xnu-344.21.73.tar.gz

[apple/xnu.git] / bsd / dev / i386 / mem.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*-
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1982, 1986, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department, and code derived from software contributed to
 * Berkeley by William Jolitz.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * from: Utah $Hdr: mem.c 1.13 89/10/08$
 *	@(#)mem.c	8.1 (Berkeley) 6/11/93
 */

#include <mach_load.h>

/*
 * Memory special file
 */

#include <sys/param.h>
#include <sys/dir.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/systm.h>
#include <sys/vm.h>
#include <sys/uio.h>
#include <sys/malloc.h>

#include <mach/vm_types.h>
#include <mach/vm_param.h>
#include <vm/vm_kern.h>		/* for kernel_map */

static caddr_t devzerobuf;

mmread(dev, uio)
	dev_t dev;
	struct uio *uio;
{

	return (mmrw(dev, uio, UIO_READ));
}

mmwrite(dev, uio)
	dev_t dev;
	struct uio *uio;
{

	return (mmrw(dev, uio, UIO_WRITE));
}

mmrw(dev, uio, rw)
	dev_t dev;
	struct uio *uio;
	enum uio_rw rw;
{
	register int o;
	register u_int c, v;
	register struct iovec *iov;
	int error = 0;
	vm_offset_t	where;
	int		spl;
	vm_size_t size;
	extern boolean_t kernacc(off_t, size_t );

	while (uio->uio_resid > 0 && error == 0) {
		iov = uio->uio_iov;
		if (iov->iov_len == 0) {
			uio->uio_iov++;
			uio->uio_iovcnt--;
			if (uio->uio_iovcnt < 0)
				panic("mmrw");
			continue;
		}
		switch (minor(dev)) {

		/* minor device 0 is physical memory */
		case 0:
			v = trunc_page(uio->uio_offset);
			if (uio->uio_offset >= mem_size)
				goto fault;

			size= PAGE_SIZE;
			if (kmem_alloc(kernel_map, &where, size) 
				!= KERN_SUCCESS) {
				goto fault;
			}
			o = uio->uio_offset - v;
			c = min(PAGE_SIZE - o, (u_int)iov->iov_len);
			error = uiomove((caddr_t) (where + o), c, uio);
			kmem_free(kernel_map, where, PAGE_SIZE);
			continue;

		/* minor device 1 is kernel memory */
		case 1:
			/* Do some sanity checking */
			if (((vm_address_t)uio->uio_offset >= VM_MAX_KERNEL_ADDRESS) ||
				((vm_address_t)uio->uio_offset <= VM_MIN_KERNEL_ADDRESS))
				goto fault;
			c = iov->iov_len;
			if (!kernacc(uio->uio_offset, c))
				goto fault;
			error = uiomove((caddr_t)uio->uio_offset, (int)c, uio);
			continue;

		/* minor device 2 is EOF/RATHOLE */
		case 2:
			if (rw == UIO_READ)
				return (0);
			c = iov->iov_len;
			break;
		case 3:
			if(devzerobuf == NULL) {
				MALLOC(devzerobuf, caddr_t,PAGE_SIZE, M_TEMP, M_WAITOK);
				bzero(devzerobuf, PAGE_SIZE);
			}
			if(uio->uio_rw == UIO_WRITE) {
				c = iov->iov_len;
				break;
			}
			c = min(iov->iov_len, PAGE_SIZE);
			error = uiomove(devzerobuf, (int)c, uio);
			continue;
		default:
			goto fault;
			break;
		}
			
		if (error)
			break;
		iov->iov_base += c;
		iov->iov_len -= c;
		uio->uio_offset += c;
		uio->uio_resid -= c;
	}
	return (error);
fault:
	return (EFAULT);
}


boolean_t
kernacc(
    off_t 	start,
    size_t	len
)
{
	off_t base;
	off_t end;
    
	base = trunc_page(start);
	end = start + len;
	
	while (base < end) {
		if(kvtophys((vm_offset_t)base) == NULL)
			return(FALSE);
		base += page_size;
	}   

	return (TRUE);
}