0,0 → 1,117 |
/* |
* 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. |
*/ |
|
/* |
* ASID management. |
* |
* Because ia64 has much wider ASIDs (18-24 bits) compared to other |
* architectures (e.g. 8 bits on mips32 and 12 bits on sparc32), it is |
* inappropriate to use same methods (i.e. genarch/mm/asid_fifo.c) for |
* all of them. |
* |
* Instead, ia64 assigns ASID values from a counter that eventually |
* overflows. When this happens, the counter is reset and all TLBs are |
* entirely invalidated. Furthermore, all address space structures, |
* except for the one with asid == ASID_KERNEL, are assigned new ASID. |
* |
* It is important to understand that, in SPARTAN, one ASID represents |
* RIDS_PER_ASID consecutive hardware RIDs (Region ID's). |
* |
* Note that the algorithm used can handle only the maximum of |
* ASID_OVERFLOW-ASID_START address spaces at a time. |
*/ |
|
#include <arch/mm/asid.h> |
#include <mm/asid.h> |
#include <mm/as.h> |
#include <mm/tlb.h> |
#include <list.h> |
#include <typedefs.h> |
#include <debug.h> |
|
/** |
* Stores the ASID to be returned next. |
* Must be only accessed when asidlock is held. |
*/ |
static asid_t next_asid = ASID_START; |
|
/** Assign next ASID. |
* |
* On ia64, this function is used only to allocate ASID |
* for a newly created address space. As a side effect, |
* it might attempt to shootdown TLBs and reassign |
* ASIDs to existing address spaces. |
* |
* When calling this function, interrupts must be disabled |
* and the asidlock must be held. |
* |
* @return ASID for new address space. |
*/ |
asid_t asid_find_free(void) |
{ |
as_t *as; |
link_t *cur; |
|
if (next_asid == ASID_OVERFLOW) { |
/* |
* The counter has overflown. |
*/ |
|
/* |
* Reset the counter. |
*/ |
next_asid = ASID_START; |
|
/* |
* Initiate TLB shootdown. |
*/ |
tlb_shootdown_start(TLB_INVL_ALL, 0, 0, 0); |
|
/* |
* Reassign ASIDs to existing address spaces. |
*/ |
for (cur = as_with_asid_head.next; cur != &as_with_asid_head; cur = cur->next) { |
ASSERT(next_asid < ASID_OVERFLOW); |
|
as = list_get_instance(cur, as_t, as_with_asid_link); |
|
spinlock_lock(&as->lock); |
as->asid = next_asid++; |
spinlock_unlock(&as->lock); |
} |
|
/* |
* Finish TLB shootdown. |
*/ |
tlb_shootdown_finalize(); |
tlb_invalidate_all(); |
} |
|
ASSERT(next_asid < ASID_OVERFLOW); |
return next_asid++; |
} |