3979450b4c
cdev will never be destroyed. Propagate the flag to devfs vnodes as VV_ETERNVALDEV. Use the flags to avoid acquiring devmtx and taking a thread reference on such nodes. In collaboration with: pho MFC after: 1 month
355 lines
9.4 KiB
C
355 lines
9.4 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_ooffset_t off;
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vm_memattr_t dummy;
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struct cdevsw *csw;
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int ref;
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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, &ref);
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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, &dummy) != 0) {
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dev_relthread(dev, ref);
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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, ref);
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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, ref, ret;
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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, &ref);
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if (csw == NULL)
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panic("dev_pager_getpage: no cdevsw");
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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_ooffset_t)offset << PAGE_SHIFT, &paddr,
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PROT_READ, &memattr);
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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, ref);
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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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for (i = 0; i < count; i++) {
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if (i != reqpage) {
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vm_page_lock(m[i]);
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vm_page_free(m[i]);
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vm_page_unlock(m[i]);
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}
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}
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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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for (i = 0; i < count; i++) {
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vm_page_lock(m[i]);
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vm_page_free(m[i]);
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vm_page_unlock(m[i]);
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}
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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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