288 lines
13 KiB
C
288 lines
13 KiB
C
/**************************************************************************/
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/* */
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/* Copyright (c) Microsoft Corporation. All rights reserved. */
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/* */
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/* This software is licensed under the Microsoft Software License */
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/* Terms for Microsoft Azure RTOS. Full text of the license can be */
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/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
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/* and in the root directory of this software. */
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/* */
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/**************************************************************************/
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/**************************************************************************/
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/**************************************************************************/
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/** */
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/** ThreadX Component */
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/** */
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/** Thread */
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/** */
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/**************************************************************************/
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/**************************************************************************/
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#define TX_SOURCE_CODE
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/* Include necessary system files. */
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#include "tx_api.h"
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#include "tx_trace.h"
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#include "tx_thread.h"
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/**************************************************************************/
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/* */
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/* FUNCTION RELEASE */
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/* */
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/* _tx_thread_priority_change PORTABLE C */
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/* 6.1 */
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/* AUTHOR */
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/* */
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/* William E. Lamie, Microsoft Corporation */
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/* */
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/* DESCRIPTION */
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/* */
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/* This function changes the priority of the specified thread. It */
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/* also returns the old priority and handles preemption if the calling */
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/* thread is currently executing and the priority change results in a */
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/* higher priority thread ready for execution. */
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/* */
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/* Note: the preemption threshold is automatically changed to the new */
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/* priority. */
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/* */
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/* INPUT */
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/* */
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/* thread_ptr Pointer to thread to suspend */
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/* new_priority New thread priority */
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/* old_priority Old thread priority */
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/* */
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/* OUTPUT */
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/* */
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/* status Completion status */
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/* */
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/* CALLS */
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/* */
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/* _tx_thread_system_resume Resume thread */
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/* _tx_thread_system_ni_resume Non-interruptable resume thread */
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/* _tx_thread_system_suspend Suspend thread */
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/* _tx_thread_system_ni_suspend Non-interruptable suspend thread */
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/* _tx_thread_system_preempt_check Check for preemption */
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/* */
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/* CALLED BY */
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/* */
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/* Application Code */
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/* */
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/* RELEASE HISTORY */
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/* */
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/* DATE NAME DESCRIPTION */
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/* */
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/* 05-19-2020 William E. Lamie Initial Version 6.0 */
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/* 09-30-2020 William E. Lamie Modified comment(s), and */
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/* change thread state from */
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/* TX_SUSPENDED to */
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/* TX_PRIORITY_CHANGE before */
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/* calling */
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/* _tx_thread_system_suspend, */
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/* resulting in version 6.1 */
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/* */
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/**************************************************************************/
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UINT _tx_thread_priority_change(TX_THREAD *thread_ptr, UINT new_priority, UINT *old_priority)
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{
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TX_INTERRUPT_SAVE_AREA
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TX_THREAD *execute_ptr;
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TX_THREAD *next_execute_ptr;
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UINT original_priority;
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/* Lockout interrupts while the thread is being suspended. */
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TX_DISABLE
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/* Save the previous priority. */
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*old_priority = thread_ptr -> tx_thread_user_priority;
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/* If trace is enabled, insert this event into the trace buffer. */
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TX_TRACE_IN_LINE_INSERT(TX_TRACE_THREAD_PRIORITY_CHANGE, thread_ptr, new_priority, thread_ptr -> tx_thread_priority, thread_ptr -> tx_thread_state, TX_TRACE_THREAD_EVENTS)
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/* Log this kernel call. */
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TX_EL_THREAD_PRIORITY_CHANGE_INSERT
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/* Determine if this thread is currently ready. */
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if (thread_ptr -> tx_thread_state != TX_READY)
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{
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/* Setup the user priority and threshold in the thread's control
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block. */
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thread_ptr -> tx_thread_user_priority = new_priority;
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thread_ptr -> tx_thread_user_preempt_threshold = new_priority;
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/* Determine if the actual thread priority should be setup, which is the
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case if the new priority is higher than the priority inheritance. */
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if (new_priority < thread_ptr -> tx_thread_inherit_priority)
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{
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/* Change thread priority to the new user's priority. */
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thread_ptr -> tx_thread_priority = new_priority;
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thread_ptr -> tx_thread_preempt_threshold = new_priority;
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}
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else
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{
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/* Change thread priority to the priority inheritance. */
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thread_ptr -> tx_thread_priority = thread_ptr -> tx_thread_inherit_priority;
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thread_ptr -> tx_thread_preempt_threshold = thread_ptr -> tx_thread_inherit_priority;
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}
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/* Restore interrupts. */
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TX_RESTORE
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}
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else
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{
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/* Set the state to priority change. */
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thread_ptr -> tx_thread_state = TX_PRIORITY_CHANGE;
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/* Pickup the next thread to execute. */
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execute_ptr = _tx_thread_execute_ptr;
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/* Save the original priority. */
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original_priority = thread_ptr -> tx_thread_priority;
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#ifdef TX_NOT_INTERRUPTABLE
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/* Increment the preempt disable flag. */
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_tx_thread_preempt_disable++;
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/* Call actual non-interruptable thread suspension routine. */
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_tx_thread_system_ni_suspend(thread_ptr, ((ULONG) 0));
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/* At this point, the preempt disable flag is still set, so we still have
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protection against all preemption. */
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/* Setup the new priority for this thread. */
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thread_ptr -> tx_thread_user_priority = new_priority;
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thread_ptr -> tx_thread_user_preempt_threshold = new_priority;
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/* Determine if the actual thread priority should be setup, which is the
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case if the new priority is higher than the priority inheritance. */
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if (new_priority < thread_ptr -> tx_thread_inherit_priority)
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{
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/* Change thread priority to the new user's priority. */
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thread_ptr -> tx_thread_priority = new_priority;
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thread_ptr -> tx_thread_preempt_threshold = new_priority;
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}
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else
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{
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/* Change thread priority to the priority inheritance. */
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thread_ptr -> tx_thread_priority = thread_ptr -> tx_thread_inherit_priority;
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thread_ptr -> tx_thread_preempt_threshold = thread_ptr -> tx_thread_inherit_priority;
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}
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/* Resume the thread with the new priority. */
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_tx_thread_system_ni_resume(thread_ptr);
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#else
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/* Increment the preempt disable flag by 2 to prevent system suspend from
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returning to the system. */
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_tx_thread_preempt_disable = _tx_thread_preempt_disable + ((UINT) 3);
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/* Set the suspending flag. */
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thread_ptr -> tx_thread_suspending = TX_TRUE;
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/* Setup the timeout period. */
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thread_ptr -> tx_thread_timer.tx_timer_internal_remaining_ticks = ((ULONG) 0);
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/* Restore interrupts. */
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TX_RESTORE
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/* The thread is ready and must first be removed from the list. Call the
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system suspend function to accomplish this. */
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_tx_thread_system_suspend(thread_ptr);
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/* At this point, the preempt disable flag is still set, so we still have
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protection against all preemption. */
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/* Setup the new priority for this thread. */
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thread_ptr -> tx_thread_user_priority = new_priority;
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thread_ptr -> tx_thread_user_preempt_threshold = new_priority;
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/* Determine if the actual thread priority should be setup, which is the
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case if the new priority is higher than the priority inheritance. */
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if (new_priority < thread_ptr -> tx_thread_inherit_priority)
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{
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/* Change thread priority to the new user's priority. */
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thread_ptr -> tx_thread_priority = new_priority;
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thread_ptr -> tx_thread_preempt_threshold = new_priority;
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}
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else
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{
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/* Change thread priority to the priority inheritance. */
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thread_ptr -> tx_thread_priority = thread_ptr -> tx_thread_inherit_priority;
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thread_ptr -> tx_thread_preempt_threshold = thread_ptr -> tx_thread_inherit_priority;
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}
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/* Resume the thread with the new priority. */
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_tx_thread_system_resume(thread_ptr);
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/* Disable interrupts. */
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TX_DISABLE
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#endif
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/* Decrement the preempt disable flag. */
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_tx_thread_preempt_disable--;
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/* Pickup the next thread to execute. */
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next_execute_ptr = _tx_thread_execute_ptr;
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/* Determine if this thread is not the next thread to execute. */
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if (thread_ptr != next_execute_ptr)
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{
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/* Make sure the thread is still ready. */
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if (thread_ptr -> tx_thread_state == TX_READY)
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{
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/* Now check and see if this thread has an equal or higher priority. */
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if (thread_ptr -> tx_thread_priority <= next_execute_ptr -> tx_thread_priority)
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{
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/* Now determine if this thread was the previously executing thread. */
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if (thread_ptr == execute_ptr)
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{
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/* Yes, this thread was previously executing before we temporarily suspended and resumed
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it in order to change the priority. A lower or same priority thread cannot be the next thread
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to execute in this case since this thread really didn't suspend. Simply reset the execute
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pointer to this thread. */
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_tx_thread_execute_ptr = thread_ptr;
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/* Determine if we moved to a lower priority. If so, move the thread to the front of its priority list. */
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if (original_priority < new_priority)
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{
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/* Ensure that this thread is placed at the front of the priority list. */
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_tx_thread_priority_list[thread_ptr -> tx_thread_priority] = thread_ptr;
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}
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}
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}
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}
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}
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/* Restore interrupts. */
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TX_RESTORE
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/* Check for preemption. */
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_tx_thread_system_preempt_check();
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}
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/* Return success if we get here! */
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return(TX_SUCCESS);
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}
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