FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/mem.c
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1988 University of Utah.
5 * Copyright (c) 1982, 1986, 1990 The Regents of the University of California.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
10 * Science Department, and code derived from software contributed to
11 * Berkeley by William Jolitz.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * from: Utah $Hdr: mem.c 1.13 89/10/08$
38 * from: @(#)mem.c 7.2 (Berkeley) 5/9/91
39 */
40
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
43
44 /*
45 * Memory special file
46 */
47
48 #include <sys/param.h>
49 #include <sys/conf.h>
50 #include <sys/fcntl.h>
51 #include <sys/ioccom.h>
52 #include <sys/kernel.h>
53 #include <sys/lock.h>
54 #include <sys/malloc.h>
55 #include <sys/memrange.h>
56 #include <sys/module.h>
57 #include <sys/mutex.h>
58 #include <sys/proc.h>
59 #include <sys/signalvar.h>
60 #include <sys/systm.h>
61 #include <sys/uio.h>
62
63 #include <machine/md_var.h>
64 #include <machine/specialreg.h>
65 #include <machine/vmparam.h>
66
67 #include <vm/vm.h>
68 #include <vm/pmap.h>
69 #include <vm/vm_extern.h>
70
71 #include <machine/memdev.h>
72
73 /*
74 * Used in /dev/mem drivers and elsewhere
75 */
76 MALLOC_DEFINE(M_MEMDESC, "memdesc", "memory range descriptors");
77
78 /* ARGSUSED */
79 int
80 memrw(struct cdev *dev, struct uio *uio, int flags)
81 {
82 struct iovec *iov;
83 void *p;
84 ssize_t orig_resid;
85 u_long v, vd;
86 u_int c;
87 int error;
88
89 error = 0;
90 orig_resid = uio->uio_resid;
91 while (uio->uio_resid > 0 && error == 0) {
92 iov = uio->uio_iov;
93 if (iov->iov_len == 0) {
94 uio->uio_iov++;
95 uio->uio_iovcnt--;
96 if (uio->uio_iovcnt < 0)
97 panic("memrw");
98 continue;
99 }
100 v = uio->uio_offset;
101 c = ulmin(iov->iov_len, PAGE_SIZE - (u_int)(v & PAGE_MASK));
102
103 switch (dev2unit(dev)) {
104 case CDEV_MINOR_KMEM:
105 /*
106 * Since c is clamped to be less or equal than
107 * PAGE_SIZE, the uiomove() call does not
108 * access past the end of the direct map.
109 */
110 if (v >= DMAP_MIN_ADDRESS &&
111 v < DMAP_MIN_ADDRESS + dmaplimit) {
112 error = uiomove((void *)v, c, uio);
113 break;
114 }
115
116 if (!kernacc((void *)v, c, uio->uio_rw == UIO_READ ?
117 VM_PROT_READ : VM_PROT_WRITE)) {
118 error = EFAULT;
119 break;
120 }
121
122 /*
123 * If the extracted address is not accessible
124 * through the direct map, then we make a
125 * private (uncached) mapping because we can't
126 * depend on the existing kernel mapping
127 * remaining valid until the completion of
128 * uiomove().
129 *
130 * XXX We cannot provide access to the
131 * physical page 0 mapped into KVA.
132 */
133 v = pmap_extract(kernel_pmap, v);
134 if (v == 0) {
135 error = EFAULT;
136 break;
137 }
138 /* FALLTHROUGH */
139 case CDEV_MINOR_MEM:
140 if (v < dmaplimit) {
141 vd = PHYS_TO_DMAP(v);
142 error = uiomove((void *)vd, c, uio);
143 break;
144 }
145 if (v > cpu_getmaxphyaddr()) {
146 error = EFAULT;
147 break;
148 }
149 p = pmap_mapdev(v, PAGE_SIZE);
150 error = uiomove(p, c, uio);
151 pmap_unmapdev(p, PAGE_SIZE);
152 break;
153 }
154 }
155 /*
156 * Don't return error if any byte was written. Read and write
157 * can return error only if no i/o was performed.
158 */
159 if (uio->uio_resid != orig_resid)
160 error = 0;
161 return (error);
162 }
163
164 /*
165 * allow user processes to MMAP some memory sections
166 * instead of going through read/write
167 */
168 /* ARGSUSED */
169 int
170 memmmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
171 int prot __unused, vm_memattr_t *memattr __unused)
172 {
173 if (dev2unit(dev) == CDEV_MINOR_MEM) {
174 if (offset > cpu_getmaxphyaddr())
175 return (-1);
176 *paddr = offset;
177 return (0);
178 }
179 return (-1);
180 }
181
182 /*
183 * Operations for changing memory attributes.
184 *
185 * This is basically just an ioctl shim for mem_range_attr_get
186 * and mem_range_attr_set.
187 */
188 int
189 memioctl_md(struct cdev *dev __unused, u_long cmd, caddr_t data, int flags,
190 struct thread *td)
191 {
192 int nd, error = 0;
193 struct mem_range_op *mo = (struct mem_range_op *)data;
194 struct mem_range_desc *md;
195
196 /* is this for us? */
197 if ((cmd != MEMRANGE_GET) &&
198 (cmd != MEMRANGE_SET))
199 return (ENOTTY);
200
201 /* any chance we can handle this? */
202 if (mem_range_softc.mr_op == NULL)
203 return (EOPNOTSUPP);
204
205 /* do we have any descriptors? */
206 if (mem_range_softc.mr_ndesc == 0)
207 return (ENXIO);
208
209 switch (cmd) {
210 case MEMRANGE_GET:
211 nd = imin(mo->mo_arg[0], mem_range_softc.mr_ndesc);
212 if (nd > 0) {
213 md = (struct mem_range_desc *)
214 malloc(nd * sizeof(struct mem_range_desc),
215 M_MEMDESC, M_WAITOK);
216 error = mem_range_attr_get(md, &nd);
217 if (!error)
218 error = copyout(md, mo->mo_desc,
219 nd * sizeof(struct mem_range_desc));
220 free(md, M_MEMDESC);
221 }
222 else
223 nd = mem_range_softc.mr_ndesc;
224 mo->mo_arg[0] = nd;
225 break;
226
227 case MEMRANGE_SET:
228 md = (struct mem_range_desc *)malloc(sizeof(struct mem_range_desc),
229 M_MEMDESC, M_WAITOK);
230 error = copyin(mo->mo_desc, md, sizeof(struct mem_range_desc));
231 /* clamp description string */
232 md->mr_owner[sizeof(md->mr_owner) - 1] = 0;
233 if (error == 0)
234 error = mem_range_attr_set(md, &mo->mo_arg[0]);
235 free(md, M_MEMDESC);
236 break;
237 }
238 return (error);
239 }
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