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NetBSD/sys/uvm/uvm_device.c

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/* $NetBSD: uvm_device.c,v 1.16 1999/04/08 10:26:21 drochner Exp $ */
/*
*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* All rights reserved.
*
* 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 Charles D. Cranor and
* Washington University.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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: Id: uvm_device.c,v 1.1.2.9 1998/02/06 05:11:47 chs Exp
*/
#include "opt_uvmhist.h"
/*
* uvm_device.c: the device pager.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_kern.h>
#include <uvm/uvm.h>
#include <uvm/uvm_device.h>
/*
* private global data structure
*
* we keep a list of active device objects in the system.
*/
LIST_HEAD(udv_list_struct, uvm_device);
static struct udv_list_struct udv_list;
static simple_lock_data_t udv_lock;
/*
* functions
*/
static void udv_init __P((void));
struct uvm_object *udv_attach __P((void *, vm_prot_t, vaddr_t, vsize_t));
static void udv_reference __P((struct uvm_object *));
static void udv_detach __P((struct uvm_object *));
static int udv_fault __P((struct uvm_faultinfo *, vaddr_t,
vm_page_t *, int, int, vm_fault_t,
vm_prot_t, int));
static boolean_t udv_flush __P((struct uvm_object *, vaddr_t,
vaddr_t, int));
static int udv_asyncget __P((struct uvm_object *, vaddr_t,
int));
static int udv_put __P((struct uvm_object *, vm_page_t *,
int, boolean_t));
/*
* master pager structure
*/
struct uvm_pagerops uvm_deviceops = {
udv_init,
udv_reference,
udv_detach,
udv_fault,
udv_flush,
NULL, /* no get function since we have udv_fault */
udv_asyncget,
udv_put,
NULL, /* no cluster function */
NULL, /* no put cluster function */
NULL, /* no share protect. no share maps for us */
NULL, /* no AIO-DONE function since no async i/o */
NULL, /* no releasepg function since no normal pages */
};
/*
* the ops!
*/
/*
* udv_init
*
* init pager private data structures.
*/
void
udv_init()
{
LIST_INIT(&udv_list);
simple_lock_init(&udv_lock);
}
/*
* udv_attach
*
* get a VM object that is associated with a device. allocate a new
* one if needed.
*
* => caller must _not_ already be holding the lock on the uvm_object.
* => in fact, nothing should be locked so that we can sleep here.
*/
struct uvm_object *
udv_attach(arg, accessprot, off, size)
void *arg;
vm_prot_t accessprot;
vaddr_t off; /* used only for access check */
vsize_t size; /* used only for access check */
{
dev_t device = *((dev_t *) arg);
struct uvm_device *udv, *lcv;
int (*mapfn) __P((dev_t, int, int));
UVMHIST_FUNC("udv_attach"); UVMHIST_CALLED(maphist);
UVMHIST_LOG(maphist, "(device=0x%x)", device,0,0,0);
/*
* before we do anything, ensure this device supports mmap
*/
mapfn = cdevsw[major(device)].d_mmap;
if (mapfn == NULL ||
mapfn == (int (*) __P((dev_t, int, int))) enodev ||
mapfn == (int (*) __P((dev_t, int, int))) nullop)
return(NULL);
/*
* Check that the specified range of the device allows the
* desired protection.
*
* XXX assumes VM_PROT_* == PROT_*
* XXX clobbers off and size, but nothing else here needs them.
*/
while (size != 0) {
if ((*mapfn)(device, off, accessprot) == -1)
return (NULL);
off += PAGE_SIZE; size -= PAGE_SIZE;
}
/*
* keep looping until we get it
*/
while (1) {
/*
* first, attempt to find it on the main list
*/
simple_lock(&udv_lock);
for (lcv = udv_list.lh_first ; lcv != NULL ; lcv = lcv->u_list.le_next) {
if (device == lcv->u_device)
break;
}
/*
* got it on main list. put a hold on it and unlock udv_lock.
*/
if (lcv) {
/*
* if someone else has a hold on it, sleep and start
* over again.
*/
if (lcv->u_flags & UVM_DEVICE_HOLD) {
lcv->u_flags |= UVM_DEVICE_WANTED;
UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, FALSE,
"udv_attach",0);
continue;
}
/* we are now holding it */
lcv->u_flags |= UVM_DEVICE_HOLD;
simple_unlock(&udv_lock);
/*
* bump reference count, unhold, return.
*/
simple_lock(&lcv->u_obj.vmobjlock);
lcv->u_obj.uo_refs++;
simple_unlock(&lcv->u_obj.vmobjlock);
simple_lock(&udv_lock);
if (lcv->u_flags & UVM_DEVICE_WANTED)
wakeup(lcv);
lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD);
simple_unlock(&udv_lock);
return(&lcv->u_obj);
}
/*
* did not find it on main list. need to malloc a new one.
*/
simple_unlock(&udv_lock);
/* NOTE: we could sleep in the following malloc() */
MALLOC(udv, struct uvm_device *, sizeof(*udv), M_TEMP, M_WAITOK);
simple_lock(&udv_lock);
/*
* now we have to double check to make sure no one added it
* to the list while we were sleeping...
*/
for (lcv = udv_list.lh_first ; lcv != NULL ;
lcv = lcv->u_list.le_next) {
if (device == lcv->u_device)
break;
}
/*
* did we lose a race to someone else? free our memory and retry.
*/
if (lcv) {
simple_unlock(&udv_lock);
FREE(udv, M_TEMP);
continue;
}
/*
* we have it! init the data structures, add to list
* and return.
*/
simple_lock_init(&udv->u_obj.vmobjlock);
udv->u_obj.pgops = &uvm_deviceops;
TAILQ_INIT(&udv->u_obj.memq); /* not used, but be safe */
udv->u_obj.uo_npages = 0;
udv->u_obj.uo_refs = 1;
udv->u_flags = 0;
udv->u_device = device;
LIST_INSERT_HEAD(&udv_list, udv, u_list);
simple_unlock(&udv_lock);
return(&udv->u_obj);
} /* while(1) loop */
/*NOTREACHED*/
}
/*
* udv_reference
*
* add a reference to a VM object. Note that the reference count must
* already be one (the passed in reference) so there is no chance of the
* udv being released or locked out here.
*
* => caller must call with object unlocked.
*/
static void
udv_reference(uobj)
struct uvm_object *uobj;
{
UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist);
simple_lock(&uobj->vmobjlock);
uobj->uo_refs++;
UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)",
uobj, uobj->uo_refs,0,0);
simple_unlock(&uobj->vmobjlock);
}
/*
* udv_detach
*
* remove a reference to a VM object.
*
* => caller must call with object unlocked and map locked.
*/
static void
udv_detach(uobj)
struct uvm_object *uobj;
{
struct uvm_device *udv = (struct uvm_device *) uobj;
UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist);
/*
* loop until done
*/
while (1) {
simple_lock(&uobj->vmobjlock);
if (uobj->uo_refs > 1) {
uobj->uo_refs--; /* drop ref! */
simple_unlock(&uobj->vmobjlock);
UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d",
uobj,uobj->uo_refs,0,0);
return;
}
#ifdef DIAGNOSTIC
if (uobj->uo_npages || uobj->memq.tqh_first)
panic("udv_detach: pages in a device object?");
#endif
/*
* now lock udv_lock
*/
simple_lock(&udv_lock);
/*
* is it being held? if so, wait until others are done.
*/
if (udv->u_flags & UVM_DEVICE_HOLD) {
/*
* want it
*/
udv->u_flags |= UVM_DEVICE_WANTED;
simple_unlock(&uobj->vmobjlock);
UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0);
continue;
}
/*
* got it! nuke it now.
*/
LIST_REMOVE(udv, u_list);
if (udv->u_flags & UVM_DEVICE_WANTED)
wakeup(udv);
FREE(udv, M_TEMP);
break; /* DONE! */
} /* while (1) loop */
UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0);
return;
}
/*
* udv_flush
*
* flush pages out of a uvm object. a no-op for devices.
*/
static boolean_t udv_flush(uobj, start, stop, flags)
struct uvm_object *uobj;
vaddr_t start, stop;
int flags;
{
return(TRUE);
}
/*
* udv_fault: non-standard fault routine for device "pages"
*
* => rather than having a "get" function, we have a fault routine
* since we don't return vm_pages we need full control over the
* pmap_enter map in
* => all the usual fault data structured are locked by the caller
* (i.e. maps(read), amap (if any), uobj)
* => on return, we unlock all fault data structures
* => flags: PGO_ALLPAGES: get all of the pages
* PGO_LOCKED: fault data structures are locked
* XXX: currently PGO_LOCKED is always required ... consider removing
* it as a flag
* => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx]
*/
static int
udv_fault(ufi, vaddr, pps, npages, centeridx, fault_type, access_type, flags)
struct uvm_faultinfo *ufi;
vaddr_t vaddr;
vm_page_t *pps;
int npages, centeridx, flags;
vm_fault_t fault_type;
vm_prot_t access_type;
{
struct vm_map_entry *entry = ufi->entry;
struct uvm_object *uobj = entry->object.uvm_obj;
struct uvm_device *udv = (struct uvm_device *)uobj;
vaddr_t curr_offset, curr_va;
paddr_t paddr;
int lcv, retval, mdpgno;
dev_t device;
int (*mapfn) __P((dev_t, int, int));
UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist);
UVMHIST_LOG(maphist," flags=%d", flags,0,0,0);
/*
* XXX: !PGO_LOCKED calls are currently not allowed (or used)
*/
if ((flags & PGO_LOCKED) == 0)
panic("udv_fault: !PGO_LOCKED fault");
/*
* we do not allow device mappings to be mapped copy-on-write
* so we kill any attempt to do so here.
*/
if (UVM_ET_ISCOPYONWRITE(entry)) {
UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)",
entry->etype, 0,0,0);
uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL);
return(VM_PAGER_ERROR);
}
/*
* get device map function.
*/
device = udv->u_device;
mapfn = cdevsw[major(device)].d_mmap;
/*
* now we must determine the offset in udv to use and the VA to
* use for pmap_enter. note that we always use orig_map's pmap
* for pmap_enter (even if we have a submap). since virtual
* addresses in a submap must match the main map, this is ok.
*/
/* udv offset = (offset from start of entry) + entry's offset */
curr_offset = (vaddr - entry->start) + entry->offset;
/* pmap va = vaddr (virtual address of pps[0]) */
curr_va = vaddr;
/*
* loop over the page range entering in as needed
*/
retval = VM_PAGER_OK;
for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE,
curr_va += PAGE_SIZE) {
if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx)
continue;
if (pps[lcv] == PGO_DONTCARE)
continue;
mdpgno = (*mapfn)(device, (int)curr_offset, access_type);
if (mdpgno == -1) {
retval = VM_PAGER_ERROR;
break;
}
paddr = pmap_phys_address(mdpgno);
UVMHIST_LOG(maphist,
" MAPPING: device: pm=0x%x, va=0x%x, pa=0x%x, at=%d",
ufi->orig_map->pmap, curr_va, (int)paddr, access_type);
pmap_enter(ufi->orig_map->pmap, curr_va, paddr, access_type, 0,
access_type);
}
uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL);
return(retval);
}
/*
* udv_asyncget: start async I/O to bring pages into ram
*
* => caller must lock object(???XXX: see if this is best)
* => a no-op for devices
*/
static int
udv_asyncget(uobj, offset, npages)
struct uvm_object *uobj;
vaddr_t offset;
int npages;
{
return(KERN_SUCCESS);
}
/*
* udv_put: flush page data to backing store.
*
* => this function should never be called (since we never have any
* page structures to "put")
*/
static int
udv_put(uobj, pps, npages, flags)
struct uvm_object *uobj;
struct vm_page **pps;
int npages, flags;
{
panic("udv_put: trying to page out to a device!");
}
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