os161/kern/vm/addrspace.c
2015-12-23 00:50:04 +00:00

183 lines
3.8 KiB
C

/*
* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
* The President and Fellows of Harvard College.
*
* 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. 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 UNIVERSITY 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 UNIVERSITY 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.
*/
#include <types.h>
#include <kern/errno.h>
#include <lib.h>
#include <addrspace.h>
#include <vm.h>
#include <proc.h>
/*
* Note! If OPT_DUMBVM is set, as is the case until you start the VM
* assignment, this file is not compiled or linked or in any way
* used. The cheesy hack versions in dumbvm.c are used instead.
*/
struct addrspace *
as_create(void)
{
struct addrspace *as;
as = kmalloc(sizeof(struct addrspace));
if (as == NULL) {
return NULL;
}
/*
* Initialize as needed.
*/
return as;
}
int
as_copy(struct addrspace *old, struct addrspace **ret)
{
struct addrspace *newas;
newas = as_create();
if (newas==NULL) {
return ENOMEM;
}
/*
* Write this.
*/
(void)old;
*ret = newas;
return 0;
}
void
as_destroy(struct addrspace *as)
{
/*
* Clean up as needed.
*/
kfree(as);
}
void
as_activate(void)
{
struct addrspace *as;
as = proc_getas();
if (as == NULL) {
/*
* Kernel thread without an address space; leave the
* prior address space in place.
*/
return;
}
/*
* Write this.
*/
}
void
as_deactivate(void)
{
/*
* Write this. For many designs it won't need to actually do
* anything. See proc.c for an explanation of why it (might)
* be needed.
*/
}
/*
* Set up a segment at virtual address VADDR of size MEMSIZE. The
* segment in memory extends from VADDR up to (but not including)
* VADDR+MEMSIZE.
*
* The READABLE, WRITEABLE, and EXECUTABLE flags are set if read,
* write, or execute permission should be set on the segment. At the
* moment, these are ignored. When you write the VM system, you may
* want to implement them.
*/
int
as_define_region(struct addrspace *as, vaddr_t vaddr, size_t memsize,
int readable, int writeable, int executable)
{
/*
* Write this.
*/
(void)as;
(void)vaddr;
(void)memsize;
(void)readable;
(void)writeable;
(void)executable;
return ENOSYS;
}
int
as_prepare_load(struct addrspace *as)
{
/*
* Write this.
*/
(void)as;
return 0;
}
int
as_complete_load(struct addrspace *as)
{
/*
* Write this.
*/
(void)as;
return 0;
}
int
as_define_stack(struct addrspace *as, vaddr_t *stackptr)
{
/*
* Write this.
*/
(void)as;
/* Initial user-level stack pointer */
*stackptr = USERSTACK;
return 0;
}