mem.c revision 130585 
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 *	from: FreeBSD: src/sys/i386/i386/mem.c,v 1.94 2001/09/26
38 *
39 * $FreeBSD: head/sys/sparc64/sparc64/mem.c 130585 2004-06-16 09:47:26Z phk $
40 */
41
42/*
43 * Memory special file
44 *
45 * NOTE: other architectures support mmap()'ing the mem and kmem devices; this
46 * might cause illegal aliases to be created for the locked kernel page(s), so
47 * it is not implemented.
48 */
49
50#include <sys/param.h>
51#include <sys/conf.h>
52#include <sys/fcntl.h>
53#include <sys/kernel.h>
54#include <sys/lock.h>
55#include <sys/module.h>
56#include <sys/mutex.h>
57#include <sys/module.h>
58#include <sys/proc.h>
59#include <sys/signalvar.h>
60#include <sys/systm.h>
61#include <sys/uio.h>
62
63#include <vm/vm.h>
64#include <vm/vm_param.h>
65#include <vm/vm_page.h>
66#include <vm/vm_kern.h>
67#include <vm/pmap.h>
68#include <vm/vm_extern.h>
69
70#include <machine/cache.h>
71#include <machine/md_var.h>
72#include <machine/pmap.h>
73#include <machine/tlb.h>
74#include <machine/upa.h>
75
76static struct cdev *memdev, *kmemdev;
77
78static	d_open_t	mmopen;
79static	d_close_t	mmclose;
80static	d_read_t	mmrw;
81
82#define CDEV_MAJOR 2
83static struct cdevsw mem_cdevsw = {
84	.d_version =	D_VERSION,
85	.d_open =	mmopen,
86	.d_close =	mmclose,
87	.d_read =	mmrw,
88	.d_write =	mmrw,
89	.d_name =	"mem",
90	.d_maj =	CDEV_MAJOR,
91	.d_flags =	D_MEM | D_NEEDGIANT,
92};
93
94static int
95mmclose(struct cdev *dev, int flags, int fmt, struct thread *td)
96{
97
98	return (0);
99}
100
101static int
102mmopen(struct cdev *dev, int flags, int fmt, struct thread *td)
103{
104	int error;
105
106	switch (minor(dev)) {
107	case 0:
108	case 1:
109		if (flags & FWRITE) {
110			error = securelevel_gt(td->td_ucred, 0);
111			if (error != 0)
112				return (error);
113		}
114		break;
115	default:
116		return (ENXIO);
117	}
118	return (0);
119}
120
121/*ARGSUSED*/
122static int
123mmrw(struct cdev *dev, struct uio *uio, int flags)
124{
125	struct iovec *iov;
126	vm_offset_t eva;
127	vm_offset_t off;
128	vm_offset_t ova;
129	vm_offset_t va;
130	vm_prot_t prot;
131	vm_paddr_t pa;
132	vm_size_t cnt;
133	vm_page_t m;
134	int color;
135	int error;
136	int i;
137
138	cnt = 0;
139	error = 0;
140	ova = 0;
141
142	GIANT_REQUIRED;
143
144	while (uio->uio_resid > 0 && error == 0) {
145		iov = uio->uio_iov;
146		if (iov->iov_len == 0) {
147			uio->uio_iov++;
148			uio->uio_iovcnt--;
149			if (uio->uio_iovcnt < 0)
150				panic("mmrw");
151			continue;
152		}
153		switch (minor(dev)) {
154		case 0:
155			/* mem (physical memory) */
156			pa = uio->uio_offset & ~PAGE_MASK;
157			if (!is_physical_memory(pa)) {
158				error = EFAULT;
159				break;
160			}
161
162			off = uio->uio_offset & PAGE_MASK;
163			cnt = PAGE_SIZE - ((vm_offset_t)iov->iov_base &
164			    PAGE_MASK);
165			cnt = min(cnt, PAGE_SIZE - off);
166			cnt = min(cnt, iov->iov_len);
167
168			m = NULL;
169			for (i = 0; phys_avail[i] != 0; i += 2) {
170				if (pa >= phys_avail[i] &&
171				    pa < phys_avail[i + 1]) {
172					m = PHYS_TO_VM_PAGE(pa);
173					break;
174				}
175			}
176
177			if (m != NULL) {
178				if (ova == 0) {
179					ova = kmem_alloc_wait(kernel_map,
180					    PAGE_SIZE * DCACHE_COLORS);
181				}
182				if ((color = m->md.color) == -1)
183					va = ova;
184				else
185					va = ova + color * PAGE_SIZE;
186				pmap_qenter(va, &m, 1);
187				error = uiomove((void *)(va + off), cnt,
188				    uio);
189				pmap_qremove(va, 1);
190			} else {
191				va = TLB_PHYS_TO_DIRECT(pa);
192				error = uiomove((void *)(va + off), cnt,
193				    uio);
194			}
195			break;
196		case 1:
197			/* kmem (kernel memory) */
198			va = trunc_page(uio->uio_offset);
199			eva = round_page(uio->uio_offset + iov->iov_len);
200
201			/*
202			 * Make sure that all of the pages are currently
203			 * resident so we don't create any zero fill pages.
204			 */
205			for (; va < eva; va += PAGE_SIZE)
206				if (pmap_kextract(va) == 0)
207					return (EFAULT);
208
209			prot = (uio->uio_rw == UIO_READ) ? VM_PROT_READ :
210			    VM_PROT_WRITE;
211			va = uio->uio_offset;
212			if (va < VM_MIN_DIRECT_ADDRESS &&
213			    kernacc((void *)va, iov->iov_len, prot) == FALSE)
214				return (EFAULT);
215
216			error = uiomove((void *)va, iov->iov_len, uio);
217			break;
218		default:
219			return (ENODEV);
220		}
221	}
222	if (ova != 0)
223		kmem_free_wakeup(kernel_map, ova, PAGE_SIZE * DCACHE_COLORS);
224	return (error);
225}
226
227static int
228mem_modevent(module_t mod, int type, void *data)
229{
230	switch(type) {
231	case MOD_LOAD:
232		if (bootverbose)
233			printf("mem: <memory & I/O>\n");
234
235		memdev = make_dev(&mem_cdevsw, 0, UID_ROOT, GID_KMEM,
236			0640, "mem");
237		kmemdev = make_dev(&mem_cdevsw, 1, UID_ROOT, GID_KMEM,
238			0640, "kmem");
239		return 0;
240
241	case MOD_UNLOAD:
242		destroy_dev(memdev);
243		destroy_dev(kmemdev);
244		return 0;
245
246	case MOD_SHUTDOWN:
247		return 0;
248
249	default:
250		return EOPNOTSUPP;
251	}
252}
253
254DEV_MODULE(mem, mem_modevent, NULL);
255