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/9.2/sys/i386/i386/mem.c 239880 2012-08-29 20:49:36Z jhb $");
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 /* ARGSUSED */
79 int
80 memrw(struct cdev *dev, struct uio *uio, int flags)
81 {
82 int o;
83 u_int c = 0;
84 vm_paddr_t pa;
85 struct iovec *iov;
86 int error = 0;
87 vm_offset_t addr;
88
89 /* XXX UPS Why ? */
90 GIANT_REQUIRED;
91
92
93 if (dev2unit(dev) != CDEV_MINOR_MEM && dev2unit(dev) != CDEV_MINOR_KMEM)
94 return EIO;
95
96 if (dev2unit(dev) == CDEV_MINOR_KMEM && uio->uio_resid > 0) {
97 if (uio->uio_offset < (vm_offset_t)VADDR(PTDPTDI, 0))
98 return (EFAULT);
99
100 if (!kernacc((caddr_t)(int)uio->uio_offset, uio->uio_resid,
101 uio->uio_rw == UIO_READ ? VM_PROT_READ : VM_PROT_WRITE))
102 return (EFAULT);
103 }
104
105 while (uio->uio_resid > 0 && error == 0) {
106 iov = uio->uio_iov;
107 if (iov->iov_len == 0) {
108 uio->uio_iov++;
109 uio->uio_iovcnt--;
110 if (uio->uio_iovcnt < 0)
111 panic("memrw");
112 continue;
113 }
114 if (dev2unit(dev) == CDEV_MINOR_MEM) {
115 pa = uio->uio_offset;
116 pa &= ~PAGE_MASK;
117 } else {
118 /*
119 * Extract the physical page since the mapping may
120 * change at any time. This avoids panics on page
121 * fault in this case but will cause reading/writing
122 * to the wrong page.
123 * Hopefully an application will notice the wrong
124 * data on read access and refrain from writing.
125 * This should be replaced by a special uiomove
126 * type function that just returns an error if there
127 * is a page fault on a kernel page.
128 */
129 addr = trunc_page(uio->uio_offset);
130 pa = pmap_extract(kernel_pmap, addr);
131 if (pa == 0)
132 return EFAULT;
133
134 }
135
136 /*
137 * XXX UPS This should just use sf_buf_alloc.
138 * Unfortunately sf_buf_alloc needs a vm_page
139 * and we may want to look at memory not covered
140 * by the page array.
141 */
142
143 sx_xlock(&memsxlock);
144 pmap_kenter((vm_offset_t)ptvmmap, pa);
145 pmap_invalidate_page(kernel_pmap,(vm_offset_t)ptvmmap);
146
147 o = (int)uio->uio_offset & PAGE_MASK;
148 c = PAGE_SIZE - o;
149 c = min(c, (u_int)iov->iov_len);
150 error = uiomove((caddr_t)&ptvmmap[o], (int)c, uio);
151 pmap_qremove((vm_offset_t)ptvmmap, 1);
152 sx_xunlock(&memsxlock);
153
154 }
155
156 return (error);
157 }
158
159 /*
160 * allow user processes to MMAP some memory sections
161 * instead of going through read/write
162 */
163 /* ARGSUSED */
164 int
165 memmmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
166 int prot __unused, vm_memattr_t *memattr __unused)
167 {
168 if (dev2unit(dev) == CDEV_MINOR_MEM)
169 *paddr = offset;
170 else if (dev2unit(dev) == CDEV_MINOR_KMEM)
171 *paddr = vtophys(offset);
172 /* else panic! */
173 return (0);
174 }
175
176 /*
177 * Operations for changing memory attributes.
178 *
179 * This is basically just an ioctl shim for mem_range_attr_get
180 * and mem_range_attr_set.
181 */
182 /* ARGSUSED */
183 int
184 memioctl(struct cdev *dev __unused, u_long cmd, caddr_t data, int flags,
185 struct thread *td)
186 {
187 int nd, error = 0;
188 struct mem_range_op *mo = (struct mem_range_op *)data;
189 struct mem_range_desc *md;
190
191 /* is this for us? */
192 if ((cmd != MEMRANGE_GET) &&
193 (cmd != MEMRANGE_SET))
194 return (ENOTTY);
195
196 /* any chance we can handle this? */
197 if (mem_range_softc.mr_op == NULL)
198 return (EOPNOTSUPP);
199
200 /* do we have any descriptors? */
201 if (mem_range_softc.mr_ndesc == 0)
202 return (ENXIO);
203
204 switch (cmd) {
205 case MEMRANGE_GET:
206 nd = imin(mo->mo_arg[0], mem_range_softc.mr_ndesc);
207 if (nd > 0) {
208 md = (struct mem_range_desc *)
209 malloc(nd * sizeof(struct mem_range_desc),
210 M_MEMDESC, M_WAITOK);
211 error = mem_range_attr_get(md, &nd);
212 if (!error)
213 error = copyout(md, mo->mo_desc,
214 nd * sizeof(struct mem_range_desc));
215 free(md, M_MEMDESC);
216 }
217 else
218 nd = mem_range_softc.mr_ndesc;
219 mo->mo_arg[0] = nd;
220 break;
221
222 case MEMRANGE_SET:
223 md = (struct mem_range_desc *)malloc(sizeof(struct mem_range_desc),
224 M_MEMDESC, M_WAITOK);
225 error = copyin(mo->mo_desc, md, sizeof(struct mem_range_desc));
226 /* clamp description string */
227 md->mr_owner[sizeof(md->mr_owner) - 1] = 0;
228 if (error == 0)
229 error = mem_range_attr_set(md, &mo->mo_arg[0]);
230 free(md, M_MEMDESC);
231 break;
232 }
233 return (error);
234 }
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