1/* $OpenBSD: mem.c,v 1.6 2017/12/14 03:30:43 guenther Exp $ */ 2 3/* 4 * Copyright (c) 1988 University of Utah. 5 * Copyright (c) 1982, 1986, 1990, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)mem.c 8.3 (Berkeley) 1/12/94 37 */ 38 39/* 40 * Memory special file 41 */ 42 43#include <sys/param.h> 44#include <sys/buf.h> 45#include <sys/filio.h> 46#include <sys/systm.h> 47#include <sys/uio.h> 48#include <sys/malloc.h> 49 50#include <machine/conf.h> 51 52#include <uvm/uvm_extern.h> 53 54caddr_t zpage; 55extern vaddr_t first_addr, last_addr; 56extern caddr_t kernelstart; 57extern void *etext; 58 59int 60mmopen(dev_t dev, int flag, int mode, struct proc *p) 61{ 62 extern int allowkmem; 63 64 switch (minor(dev)) { 65 case 0: 66 case 1: 67 if (securelevel <= 0 || allowkmem) 68 break; 69 return (EPERM); 70 case 2: 71 case 12: 72 break; 73 default: 74 return (ENXIO); 75 } 76 return (0); 77} 78 79int 80mmclose(dev_t dev, int flag, int mode, struct proc *p) 81{ 82 83 return (0); 84} 85 86int 87mmrw(dev_t dev, struct uio *uio, int flags) 88{ 89 vaddr_t v; 90 size_t c; 91 struct iovec *iov; 92 int error = 0; 93 94 while (uio->uio_resid > 0 && error == 0) { 95 iov = uio->uio_iov; 96 if (iov->iov_len == 0) { 97 uio->uio_iov++; 98 uio->uio_iovcnt--; 99 if (uio->uio_iovcnt < 0) 100 panic("mmrw"); 101 continue; 102 } 103 switch (minor(dev)) { 104 105 /* minor device 0 is physical memory */ 106 case 0: 107 v = uio->uio_offset; 108 error = uiomove((caddr_t)v, uio->uio_resid, uio); 109 continue; 110 111 /* minor device 1 is kernel memory */ 112 case 1: 113 v = uio->uio_offset; 114 c = ulmin(iov->iov_len, MAXPHYS); 115 if (v >= (vaddr_t)&kernelstart && 116 v < (vaddr_t)first_addr) { 117 if (v < (vaddr_t)etext && 118 uio->uio_rw == UIO_WRITE) 119 return (EFAULT); 120 } else if (!uvm_kernacc((caddr_t)v, c, 121 uio->uio_rw == UIO_READ ? B_READ : B_WRITE)) 122 return (EFAULT); 123 error = uiomove((caddr_t)v, c, uio); 124 continue; 125 126 /* minor device 2 is /dev/null */ 127 case 2: 128 if (uio->uio_rw == UIO_WRITE) 129 uio->uio_resid = 0; 130 return (0); 131 132 /* minor device 12 is /dev/zero */ 133 case 12: 134 if (uio->uio_rw == UIO_WRITE) { 135 c = iov->iov_len; 136 break; 137 } 138 if (zpage == NULL) 139 zpage = malloc(PAGE_SIZE, M_TEMP, 140 M_WAITOK | M_ZERO); 141 c = ulmin(iov->iov_len, PAGE_SIZE); 142 error = uiomove(zpage, c, uio); 143 continue; 144 145 default: 146 return (ENXIO); 147 } 148 if (error) 149 break; 150 iov->iov_base += c; 151 iov->iov_len -= c; 152 uio->uio_offset += c; 153 uio->uio_resid -= c; 154 } 155 156 return (error); 157} 158 159paddr_t 160mmmmap(dev_t dev, off_t off, int prot) 161{ 162 return (-1); 163} 164 165int 166mmioctl(dev_t dev, u_long cmd, caddr_t data, int flags, struct proc *p) 167{ 168 switch (cmd) { 169 case FIONBIO: 170 case FIOASYNC: 171 /* handled by fd layer */ 172 return 0; 173 } 174 175 return (EOPNOTSUPP); 176} 177