amd64 and i386. Essentially, fictitious pages provide a mechanism for creating aliases for either normal or device-backed pages. Therefore, pmap_page_set_memattr() on a fictitious page needn't update the direct map or flush the cache. Such actions are the responsibility of the "primary" instance of the page or the device driver that "owns" the physical address. For example, these actions are already performed by pmap_mapdev(). The device pager needn't restore the memory attributes on a fictitious page before releasing it. It's now pointless. Add pmap_page_set_memattr() to the Xen pmap. Approved by: re (kib)
352 lines
9.3 KiB
C
352 lines
9.3 KiB
C
/*-
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* Copyright (c) 1990 University of Utah.
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the Systems Programming Group of the University of Utah Computer
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* Science Department.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)device_pager.c 8.1 (Berkeley) 6/11/93
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/lock.h>
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#include <sys/proc.h>
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#include <sys/mutex.h>
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#include <sys/mman.h>
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#include <sys/sx.h>
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#include <vm/vm.h>
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#include <vm/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_pager.h>
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#include <vm/uma.h>
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static void dev_pager_init(void);
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static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
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vm_ooffset_t, struct ucred *);
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static void dev_pager_dealloc(vm_object_t);
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static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int);
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static void dev_pager_putpages(vm_object_t, vm_page_t *, int,
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boolean_t, int *);
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static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *,
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int *);
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/* list of device pager objects */
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static struct pagerlst dev_pager_object_list;
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/* protect list manipulation */
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static struct mtx dev_pager_mtx;
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static uma_zone_t fakepg_zone;
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static vm_page_t dev_pager_getfake(vm_paddr_t, vm_memattr_t);
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static void dev_pager_putfake(vm_page_t);
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static void dev_pager_updatefake(vm_page_t, vm_paddr_t, vm_memattr_t);
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struct pagerops devicepagerops = {
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.pgo_init = dev_pager_init,
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.pgo_alloc = dev_pager_alloc,
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.pgo_dealloc = dev_pager_dealloc,
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.pgo_getpages = dev_pager_getpages,
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.pgo_putpages = dev_pager_putpages,
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.pgo_haspage = dev_pager_haspage,
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};
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static void
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dev_pager_init()
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{
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TAILQ_INIT(&dev_pager_object_list);
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mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
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fakepg_zone = uma_zcreate("DP fakepg", sizeof(struct vm_page),
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NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
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UMA_ZONE_NOFREE|UMA_ZONE_VM);
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}
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/*
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* MPSAFE
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*/
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static vm_object_t
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dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
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vm_ooffset_t foff, struct ucred *cred)
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{
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struct cdev *dev;
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vm_object_t object, object1;
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vm_pindex_t pindex;
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unsigned int npages;
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vm_paddr_t paddr;
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vm_offset_t off;
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struct cdevsw *csw;
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/*
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* Offset should be page aligned.
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*/
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if (foff & PAGE_MASK)
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return (NULL);
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size = round_page(size);
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pindex = OFF_TO_IDX(foff + size);
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/*
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* Make sure this device can be mapped.
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*/
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dev = handle;
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csw = dev_refthread(dev);
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if (csw == NULL)
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return (NULL);
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/*
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* Check that the specified range of the device allows the desired
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* protection.
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*
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* XXX assumes VM_PROT_* == PROT_*
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*/
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npages = OFF_TO_IDX(size);
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for (off = foff; npages--; off += PAGE_SIZE)
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if ((*csw->d_mmap)(dev, off, &paddr, (int)prot) != 0) {
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dev_relthread(dev);
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return (NULL);
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}
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mtx_lock(&dev_pager_mtx);
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/*
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* Look up pager, creating as necessary.
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*/
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object1 = NULL;
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object = vm_pager_object_lookup(&dev_pager_object_list, handle);
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if (object == NULL) {
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/*
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* Allocate object and associate it with the pager. Initialize
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* the object's pg_color based upon the physical address of the
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* device's memory.
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*/
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mtx_unlock(&dev_pager_mtx);
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object1 = vm_object_allocate(OBJT_DEVICE, pindex);
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object1->flags |= OBJ_COLORED;
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object1->pg_color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
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mtx_lock(&dev_pager_mtx);
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object = vm_pager_object_lookup(&dev_pager_object_list, handle);
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if (object != NULL) {
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/*
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* We raced with other thread while allocating object.
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*/
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if (pindex > object->size)
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object->size = pindex;
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} else {
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object = object1;
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object1 = NULL;
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object->handle = handle;
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TAILQ_INIT(&object->un_pager.devp.devp_pglist);
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TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
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pager_object_list);
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}
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} else {
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if (pindex > object->size)
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object->size = pindex;
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}
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mtx_unlock(&dev_pager_mtx);
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dev_relthread(dev);
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vm_object_deallocate(object1);
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return (object);
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}
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static void
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dev_pager_dealloc(object)
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vm_object_t object;
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{
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vm_page_t m;
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VM_OBJECT_UNLOCK(object);
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mtx_lock(&dev_pager_mtx);
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TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
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mtx_unlock(&dev_pager_mtx);
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VM_OBJECT_LOCK(object);
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/*
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* Free up our fake pages.
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*/
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while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != NULL) {
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TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
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dev_pager_putfake(m);
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}
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}
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static int
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dev_pager_getpages(object, m, count, reqpage)
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vm_object_t object;
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vm_page_t *m;
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int count;
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int reqpage;
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{
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vm_pindex_t offset;
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vm_paddr_t paddr;
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vm_page_t m_paddr, page;
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vm_memattr_t memattr;
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struct cdev *dev;
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int i, ret;
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int prot;
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struct cdevsw *csw;
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struct thread *td;
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struct file *fpop;
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VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
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dev = object->handle;
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page = m[reqpage];
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offset = page->pindex;
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memattr = object->memattr;
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VM_OBJECT_UNLOCK(object);
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csw = dev_refthread(dev);
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if (csw == NULL)
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panic("dev_pager_getpage: no cdevsw");
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prot = PROT_READ; /* XXX should pass in? */
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td = curthread;
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fpop = td->td_fpop;
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td->td_fpop = NULL;
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ret = (*csw->d_mmap)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot);
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KASSERT(ret == 0, ("dev_pager_getpage: map function returns error"));
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td->td_fpop = fpop;
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dev_relthread(dev);
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/* If "paddr" is a real page, perform a sanity check on "memattr". */
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if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
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pmap_page_get_memattr(m_paddr) != memattr) {
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memattr = pmap_page_get_memattr(m_paddr);
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printf(
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"WARNING: A device driver has set \"memattr\" inconsistently.\n");
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}
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if ((page->flags & PG_FICTITIOUS) != 0) {
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/*
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* If the passed in reqpage page is a fake page, update it with
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* the new physical address.
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*/
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VM_OBJECT_LOCK(object);
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dev_pager_updatefake(page, paddr, memattr);
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if (count > 1) {
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vm_page_lock_queues();
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for (i = 0; i < count; i++) {
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if (i != reqpage)
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vm_page_free(m[i]);
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}
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vm_page_unlock_queues();
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}
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} else {
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/*
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* Replace the passed in reqpage page with our own fake page and
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* free up the all of the original pages.
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*/
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page = dev_pager_getfake(paddr, memattr);
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VM_OBJECT_LOCK(object);
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TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
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vm_page_lock_queues();
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for (i = 0; i < count; i++)
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vm_page_free(m[i]);
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vm_page_unlock_queues();
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vm_page_insert(page, object, offset);
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m[reqpage] = page;
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}
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page->valid = VM_PAGE_BITS_ALL;
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return (VM_PAGER_OK);
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}
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static void
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dev_pager_putpages(object, m, count, sync, rtvals)
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vm_object_t object;
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vm_page_t *m;
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int count;
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boolean_t sync;
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int *rtvals;
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{
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panic("dev_pager_putpage called");
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}
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static boolean_t
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dev_pager_haspage(object, pindex, before, after)
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vm_object_t object;
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vm_pindex_t pindex;
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int *before;
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int *after;
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{
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if (before != NULL)
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*before = 0;
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if (after != NULL)
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*after = 0;
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return (TRUE);
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}
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/*
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* Create a fictitious page with the specified physical address and memory
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* attribute. The memory attribute is the only the machine-dependent aspect
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* of a fictitious page that must be initialized.
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*/
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static vm_page_t
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dev_pager_getfake(vm_paddr_t paddr, vm_memattr_t memattr)
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{
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vm_page_t m;
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m = uma_zalloc(fakepg_zone, M_WAITOK | M_ZERO);
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m->phys_addr = paddr;
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/* Fictitious pages don't use "segind". */
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m->flags = PG_FICTITIOUS;
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/* Fictitious pages don't use "order" or "pool". */
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m->oflags = VPO_BUSY;
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m->wire_count = 1;
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pmap_page_set_memattr(m, memattr);
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return (m);
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}
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/*
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* Release a fictitious page.
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*/
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static void
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dev_pager_putfake(vm_page_t m)
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{
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if (!(m->flags & PG_FICTITIOUS))
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panic("dev_pager_putfake: bad page");
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uma_zfree(fakepg_zone, m);
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}
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/*
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* Update the given fictitious page to the specified physical address and
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* memory attribute.
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*/
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static void
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dev_pager_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
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{
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if (!(m->flags & PG_FICTITIOUS))
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panic("dev_pager_updatefake: bad page");
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m->phys_addr = paddr;
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pmap_page_set_memattr(m, memattr);
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}
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