NetBSD/sys/uvm/uvm_device.c

452 lines
11 KiB
C

/* $NetBSD: uvm_device.c,v 1.64 2014/12/14 23:48:58 chs 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.
*
* 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
*/
/*
* uvm_device.c: the device pager.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_device.c,v 1.64 2014/12/14 23:48:58 chs Exp $");
#include "opt_uvmhist.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/proc.h>
#include <sys/kmem.h>
#include <uvm/uvm.h>
#include <uvm/uvm_device.h>
#include <uvm/uvm_pmap.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 kmutex_t udv_lock;
/*
* functions
*/
static void udv_init(void);
static void udv_reference(struct uvm_object *);
static void udv_detach(struct uvm_object *);
static int udv_fault(struct uvm_faultinfo *, vaddr_t,
struct vm_page **, int, int, vm_prot_t,
int);
/*
* master pager structure
*/
const struct uvm_pagerops uvm_deviceops = {
.pgo_init = udv_init,
.pgo_reference = udv_reference,
.pgo_detach = udv_detach,
.pgo_fault = udv_fault,
};
/*
* the ops!
*/
/*
* udv_init
*
* init pager private data structures.
*/
static void
udv_init(void)
{
LIST_INIT(&udv_list);
mutex_init(&udv_lock, MUTEX_DEFAULT, IPL_NONE);
}
/*
* 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(dev_t device, vm_prot_t accessprot,
voff_t off, /* used only for access check */
vsize_t size /* used only for access check */)
{
struct uvm_device *udv, *lcv;
const struct cdevsw *cdev;
dev_type_mmap((*mapfn));
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
*/
cdev = cdevsw_lookup(device);
if (cdev == NULL) {
return (NULL);
}
mapfn = cdev->d_mmap;
if (mapfn == NULL || mapfn == nommap || mapfn == nullmmap) {
return(NULL);
}
/*
* Negative offsets on the object are not allowed.
*/
if ((cdev->d_flag & D_NEGOFFSAFE) == 0 &&
off != UVM_UNKNOWN_OFFSET && off < 0)
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 (cdev_mmap(device, off, accessprot) == -1) {
return (NULL);
}
off += PAGE_SIZE; size -= PAGE_SIZE;
}
/*
* keep looping until we get it
*/
for (;;) {
/*
* first, attempt to find it on the main list
*/
mutex_enter(&udv_lock);
LIST_FOREACH(lcv, &udv_list, u_list) {
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;
mutex_exit(&udv_lock);
/*
* bump reference count, unhold, return.
*/
mutex_enter(lcv->u_obj.vmobjlock);
lcv->u_obj.uo_refs++;
mutex_exit(lcv->u_obj.vmobjlock);
mutex_enter(&udv_lock);
if (lcv->u_flags & UVM_DEVICE_WANTED)
wakeup(lcv);
lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD);
mutex_exit(&udv_lock);
return(&lcv->u_obj);
}
/*
* Did not find it on main list. Need to allocate a new one.
*/
mutex_exit(&udv_lock);
/* Note: both calls may allocate memory and sleep. */
udv = kmem_alloc(sizeof(*udv), KM_SLEEP);
uvm_obj_init(&udv->u_obj, &uvm_deviceops, true, 1);
mutex_enter(&udv_lock);
/*
* now we have to double check to make sure no one added it
* to the list while we were sleeping...
*/
LIST_FOREACH(lcv, &udv_list, u_list) {
if (device == lcv->u_device)
break;
}
/*
* did we lose a race to someone else?
* free our memory and retry.
*/
if (lcv) {
mutex_exit(&udv_lock);
uvm_obj_destroy(&udv->u_obj, true);
kmem_free(udv, sizeof(*udv));
continue;
}
/*
* we have it! init the data structures, add to list
* and return.
*/
udv->u_flags = 0;
udv->u_device = device;
LIST_INSERT_HEAD(&udv_list, udv, u_list);
mutex_exit(&udv_lock);
return(&udv->u_obj);
}
/*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(struct uvm_object *uobj)
{
UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist);
mutex_enter(uobj->vmobjlock);
uobj->uo_refs++;
UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)",
uobj, uobj->uo_refs,0,0);
mutex_exit(uobj->vmobjlock);
}
/*
* udv_detach
*
* remove a reference to a VM object.
*
* => caller must call with object unlocked and map locked.
*/
static void
udv_detach(struct uvm_object *uobj)
{
struct uvm_device *udv = (struct uvm_device *)uobj;
UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist);
/*
* loop until done
*/
again:
mutex_enter(uobj->vmobjlock);
if (uobj->uo_refs > 1) {
uobj->uo_refs--;
mutex_exit(uobj->vmobjlock);
UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d",
uobj,uobj->uo_refs,0,0);
return;
}
/*
* is it being held? if so, wait until others are done.
*/
mutex_enter(&udv_lock);
if (udv->u_flags & UVM_DEVICE_HOLD) {
udv->u_flags |= UVM_DEVICE_WANTED;
mutex_exit(uobj->vmobjlock);
UVM_UNLOCK_AND_WAIT(udv, &udv_lock, false, "udv_detach",0);
goto again;
}
/*
* got it! nuke it now.
*/
LIST_REMOVE(udv, u_list);
if (udv->u_flags & UVM_DEVICE_WANTED)
wakeup(udv);
mutex_exit(&udv_lock);
mutex_exit(uobj->vmobjlock);
uvm_obj_destroy(uobj, true);
kmem_free(udv, sizeof(*udv));
UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0);
}
/*
* 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(struct uvm_faultinfo *ufi, vaddr_t vaddr, struct vm_page **pps,
int npages, int centeridx, vm_prot_t access_type,
int flags)
{
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_va;
off_t curr_offset;
paddr_t paddr, mdpgno;
u_int mmapflags;
int lcv, retval;
dev_t device;
vm_prot_t mapprot;
UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist);
UVMHIST_LOG(maphist," flags=%d", flags,0,0,0);
/*
* 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);
return(EIO);
}
/*
* get device map function.
*/
device = udv->u_device;
if (cdevsw_lookup(device) == NULL) {
/* XXX This should not happen */
uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj);
return (EIO);
}
/*
* 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 = entry->offset + (vaddr - entry->start);
/* pmap va = vaddr (virtual address of pps[0]) */
curr_va = vaddr;
/*
* loop over the page range entering in as needed
*/
retval = 0;
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 = cdev_mmap(device, curr_offset, access_type);
if (mdpgno == -1) {
retval = EIO;
break;
}
paddr = pmap_phys_address(mdpgno);
mmapflags = pmap_mmap_flags(mdpgno);
mapprot = ufi->entry->protection;
UVMHIST_LOG(maphist,
" MAPPING: device: pm=0x%x, va=0x%x, pa=0x%lx, at=%d",
ufi->orig_map->pmap, curr_va, paddr, mapprot);
if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, mapprot,
PMAP_CANFAIL | mapprot | mmapflags) != 0) {
/*
* pmap_enter() didn't have the resource to
* enter this mapping. Unlock everything,
* wait for the pagedaemon to free up some
* pages, and then tell uvm_fault() to start
* the fault again.
*
* XXX Needs some rethinking for the PGO_ALLPAGES
* XXX case.
*/
pmap_update(ufi->orig_map->pmap); /* sync what we have so far */
uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap,
uobj);
uvm_wait("udv_fault");
return (ERESTART);
}
}
pmap_update(ufi->orig_map->pmap);
uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj);
return (retval);
}