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/6.1/sys/i386/i386/mem.c 158179 2006-04-30 16:44:43Z cvs2svn $");
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 static struct sx memsxlock;
76 SX_SYSINIT(memsxlockinit, &memsxlock, "/dev/mem lock");
77
78
79 /* ARGSUSED */
80 int
81 memrw(struct cdev *dev, struct uio *uio, int flags)
82 {
83 int o;
84 u_int c = 0;
85 vm_paddr_t pa;
86 struct iovec *iov;
87 int error = 0;
88 vm_offset_t addr;
89
90 /* XXX UPS Why ? */
91 GIANT_REQUIRED;
92
93
94 if (minor(dev) != CDEV_MINOR_MEM && minor(dev) != CDEV_MINOR_KMEM)
95 return EIO;
96
97 if ( minor(dev) == CDEV_MINOR_KMEM && uio->uio_resid > 0) {
98 if (uio->uio_offset < (vm_offset_t)VADDR(PTDPTDI, 0))
99 return (EFAULT);
100
101 if (!kernacc((caddr_t)(int)uio->uio_offset, uio->uio_resid,
102 uio->uio_rw == UIO_READ ? VM_PROT_READ : VM_PROT_WRITE))
103 return (EFAULT);
104 }
105
106 while (uio->uio_resid > 0 && error == 0) {
107 iov = uio->uio_iov;
108 if (iov->iov_len == 0) {
109 uio->uio_iov++;
110 uio->uio_iovcnt--;
111 if (uio->uio_iovcnt < 0)
112 panic("memrw");
113 continue;
114 }
115 if (minor(dev) == CDEV_MINOR_MEM) {
116 pa = uio->uio_offset;
117 pa &= ~PAGE_MASK;
118 } else {
119 /*
120 * Extract the physical page since the mapping may
121 * change at any time. This avoids panics on page
122 * fault in this case but will cause reading/writing
123 * to the wrong page.
124 * Hopefully an application will notice the wrong
125 * data on read access and refrain from writing.
126 * This should be replaced by a special uiomove
127 * type function that just returns an error if there
128 * is a page fault on a kernel page.
129 */
130 addr = trunc_page(uio->uio_offset);
131 pa = pmap_extract(kernel_pmap, addr);
132 if (pa == 0)
133 return EFAULT;
134
135 }
136
137 /*
138 * XXX UPS This should just use sf_buf_alloc.
139 * Unfortunately sf_buf_alloc needs a vm_page
140 * and we may want to look at memory not covered
141 * by the page array.
142 */
143
144 sx_xlock(&memsxlock);
145 pmap_kenter((vm_offset_t)ptvmmap, pa);
146 pmap_invalidate_page(kernel_pmap,(vm_offset_t)ptvmmap);
147
148 o = (int)uio->uio_offset & PAGE_MASK;
149 c = PAGE_SIZE - o;
150 c = min(c, (u_int)iov->iov_len);
151 error = uiomove((caddr_t)&ptvmmap[o], (int)c, uio);
152 pmap_qremove((vm_offset_t)ptvmmap, 1);
153 sx_xunlock(&memsxlock);
154
155 }
156
157 return (error);
158 }
159
160 /*
161 * allow user processes to MMAP some memory sections
162 * instead of going through read/write
163 */
164 /* ARGSUSED */
165 int
166 memmmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr,
167 int prot __unused)
168 {
169 if (minor(dev) == CDEV_MINOR_MEM)
170 *paddr = offset;
171 else if (minor(dev) == CDEV_MINOR_KMEM)
172 *paddr = vtophys(offset);
173 /* else panic! */
174 return (0);
175 }
176
177 /*
178 * Operations for changing memory attributes.
179 *
180 * This is basically just an ioctl shim for mem_range_attr_get
181 * and mem_range_attr_set.
182 */
183 /* ARGSUSED */
184 int
185 memioctl(struct cdev *dev __unused, u_long cmd, caddr_t data, int flags,
186 struct thread *td)
187 {
188 int nd, error = 0;
189 struct mem_range_op *mo = (struct mem_range_op *)data;
190 struct mem_range_desc *md;
191
192 /* is this for us? */
193 if ((cmd != MEMRANGE_GET) &&
194 (cmd != MEMRANGE_SET))
195 return (ENOTTY);
196
197 /* any chance we can handle this? */
198 if (mem_range_softc.mr_op == NULL)
199 return (EOPNOTSUPP);
200
201 /* do we have any descriptors? */
202 if (mem_range_softc.mr_ndesc == 0)
203 return (ENXIO);
204
205 switch (cmd) {
206 case MEMRANGE_GET:
207 nd = imin(mo->mo_arg[0], mem_range_softc.mr_ndesc);
208 if (nd > 0) {
209 md = (struct mem_range_desc *)
210 malloc(nd * sizeof(struct mem_range_desc),
211 M_MEMDESC, M_WAITOK);
212 error = mem_range_attr_get(md, &nd);
213 if (!error)
214 error = copyout(md, mo->mo_desc,
215 nd * sizeof(struct mem_range_desc));
216 free(md, M_MEMDESC);
217 }
218 else
219 nd = mem_range_softc.mr_ndesc;
220 mo->mo_arg[0] = nd;
221 break;
222
223 case MEMRANGE_SET:
224 md = (struct mem_range_desc *)malloc(sizeof(struct mem_range_desc),
225 M_MEMDESC, M_WAITOK);
226 error = copyin(mo->mo_desc, md, sizeof(struct mem_range_desc));
227 /* clamp description string */
228 md->mr_owner[sizeof(md->mr_owner) - 1] = 0;
229 if (error == 0)
230 error = mem_range_attr_set(md, &mo->mo_arg[0]);
231 free(md, M_MEMDESC);
232 break;
233 }
234 return (error);
235 }
236
237 void
238 dev_mem_md_init(void)
239 {
240 if (mem_range_softc.mr_op != NULL)
241 mem_range_softc.mr_op->init(&mem_range_softc);
242 }
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