FreeBSD-5.3/sys/vm/device_pager.c
/*
* Copyright (c) 1990 University of Utah.
* Copyright (c) 1991, 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.
*
* 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.
* 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.
*
* @(#)device_pager.c 8.1 (Berkeley) 6/11/93
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/vm/device_pager.c,v 1.75 2004/08/04 08:58:58 dfr Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/lock.h>
#include <sys/proc.h>
#include <sys/mutex.h>
#include <sys/mman.h>
#include <sys/sx.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/uma.h>
static void dev_pager_init(void);
static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
vm_ooffset_t);
static void dev_pager_dealloc(vm_object_t);
static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int);
static void dev_pager_putpages(vm_object_t, vm_page_t *, int,
boolean_t, int *);
static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *,
int *);
/* list of device pager objects */
static struct pagerlst dev_pager_object_list;
/* protect against object creation */
static struct sx dev_pager_sx;
/* protect list manipulation */
static struct mtx dev_pager_mtx;
static uma_zone_t fakepg_zone;
static vm_page_t dev_pager_getfake(vm_paddr_t);
static void dev_pager_putfake(vm_page_t);
static void dev_pager_updatefake(vm_page_t, vm_paddr_t);
struct pagerops devicepagerops = {
.pgo_init = dev_pager_init,
.pgo_alloc = dev_pager_alloc,
.pgo_dealloc = dev_pager_dealloc,
.pgo_getpages = dev_pager_getpages,
.pgo_putpages = dev_pager_putpages,
.pgo_haspage = dev_pager_haspage,
};
static void
dev_pager_init()
{
TAILQ_INIT(&dev_pager_object_list);
sx_init(&dev_pager_sx, "dev_pager create");
mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
fakepg_zone = uma_zcreate("DP fakepg", sizeof(struct vm_page),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
UMA_ZONE_NOFREE|UMA_ZONE_VM);
}
/*
* MPSAFE
*/
static vm_object_t
dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff)
{
struct cdev *dev;
d_mmap_t *mapfunc;
vm_object_t object;
vm_pindex_t pindex;
unsigned int npages;
vm_paddr_t paddr;
vm_offset_t off;
/*
* Offset should be page aligned.
*/
if (foff & PAGE_MASK)
return (NULL);
size = round_page(size);
pindex = OFF_TO_IDX(foff + size);
/*
* Make sure this device can be mapped.
*/
dev = handle;
mtx_lock(&Giant);
mapfunc = devsw(dev)->d_mmap;
if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop) {
printf("obsolete map function %p\n", (void *)mapfunc);
mtx_unlock(&Giant);
return (NULL);
}
/*
* Check that the specified range of the device allows the desired
* protection.
*
* XXX assumes VM_PROT_* == PROT_*
*/
npages = OFF_TO_IDX(size);
for (off = foff; npages--; off += PAGE_SIZE)
if ((*mapfunc)(dev, off, &paddr, (int)prot) != 0) {
mtx_unlock(&Giant);
return (NULL);
}
/*
* Lock to prevent object creation race condition.
*/
sx_xlock(&dev_pager_sx);
/*
* Look up pager, creating as necessary.
*/
object = vm_pager_object_lookup(&dev_pager_object_list, handle);
if (object == NULL) {
/*
* Allocate object and associate it with the pager.
*/
object = vm_object_allocate(OBJT_DEVICE, pindex);
object->handle = handle;
TAILQ_INIT(&object->un_pager.devp.devp_pglist);
mtx_lock(&dev_pager_mtx);
TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list);
mtx_unlock(&dev_pager_mtx);
} else {
/*
* Gain a reference to the object.
*/
vm_object_reference(object);
if (pindex > object->size)
object->size = pindex;
}
sx_xunlock(&dev_pager_sx);
mtx_unlock(&Giant);
return (object);
}
static void
dev_pager_dealloc(object)
vm_object_t object;
{
vm_page_t m;
mtx_lock(&dev_pager_mtx);
TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
mtx_unlock(&dev_pager_mtx);
/*
* Free up our fake pages.
*/
while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) {
TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
dev_pager_putfake(m);
}
}
static int
dev_pager_getpages(object, m, count, reqpage)
vm_object_t object;
vm_page_t *m;
int count;
int reqpage;
{
vm_pindex_t offset;
vm_paddr_t paddr;
vm_page_t page;
struct cdev *dev;
int i, ret;
d_mmap_t *mapfunc;
int prot;
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
dev = object->handle;
offset = m[reqpage]->pindex;
VM_OBJECT_UNLOCK(object);
mtx_lock(&Giant);
prot = PROT_READ; /* XXX should pass in? */
mapfunc = devsw(dev)->d_mmap;
if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop)
panic("dev_pager_getpage: no map function");
ret = (*mapfunc)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot);
KASSERT(ret == 0, ("dev_pager_getpage: map function returns error"));
mtx_unlock(&Giant);
if ((m[reqpage]->flags & PG_FICTITIOUS) != 0) {
/*
* If the passed in reqpage page is a fake page, update it with
* the new physical address.
*/
VM_OBJECT_LOCK(object);
dev_pager_updatefake(m[reqpage], paddr);
if (count > 1) {
vm_page_lock_queues();
for (i = 0; i < count; i++) {
if (i != reqpage)
vm_page_free(m[i]);
}
vm_page_unlock_queues();
}
} else {
/*
* Replace the passed in reqpage page with our own fake page and
* free up the all of the original pages.
*/
page = dev_pager_getfake(paddr);
VM_OBJECT_LOCK(object);
TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
vm_page_lock_queues();
for (i = 0; i < count; i++)
vm_page_free(m[i]);
vm_page_unlock_queues();
vm_page_insert(page, object, offset);
m[reqpage] = page;
}
return (VM_PAGER_OK);
}
static void
dev_pager_putpages(object, m, count, sync, rtvals)
vm_object_t object;
vm_page_t *m;
int count;
boolean_t sync;
int *rtvals;
{
panic("dev_pager_putpage called");
}
static boolean_t
dev_pager_haspage(object, pindex, before, after)
vm_object_t object;
vm_pindex_t pindex;
int *before;
int *after;
{
if (before != NULL)
*before = 0;
if (after != NULL)
*after = 0;
return (TRUE);
}
static vm_page_t
dev_pager_getfake(paddr)
vm_paddr_t paddr;
{
vm_page_t m;
m = uma_zalloc(fakepg_zone, M_WAITOK);
m->flags = PG_BUSY | PG_FICTITIOUS;
m->valid = VM_PAGE_BITS_ALL;
m->dirty = 0;
m->busy = 0;
m->queue = PQ_NONE;
m->object = NULL;
m->wire_count = 1;
m->hold_count = 0;
m->phys_addr = paddr;
return (m);
}
static void
dev_pager_putfake(m)
vm_page_t m;
{
if (!(m->flags & PG_FICTITIOUS))
panic("dev_pager_putfake: bad page");
uma_zfree(fakepg_zone, m);
}
static void
dev_pager_updatefake(m, paddr)
vm_page_t m;
vm_paddr_t paddr;
{
if (!(m->flags & PG_FICTITIOUS))
panic("dev_pager_updatefake: bad page");
m->phys_addr = paddr;
m->valid = VM_PAGE_BITS_ALL;
}