mem.c revision 331722 
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: stable/11/sys/mips/mips/mem.c 331722 2018-03-29 02:50:57Z eadler $");
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/kernel.h>
50#include <sys/lock.h>
51#include <sys/malloc.h>
52#include <sys/memrange.h>
53#include <sys/module.h>
54#include <sys/mutex.h>
55#include <sys/proc.h>
56#include <sys/msgbuf.h>
57#include <sys/systm.h>
58#include <sys/signalvar.h>
59#include <sys/uio.h>
60
61#include <machine/md_var.h>
62#include <machine/vmparam.h>
63
64#include <vm/vm.h>
65#include <vm/pmap.h>
66#include <vm/vm_extern.h>
67#include <vm/vm_page.h>
68
69#include <machine/memdev.h>
70
71struct mem_range_softc mem_range_softc;
72
73/* ARGSUSED */
74int
75memrw(struct cdev *dev, struct uio *uio, int flags)
76{
77	struct iovec *iov;
78	int error = 0;
79	vm_offset_t va, eva, off, v;
80	vm_prot_t prot;
81	struct vm_page m;
82	vm_page_t marr;
83	vm_size_t cnt;
84
85	cnt = 0;
86	error = 0;
87
88	pmap_page_init(&m);
89	while (uio->uio_resid > 0 && !error) {
90		iov = uio->uio_iov;
91		if (iov->iov_len == 0) {
92			uio->uio_iov++;
93			uio->uio_iovcnt--;
94			if (uio->uio_iovcnt < 0)
95				panic("memrw");
96			continue;
97		}
98		if (dev2unit(dev) == CDEV_MINOR_MEM) {
99			v = uio->uio_offset;
100
101			off = uio->uio_offset & PAGE_MASK;
102			cnt = PAGE_SIZE - ((vm_offset_t)iov->iov_base &
103			    PAGE_MASK);
104			cnt = min(cnt, PAGE_SIZE - off);
105			cnt = min(cnt, iov->iov_len);
106
107			m.phys_addr = trunc_page(v);
108			marr = &m;
109			error = uiomove_fromphys(&marr, off, cnt, uio);
110		}
111		else if (dev2unit(dev) == CDEV_MINOR_KMEM) {
112			va = uio->uio_offset;
113
114			va = trunc_page(uio->uio_offset);
115			eva = round_page(uio->uio_offset
116			    + iov->iov_len);
117
118			/*
119			 * Make sure that all the pages are currently resident
120			 * so that we don't create any zero-fill pages.
121			 */
122			if (va >= VM_MIN_KERNEL_ADDRESS &&
123			    eva <= VM_MAX_KERNEL_ADDRESS) {
124				for (; va < eva; va += PAGE_SIZE)
125					if (pmap_extract(kernel_pmap, va) == 0)
126						return (EFAULT);
127
128				prot = (uio->uio_rw == UIO_READ)
129				    ? VM_PROT_READ : VM_PROT_WRITE;
130
131				va = uio->uio_offset;
132				if (kernacc((void *) va, iov->iov_len, prot)
133				    == FALSE)
134					return (EFAULT);
135			}
136
137			va = uio->uio_offset;
138			error = uiomove((void *)va, iov->iov_len, uio);
139			continue;
140		}
141	}
142
143	return (error);
144}
145
146/*
147 * allow user processes to MMAP some memory sections
148 * instead of going through read/write
149 */
150int
151memmmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
152    int prot, vm_memattr_t *memattr)
153{
154	if (dev2unit(dev) != CDEV_MINOR_MEM)
155		return (-1);
156
157	*paddr = offset;
158
159	return (0);
160}
161