166 lines
5.3 KiB
C
166 lines
5.3 KiB
C
/* nanocontextentry.c - VxMicro nanokernel context entry/exit logic */
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/*
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* Copyright (c) 2010-2014 Wind River Systems, Inc.
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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 are met:
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*
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* 1) Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2) Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3) Neither the name of Wind River Systems nor the names of its contributors
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* may be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN 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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DESCRIPTION
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This module provides a wrapper around a context entry point for starting and
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ending the context, be it a task or a fiber.
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*/
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#include <toolchain.h>
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#include <sections.h>
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#ifdef CONFIG_MICROKERNEL
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#include <microkernel/k_struct.h>
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#include <microkernel.h>
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#endif /* CONFIG_MICROKERNEL */
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#include <nanok.h>
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#include <nanocontextentry.h>
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#include <misc/printk.h>
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#if defined(CONFIG_HOST_TOOLS_SUPPORT)
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/*******************************************************************************
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*
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* _ContextExitRtn - context exit routine
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*
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* This function is invoked when the specified context is aborted, either
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* normally or abnormally. It is called for the termination of any context,
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* (fibers and tasks).
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*
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* This routine must be invoked from a fiber to guarantee that the list
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* of contexts does not change in mid-operation.
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*
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* RETURNS: N/A
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*
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* \NOMANUAL
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*/
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void _ContextExitRtn(tCCS *pContext)
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{
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/*
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* Remove context from the list of contexts. This singly linked list of
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* contexts maintains ALL the contexts in the system: both tasks and
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* fibers regardless of whether they are runnable.
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*/
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if (pContext == _NanoKernel.contexts) {
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_NanoKernel.contexts = _NanoKernel.contexts->activeLink;
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} else {
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tCCS *pPrevContext;
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pPrevContext = _NanoKernel.contexts;
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while (pContext != pPrevContext->activeLink) {
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pPrevContext = pPrevContext->activeLink;
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}
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pPrevContext->activeLink = pContext->activeLink;
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}
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}
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#endif /* CONFIG_HOST_TOOLS_SUPPORT */
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/*******************************************************************************
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*
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* _ContextEntryRtn - common context entry point function for kernel contexts
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*
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* This function serves as the entry point for _all_ kernel contexts, i.e. both
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* task and fiber contexts are instantiated such that initial execution starts
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* here.
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*
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* This routine invokes the actual task or fiber entry point function and
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* passes it three arguments. It also handles graceful termination of the
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* task or fiber if the entry point function ever returns.
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*
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* INTERNAL
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* The 'noreturn' attribute is applied to this function so that the compiler
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* can dispense with generating the usual preamble that is only required for
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* functions that actually return.
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*
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* The analogous entry point function for user-mode task contexts is called
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* _ContextUsrEntryRtn().
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*
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* RETURNS: Does not return
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*
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* \NOMANUAL
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*/
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FUNC_NORETURN void _ContextEntryRtn(
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_ContextEntry pEntry, /* address of app entry point function */
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_ContextArg parameter1, /* 1st arg to app entry point function */
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_ContextArg parameter2, /* 2nd arg to app entry point function */
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_ContextArg parameter3 /* 3rd arg to app entry point function */
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)
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{
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/* Execute the "application" entry point function */
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pEntry(parameter1, parameter2, parameter3);
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/* Determine if context can legally terminate itself via "return" */
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if (_context_essential_check(NULL)) {
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#ifdef CONFIG_NANOKERNEL
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/*
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* Nanokernel's background task must always be present,
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* so if it has nothing left to do just let it idle forever
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*/
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while (((_NanoKernel.current)->flags & TASK) == TASK) {
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nano_cpu_idle();
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}
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#endif /* CONFIG_NANOKERNEL */
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/* Loss of essential context is a system fatal error */
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_NanoFatalErrorHandler(_NANO_ERR_INVALID_TASK_EXIT,
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&__defaultEsf);
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}
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/* Gracefully terminate the currently executing context */
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#ifdef CONFIG_MICROKERNEL
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if (((_NanoKernel.current)->flags & TASK) == TASK) {
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extern FUNC_NORETURN void _TaskAbort(void);
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_TaskAbort();
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} else
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#endif /* CONFIG_MICROKERNEL */
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{
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fiber_abort();
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}
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/*
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* Compiler can't tell that fiber_abort() won't return and issues
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* a warning unless we explicitly tell it that control never gets this
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* far.
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*/
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CODE_UNREACHABLE;
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}
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