/*
* Copyright (c) 2001-2004 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_generic_mm
* @{
*/
/**
* @file
* @brief Generic TLB shootdown algorithm.
*
* The algorithm implemented here is based on the CMU TLB shootdown
* algorithm and is further simplified (e.g. all CPUs receive all TLB
* shootdown messages).
*/
#include <mm/tlb.h>
#include <mm/asid.h>
#include <arch/mm/tlb.h>
#include <assert.h>
#include <smp/ipi.h>
#include <synch/spinlock.h>
#include <atomic.h>
#include <arch/interrupt.h>
#include <config.h>
#include <arch.h>
#include <panic.h>
#include <cpu.h>
void tlb_init(void)
{
tlb_arch_init();
}
#ifdef CONFIG_SMP
/**
* This lock is used for synchronisation between sender and
* recipients of TLB shootdown message. It must be acquired
* before CPU structure lock.
*
*/
IRQ_SPINLOCK_STATIC_INITIALIZE(tlblock);
/** Send TLB shootdown message.
*
* This function attempts to deliver TLB shootdown message
* to all other processors.
*
* @param type Type describing scope of shootdown.
* @param asid Address space, if required by type.
* @param page Virtual page address, if required by type.
* @param count Number of pages, if required by type.
*
* @return The interrupt priority level as it existed prior to this call.
*
*/
ipl_t tlb_shootdown_start(tlb_invalidate_type_t type, asid_t asid,
uintptr_t page, size_t count)
{
ipl_t ipl = interrupts_disable();
CPU->tlb_active = false;
irq_spinlock_lock(&tlblock, false);
size_t i;
for (i = 0; i < config.cpu_count; i++) {
if (i == CPU->id)
continue;
cpu_t *cpu = &cpus[i];
irq_spinlock_lock(&cpu->tlb_lock, false);
if (cpu->tlb_messages_count == TLB_MESSAGE_QUEUE_LEN) {
/*
* The message queue is full.
* Erase the queue and store one TLB_INVL_ALL message.
*/
cpu->tlb_messages_count = 1;
cpu->tlb_messages[0].type = TLB_INVL_ALL;
cpu->tlb_messages[0].asid = ASID_INVALID;
cpu->tlb_messages[0].page = 0;
cpu->tlb_messages[0].count = 0;
} else {
/*
* Enqueue the message.
*/
size_t idx = cpu->tlb_messages_count++;
cpu->tlb_messages[idx].type = type;
cpu->tlb_messages[idx].asid = asid;
cpu->tlb_messages[idx].page = page;
cpu->tlb_messages[idx].count = count;
}
irq_spinlock_unlock(&cpu->tlb_lock, false);
}
tlb_shootdown_ipi_send();
busy_wait:
for (i = 0; i < config.cpu_count; i++) {
if (cpus[i].tlb_active)
goto busy_wait;
}
return ipl;
}
/** Finish TLB shootdown sequence.
*
* @param ipl Previous interrupt priority level.
*
*/
void tlb_shootdown_finalize(ipl_t ipl)
{
irq_spinlock_unlock(&tlblock, false);
CPU->tlb_active = true;
interrupts_restore(ipl);
}
void tlb_shootdown_ipi_send(void)
{
ipi_broadcast(VECTOR_TLB_SHOOTDOWN_IPI);
}
/** Receive TLB shootdown message.
*
*/
void tlb_shootdown_ipi_recv(void)
{
assert(CPU);
CPU->tlb_active = false;
irq_spinlock_lock(&tlblock, false);
irq_spinlock_unlock(&tlblock, false);
irq_spinlock_lock(&CPU->tlb_lock, false);
assert(CPU->tlb_messages_count <= TLB_MESSAGE_QUEUE_LEN);
size_t i;
for (i = 0; i < CPU->tlb_messages_count; i++) {
tlb_invalidate_type_t type = CPU->tlb_messages[i].type;
asid_t asid = CPU->tlb_messages[i].asid;
uintptr_t page = CPU->tlb_messages[i].page;
size_t count = CPU->tlb_messages[i].count;
switch (type) {
case TLB_INVL_ALL:
tlb_invalidate_all();
break;
case TLB_INVL_ASID:
tlb_invalidate_asid(asid);
break;
case TLB_INVL_PAGES:
assert(count);
tlb_invalidate_pages(asid, page, count);
break;
default:
panic("Unknown type (%d).", type);
break;
}
if (type == TLB_INVL_ALL)
break;
}
CPU->tlb_messages_count = 0;
irq_spinlock_unlock(&CPU->tlb_lock, false);
CPU->tlb_active = true;
}
#endif /* CONFIG_SMP */
/** @}
*/