bsd/dev/i386/mem.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*-
  23  * Copyright (c) 1988 University of Utah.
  24  * Copyright (c) 1982, 1986, 1990, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  *
  27  * This code is derived from software contributed to Berkeley by
  28  * the Systems Programming Group of the University of Utah Computer
  29  * Science Department, and code derived from software contributed to
  30  * Berkeley by William Jolitz.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice, this list of conditions and the following disclaimer.
  37  * 2. Redistributions in binary form must reproduce the above copyright
  38  *    notice, this list of conditions and the following disclaimer in the
  39  *    documentation and/or other materials provided with the distribution.
  40  * 3. All advertising materials mentioning features or use of this software
  41  *    must display the following acknowledgement:
  42  *      This product includes software developed by the University of
  43  *      California, Berkeley and its contributors.
  44  * 4. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  *
  60  * from: Utah $Hdr: mem.c 1.13 89/10/08$
  61  *      @(#)mem.c       8.1 (Berkeley) 6/11/93
  62  */
  63
  64 #include <mach_load.h>
  65
  66 /*
  67  * Memory special file
  68  */
  69
  70 #include <sys/param.h>
  71 #include <sys/dir.h>
  72 #include <sys/proc.h>
  73 #include <sys/buf.h>
  74 #include <sys/systm.h>
  75 #include <sys/vm.h>
  76 #include <sys/uio.h>
  77 #include <sys/malloc.h>
  78
  79 #include <mach/vm_types.h>
  80 #include <mach/vm_param.h>
  81 #include <vm/vm_kern.h>         /* for kernel_map */
  82
  83 static caddr_t devzerobuf;
  84
  85 mmread(dev, uio)
  86         dev_t dev;
  87         struct uio *uio;
  88 {
  89
  90         return (mmrw(dev, uio, UIO_READ));
  91 }
  92
  93 mmwrite(dev, uio)
  94         dev_t dev;
  95         struct uio *uio;
  96 {
  97
  98         return (mmrw(dev, uio, UIO_WRITE));
  99 }
 100
 101 mmrw(dev, uio, rw)
 102         dev_t dev;
 103         struct uio *uio;
 104         enum uio_rw rw;
 105 {
 106         register int o;
 107         register u_int c, v;
 108         register struct iovec *iov;
 109         int error = 0;
 110         vm_offset_t     where;
 111         int             spl;
 112         vm_size_t size;
 113         extern boolean_t kernacc(off_t, size_t );
 114
 115         while (uio->uio_resid > 0 && error == 0) {
 116                 iov = uio->uio_iov;
 117                 if (iov->iov_len == 0) {
 118                         uio->uio_iov++;
 119                         uio->uio_iovcnt--;
 120                         if (uio->uio_iovcnt < 0)
 121                                 panic("mmrw");
 122                         continue;
 123                 }
 124                 switch (minor(dev)) {
 125
 126                 /* minor device 0 is physical memory */
 127                 case 0:
 128                         v = trunc_page(uio->uio_offset);
 129                         if (uio->uio_offset >= mem_size)
 130                                 goto fault;
 131
 132                         size= PAGE_SIZE;
 133                         if (kmem_alloc(kernel_map, &where, size)
 134                                 != KERN_SUCCESS) {
 135                                 goto fault;
 136                         }
 137                         o = uio->uio_offset - v;
 138                         c = min(PAGE_SIZE - o, (u_int)iov->iov_len);
 139                         error = uiomove((caddr_t) (where + o), c, uio);
 140                         kmem_free(kernel_map, where, PAGE_SIZE);
 141                         continue;
 142
 143                 /* minor device 1 is kernel memory */
 144                 case 1:
 145                         /* Do some sanity checking */
 146                         if (((vm_address_t)uio->uio_offset >= VM_MAX_KERNEL_ADDRESS) ||
 147                                 ((vm_address_t)uio->uio_offset <= VM_MIN_KERNEL_ADDRESS))
 148                                 goto fault;
 149                         c = iov->iov_len;
 150                         if (!kernacc(uio->uio_offset, c))
 151                                 goto fault;
 152                         error = uiomove((caddr_t)uio->uio_offset, (int)c, uio);
 153                         continue;
 154
 155                 /* minor device 2 is EOF/RATHOLE */
 156                 case 2:
 157                         if (rw == UIO_READ)
 158                                 return (0);
 159                         c = iov->iov_len;
 160                         break;
 161                 case 3:
 162                         if(devzerobuf == NULL) {
 163                                 MALLOC(devzerobuf, caddr_t,PAGE_SIZE, M_TEMP, M_WAITOK);
 164                                 bzero(devzerobuf, PAGE_SIZE);
 165                         }
 166                         if(uio->uio_rw == UIO_WRITE) {
 167                                 c = iov->iov_len;
 168                                 break;
 169                         }
 170                         c = min(iov->iov_len, PAGE_SIZE);
 171                         error = uiomove(devzerobuf, (int)c, uio);
 172                         continue;
 173                 default:
 174                         goto fault;
 175                         break;
 176                 }
 177
 178                 if (error)
 179                         break;
 180                 iov->iov_base += c;
 181                 iov->iov_len -= c;
 182                 uio->uio_offset += c;
 183                 uio->uio_resid -= c;
 184         }
 185         return (error);
 186 fault:
 187         return (EFAULT);
 188 }
 189
 190
 191 boolean_t
 192 kernacc(
 193     off_t       start,
 194     size_t      len
 195 )
 196 {
 197         off_t base;
 198         off_t end;
 199
 200         base = trunc_page(start);
 201         end = start + len;
 202
 203         while (base < end) {
 204                 if(kvtophys((vm_offset_t)base) == NULL)
 205                         return(FALSE);
 206                 base += page_size;
 207         }
 208
 209         return (TRUE);
 210 }