/*
* 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 kernel_genarch_mm
* @{
*/
/**
* @file
* @brief FIFO queue ASID management.
*
* Architectures that link with this file keep the unallocated ASIDs
* in FIFO queue. The queue can be statically (e.g. mips32) or
* dynamically allocated (e.g ia64 and sparc64).
*/
#include <genarch/mm/asid_fifo.h>
#include <arch/mm/asid.h>
#include <mm/asid.h>
#include <adt/fifo.h>
#define FIFO_STATIC_LIMIT 1024
#define FIFO_STATIC (ASIDS_ALLOCABLE<FIFO_STATIC_LIMIT)
/**
* FIFO queue containing unassigned ASIDs.
* Can be only accessed when asidlock is held.
*/
#if FIFO_STATIC
FIFO_INITIALIZE_STATIC(free_asids, asid_t, ASIDS_ALLOCABLE);
#else
FIFO_INITIALIZE_DYNAMIC(free_asids, asid_t, ASIDS_ALLOCABLE);
#endif
/** Initialize data structures for O(1) ASID allocation and deallocation. */
void asid_fifo_init(void)
{
int i;
#if (!FIFO_STATIC)
fifo_create(free_asids);
if (!free_asids.fifo)
panic("Not enough memory to allocate ASID FIFO");
// TODO: There really is no reason not to statically allocate it
// except to keep binary size low. Once kernel is a regular ELF
// binary supporting .bss section (wip as of the late 2018),
// the dynamic option should be removed.
#endif
for (i = 0; i < ASIDS_ALLOCABLE; i++) {
fifo_push(free_asids, ASID_START + i);
}
}
/** Allocate free ASID.
*
* Allocation runs in O(1).
*
* @return Free ASID.
*/
asid_t asid_find_free(void)
{
return fifo_pop(free_asids);
}
/** Return ASID among free ASIDs.
*
* This operation runs in O(1).
*
* @param asid ASID being freed.
*/
void asid_put_arch(asid_t asid)
{
fifo_push(free_asids, asid);
}
/** @}
*/