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684 jermar 1
/*
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 * Copyright (c) 2006 Jakub Jermar
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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/** @addtogroup genarchmm
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 * @{
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 */
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/**
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 * @file
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 * @brief   Virtual Address Translation (VAT) for global page hash table.
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 */
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#include <genarch/mm/page_ht.h>
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#include <mm/page.h>
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#include <arch/mm/page.h>
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#include <mm/frame.h>
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#include <mm/slab.h>
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#include <mm/as.h>
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#include <arch/mm/asid.h>
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#include <arch/types.h>
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#include <arch/asm.h>
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#include <synch/spinlock.h>
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#include <arch.h>
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#include <debug.h>
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#include <memstr.h>
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#include <adt/hash_table.h>
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#include <align.h>
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static index_t hash(unative_t key[]);
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static bool compare(unative_t key[], count_t keys, link_t *item);
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static void remove_callback(link_t *item);
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2292 hudecek 58
static void ht_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame,
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    int flags);
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static void ht_mapping_remove(as_t *as, uintptr_t page);
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static pte_t *ht_mapping_find(as_t *as, uintptr_t page);
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/**
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 * This lock protects the page hash table. It must be acquired
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 * after address space lock and after any address space area
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 * locks.
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 */
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mutex_t page_ht_lock;
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/**
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 * Page hash table.
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 * The page hash table may be accessed only when page_ht_lock is held.
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 */
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hash_table_t page_ht;
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/** Hash table operations for page hash table. */
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hash_table_operations_t ht_operations = {
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    .hash = hash,
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    .compare = compare,
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    .remove_callback = remove_callback
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};
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/** Page mapping operations for page hash table architectures. */
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page_mapping_operations_t ht_mapping_operations = {
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    .mapping_insert = ht_mapping_insert,
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    .mapping_remove = ht_mapping_remove,
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    .mapping_find = ht_mapping_find
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};
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792 jermar 90
/** Compute page hash table index.
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 *
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 * @param key Array of two keys (i.e. page and address space).
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 *
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 * @return Index into page hash table.
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 */
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index_t hash(unative_t key[])
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{
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    as_t *as = (as_t *) key[KEY_AS];
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    uintptr_t page = (uintptr_t) key[KEY_PAGE];
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    index_t index;
101
 
102
    /*
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     * Virtual page addresses have roughly the same probability
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     * of occurring. Least significant bits of VPN compose the
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     * hash index.
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     */
2292 hudecek 107
    index = ((page >> PAGE_WIDTH) & (PAGE_HT_ENTRIES - 1));
792 jermar 108
 
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    /*
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     * Address space structures are likely to be allocated from
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     * similar addresses. Least significant bits compose the
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     * hash index.
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     */
2292 hudecek 114
    index |= ((unative_t) as) & (PAGE_HT_ENTRIES - 1);
792 jermar 115
 
116
    return index;
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}
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119
/** Compare page hash table item with page and/or address space.
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 *
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 * @param key Array of one or two keys (i.e. page and/or address space).
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 * @param keys Number of keys passed.
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 * @param item Item to compare the keys with.
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 *
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 * @return true on match, false otherwise.
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 */
1780 jermar 127
bool compare(unative_t key[], count_t keys, link_t *item)
792 jermar 128
{
129
    pte_t *t;
130
 
131
    ASSERT(item);
132
    ASSERT((keys > 0) && (keys <= PAGE_HT_KEYS));
133
 
134
    /*
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     * Convert item to PTE.
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     */
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    t = hash_table_get_instance(item, pte_t, link);
792 jermar 138
 
139
    if (keys == PAGE_HT_KEYS) {
2292 hudecek 140
        return (key[KEY_AS] == (uintptr_t) t->as) &&
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            (key[KEY_PAGE] == t->page);
792 jermar 142
    } else {
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        return (key[KEY_AS] == (uintptr_t) t->as);
792 jermar 144
    }
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}
146
 
147
/** Callback on page hash table item removal.
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 *
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 * @param item Page hash table item being removed.
150
 */
151
void remove_callback(link_t *item)
152
{
153
    pte_t *t;
154
 
155
    ASSERT(item);
156
 
157
    /*
158
     * Convert item to PTE.
159
     */
793 jermar 160
    t = hash_table_get_instance(item, pte_t, link);
792 jermar 161
 
162
    free(t);
163
}
164
 
684 jermar 165
/** Map page to frame using page hash table.
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 *
1248 jermar 167
 * Map virtual address page to physical address frame
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 * using flags.
684 jermar 169
 *
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 * The page table must be locked and interrupts must be disabled.
756 jermar 171
 *
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 * @param as Address space to which page belongs.
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 * @param page Virtual address of the page to be mapped.
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 * @param frame Physical address of memory frame to which the mapping is done.
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 * @param flags Flags to be used for mapping.
176
 */
1780 jermar 177
void ht_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags)
684 jermar 178
{
792 jermar 179
    pte_t *t;
2292 hudecek 180
    unative_t key[2] = {
181
        (uintptr_t) as,
182
        page = ALIGN_DOWN(page, PAGE_SIZE)
183
    };
699 jermar 184
 
792 jermar 185
    if (!hash_table_find(&page_ht, key)) {
823 jermar 186
        t = (pte_t *) malloc(sizeof(pte_t), FRAME_ATOMIC);
792 jermar 187
        ASSERT(t != NULL);
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189
        t->g = (flags & PAGE_GLOBAL) != 0;
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        t->x = (flags & PAGE_EXEC) != 0;
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        t->w = (flags & PAGE_WRITE) != 0;
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        t->k = !(flags & PAGE_USER);
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        t->c = (flags & PAGE_CACHEABLE) != 0;
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        t->p = !(flags & PAGE_NOT_PRESENT);
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        t->as = as;
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        t->page = ALIGN_DOWN(page, PAGE_SIZE);
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        t->frame = ALIGN_DOWN(frame, FRAME_SIZE);
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792 jermar 200
        hash_table_insert(&page_ht, key, &t->link);
699 jermar 201
    }
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}
203
 
826 jermar 204
/** Remove mapping of page from page hash table.
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 *
1248 jermar 206
 * Remove any mapping of page within address space as.
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 * TLB shootdown should follow in order to make effects of
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 * this call visible.
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 *
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 * The page table must be locked and interrupts must be disabled.
826 jermar 211
 *
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 * @param as Address space to wich page belongs.
213
 * @param page Virtual address of the page to be demapped.
214
 */
1780 jermar 215
void ht_mapping_remove(as_t *as, uintptr_t page)
826 jermar 216
{
2292 hudecek 217
    unative_t key[2] = {
218
        (uintptr_t) as,
219
        page = ALIGN_DOWN(page, PAGE_SIZE)
220
    };
826 jermar 221
 
222
    /*
223
     * Note that removed PTE's will be freed
224
     * by remove_callback().
225
     */
226
    hash_table_remove(&page_ht, key, 2);
227
}
228
 
229
 
684 jermar 230
/** Find mapping for virtual page in page hash table.
231
 *
232
 * Find mapping for virtual page.
233
 *
1044 jermar 234
 * The page table must be locked and interrupts must be disabled.
746 jermar 235
 *
1248 jermar 236
 * @param as Address space to wich page belongs.
684 jermar 237
 * @param page Virtual page.
238
 *
699 jermar 239
 * @return NULL if there is no such mapping; requested mapping otherwise.
684 jermar 240
 */
1780 jermar 241
pte_t *ht_mapping_find(as_t *as, uintptr_t page)
684 jermar 242
{
792 jermar 243
    link_t *hlp;
244
    pte_t *t = NULL;
2292 hudecek 245
    unative_t key[2] = {
246
        (uintptr_t) as,
247
        page = ALIGN_DOWN(page, PAGE_SIZE)
248
    };
699 jermar 249
 
792 jermar 250
    hlp = hash_table_find(&page_ht, key);
251
    if (hlp)
793 jermar 252
        t = hash_table_get_instance(hlp, pte_t, link);
792 jermar 253
 
746 jermar 254
    return t;
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}
1702 cejka 256
 
1851 jermar 257
/** @}
1702 cejka 258
 */