e24f281401
The three fixes are to handle cases in the SMP configuration where one CPU does need to make modifications to TCB and data structures on a task that could be running running on another CPU. Those three cases are task_delete(), task_restart(), and execution of signal handles. In all three cases the solutions is basically the same: (1) Call sched_cpu_pause(tcb) to pause the CPU on which the task is running, (2) perform the necessary operations, then (3) call up_cpu_resume() to restart the paused CPU.
219 lines
6.4 KiB
C
219 lines
6.4 KiB
C
/****************************************************************************
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* sched/task/task_restart.c
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*
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* Copyright (C) 2007, 2009, 2012-2013, 2016 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 <sys/types.h>
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#include <sched.h>
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#include <errno.h>
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#include <nuttx/irq.h>
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#include <nuttx/arch.h>
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#include "sched/sched.h"
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#include "group/group.h"
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#include "signal/signal.h"
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#include "task/task.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: task_restart
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*
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* Description:
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* This function "restarts" a task. The task is first terminated and then
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* reinitialized with same ID, priority, original entry point, stack size,
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* and parameters it had when it was first started.
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*
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* Inputs:
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* pid - The task ID of the task to delete. An ID of zero signifies the
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* calling task.
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*
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* Return Value:
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* OK on sucess; ERROR on failure.
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*
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* This function can fail if:
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* (1) A pid of zero or the pid of the calling task is provided
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* (functionality not implemented)
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* (2) The pid is not associated with any task known to the system.
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*
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****************************************************************************/
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int task_restart(pid_t pid)
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{
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FAR struct tcb_s *rtcb;
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FAR struct task_tcb_s *tcb;
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FAR dq_queue_t *tasklist;
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irqstate_t flags;
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int errcode;
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#ifdef CONFIG_SMP
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int cpu;
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#endif
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int ret;
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/* Check if the task to restart is the calling task */
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rtcb = this_task();
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if ((pid == 0) || (pid == rtcb->pid))
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{
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/* Not implemented */
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errcode = ENOSYS;
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goto errout_with_lock;
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}
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/* We are restarting some other task than ourselves. Make sure that the
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* task does not change its state while we are executing. In the single
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* CPU state this could be done by disabling pre-emption. But we will
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* a little stronger medicine on the SMP case: The task make be running
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* on another CPU.
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*/
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flags = enter_critical_section();
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/* Find for the TCB associated with matching pid */
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tcb = (FAR struct task_tcb_s *)sched_gettcb(pid);
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#ifndef CONFIG_DISABLE_PTHREAD
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if (!tcb || (tcb->cmn.flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_PTHREAD)
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#else
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if (!tcb)
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#endif
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{
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/* There is no TCB with this pid or, if there is, it is not a task. */
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errcode = ESRCH;
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goto errout_with_lock;
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}
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#ifdef CONFIG_SMP
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/* If the task is running on another CPU, then pause that CPU. We can
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* then manipulate the TCB of the restarted task and when we resume the
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* that CPU, the restart take effect.
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*/
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cpu = sched_cpu_pause(&tcb->cmn);
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#endif /* CONFIG_SMP */
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/* Try to recover from any bad states */
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task_recover((FAR struct tcb_s *)tcb);
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/* Kill any children of this thread */
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#ifdef HAVE_GROUP_MEMBERS
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(void)group_killchildren(tcb);
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#endif
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/* Remove the TCB from whatever list it is in. After this point, the TCB
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* should no longer be accessible to the system
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*/
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#ifdef CONFIG_SMP
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tasklist = TLIST_HEAD(tcb->cmn.task_state, tcb->cmn.cpu);
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#else
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tasklist = TLIST_HEAD(tcb->cmn.task_state);
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#endif
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dq_rem((FAR dq_entry_t *)tcb, tasklist);
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tcb->cmn.task_state = TSTATE_TASK_INVALID;
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/* Deallocate anything left in the TCB's queues */
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sig_cleanup((FAR struct tcb_s *)tcb); /* Deallocate Signal lists */
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/* Reset the current task priority */
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tcb->cmn.sched_priority = tcb->cmn.init_priority;
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/* Reset the base task priority and the number of pending reprioritizations */
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#ifdef CONFIG_PRIORITY_INHERITANCE
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tcb->cmn.base_priority = tcb->cmn.init_priority;
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# if CONFIG_SEM_NNESTPRIO > 0
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tcb->cmn.npend_reprio = 0;
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# endif
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#endif
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/* Re-initialize the processor-specific portion of the TCB. This will
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* reset the entry point and the start-up parameters
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*/
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up_initial_state((FAR struct tcb_s *)tcb);
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/* Add the task to the inactive task list */
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dq_addfirst((FAR dq_entry_t *)tcb, (FAR dq_queue_t *)&g_inactivetasks);
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tcb->cmn.task_state = TSTATE_TASK_INACTIVE;
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#ifdef CONFIG_SMP
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/* Resume the paused CPU (if any) */
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if (cpu >= 0)
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{
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ret = up_cpu_resume(cpu);
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if (ret < 0)
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{
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errcode = -ret;
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goto errout_with_lock;
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}
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}
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#endif /* CONFIG_SMP */
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/* Activate the task */
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ret = task_activate((FAR struct tcb_s *)tcb);
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if (ret != OK)
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{
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(void)task_delete(pid);
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errcode = -ret;
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goto errout_with_lock;
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}
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leave_critical_section(flags);
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return OK;
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errout_with_lock:
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set_errno(errcode);
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leave_critical_section(flags);
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return ERROR;
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}
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