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NetBSD/sys/uvm/uvm_bio.c

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/* $NetBSD: uvm_bio.c,v 1.39 2005/06/27 02:19:48 thorpej Exp $ */
/*
* Copyright (c) 1998 Chuck Silvers.
* 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. 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.
*
*/
/*
* uvm_bio.c: buffered i/o object mapping cache
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_bio.c,v 1.39 2005/06/27 02:19:48 thorpej Exp $");
#include "opt_uvmhist.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <uvm/uvm.h>
/*
* global data structures
*/
/*
* local functions
*/
static int ubc_fault(struct uvm_faultinfo *, vaddr_t, struct vm_page **,
int, int, vm_fault_t, vm_prot_t, int);
static struct ubc_map *ubc_find_mapping(struct uvm_object *, voff_t);
/*
* local data structues
*/
#define UBC_HASH(uobj, offset) \
(((((u_long)(uobj)) >> 8) + (((u_long)(offset)) >> PAGE_SHIFT)) & \
ubc_object.hashmask)
#define UBC_QUEUE(offset) \
(&ubc_object.inactive[(((u_long)(offset)) >> ubc_winshift) & \
(UBC_NQUEUES - 1)])
#define UBC_UMAP_ADDR(u) \
(vaddr_t)(ubc_object.kva + (((u) - ubc_object.umap) << ubc_winshift))
#define UMAP_PAGES_LOCKED 0x0001
#define UMAP_MAPPING_CACHED 0x0002
struct ubc_map
{
struct uvm_object * uobj; /* mapped object */
voff_t offset; /* offset into uobj */
voff_t writeoff; /* write offset */
vsize_t writelen; /* write len */
int refcount; /* refcount on mapping */
int flags; /* extra state */
LIST_ENTRY(ubc_map) hash; /* hash table */
TAILQ_ENTRY(ubc_map) inactive; /* inactive queue */
};
static struct ubc_object
{
struct uvm_object uobj; /* glue for uvm_map() */
char *kva; /* where ubc_object is mapped */
struct ubc_map *umap; /* array of ubc_map's */
LIST_HEAD(, ubc_map) *hash; /* hashtable for cached ubc_map's */
u_long hashmask; /* mask for hashtable */
TAILQ_HEAD(ubc_inactive_head, ubc_map) *inactive;
/* inactive queues for ubc_map's */
} ubc_object;
struct uvm_pagerops ubc_pager =
{
NULL, /* init */
NULL, /* reference */
NULL, /* detach */
ubc_fault, /* fault */
/* ... rest are NULL */
};
int ubc_nwins = UBC_NWINS;
int ubc_winshift = UBC_WINSHIFT;
int ubc_winsize;
#if defined(PMAP_PREFER)
int ubc_nqueues;
#define UBC_NQUEUES ubc_nqueues
#else
#define UBC_NQUEUES 1
#endif
/*
* ubc_init
*
* init pager private data structures.
*/
void
ubc_init(void)
{
struct ubc_map *umap;
vaddr_t va;
int i;
/*
* Make sure ubc_winshift is sane.
*/
if (ubc_winshift < PAGE_SHIFT)
ubc_winshift = PAGE_SHIFT;
/*
* init ubc_object.
* alloc and init ubc_map's.
* init inactive queues.
* alloc and init hashtable.
* map in ubc_object.
*/
UVM_OBJ_INIT(&ubc_object.uobj, &ubc_pager, UVM_OBJ_KERN);
ubc_object.umap = malloc(ubc_nwins * sizeof(struct ubc_map),
M_TEMP, M_NOWAIT);
if (ubc_object.umap == NULL)
panic("ubc_init: failed to allocate ubc_map");
memset(ubc_object.umap, 0, ubc_nwins * sizeof(struct ubc_map));
if (ubc_winshift < PAGE_SHIFT) {
ubc_winshift = PAGE_SHIFT;
}
va = (vaddr_t)1L;
#ifdef PMAP_PREFER
PMAP_PREFER(0, &va, 0, 0); /* kernel is never topdown */
ubc_nqueues = va >> ubc_winshift;
if (ubc_nqueues == 0) {
ubc_nqueues = 1;
}
#endif
ubc_winsize = 1 << ubc_winshift;
ubc_object.inactive = malloc(UBC_NQUEUES *
sizeof(struct ubc_inactive_head), M_TEMP, M_NOWAIT);
if (ubc_object.inactive == NULL)
panic("ubc_init: failed to allocate inactive queue heads");
for (i = 0; i < UBC_NQUEUES; i++) {
TAILQ_INIT(&ubc_object.inactive[i]);
}
for (i = 0; i < ubc_nwins; i++) {
umap = &ubc_object.umap[i];
TAILQ_INSERT_TAIL(&ubc_object.inactive[i & (UBC_NQUEUES - 1)],
umap, inactive);
}
ubc_object.hash = hashinit(ubc_nwins, HASH_LIST, M_TEMP, M_NOWAIT,
&ubc_object.hashmask);
for (i = 0; i <= ubc_object.hashmask; i++) {
LIST_INIT(&ubc_object.hash[i]);
}
if (uvm_map(kernel_map, (vaddr_t *)&ubc_object.kva,
ubc_nwins << ubc_winshift, &ubc_object.uobj, 0, (vsize_t)va,
UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
UVM_ADV_RANDOM, UVM_FLAG_NOMERGE)) != 0) {
panic("ubc_init: failed to map ubc_object");
}
UVMHIST_INIT(ubchist, 300);
}
/*
* ubc_fault: fault routine for ubc mapping
*/
static int
ubc_fault(struct uvm_faultinfo *ufi, vaddr_t ign1, struct vm_page **ign2,
int ign3, int ign4, vm_fault_t fault_type, vm_prot_t access_type,
int flags)
{
struct uvm_object *uobj;
struct ubc_map *umap;
vaddr_t va, eva, ubc_offset, slot_offset;
int i, error, npages;
struct vm_page *pgs[ubc_winsize >> PAGE_SHIFT], *pg;
vm_prot_t prot;
UVMHIST_FUNC("ubc_fault"); UVMHIST_CALLED(ubchist);
/*
* no need to try with PGO_LOCKED...
* we don't need to have the map locked since we know that
* no one will mess with it until our reference is released.
*/
if (flags & PGO_LOCKED) {
uvmfault_unlockall(ufi, NULL, &ubc_object.uobj, NULL);
flags &= ~PGO_LOCKED;
}
va = ufi->orig_rvaddr;
ubc_offset = va - (vaddr_t)ubc_object.kva;
umap = &ubc_object.umap[ubc_offset >> ubc_winshift];
KASSERT(umap->refcount != 0);
slot_offset = ubc_offset & (ubc_winsize - 1);
/*
* some platforms cannot write to individual bytes atomically, so
* software has to do read/modify/write of larger quantities instead.
* this means that the access_type for "write" operations
* can be VM_PROT_READ, which confuses us mightily.
*
* deal with this by resetting access_type based on the info
* that ubc_alloc() stores for us.
*/
access_type = umap->writelen ? VM_PROT_WRITE : VM_PROT_READ;
UVMHIST_LOG(ubchist, "va 0x%lx ubc_offset 0x%lx access_type %d",
va, ubc_offset, access_type, 0);
#ifdef DIAGNOSTIC
if ((access_type & VM_PROT_WRITE) != 0) {
if (slot_offset < trunc_page(umap->writeoff) ||
umap->writeoff + umap->writelen <= slot_offset) {
panic("ubc_fault: out of range write");
}
}
#endif
/* no umap locking needed since we have a ref on the umap */
uobj = umap->uobj;
if ((access_type & VM_PROT_WRITE) == 0) {
npages = (ubc_winsize - slot_offset) >> PAGE_SHIFT;
} else {
npages = (round_page(umap->offset + umap->writeoff +
umap->writelen) - (umap->offset + slot_offset))
>> PAGE_SHIFT;
flags |= PGO_PASTEOF;
}
again:
memset(pgs, 0, sizeof (pgs));
simple_lock(&uobj->vmobjlock);
UVMHIST_LOG(ubchist, "slot_offset 0x%x writeoff 0x%x writelen 0x%x ",
slot_offset, umap->writeoff, umap->writelen, 0);
UVMHIST_LOG(ubchist, "getpages uobj %p offset 0x%x npages %d",
uobj, umap->offset + slot_offset, npages, 0);
error = (*uobj->pgops->pgo_get)(uobj, umap->offset + slot_offset, pgs,
&npages, 0, access_type, 0, flags);
UVMHIST_LOG(ubchist, "getpages error %d npages %d", error, npages, 0,
0);
if (error == EAGAIN) {
tsleep(&lbolt, PVM, "ubc_fault", 0);
goto again;
}
if (error) {
return error;
}
va = ufi->orig_rvaddr;
eva = ufi->orig_rvaddr + (npages << PAGE_SHIFT);
UVMHIST_LOG(ubchist, "va 0x%lx eva 0x%lx", va, eva, 0, 0);
simple_lock(&uobj->vmobjlock);
uvm_lock_pageq();
for (i = 0; va < eva; i++, va += PAGE_SIZE) {
/*
* for virtually-indexed, virtually-tagged caches we should
* avoid creating writable mappings when we don't absolutely
* need them, since the "compatible alias" trick doesn't work
* on such caches. otherwise, we can always map the pages
* writable.
*/
#ifdef PMAP_CACHE_VIVT
prot = VM_PROT_READ | access_type;
#else
prot = VM_PROT_READ | VM_PROT_WRITE;
#endif
UVMHIST_LOG(ubchist, "pgs[%d] = %p", i, pgs[i], 0, 0);
pg = pgs[i];
if (pg == NULL || pg == PGO_DONTCARE) {
continue;
}
if (pg->flags & PG_WANTED) {
wakeup(pg);
}
KASSERT((pg->flags & PG_FAKE) == 0);
if (pg->flags & PG_RELEASED) {
uvm_pagefree(pg);
continue;
}
if (pg->loan_count != 0) {
/*
* avoid unneeded loan break if possible.
*/
if ((access_type & VM_PROT_WRITE) == 0)
prot &= ~VM_PROT_WRITE;
if (prot & VM_PROT_WRITE) {
uvm_unlock_pageq();
pg = uvm_loanbreak(pg);
uvm_lock_pageq();
if (pg == NULL)
continue; /* will re-fault */
}
}
KASSERT(access_type == VM_PROT_READ ||
(pg->flags & PG_RDONLY) == 0);
pmap_enter(ufi->orig_map->pmap, va, VM_PAGE_TO_PHYS(pg),
(pg->flags & PG_RDONLY) ? prot & ~VM_PROT_WRITE : prot,
access_type);
uvm_pageactivate(pg);
pg->flags &= ~(PG_BUSY);
UVM_PAGE_OWN(pg, NULL);
}
uvm_unlock_pageq();
simple_unlock(&uobj->vmobjlock);
pmap_update(ufi->orig_map->pmap);
return 0;
}
/*
* local functions
*/
static struct ubc_map *
ubc_find_mapping(struct uvm_object *uobj, voff_t offset)
{
struct ubc_map *umap;
LIST_FOREACH(umap, &ubc_object.hash[UBC_HASH(uobj, offset)], hash) {
if (umap->uobj == uobj && umap->offset == offset) {
return umap;
}
}
return NULL;
}
/*
* ubc interface functions
*/
/*
* ubc_alloc: allocate a file mapping window
*/
void *
ubc_alloc(struct uvm_object *uobj, voff_t offset, vsize_t *lenp, int flags)
{
vaddr_t slot_offset, va;
struct ubc_map *umap;
voff_t umap_offset;
int error;
UVMHIST_FUNC("ubc_alloc"); UVMHIST_CALLED(ubchist);
UVMHIST_LOG(ubchist, "uobj %p offset 0x%lx len 0x%lx",
uobj, offset, *lenp, 0);
KASSERT(*lenp > 0);
umap_offset = (offset & ~((voff_t)ubc_winsize - 1));
slot_offset = (vaddr_t)(offset & ((voff_t)ubc_winsize - 1));
*lenp = MIN(*lenp, ubc_winsize - slot_offset);
/*
* the object is always locked here, so we don't need to add a ref.
*/
again:
simple_lock(&ubc_object.uobj.vmobjlock);
umap = ubc_find_mapping(uobj, umap_offset);
if (umap == NULL) {
umap = TAILQ_FIRST(UBC_QUEUE(offset));
if (umap == NULL) {
simple_unlock(&ubc_object.uobj.vmobjlock);
tsleep(&lbolt, PVM, "ubc_alloc", 0);
goto again;
}
/*
* remove from old hash (if any), add to new hash.
*/
if (umap->uobj != NULL) {
LIST_REMOVE(umap, hash);
}
umap->uobj = uobj;
umap->offset = umap_offset;
LIST_INSERT_HEAD(&ubc_object.hash[UBC_HASH(uobj, umap_offset)],
umap, hash);
va = UBC_UMAP_ADDR(umap);
if (umap->flags & UMAP_MAPPING_CACHED) {
umap->flags &= ~UMAP_MAPPING_CACHED;
pmap_remove(pmap_kernel(), va, va + ubc_winsize);
pmap_update(pmap_kernel());
}
} else {
va = UBC_UMAP_ADDR(umap);
}
if (umap->refcount == 0) {
TAILQ_REMOVE(UBC_QUEUE(offset), umap, inactive);
}
#ifdef DIAGNOSTIC
if ((flags & UBC_WRITE) && (umap->writeoff || umap->writelen)) {
panic("ubc_alloc: concurrent writes uobj %p", uobj);
}
#endif
if (flags & UBC_WRITE) {
umap->writeoff = slot_offset;
umap->writelen = *lenp;
}
umap->refcount++;
simple_unlock(&ubc_object.uobj.vmobjlock);
UVMHIST_LOG(ubchist, "umap %p refs %d va %p flags 0x%x",
umap, umap->refcount, va, flags);
if (flags & UBC_FAULTBUSY) {
int npages = (*lenp + PAGE_SIZE - 1) >> PAGE_SHIFT;
struct vm_page *pgs[npages];
int gpflags = PGO_SYNCIO|PGO_OVERWRITE|PGO_PASTEOF;
int i;
KDASSERT(flags & UBC_WRITE);
if (umap->flags & UMAP_MAPPING_CACHED) {
umap->flags &= ~UMAP_MAPPING_CACHED;
pmap_remove(pmap_kernel(), va, va + ubc_winsize);
}
memset(pgs, 0, sizeof(pgs));
simple_lock(&uobj->vmobjlock);
error = (*uobj->pgops->pgo_get)(uobj, trunc_page(offset), pgs,
&npages, 0, VM_PROT_READ | VM_PROT_WRITE, 0, gpflags);
UVMHIST_LOG(ubchist, "faultbusy getpages %d", error, 0, 0, 0);
if (error) {
goto out;
}
for (i = 0; i < npages; i++) {
pmap_kenter_pa(va + slot_offset + (i << PAGE_SHIFT),
VM_PAGE_TO_PHYS(pgs[i]),
VM_PROT_READ | VM_PROT_WRITE);
}
pmap_update(pmap_kernel());
umap->flags |= UMAP_PAGES_LOCKED;
}
out:
return (void *)(va + slot_offset);
}
/*
* ubc_release: free a file mapping window.
*/
void
ubc_release(void *va, int flags)
{
struct ubc_map *umap;
struct uvm_object *uobj;
vaddr_t umapva;
boolean_t unmapped;
UVMHIST_FUNC("ubc_release"); UVMHIST_CALLED(ubchist);
UVMHIST_LOG(ubchist, "va %p", va, 0, 0, 0);
umap = &ubc_object.umap[((char *)va - ubc_object.kva) >> ubc_winshift];
umapva = UBC_UMAP_ADDR(umap);
uobj = umap->uobj;
KASSERT(uobj != NULL);
if (umap->flags & UMAP_PAGES_LOCKED) {
int slot_offset = umap->writeoff;
int endoff = umap->writeoff + umap->writelen;
int zerolen = round_page(endoff) - endoff;
int npages = (int)(round_page(umap->writeoff + umap->writelen)
- trunc_page(umap->writeoff)) >> PAGE_SHIFT;
struct vm_page *pgs[npages];
paddr_t pa;
int i;
boolean_t rv;
if (zerolen) {
memset((char *)umapva + endoff, 0, zerolen);
}
umap->flags &= ~UMAP_PAGES_LOCKED;
uvm_lock_pageq();
for (i = 0; i < npages; i++) {
rv = pmap_extract(pmap_kernel(),
umapva + slot_offset + (i << PAGE_SHIFT), &pa);
KASSERT(rv);
pgs[i] = PHYS_TO_VM_PAGE(pa);
pgs[i]->flags &= ~(PG_FAKE|PG_CLEAN);
KASSERT(pgs[i]->loan_count == 0);
uvm_pageactivate(pgs[i]);
}
uvm_unlock_pageq();
pmap_kremove(umapva, ubc_winsize);
pmap_update(pmap_kernel());
simple_lock(&uobj->vmobjlock);
uvm_page_unbusy(pgs, npages);
simple_unlock(&uobj->vmobjlock);
unmapped = TRUE;
} else {
unmapped = FALSE;
}
simple_lock(&ubc_object.uobj.vmobjlock);
umap->writeoff = 0;
umap->writelen = 0;
umap->refcount--;
if (umap->refcount == 0) {
if (flags & UBC_UNMAP) {
/*
* Invalidate any cached mappings if requested.
* This is typically used to avoid leaving
* incompatible cache aliases around indefinitely.
*/
pmap_remove(pmap_kernel(), umapva,
umapva + ubc_winsize);
umap->flags &= ~UMAP_MAPPING_CACHED;
pmap_update(pmap_kernel());
LIST_REMOVE(umap, hash);
umap->uobj = NULL;
TAILQ_INSERT_HEAD(UBC_QUEUE(umap->offset), umap,
inactive);
} else {
if (!unmapped) {
umap->flags |= UMAP_MAPPING_CACHED;
}
TAILQ_INSERT_TAIL(UBC_QUEUE(umap->offset), umap,
inactive);
}
}
UVMHIST_LOG(ubchist, "umap %p refs %d", umap, umap->refcount, 0, 0);
simple_unlock(&ubc_object.uobj.vmobjlock);
}
#if 0 /* notused */
/*
* removing a range of mappings from the ubc mapping cache.
*/
void
ubc_flush(struct uvm_object *uobj, voff_t start, voff_t end)
{
struct ubc_map *umap;
vaddr_t va;
UVMHIST_FUNC("ubc_flush"); UVMHIST_CALLED(ubchist);
UVMHIST_LOG(ubchist, "uobj %p start 0x%lx end 0x%lx",
uobj, start, end, 0);
simple_lock(&ubc_object.uobj.vmobjlock);
for (umap = ubc_object.umap;
umap < &ubc_object.umap[ubc_nwins];
umap++) {
if (umap->uobj != uobj || umap->offset < start ||
(umap->offset >= end && end != 0) ||
umap->refcount > 0) {
continue;
}
/*
* remove from hash,
* move to head of inactive queue.
*/
va = (vaddr_t)(ubc_object.kva +
((umap - ubc_object.umap) << ubc_winshift));
pmap_remove(pmap_kernel(), va, va + ubc_winsize);
LIST_REMOVE(umap, hash);
umap->uobj = NULL;
TAILQ_REMOVE(UBC_QUEUE(umap->offset), umap, inactive);
TAILQ_INSERT_HEAD(UBC_QUEUE(umap->offset), umap, inactive);
}
pmap_update(pmap_kernel());
simple_unlock(&ubc_object.uobj.vmobjlock);
}
#endif /* notused */
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