180 lines
7.4 KiB
C
180 lines
7.4 KiB
C
/****************************************************************************
|
|
* sched/paging/pg_miss.c
|
|
*
|
|
* Copyright (C) 2010 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <gnutt@nuttx.org>
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. 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.
|
|
* 3. Neither the name NuttX nor the names of its contributors may be
|
|
* used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "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
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <errno.h>
|
|
#include <debug.h>
|
|
|
|
#include <nuttx/arch.h>
|
|
#include <nuttx/sched.h>
|
|
#include <nuttx/page.h>
|
|
|
|
#ifdef CONFIG_PAGING
|
|
|
|
#include "sched/sched.h"
|
|
#include "paging/paging.h"
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: pg_miss
|
|
*
|
|
* Description:
|
|
* This function is called from architecture-specific memory segmentation
|
|
* fault handling logic. This function will perform the following
|
|
* operations:
|
|
*
|
|
* 1) Sanity checking.
|
|
* - ASSERT if the currently executing task is the page fill worker
|
|
* thread. The page fill worker thread is how the page fault
|
|
* is resolved and all logic associated with the page fill worker
|
|
* must be "locked" and always present in memory.
|
|
* - ASSERT if an interrupt was executing at the time of the exception.
|
|
* 2) Block the currently executing task.
|
|
* - Call up_block_task() to block the task at the head of the ready-
|
|
* to-run list. This should cause an interrupt level context switch
|
|
* to the next highest priority task.
|
|
* - The blocked task will be marked with state TSTATE_WAIT_PAGEFILL
|
|
* and will be retained in the g_waitingforfill prioritized task
|
|
* list.
|
|
* 3) Boost the page fill worker thread priority.
|
|
* - Check the priority of the task at the head of the g_waitingforfill
|
|
* list. If the priority of that task is higher than the current
|
|
* priority of the page fill worker thread, then boost the priority
|
|
* of the page fill worker thread to that priority.
|
|
* 4) Signal the page fill worker thread.
|
|
* - Is there a page fill pending? If not then signal the worker
|
|
* thread to start working on the queued page fill requests.
|
|
*
|
|
* Input Parameters:
|
|
* None - The head of the ready-to-run list is assumed to be task that
|
|
* caused the exception.
|
|
*
|
|
* Returned Value:
|
|
* None - Either this function function succeeds or an assertion occurs.
|
|
*
|
|
* Assumptions:
|
|
* - It is assumed that this function is called from the level of an
|
|
* exception handler and that all interrupts are disabled.
|
|
* - It is assumed that currently executing task (the one at the head of
|
|
* the ready-to-run list) is the one that cause the fault. This will
|
|
* always be true unless the page fault occurred in an interrupt handler.
|
|
* Interrupt handling logic must always be present and "locked" into
|
|
* memory.
|
|
* - As mentioned above, the task causing the page fault must not be the
|
|
* page fill worker thread because that is the only way to complete the
|
|
* page fill.
|
|
*
|
|
* NOTES:
|
|
* 1. One way to accomplish this would be a two pass link phase:
|
|
* - In the first phase, create a partially linked objected containing
|
|
* all interrupt/exception handling logic, the page fill worker thread
|
|
* plus all parts of the IDLE thread (which must always be available
|
|
* for execution).
|
|
* - All of the .text and .rodata sections of this partial link should
|
|
* be collected into a single section.
|
|
* - The second link would link the partially linked object along with
|
|
* the remaining object to produce the final binary. The linker
|
|
* script should position the "special" section so that it lies
|
|
* in a reserved, "non-swappable" region.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void pg_miss(void)
|
|
{
|
|
FAR struct tcb_s *ftcb = (FAR struct tcb_s *)g_readytorun.head;
|
|
FAR struct tcb_s *wtcb;
|
|
|
|
/* Sanity checking
|
|
*
|
|
* ASSERT if the currently executing task is the page fill worker thread.
|
|
* The page fill worker thread is how the page fault is resolved and
|
|
* all logic associated with the page fill worker must be "locked" and
|
|
* always present in memory.
|
|
*/
|
|
|
|
pglldbg("Blocking TCB: %p PID: %d\n", ftcb, ftcb->pid);
|
|
DEBUGASSERT(g_pgworker != ftcb->pid);
|
|
|
|
/* Block the currently executing task
|
|
* - Call up_block_task() to block the task at the head of the ready-
|
|
* to-run list. This should cause an interrupt level context switch
|
|
* to the next highest priority task.
|
|
* - The blocked task will be marked with state TSTATE_WAIT_PAGEFILL
|
|
* and will be retained in the g_waitingforfill prioritized task list.
|
|
*/
|
|
|
|
up_block_task(ftcb, TSTATE_WAIT_PAGEFILL);
|
|
|
|
/* Boost the page fill worker thread priority.
|
|
* - Check the priority of the task at the head of the g_waitingforfill
|
|
* list. If the priority of that task is higher than the current
|
|
* priority of the page fill worker thread, then boost the priority
|
|
* of the page fill worker thread to that priority.
|
|
*/
|
|
|
|
wtcb = sched_gettcb(g_pgworker);
|
|
DEBUGASSERT(wtcb != NULL);
|
|
|
|
if (wtcb->sched_priority < ftcb->sched_priority)
|
|
{
|
|
/* Reprioritize the page fill worker thread */
|
|
|
|
pgllvdbg("New worker priority. %d->%d\n",
|
|
wtcb->sched_priority, ftcb->sched_priority);
|
|
sched_setpriority(wtcb, ftcb->sched_priority);
|
|
}
|
|
|
|
/* Signal the page fill worker thread.
|
|
* - Is there a page fill pending? If not then signal the worker
|
|
* thread to start working on the queued page fill requests.
|
|
*/
|
|
|
|
if (!g_pftcb)
|
|
{
|
|
pglldbg("Signaling worker. PID: %d\n", g_pgworker);
|
|
kill(g_pgworker, SIGWORK);
|
|
}
|
|
}
|
|
|
|
#endif /* CONFIG_PAGING */
|