6a3c2aded6
* Simplify EINTR/ECANCEL error handling 1. Add semaphore uninterruptible wait function 2 .Replace semaphore wait loop with a single uninterruptible wait 3. Replace all sem_xxx to nxsem_xxx * Unify the void cast usage 1. Remove void cast for function because many place ignore the returned value witout cast 2. Replace void cast for variable with UNUSED macro
185 lines
7.5 KiB
C
185 lines
7.5 KiB
C
/****************************************************************************
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* sched/paging/pg_miss.c
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*
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* Copyright (C) 2010, 2017-2018 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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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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* 1. 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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <nuttx/sched.h>
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#include <nuttx/page.h>
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#include <nuttx/signal.h>
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#ifdef CONFIG_PAGING
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#include "sched/sched.h"
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#include "paging/paging.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pg_miss
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*
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* Description:
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* This function is called from architecture-specific memory segmentation
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* fault handling logic. This function will perform the following
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* operations:
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*
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* 1) Sanity checking.
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* - ASSERT if the currently executing task is the page fill worker
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* thread. The page fill worker thread is how the page fault
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* is resolved and all logic associated with the page fill worker
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* must be "locked" and always present in memory.
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* - ASSERT if an interrupt was executing at the time of the exception.
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* 2) Block the currently executing task.
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* - Call up_block_task() to block the task at the head of the ready-
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* to-run list. This should cause an interrupt level context switch
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* to the next highest priority task.
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* - The blocked task will be marked with state TSTATE_WAIT_PAGEFILL
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* and will be retained in the g_waitingforfill prioritized task
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* list.
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* 3) Boost the page fill worker thread priority.
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* - Check the priority of the task at the head of the g_waitingforfill
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* list. If the priority of that task is higher than the current
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* priority of the page fill worker thread, then boost the priority
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* of the page fill worker thread to that priority.
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* 4) Signal the page fill worker thread.
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* - Is there a page fill pending? If not then signal the worker
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* thread to start working on the queued page fill requests.
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*
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* Input Parameters:
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* None - The head of the ready-to-run list is assumed to be task that
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* caused the exception.
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*
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* Returned Value:
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* None - Either this function function succeeds or an assertion occurs.
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*
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* Assumptions:
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* - It is assumed that this function is called from the level of an
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* exception handler and that all interrupts are disabled.
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* - It is assumed that currently executing task (the one at the head of
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* the ready-to-run list) is the one that cause the fault. This will
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* always be true unless the page fault occurred in an interrupt handler.
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* Interrupt handling logic must always be present and "locked" into
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* memory.
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* - As mentioned above, the task causing the page fault must not be the
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* page fill worker thread because that is the only way to complete the
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* page fill.
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*
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* NOTES:
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* 1. One way to accomplish this would be a two pass link phase:
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* - In the first phase, create a partially linked objected containing
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* all interrupt/exception handling logic, the page fill worker thread
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* plus all parts of the IDLE thread (which must always be available
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* for execution).
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* - All of the .text and .rodata sections of this partial link should
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* be collected into a single section.
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* - The second link would link the partially linked object along with
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* the remaining object to produce the final binary. The linker
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* script should position the "special" section so that it lies
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* in a reserved, "non-swappable" region.
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*
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****************************************************************************/
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void pg_miss(void)
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{
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FAR struct tcb_s *ftcb = this_task();
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FAR struct tcb_s *wtcb;
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/* Sanity checking
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*
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* ASSERT if the currently executing task is the page fill worker thread.
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* The page fill worker thread is how the page fault is resolved and
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* all logic associated with the page fill worker must be "locked" and
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* always present in memory.
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*/
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pginfo("Blocking TCB: %p PID: %d\n", ftcb, ftcb->pid);
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DEBUGASSERT(g_pgworker != ftcb->pid);
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/* Block the currently executing task
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* - Call up_block_task() to block the task at the head of the ready-
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* to-run list. This should cause an interrupt level context switch
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* to the next highest priority task.
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* - The blocked task will be marked with state TSTATE_WAIT_PAGEFILL
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* and will be retained in the g_waitingforfill prioritized task list.
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*
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* Need to firstly check that this is not the idle task,descheduling
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* that isn't going to end well.
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*/
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DEBUGASSERT(NULL != ftcb->flink);
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up_block_task(ftcb, TSTATE_WAIT_PAGEFILL);
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/* Boost the page fill worker thread priority.
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* - Check the priority of the task at the head of the g_waitingforfill
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* list. If the priority of that task is higher than the current
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* priority of the page fill worker thread, then boost the priority
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* of the page fill worker thread to that priority.
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*/
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wtcb = sched_gettcb(g_pgworker);
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DEBUGASSERT(wtcb != NULL);
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if (wtcb->sched_priority < ftcb->sched_priority)
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{
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/* Reprioritize the page fill worker thread */
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pginfo("New worker priority. %d->%d\n",
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wtcb->sched_priority, ftcb->sched_priority);
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nxsched_setpriority(wtcb, ftcb->sched_priority);
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}
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/* Signal the page fill worker thread.
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* - Is there a page fill pending? If not then signal the worker
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* thread to start working on the queued page fill requests.
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*/
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if (!g_pftcb)
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{
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pginfo("Signaling worker. PID: %d\n", g_pgworker);
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nxsig_kill(g_pgworker, SIGWORK);
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}
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}
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#endif /* CONFIG_PAGING */
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