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730 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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 */
1266 jermar 28
 
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/**
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 * @file    asid_fifo.c
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 * @brief   FIFO queue ASID management.
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 *
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 * Architectures that link with this file keep the unallocated ASIDs
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 * in FIFO queue. The queue can be statically (e.g. mips32) or
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 * dynamically allocated (e.g ia64 and sparc64).
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 */
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#include <genarch/mm/asid_fifo.h>
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#include <arch/mm/asid.h>
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#include <mm/asid.h>
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#include <typedefs.h>
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#include <adt/fifo.h>
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#define FIFO_STATIC_LIMIT   1024
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#define FIFO_STATIC     (ASIDS_ALLOCABLE<FIFO_STATIC_LIMIT)
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/**
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 * FIFO queue containing unassigned ASIDs.
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 * Can be only accessed when asidlock is held.
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 */
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#if FIFO_STATIC
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FIFO_INITIALIZE_STATIC(free_asids, asid_t, ASIDS_ALLOCABLE);
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#else
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FIFO_INITIALIZE_DYNAMIC(free_asids, asid_t, ASIDS_ALLOCABLE);
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#endif
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/** Initialize data structures for O(1) ASID allocation and deallocation. */
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void asid_fifo_init(void)
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{
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    int i;
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    #if (!FIFO_STATIC)
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    fifo_create(free_asids);
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    #endif
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    for (i = 0; i < ASIDS_ALLOCABLE; i++) {
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        fifo_push(free_asids, ASID_START + i);
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    }
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}
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/** Allocate free ASID.
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 *
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 * Allocation runs in O(1).
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 *
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 * @return Free ASID.
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 */
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asid_t asid_find_free(void)
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{
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    return fifo_pop(free_asids);
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}
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/** Return ASID among free ASIDs.
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 *
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 * This operation runs in O(1).
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 *
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 * @param asid ASID being freed.
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 */
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void asid_put_arch(asid_t asid)
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{
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    fifo_push(free_asids, asid);
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}