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1.1 nbrk 1: /* $OpenBSD: mem.c,v 1.20 2005/10/23 19:00:26 martin Exp $ */
2: /* $NetBSD: mem.c,v 1.22 1999/03/27 00:30:07 mycroft Exp $ */
3:
4: /*
5: * Copyright (c) 1988 University of Utah.
6: * Copyright (c) 1982, 1986, 1990, 1993
7: * The Regents of the University of California. All rights reserved.
8: *
9: * This code is derived from software contributed to Berkeley by
10: * the Systems Programming Group of the University of Utah Computer
11: * Science Department.
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: * @(#)mem.c 8.3 (Berkeley) 1/12/94
38: */
39:
40: /*
41: * Memory special file
42: */
43:
44: #include <sys/param.h>
45: #include <sys/conf.h>
46: #include <sys/buf.h>
47: #include <sys/proc.h>
48: #include <sys/systm.h>
49: #include <sys/uio.h>
50: #include <sys/malloc.h>
51:
52: #include <machine/cpu.h>
53:
54: #include <uvm/uvm_extern.h>
55:
56: extern u_long maxaddr;
57:
58: static caddr_t devzeropage;
59:
60: #define mmread mmrw
61: #define mmwrite mmrw
62: cdev_decl(mm);
63:
64: /*ARGSUSED*/
65: int
66: mmopen(dev, flag, mode, p)
67: dev_t dev;
68: int flag, mode;
69: struct proc *p;
70: {
71:
72: switch (minor(dev)) {
73: case 0:
74: case 1:
75: case 2:
76: case 12:
77: return (0);
78: default:
79: return (ENXIO);
80: }
81: }
82:
83: /*ARGSUSED*/
84: int
85: mmclose(dev, flag, mode, p)
86: dev_t dev;
87: int flag, mode;
88: struct proc *p;
89: {
90:
91: return (0);
92: }
93:
94: /*ARGSUSED*/
95: int
96: mmrw(dev, uio, flags)
97: dev_t dev;
98: struct uio *uio;
99: int flags;
100: {
101: vaddr_t o, v;
102: int c;
103: struct iovec *iov;
104: int error = 0;
105: static int physlock;
106: vm_prot_t prot;
107:
108: if (minor(dev) == 0) {
109: /* lock against other uses of shared vmmap */
110: while (physlock > 0) {
111: physlock++;
112: error = tsleep((caddr_t)&physlock, PZERO | PCATCH,
113: "mmrw", 0);
114: if (error)
115: return (error);
116: }
117: physlock = 1;
118: }
119: while (uio->uio_resid > 0 && error == 0) {
120: iov = uio->uio_iov;
121: if (iov->iov_len == 0) {
122: uio->uio_iov++;
123: uio->uio_iovcnt--;
124: if (uio->uio_iovcnt < 0)
125: panic("mmrw");
126: continue;
127: }
128: switch (minor(dev)) {
129:
130: /* minor device 0 is physical memory */
131: case 0:
132: v = uio->uio_offset;
133:
134: /*
135: * Only allow reads in physical RAM.
136: */
137: if (v >= maxaddr || v < 0) {
138: error = EFAULT;
139: goto unlock;
140: }
141:
142: prot = uio->uio_rw == UIO_READ ? VM_PROT_READ :
143: VM_PROT_WRITE;
144: pmap_enter(pmap_kernel(), (vaddr_t)vmmap,
145: trunc_page(v), prot, prot|PMAP_WIRED);
146: pmap_update(pmap_kernel());
147: o = m68k_page_offset(uio->uio_offset);
148: c = min(uio->uio_resid, (int)(NBPG - o));
149: error = uiomove((caddr_t)vmmap + o, c, uio);
150: pmap_remove(pmap_kernel(), (vaddr_t)vmmap,
151: (vaddr_t)vmmap + NBPG);
152: pmap_update(pmap_kernel());
153: continue;
154:
155: /* minor device 1 is kernel memory */
156: case 1:
157: v = uio->uio_offset;
158: c = min(iov->iov_len, MAXPHYS);
159: if (!uvm_kernacc((caddr_t)v, c,
160: uio->uio_rw == UIO_READ ? B_READ : B_WRITE))
161: return (EFAULT);
162: error = uiomove((caddr_t)v, c, uio);
163: continue;
164:
165: /* minor device 2 is EOF/RATHOLE */
166: case 2:
167: if (uio->uio_rw == UIO_WRITE)
168: uio->uio_resid = 0;
169: return (0);
170:
171: /* minor device 12 (/dev/zero) is source of nulls on read, rathole on write */
172: case 12:
173: if (uio->uio_rw == UIO_WRITE) {
174: c = iov->iov_len;
175: break;
176: }
177:
178: /*
179: * On the first call, allocate and zero a page
180: * of memory for use with /dev/zero.
181: */
182: if (devzeropage == NULL) {
183: devzeropage = (caddr_t)
184: malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
185: bzero(devzeropage, PAGE_SIZE);
186: }
187: c = min(iov->iov_len, PAGE_SIZE);
188: error = uiomove(devzeropage, c, uio);
189: continue;
190:
191: default:
192: return (ENXIO);
193: }
194: if (error)
195: break;
196: iov->iov_base = (caddr_t)iov->iov_base + c;
197: iov->iov_len -= c;
198: uio->uio_offset += c;
199: uio->uio_resid -= c;
200: }
201: if (minor(dev) == 0) {
202: unlock:
203: if (physlock > 1)
204: wakeup((caddr_t)&physlock);
205: physlock = 0;
206: }
207: return (error);
208: }
209:
210: paddr_t
211: mmmmap(dev, off, prot)
212: dev_t dev;
213: off_t off;
214: int prot;
215: {
216: /*
217: * /dev/mem is the only one that makes sense through this
218: * interface. For /dev/kmem any physaddr we return here
219: * could be transient and hence incorrect or invalid at
220: * a later time. /dev/null just doesn't make any sense
221: * and /dev/zero is a hack that is handled via the default
222: * pager in mmap().
223: */
224: if (minor(dev) != 0)
225: return (-1);
226:
227: /*
228: * Only allow access to physical RAM.
229: */
230: if ((u_int)off >= maxaddr)
231: return (-1);
232:
233: return (atop((u_int)off));
234: }
235:
236: int
237: mmioctl(dev, cmd, data, flags, p)
238: dev_t dev;
239: u_long cmd;
240: caddr_t data;
241: int flags;
242: struct proc *p;
243: {
244: return (EOPNOTSUPP);
245: }