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/* |
* 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. |
*/ |
|
/** @addtogroup genarchmm |
* @{ |
*/ |
|
/** |
* @file |
* @brief Virtual Address Translation (VAT) for global page hash table. |
*/ |
|
#include <genarch/mm/page_ht.h> |
#include <mm/page.h> |
#include <arch/mm/page.h> |
#include <mm/frame.h> |
#include <mm/slab.h> |
#include <mm/as.h> |
#include <arch/mm/asid.h> |
#include <arch/types.h> |
#include <arch/asm.h> |
#include <synch/spinlock.h> |
#include <arch.h> |
#include <debug.h> |
#include <memstr.h> |
#include <adt/hash_table.h> |
#include <align.h> |
|
static index_t hash(unative_t key[]); |
static bool compare(unative_t key[], count_t keys, link_t *item); |
static void remove_callback(link_t *item); |
|
static void ht_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags); |
static void ht_mapping_remove(as_t *as, uintptr_t page); |
static pte_t *ht_mapping_find(as_t *as, uintptr_t page); |
|
/** |
* This lock protects the page hash table. It must be acquired |
* after address space lock and after any address space area |
* locks. |
*/ |
mutex_t page_ht_lock; |
|
/** |
* Page hash table. |
* The page hash table may be accessed only when page_ht_lock is held. |
*/ |
hash_table_t page_ht; |
|
/** Hash table operations for page hash table. */ |
hash_table_operations_t ht_operations = { |
.hash = hash, |
.compare = compare, |
.remove_callback = remove_callback |
}; |
|
/** Page mapping operations for page hash table architectures. */ |
page_mapping_operations_t ht_mapping_operations = { |
.mapping_insert = ht_mapping_insert, |
.mapping_remove = ht_mapping_remove, |
.mapping_find = ht_mapping_find |
}; |
|
/** Compute page hash table index. |
* |
* @param key Array of two keys (i.e. page and address space). |
* |
* @return Index into page hash table. |
*/ |
index_t hash(unative_t key[]) |
{ |
as_t *as = (as_t *) key[KEY_AS]; |
uintptr_t page = (uintptr_t) key[KEY_PAGE]; |
index_t index; |
|
/* |
* Virtual page addresses have roughly the same probability |
* of occurring. Least significant bits of VPN compose the |
* hash index. |
*/ |
index = ((page >> PAGE_WIDTH) & (PAGE_HT_ENTRIES-1)); |
|
/* |
* Address space structures are likely to be allocated from |
* similar addresses. Least significant bits compose the |
* hash index. |
*/ |
index |= ((unative_t) as) & (PAGE_HT_ENTRIES-1); |
|
return index; |
} |
|
/** Compare page hash table item with page and/or address space. |
* |
* @param key Array of one or two keys (i.e. page and/or address space). |
* @param keys Number of keys passed. |
* @param item Item to compare the keys with. |
* |
* @return true on match, false otherwise. |
*/ |
bool compare(unative_t key[], count_t keys, link_t *item) |
{ |
pte_t *t; |
|
ASSERT(item); |
ASSERT((keys > 0) && (keys <= PAGE_HT_KEYS)); |
|
/* |
* Convert item to PTE. |
*/ |
t = hash_table_get_instance(item, pte_t, link); |
|
if (keys == PAGE_HT_KEYS) { |
return (key[KEY_AS] == (uintptr_t) t->as) && (key[KEY_PAGE] == t->page); |
} else { |
return (key[KEY_AS] == (uintptr_t) t->as); |
} |
} |
|
/** Callback on page hash table item removal. |
* |
* @param item Page hash table item being removed. |
*/ |
void remove_callback(link_t *item) |
{ |
pte_t *t; |
|
ASSERT(item); |
|
/* |
* Convert item to PTE. |
*/ |
t = hash_table_get_instance(item, pte_t, link); |
|
free(t); |
} |
|
/** Map page to frame using page hash table. |
* |
* Map virtual address page to physical address frame |
* using flags. |
* |
* The page table must be locked and interrupts must be disabled. |
* |
* @param as Address space to which page belongs. |
* @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. |
*/ |
void ht_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags) |
{ |
pte_t *t; |
unative_t key[2] = { (uintptr_t) as, page = ALIGN_DOWN(page, PAGE_SIZE) }; |
|
if (!hash_table_find(&page_ht, key)) { |
t = (pte_t *) malloc(sizeof(pte_t), FRAME_ATOMIC); |
ASSERT(t != NULL); |
|
t->g = (flags & PAGE_GLOBAL) != 0; |
t->x = (flags & PAGE_EXEC) != 0; |
t->w = (flags & PAGE_WRITE) != 0; |
t->k = !(flags & PAGE_USER); |
t->c = (flags & PAGE_CACHEABLE) != 0; |
t->p = !(flags & PAGE_NOT_PRESENT); |
|
t->as = as; |
t->page = ALIGN_DOWN(page, PAGE_SIZE); |
t->frame = ALIGN_DOWN(frame, FRAME_SIZE); |
|
hash_table_insert(&page_ht, key, &t->link); |
} |
} |
|
/** Remove mapping of page from page hash table. |
* |
* Remove any mapping of page within address space as. |
* TLB shootdown should follow in order to make effects of |
* this call visible. |
* |
* The page table must be locked and interrupts must be disabled. |
* |
* @param as Address space to wich page belongs. |
* @param page Virtual address of the page to be demapped. |
*/ |
void ht_mapping_remove(as_t *as, uintptr_t page) |
{ |
unative_t key[2] = { (uintptr_t) as, page = ALIGN_DOWN(page, PAGE_SIZE) }; |
|
/* |
* Note that removed PTE's will be freed |
* by remove_callback(). |
*/ |
hash_table_remove(&page_ht, key, 2); |
} |
|
|
/** Find mapping for virtual page in page hash table. |
* |
* Find mapping for virtual page. |
* |
* The page table must be locked and interrupts must be disabled. |
* |
* @param as Address space to wich page belongs. |
* @param page Virtual page. |
* |
* @return NULL if there is no such mapping; requested mapping otherwise. |
*/ |
pte_t *ht_mapping_find(as_t *as, uintptr_t page) |
{ |
link_t *hlp; |
pte_t *t = NULL; |
unative_t key[2] = { (uintptr_t) as, page = ALIGN_DOWN(page, PAGE_SIZE) }; |
|
hlp = hash_table_find(&page_ht, key); |
if (hlp) |
t = hash_table_get_instance(hlp, pte_t, link); |
|
return t; |
} |
|
/** @} |
*/ |