120 lines
4.0 KiB
C
120 lines
4.0 KiB
C
/****************************************************************************
|
|
* sched/sched/sched_cpupause.c
|
|
*
|
|
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <gnutt@nuttx.org>
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
* 3. Neither the name NuttX nor the names of its contributors may be
|
|
* used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <sys/types.h>
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
|
|
#include <nuttx/arch.h>
|
|
#include <nuttx/sched_note.h>
|
|
|
|
#include "sched/sched.h"
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: sched_cpu_pause
|
|
*
|
|
* Description:
|
|
* Check if task associated with 'tcb' is running on a different CPU. If
|
|
* so then pause that CPU and return its CPU index.
|
|
*
|
|
* Input Parameters:
|
|
* tcb - The TCB of the task to be conditionally paused.
|
|
*
|
|
* Returned Value:
|
|
* If a CPU is pauses its non-negative CPU index is returned. This index
|
|
* may then be used to resume the CPU. If the task is not running at all
|
|
* (or if an error occurs), then a negated errno value is returned. -ESRCH
|
|
* is returned in the case where the task is not running on any CPU.
|
|
*
|
|
* Assumptions:
|
|
* This function was called in a critical section. In that case, no tasks
|
|
* may started or may exit until the we leave the critical section. This
|
|
* critical section should extend until up_cpu_resume() is called in the
|
|
* typical case.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int sched_cpu_pause(FAR struct tcb_s *tcb)
|
|
{
|
|
int cpu;
|
|
int ret;
|
|
|
|
DEBUGASSERT(tcb != NULL);
|
|
|
|
/* If the task is not running at all then our job is easy */
|
|
|
|
cpu = tcb->cpu;
|
|
if (tcb->task_state != TSTATE_TASK_RUNNING)
|
|
{
|
|
return -ESRCH;
|
|
}
|
|
|
|
/* Check the CPU that the task is running on */
|
|
|
|
DEBUGASSERT(cpu != this_cpu() && (unsigned int)cpu < CONFIG_SMP_NCPUS);
|
|
if (cpu == this_cpu())
|
|
{
|
|
/* We can't pause ourself */
|
|
|
|
return -EACCES;
|
|
}
|
|
|
|
/* Pause the CPU that the task is running on */
|
|
|
|
ret = up_cpu_pause(cpu);
|
|
if (ret < 0)
|
|
{
|
|
return ret;
|
|
}
|
|
|
|
/* Return the CPU that the task is running on */
|
|
|
|
return cpu;
|
|
}
|
|
|
|
#endif /* CONFIG_SMP */
|