273 lines
7.0 KiB
C
273 lines
7.0 KiB
C
/* nanokernel thread support */
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/*
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* Copyright (c) 2010-2014 Wind River Systems, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* DESCRIPTION
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* This module provides general purpose thread support, with applies to both
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* tasks or fibers.
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*/
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#include <toolchain.h>
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#include <sections.h>
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#include <nano_private.h>
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#include <misc/printk.h>
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#include <sys_clock.h>
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#include <drivers/system_timer.h>
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nano_thread_id_t sys_thread_self_get(void)
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{
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return _nanokernel.current;
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}
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nano_context_type_t sys_execution_context_type_get(void)
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{
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if (_IS_IN_ISR())
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return NANO_CTX_ISR;
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if ((_nanokernel.current->flags & TASK) == TASK)
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return NANO_CTX_TASK;
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return NANO_CTX_FIBER;
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}
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/**
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*
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* @brief Mark thread as essential to system
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*
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* This function tags the running fiber or task as essential to system
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* option; exceptions raised by this thread will be treated as a fatal
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* system error.
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*
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* @return N/A
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*/
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void _thread_essential_set(void)
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{
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_nanokernel.current->flags |= ESSENTIAL;
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}
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/**
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*
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* @brief Mark thread as not essential to system
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*
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* This function tags the running fiber or task as not essential to system
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* option; exceptions raised by this thread may be recoverable.
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* (This is the default tag for a thread.)
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*
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* @return N/A
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*/
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void _thread_essential_clear(void)
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{
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_nanokernel.current->flags &= ~ESSENTIAL;
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}
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/**
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*
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* @brief Is the specified thread essential?
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*
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* This routine indicates if the specified thread is an essential system
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* thread. A NULL thread pointer indicates that the current thread is
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* to be queried.
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*
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* @return Non-zero if specified thread is essential, zero if it is not
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*/
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int _is_thread_essential(struct tcs *pCtx /* pointer to thread */
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)
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{
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return ((pCtx == NULL) ? _nanokernel.current : pCtx)->flags & ESSENTIAL;
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}
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/*
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* Don't build sys_thread_busy_wait() for ARM, since intrinsics libraries in
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* current Zephyr SDK use non-Thumb code that isn't supported on Cortex-M CPUs.
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* For the time being any ARM-based application that attempts to use this API
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* will get a link error (which is preferable to a mysterious exception).
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*
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* @param usec_to_wait
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*
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* @return N/A
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*/
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#ifndef CONFIG_ARM
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void sys_thread_busy_wait(uint32_t usec_to_wait)
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{
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/* use 64-bit math to prevent overflow when multiplying */
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uint32_t cycles_to_wait = (uint32_t)(
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(uint64_t)usec_to_wait *
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(uint64_t)sys_clock_hw_cycles_per_sec /
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(uint64_t)USEC_PER_SEC
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);
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uint32_t start_cycles = _sys_clock_cycle_get();
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for (;;) {
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uint32_t current_cycles = _sys_clock_cycle_get();
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/* this handles the rollover on an unsigned 32-bit value */
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if ((current_cycles - start_cycles) >= cycles_to_wait) {
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break;
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}
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}
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}
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#endif /* CONFIG_ARM */
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#ifdef CONFIG_THREAD_CUSTOM_DATA
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/**
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*
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* @brief Set thread's custom data
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*
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* This routine sets the custom data value for the current task or fiber.
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* Custom data is not used by the kernel itself, and is freely available
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* for the thread to use as it sees fit.
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*
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* @param value New to set the thread's custom data to.
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*
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* @return N/A
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*/
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void sys_thread_custom_data_set(void *value)
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{
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_nanokernel.current->custom_data = value;
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}
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/**
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*
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* @brief Get thread's custom data
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*
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* This function returns the custom data value for the current task or fiber.
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*
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* @return current handle value
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*/
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void *sys_thread_custom_data_get(void)
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{
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return _nanokernel.current->custom_data;
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}
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#endif /* CONFIG_THREAD_CUSTOM_DATA */
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#if defined(CONFIG_THREAD_MONITOR)
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/**
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*
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* @brief Thread exit routine
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*
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* This function is invoked when the specified thread is aborted, either
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* normally or abnormally. It is called for the termination of any thread,
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* (fibers and tasks).
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*
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* This routine must be invoked either from a fiber or from a task with
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* interrupts locked to guarantee that the list of threads does not change in
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* mid-operation. It cannot be called from ISR context.
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*
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* @return N/A
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*/
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void _thread_exit(struct tcs *thread)
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{
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/*
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* Remove thread from the list of threads. This singly linked list of
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* threads maintains ALL the threads 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 (thread == _nanokernel.threads) {
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_nanokernel.threads = _nanokernel.threads->next_thread;
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} else {
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struct tcs *prev_thread;
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prev_thread = _nanokernel.threads;
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while (thread != prev_thread->next_thread) {
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prev_thread = prev_thread->next_thread;
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}
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prev_thread->next_thread = thread->next_thread;
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}
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}
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#endif /* CONFIG_THREAD_MONITOR */
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/**
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*
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* @brief Common thread entry point function
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*
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* This function serves as the entry point for _all_ threads, i.e. both
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* task and fibers 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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* @param pEntry address of the app entry point function
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* @param parameter1 1st arg to the app entry point function
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* @param parameter2 2nd arg to the app entry point function
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* @param parameter3 3rd arg to the app entry point function
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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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* @return Does not return
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*
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*/
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FUNC_NORETURN void _thread_entry(_thread_entry_t pEntry,
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_thread_arg_t parameter1,
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_thread_arg_t parameter2,
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_thread_arg_t parameter3)
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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 thread can legally terminate itself via "return" */
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if (_is_thread_essential(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 thread is a system fatal error */
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_NanoFatalErrorHandler(_NANO_ERR_INVALID_TASK_EXIT,
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&_default_esf);
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}
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/* Gracefully terminate the currently executing thread */
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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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