/*
* Copyright (C) 2006 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - 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.
*/
#include <genarch/mm/page_ht.h>
#include <mm/page.h>
#include <mm/frame.h>
#include <mm/heap.h>
#include <mm/as.h>
#include <arch/mm/asid.h>
#include <arch/types.h>
#include <typedefs.h>
#include <arch/asm.h>
#include <synch/spinlock.h>
#include <arch.h>
#include <debug.h>
/**
* This lock protects the page hash table. Note that software must
* be still careful about ordering of writes to ensure consistent
* view of the page hash table for hardware helpers such as VHPT
* walker on ia64.
*/
SPINLOCK_INITIALIZE(page_ht_lock);
/**
* Page hash table pointer.
* The page hash table may be accessed only when page_ht_lock is held.
*/
pte_t *page_ht = NULL;
static void ht_mapping_insert(as_t *as, __address page, __address frame, int flags, __address root);
static pte_t *ht_mapping_find(as_t *as, __address page, __address root);
page_operations_t page_ht_operations = {
.mapping_insert = ht_mapping_insert,
.mapping_find = ht_mapping_find
};
/** Map page to frame using page hash table.
*
* Map virtual address 'page' to physical address 'frame'
* using 'flags'. In order not to disturb hardware searching,
* new mappings are appended to the end of the collision
* chain.
*
* @param as Address space to which page belongs. Must be locked prior the call.
* @param page Virtual address of the page to be mapped.
* @param frame Physical address of memory frame to which the mapping is done.
* @param flags Flags to be used for mapping.
* @param root Ignored.
*/
void ht_mapping_insert(as_t *as, __address page, __address frame, int flags, __address root)
{
pte_t *t, *u;
ipl_t ipl;
ipl = interrupts_disable();
spinlock_lock(&page_ht_lock);
t = HT_HASH(page, as->asid);
if (!HT_SLOT_EMPTY(t)) {
/*
* The slot is occupied.
* Walk through the collision chain and append the mapping to its end.
*/
do {
u = t;
if (HT_COMPARE(page, as->asid, t)) {
/*
* Nothing to do,
* the record is already there.
*/
spinlock_unlock(&page_ht_lock);
interrupts_restore(ipl);
return;
}
} while ((t = HT_GET_NEXT(t)));
t
= (pte_t
*) malloc(sizeof(pte_t
)); /* FIXME: use slab allocator for this */ if (!t)
panic("could not allocate memory\n");
HT_SET_NEXT(u, t);
}
HT_SET_RECORD(t, page, as->asid, frame, flags);
HT_SET_NEXT(t, NULL);
spinlock_unlock(&page_ht_lock);
interrupts_restore(ipl);
}
/** Find mapping for virtual page in page hash table.
*
* Find mapping for virtual page.
*
* Interrupts must be disabled.
*
* @param as Address space to wich page belongs. Must be locked prior the call.
* @param page Virtual page.
* @param root Ignored.
*
* @return NULL if there is no such mapping; requested mapping otherwise.
*/
pte_t *ht_mapping_find(as_t *as, __address page, __address root)
{
pte_t *t;
spinlock_lock(&page_ht_lock);
t = HT_HASH(page, as->asid);
if (!HT_SLOT_EMPTY(t)) {
while (!HT_COMPARE(page, as->asid, t) && HT_GET_NEXT(t))
t = HT_GET_NEXT(t);
t = HT_COMPARE(page, as->asid, t) ? t : NULL;
} else {
t = NULL;
}
spinlock_unlock(&page_ht_lock);
return t;
}
/** Invalidate page hash table.
*
* Interrupts must be disabled.
*/
void ht_invalidate_all(void)
{
pte_t *t, *u;
int i;
spinlock_lock(&page_ht_lock);
for (i = 0; i < HT_ENTRIES; i++) {
if (!HT_SLOT_EMPTY(&page_ht[i])) {
t = HT_GET_NEXT(&page_ht[i]);
while (t) {
u = t;
t = HT_GET_NEXT(t);
free(u
); /* FIXME: use slab allocator for this */ }
HT_INVALIDATE_SLOT(&page_ht[i]);
}
}
spinlock_unlock(&page_ht_lock);
}