bsd/dev/i386/mem.c

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*-
  29  * Copyright (c) 1988 University of Utah.
  30  * Copyright (c) 1982, 1986, 1990, 1993
  31  *      The Regents of the University of California.  All rights reserved.
  32  *
  33  * This code is derived from software contributed to Berkeley by
  34  * the Systems Programming Group of the University of Utah Computer
  35  * Science Department, and code derived from software contributed to
  36  * Berkeley by William Jolitz.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  * 3. All advertising materials mentioning features or use of this software
  47  *    must display the following acknowledgement:
  48  *      This product includes software developed by the University of
  49  *      California, Berkeley and its contributors.
  50  * 4. Neither the name of the University nor the names of its contributors
  51  *    may be used to endorse or promote products derived from this software
  52  *    without specific prior written permission.
  53  *
  54  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  64  * SUCH DAMAGE.
  65  *
  66  * from: Utah $Hdr: mem.c 1.13 89/10/08$
  67  *      @(#)mem.c       8.1 (Berkeley) 6/11/93
  68  */
  69
  70 #include <mach_load.h>
  71
  72 /*
  73  * Memory special file
  74  */
  75
  76 #include <sys/param.h>
  77 #include <sys/dir.h>
  78 #include <sys/proc.h>
  79 #include <sys/systm.h>
  80 #include <sys/conf.h>
  81 #include <sys/vm.h>
  82 #include <sys/uio_internal.h>
  83 #include <sys/malloc.h>
  84
  85 #include <mach/vm_types.h>
  86 #include <mach/vm_param.h>
  87 #include <vm/vm_kern.h>         /* for kernel_map */
  88
  89 extern addr64_t  kvtophys(vm_offset_t va);
  90 extern boolean_t kernacc(off_t, size_t );
  91 #if !defined(SECURE_KERNEL)
  92 extern int setup_kmem;
  93 #endif
  94
  95 static caddr_t devzerobuf;
  96
  97 int mmread(dev_t dev, struct uio *uio);
  98 int mmwrite(dev_t dev, struct uio *uio);
  99 int mmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p);
 100 int mmrw(dev_t dev, struct uio *uio, enum uio_rw rw);
 101
 102 int
 103 mmread(dev_t dev, struct uio *uio)
 104 {
 105
 106         return (mmrw(dev, uio, UIO_READ));
 107 }
 108
 109 int
 110 mmwrite(dev_t dev, struct uio *uio)
 111 {
 112
 113         return (mmrw(dev, uio, UIO_WRITE));
 114 }
 115
 116 int
 117 mmioctl(dev_t dev, u_long cmd, __unused caddr_t data,
 118                 __unused int flag, __unused struct proc *p)
 119 {
 120         int minnum = minor(dev);
 121
 122         if (0 == minnum || 1 == minnum) {
 123                 /* /dev/mem and /dev/kmem */
 124 #if defined(SECURE_KERNEL)
 125                 return (ENODEV);
 126 #else
 127                 if (0 == setup_kmem)
 128                         return (EINVAL);
 129 #endif
 130         }
 131
 132         switch (cmd) {
 133         case FIONBIO:
 134         case FIOASYNC:
 135                 /* OK to do nothing: we always return immediately */
 136                 break;
 137         default:
 138                 return ENODEV;
 139         }
 140
 141         return (0);
 142 }
 143
 144 int
 145 mmrw(dev_t dev, struct uio *uio, enum uio_rw rw)
 146 {
 147         register int o;
 148         register u_int c, v;
 149         int error = 0;
 150         vm_offset_t     where;
 151         vm_size_t size;
 152
 153
 154         while (uio_resid(uio) > 0 && error == 0) {
 155                 uio_update(uio, 0);
 156
 157                 switch (minor(dev)) {
 158
 159                 /* minor device 0 is physical memory */
 160                 case 0:
 161 #if defined(SECURE_KERNEL)
 162                         return(ENODEV);
 163 #else
 164                         if (setup_kmem == 0)
 165                                 return(ENODEV);
 166 #endif
 167
 168                         v = trunc_page(uio->uio_offset);
 169                         if (uio->uio_offset >= (off_t)mem_size)
 170                                 goto fault;
 171
 172                         size= PAGE_SIZE;
 173                         if (kmem_alloc(kernel_map, &where, size)
 174                                 != KERN_SUCCESS) {
 175                                 goto fault;
 176                         }
 177                         o = uio->uio_offset - v;
 178                         c = min(PAGE_SIZE - o, uio_curriovlen(uio));
 179                         error = uiomove((caddr_t) (where + o), c, uio);
 180                         kmem_free(kernel_map, where, PAGE_SIZE);
 181                         continue;
 182
 183                 /* minor device 1 is kernel memory */
 184                 case 1:
 185 #if defined(SECURE_KERNEL)
 186                         return(ENODEV);
 187 #else
 188                         if (setup_kmem == 0)
 189                                 return(ENODEV);
 190 #endif
 191                         /* Do some sanity checking */
 192                         if (((vm_address_t)uio->uio_offset >= VM_MAX_KERNEL_ADDRESS) ||
 193                                 ((vm_address_t)uio->uio_offset <= VM_MIN_KERNEL_AND_KEXT_ADDRESS))
 194                                 goto fault;
 195                         c = uio_curriovlen(uio);
 196                         if (!kernacc(uio->uio_offset, c))
 197                                 goto fault;
 198                         error = uiomove((caddr_t)(uintptr_t)uio->uio_offset,
 199                                         (int)c, uio);
 200                         continue;
 201
 202                 /* minor device 2 is EOF/RATHOLE */
 203                 case 2:
 204                         if (rw == UIO_READ)
 205                                 return (0);
 206                         c = uio_curriovlen(uio);
 207                         break;
 208                 case 3:
 209                         if(devzerobuf == NULL) {
 210                                 MALLOC(devzerobuf, caddr_t,PAGE_SIZE, M_TEMP, M_WAITOK);
 211                                 bzero(devzerobuf, PAGE_SIZE);
 212                         }
 213                         if(uio->uio_rw == UIO_WRITE) {
 214                                 c = uio_curriovlen(uio);
 215                                 break;
 216                         }
 217                         c = min(uio_curriovlen(uio), PAGE_SIZE);
 218                         error = uiomove(devzerobuf, (int)c, uio);
 219                         continue;
 220                 default:
 221                         goto fault;
 222                         break;
 223                 }
 224
 225                 if (error)
 226                         break;
 227                 uio_update(uio, c);
 228         }
 229         return (error);
 230 fault:
 231         return (EFAULT);
 232 }
 233
 234
 235 boolean_t
 236 kernacc(
 237     off_t       start,
 238     size_t      len
 239 )
 240 {
 241         off_t base;
 242         off_t end;
 243
 244         base = trunc_page(start);
 245         end = start + len;
 246
 247         while (base < end) {
 248           if(kvtophys((vm_offset_t)base) == 0ULL)
 249                         return(FALSE);
 250                 base += page_size;
 251         }
 252
 253         return (TRUE);
 254 }