FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/mem.c
1 /*-
2 * Copyright (c) 1988 University of Utah.
3 * Copyright (c) 1982, 1986, 1990 The Regents of the University of California.
4 * All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * the Systems Programming Group of the University of Utah Computer
8 * Science Department, and code derived from software contributed to
9 * Berkeley by William Jolitz.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 4. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * from: Utah $Hdr: mem.c 1.13 89/10/08$
36 * from: @(#)mem.c 7.2 (Berkeley) 5/9/91
37 */
38
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD: releng/8.3/sys/i386/i386/mem.c 219212 2011-03-03 00:24:55Z jkim $");
41
42 /*
43 * Memory special file
44 */
45
46 #include <sys/param.h>
47 #include <sys/conf.h>
48 #include <sys/fcntl.h>
49 #include <sys/ioccom.h>
50 #include <sys/kernel.h>
51 #include <sys/lock.h>
52 #include <sys/malloc.h>
53 #include <sys/memrange.h>
54 #include <sys/module.h>
55 #include <sys/mutex.h>
56 #include <sys/sx.h>
57 #include <sys/proc.h>
58 #include <sys/signalvar.h>
59 #include <sys/systm.h>
60 #include <sys/uio.h>
61
62 #include <machine/specialreg.h>
63
64 #include <vm/vm.h>
65 #include <vm/pmap.h>
66 #include <vm/vm_extern.h>
67
68 #include <machine/memdev.h>
69
70 /*
71 * Used in /dev/mem drivers and elsewhere
72 */
73 MALLOC_DEFINE(M_MEMDESC, "memdesc", "memory range descriptors");
74
75 struct mem_range_softc mem_range_softc;
76
77 static struct sx memsxlock;
78 SX_SYSINIT(memsxlockinit, &memsxlock, "/dev/mem lock");
79
80 /* ARGSUSED */
81 int
82 memrw(struct cdev *dev, struct uio *uio, int flags)
83 {
84 int o;
85 u_int c = 0;
86 vm_paddr_t pa;
87 struct iovec *iov;
88 int error = 0;
89 vm_offset_t addr;
90
91 /* XXX UPS Why ? */
92 GIANT_REQUIRED;
93
94
95 if (dev2unit(dev) != CDEV_MINOR_MEM && dev2unit(dev) != CDEV_MINOR_KMEM)
96 return EIO;
97
98 if (dev2unit(dev) == CDEV_MINOR_KMEM && uio->uio_resid > 0) {
99 if (uio->uio_offset < (vm_offset_t)VADDR(PTDPTDI, 0))
100 return (EFAULT);
101
102 if (!kernacc((caddr_t)(int)uio->uio_offset, uio->uio_resid,
103 uio->uio_rw == UIO_READ ? VM_PROT_READ : VM_PROT_WRITE))
104 return (EFAULT);
105 }
106
107 while (uio->uio_resid > 0 && error == 0) {
108 iov = uio->uio_iov;
109 if (iov->iov_len == 0) {
110 uio->uio_iov++;
111 uio->uio_iovcnt--;
112 if (uio->uio_iovcnt < 0)
113 panic("memrw");
114 continue;
115 }
116 if (dev2unit(dev) == CDEV_MINOR_MEM) {
117 pa = uio->uio_offset;
118 pa &= ~PAGE_MASK;
119 } else {
120 /*
121 * Extract the physical page since the mapping may
122 * change at any time. This avoids panics on page
123 * fault in this case but will cause reading/writing
124 * to the wrong page.
125 * Hopefully an application will notice the wrong
126 * data on read access and refrain from writing.
127 * This should be replaced by a special uiomove
128 * type function that just returns an error if there
129 * is a page fault on a kernel page.
130 */
131 addr = trunc_page(uio->uio_offset);
132 pa = pmap_extract(kernel_pmap, addr);
133 if (pa == 0)
134 return EFAULT;
135
136 }
137
138 /*
139 * XXX UPS This should just use sf_buf_alloc.
140 * Unfortunately sf_buf_alloc needs a vm_page
141 * and we may want to look at memory not covered
142 * by the page array.
143 */
144
145 sx_xlock(&memsxlock);
146 pmap_kenter((vm_offset_t)ptvmmap, pa);
147 pmap_invalidate_page(kernel_pmap,(vm_offset_t)ptvmmap);
148
149 o = (int)uio->uio_offset & PAGE_MASK;
150 c = PAGE_SIZE - o;
151 c = min(c, (u_int)iov->iov_len);
152 error = uiomove((caddr_t)&ptvmmap[o], (int)c, uio);
153 pmap_qremove((vm_offset_t)ptvmmap, 1);
154 sx_xunlock(&memsxlock);
155
156 }
157
158 return (error);
159 }
160
161 /*
162 * allow user processes to MMAP some memory sections
163 * instead of going through read/write
164 */
165 /* ARGSUSED */
166 int
167 memmmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr,
168 int prot __unused)
169 {
170 if (dev2unit(dev) == CDEV_MINOR_MEM)
171 *paddr = offset;
172 else if (dev2unit(dev) == CDEV_MINOR_KMEM)
173 *paddr = vtophys(offset);
174 /* else panic! */
175 return (0);
176 }
177
178 /*
179 * Operations for changing memory attributes.
180 *
181 * This is basically just an ioctl shim for mem_range_attr_get
182 * and mem_range_attr_set.
183 */
184 /* ARGSUSED */
185 int
186 memioctl(struct cdev *dev __unused, u_long cmd, caddr_t data, int flags,
187 struct thread *td)
188 {
189 int nd, error = 0;
190 struct mem_range_op *mo = (struct mem_range_op *)data;
191 struct mem_range_desc *md;
192
193 /* is this for us? */
194 if ((cmd != MEMRANGE_GET) &&
195 (cmd != MEMRANGE_SET))
196 return (ENOTTY);
197
198 /* any chance we can handle this? */
199 if (mem_range_softc.mr_op == NULL)
200 return (EOPNOTSUPP);
201
202 /* do we have any descriptors? */
203 if (mem_range_softc.mr_ndesc == 0)
204 return (ENXIO);
205
206 switch (cmd) {
207 case MEMRANGE_GET:
208 nd = imin(mo->mo_arg[0], mem_range_softc.mr_ndesc);
209 if (nd > 0) {
210 md = (struct mem_range_desc *)
211 malloc(nd * sizeof(struct mem_range_desc),
212 M_MEMDESC, M_WAITOK);
213 error = mem_range_attr_get(md, &nd);
214 if (!error)
215 error = copyout(md, mo->mo_desc,
216 nd * sizeof(struct mem_range_desc));
217 free(md, M_MEMDESC);
218 }
219 else
220 nd = mem_range_softc.mr_ndesc;
221 mo->mo_arg[0] = nd;
222 break;
223
224 case MEMRANGE_SET:
225 md = (struct mem_range_desc *)malloc(sizeof(struct mem_range_desc),
226 M_MEMDESC, M_WAITOK);
227 error = copyin(mo->mo_desc, md, sizeof(struct mem_range_desc));
228 /* clamp description string */
229 md->mr_owner[sizeof(md->mr_owner) - 1] = 0;
230 if (error == 0)
231 error = mem_range_attr_set(md, &mo->mo_arg[0]);
232 free(md, M_MEMDESC);
233 break;
234 }
235 return (error);
236 }
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