIZE, ZALIGN_NONE); /* zeroed */ |
262 | } |
263 | STARTUP(ZALLOC, STARTUP_RANK_LAST, devzerobuf_init); |
264 | |
265 | #if CONFIG_DEV_KMEM |
266 | void |
267 | dev_kmem_init(void) |
268 | { |
269 | uint32_t kmem; |
270 | |
271 | if (PE_i_can_has_debugger(NULL) && |
272 | PE_parse_boot_argn("kmem" , &kmem, sizeof(kmem))) { |
273 | if (kmem & 0x1) { |
274 | dev_kmem_enabled = TRUE; |
275 | } |
276 | if (kmem & 0x2) { |
277 | dev_kmem_mask_top_bit = TRUE; |
278 | } |
279 | } |
280 | } |
281 | |
282 | boolean_t |
283 | kernacc( |
284 | off_t start, |
285 | size_t len |
286 | ) |
287 | { |
288 | off_t base; |
289 | off_t end; |
290 | |
291 | base = trunc_page(start); |
292 | end = start + len; |
293 | |
294 | while (base < end) { |
295 | if (kvtophys((vm_offset_t)base) == 0ULL) { |
296 | return FALSE; |
297 | } |
298 | base += page_size; |
299 | } |
300 | |
301 | return TRUE; |
302 | } |
303 | |
304 | #endif /* CONFIG_DEV_KMEM */ |
305 | |
306 | /* |
307 | * Returns true if dev is /dev/mem or /dev/kmem. |
308 | */ |
309 | boolean_t |
310 | iskmemdev(dev_t dev) |
311 | { |
312 | return major(dev) == 3 && minor(dev) < 2; |
313 | } |
314 | |