bsd/dev/i386/mem.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*-
  26  * Copyright (c) 1988 University of Utah.
  27  * Copyright (c) 1982, 1986, 1990, 1993
  28  *      The Regents of the University of California.  All rights reserved.
  29  *
  30  * This code is derived from software contributed to Berkeley by
  31  * the Systems Programming Group of the University of Utah Computer
  32  * Science Department, and code derived from software contributed to
  33  * Berkeley by William Jolitz.
  34  *
  35  * Redistribution and use in source and binary forms, with or without
  36  * modification, are permitted provided that the following conditions
  37  * are met:
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  * 2. Redistributions in binary form must reproduce the above copyright
  41  *    notice, this list of conditions and the following disclaimer in the
  42  *    documentation and/or other materials provided with the distribution.
  43  * 3. All advertising materials mentioning features or use of this software
  44  *    must display the following acknowledgement:
  45  *      This product includes software developed by the University of
  46  *      California, Berkeley and its contributors.
  47  * 4. Neither the name of the University nor the names of its contributors
  48  *    may be used to endorse or promote products derived from this software
  49  *    without specific prior written permission.
  50  *
  51  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  54  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  *
  63  * from: Utah $Hdr: mem.c 1.13 89/10/08$
  64  *      @(#)mem.c       8.1 (Berkeley) 6/11/93
  65  */
  66
  67 #include <mach_load.h>
  68
  69 /*
  70  * Memory special file
  71  */
  72
  73 #include <sys/param.h>
  74 #include <sys/dir.h>
  75 #include <sys/proc.h>
  76 #include <sys/buf.h>
  77 #include <sys/systm.h>
  78 #include <sys/vm.h>
  79 #include <sys/uio.h>
  80 #include <sys/malloc.h>
  81
  82 #include <mach/vm_types.h>
  83 #include <mach/vm_param.h>
  84 #include <vm/vm_kern.h>         /* for kernel_map */
  85
  86 static caddr_t devzerobuf;
  87
  88 mmread(dev, uio)
  89         dev_t dev;
  90         struct uio *uio;
  91 {
  92
  93         return (mmrw(dev, uio, UIO_READ));
  94 }
  95
  96 mmwrite(dev, uio)
  97         dev_t dev;
  98         struct uio *uio;
  99 {
 100
 101         return (mmrw(dev, uio, UIO_WRITE));
 102 }
 103
 104 mmrw(dev, uio, rw)
 105         dev_t dev;
 106         struct uio *uio;
 107         enum uio_rw rw;
 108 {
 109         register int o;
 110         register u_int c, v;
 111         register struct iovec *iov;
 112         int error = 0;
 113         vm_offset_t     where;
 114         int             spl;
 115         vm_size_t size;
 116         extern boolean_t kernacc(off_t, size_t );
 117
 118         while (uio->uio_resid > 0 && error == 0) {
 119                 iov = uio->uio_iov;
 120                 if (iov->iov_len == 0) {
 121                         uio->uio_iov++;
 122                         uio->uio_iovcnt--;
 123                         if (uio->uio_iovcnt < 0)
 124                                 panic("mmrw");
 125                         continue;
 126                 }
 127                 switch (minor(dev)) {
 128
 129                 /* minor device 0 is physical memory */
 130                 case 0:
 131                         v = trunc_page(uio->uio_offset);
 132                         if (uio->uio_offset >= mem_size)
 133                                 goto fault;
 134
 135                         size= PAGE_SIZE;
 136                         if (kmem_alloc(kernel_map, &where, size)
 137                                 != KERN_SUCCESS) {
 138                                 goto fault;
 139                         }
 140                         o = uio->uio_offset - v;
 141                         c = min(PAGE_SIZE - o, (u_int)iov->iov_len);
 142                         error = uiomove((caddr_t) (where + o), c, uio);
 143                         kmem_free(kernel_map, where, PAGE_SIZE);
 144                         continue;
 145
 146                 /* minor device 1 is kernel memory */
 147                 case 1:
 148                         /* Do some sanity checking */
 149                         if (((vm_address_t)uio->uio_offset >= VM_MAX_KERNEL_ADDRESS) ||
 150                                 ((vm_address_t)uio->uio_offset <= VM_MIN_KERNEL_ADDRESS))
 151                                 goto fault;
 152                         c = iov->iov_len;
 153                         if (!kernacc(uio->uio_offset, c))
 154                                 goto fault;
 155                         error = uiomove((caddr_t)uio->uio_offset, (int)c, uio);
 156                         continue;
 157
 158                 /* minor device 2 is EOF/RATHOLE */
 159                 case 2:
 160                         if (rw == UIO_READ)
 161                                 return (0);
 162                         c = iov->iov_len;
 163                         break;
 164                 case 3:
 165                         if(devzerobuf == NULL) {
 166                                 MALLOC(devzerobuf, caddr_t,PAGE_SIZE, M_TEMP, M_WAITOK);
 167                                 bzero(devzerobuf, PAGE_SIZE);
 168                         }
 169                         if(uio->uio_rw == UIO_WRITE) {
 170                                 c = iov->iov_len;
 171                                 break;
 172                         }
 173                         c = min(iov->iov_len, PAGE_SIZE);
 174                         error = uiomove(devzerobuf, (int)c, uio);
 175                         continue;
 176                 default:
 177                         goto fault;
 178                         break;
 179                 }
 180
 181                 if (error)
 182                         break;
 183                 iov->iov_base += c;
 184                 iov->iov_len -= c;
 185                 uio->uio_offset += c;
 186                 uio->uio_resid -= c;
 187         }
 188         return (error);
 189 fault:
 190         return (EFAULT);
 191 }
 192
 193
 194 boolean_t
 195 kernacc(
 196     off_t       start,
 197     size_t      len
 198 )
 199 {
 200         off_t base;
 201         off_t end;
 202
 203         base = trunc_page(start);
 204         end = start + len;
 205
 206         while (base < end) {
 207                 if(kvtophys((vm_offset_t)base) == NULL)
 208                         return(FALSE);
 209                 base += page_size;
 210         }
 211
 212         return (TRUE);
 213 }