131 lines
3.8 KiB
C
131 lines
3.8 KiB
C
/*
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* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
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* All rights reserved.
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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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* * 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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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* @author Stefan Lankes
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* @file include/eduos/tasks.h
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* @brief Task related
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*
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* Create and leave tasks or fork them.
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*/
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#ifndef __TASKS_H__
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#define __TASKS_H__
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#include <eduos/stddef.h>
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#include <eduos/tasks_types.h>
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#include <asm/tasks.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** @brief System call to terminate a user level process */
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void NORETURN sys_exit(int);
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/** @brief Task switcher
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*
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* Timer-interrupted use of this function for task switching
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*
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* @return
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* - 0 no context switch
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* - !0 address of the old stack pointer
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*/
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size_t** scheduler(void);
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/** @brief Initialize the multitasking subsystem
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*
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* This procedure sets the current task to the
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* current "task" (there are no tasks, yet) and that was it.
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*
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* @return
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* - 0 on success
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* - -ENOMEM (-12) on failure
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*/
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int multitasking_init(void);
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/** @brief create a kernel-level task.
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*
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* @param id The value behind this pointer will be set to the new task's id
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* @param ep Pointer to the entry function for the new task
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* @param args Arguments the task shall start with
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* @param prio Desired priority of the new kernel task
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*
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* @return
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* - 0 on success
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* - -EINVAL (-22) on failure
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*/
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int create_kernel_task(tid_t* id, entry_point_t ep, void* args, uint8_t prio);
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/** @brief determine the highest priority of all tasks, which are ready
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*
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* @return
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* - return highest priority
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* - if no task is ready, the function returns an invalid value (> MAX_PRIO)
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*/
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uint32_t get_highest_priority(void);
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/** @brief Call to rescheduling
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*
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* This is a purely assembled procedure for rescheduling
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*/
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void reschedule(void);
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/** @brief Wake up a blocked task
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*
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* The task's status will be changed to TASK_READY
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*
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* @return
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* - 0 on success
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* - -EINVAL (-22) on failure
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*/
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int wakeup_task(tid_t);
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/** @brief Block current task
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*
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* The current task's status will be changed to TASK_BLOCKED
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*
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* @return
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* - 0 on success
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* - -EINVAL (-22) on failure
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*/
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int block_current_task(void);
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/** @brief Abort current task */
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void NORETURN abort(void);
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/** @brief This function shall be called by leaving kernel-level tasks */
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void NORETURN leave_kernel_task(void);
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/** @brief This function shall be called by leaving user-level tasks */
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void NORETURN leave_user_task(void);
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#ifdef __cplusplus
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}
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#endif
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#endif
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