The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/mips/mips/mem.c

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    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: releng/8.4/sys/mips/mips/mem.c 219212 2011-03-03 00:24:55Z jkim $");
   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 
   71 struct mem_range_softc mem_range_softc;
   72 
   73 /* ARGSUSED */
   74 int
   75 memrw(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         GIANT_REQUIRED;
   89 
   90         while (uio->uio_resid > 0 && !error) {
   91                 iov = uio->uio_iov;
   92                 if (iov->iov_len == 0) {
   93                         uio->uio_iov++;
   94                         uio->uio_iovcnt--;
   95                         if (uio->uio_iovcnt < 0)
   96                                 panic("memrw");
   97                         continue;
   98                 }
   99                 if (dev2unit(dev) == CDEV_MINOR_MEM) {
  100                         v = uio->uio_offset;
  101 
  102                         off = uio->uio_offset & PAGE_MASK;
  103                         cnt = PAGE_SIZE - ((vm_offset_t)iov->iov_base &
  104                             PAGE_MASK);
  105                         cnt = min(cnt, PAGE_SIZE - off);
  106                         cnt = min(cnt, iov->iov_len);
  107 
  108                         m.phys_addr = trunc_page(v);
  109                         marr = &m;
  110                         error = uiomove_fromphys(&marr, off, cnt, uio);
  111                 }
  112                 else if (dev2unit(dev) == CDEV_MINOR_KMEM) {
  113                         va = uio->uio_offset;
  114 
  115                         va = trunc_page(uio->uio_offset);
  116                         eva = round_page(uio->uio_offset
  117                             + iov->iov_len);
  118 
  119                         /* 
  120                          * Make sure that all the pages are currently resident
  121                          * so that we don't create any zero-fill pages.
  122                          */
  123                         if (va >= VM_MIN_KERNEL_ADDRESS &&
  124                             eva <= VM_MAX_KERNEL_ADDRESS) {
  125                                 for (; va < eva; va += PAGE_SIZE)
  126                                         if (pmap_extract(kernel_pmap, va) == 0)
  127                                                 return (EFAULT);
  128 
  129                                 prot = (uio->uio_rw == UIO_READ)
  130                                     ? VM_PROT_READ : VM_PROT_WRITE;
  131 
  132                                 va = uio->uio_offset;
  133                                 if (kernacc((void *) va, iov->iov_len, prot)
  134                                     == FALSE)
  135                                         return (EFAULT);
  136                         }
  137 
  138                         va = uio->uio_offset;
  139                         error = uiomove((void *)va, iov->iov_len, uio);
  140                         continue;
  141                 }
  142         }
  143 
  144         return (error);
  145 }
  146 
  147 /*
  148  * allow user processes to MMAP some memory sections
  149  * instead of going through read/write
  150  */
  151 int
  152 memmmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int prot)
  153 {
  154         /*
  155          * /dev/mem is the only one that makes sense through this
  156          * interface.  For /dev/kmem any physaddr we return here
  157          * could be transient and hence incorrect or invalid at
  158          * a later time.
  159          */
  160         if (dev2unit(dev) != CDEV_MINOR_MEM)
  161                 return (-1);
  162 
  163         *paddr = offset;
  164 
  165         return (0);
  166 }

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