text: /****************************************************************************
   *  arch/mips/src/mips32/up_releasepending.c
   *
   *   Copyright (C) 2011, 2014-2015 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 <sched.h>
  #include <syscall.h>
  #include <debug.h>
  
  #include <nuttx/arch.h>
  #include <nuttx/sched.h>
  
  #include "sched/sched.h"
  #include "group/group.h"
  #include "up_internal.h"
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: up_release_pending
   *
   * Description:
   *   Release and ready-to-run tasks that have
   *   collected in the pending task list.  This can call a
   *   context switch if a new task is placed at the head of
   *   the ready to run list.
   *
   ****************************************************************************/
  
  void up_release_pending(void)
  {
    struct tcb_s *rtcb = this_task();
  
    sinfo("From TCB=%p\n", rtcb);
  
    /* Merge the g_pendingtasks list into the ready-to-run task list */
  
    /* sched_lock(); */
    if (sched_mergepending())
      {
        /* The currently active task has changed!  We will need to switch
         * contexts.
         *
         * Update scheduler parameters.
         */
  
        sched_suspend_scheduler(rtcb);
  
        /* Are we operating in interrupt context? */
  
        if (g_current_regs)
          {
            /* Yes, then we have to do things differently.
             * Just copy the g_current_regs into the OLD rtcb.
             */
  
             up_savestate(rtcb->xcp.regs);
  
            /* Restore the exception context of the rtcb at the (new) head
             * of the ready-to-run task list.
             */
  
            rtcb = this_task();
  
            /* Update scheduler parameters */
  
            sched_resume_scheduler(rtcb);
  
            /* Then switch contexts.  Any necessary address environment
             * changes will be made when the interrupt returns.
             */
  
            up_restorestate(rtcb->xcp.regs);
          }
  
        /* No, then we will need to perform the user context switch */
  
        else
          {
            /* Switch context to the context of the task at the head of the
             * ready to run list.
             */
  
            struct tcb_s *nexttcb = this_task();
  
  #ifdef CONFIG_ARCH_ADDRENV
            /* Make sure that the address environment for the previously
             * running task is closed down gracefully (data caches dump,
             * MMU flushed) and set up the address environment for the new
             * thread at the head of the ready-to-run list.
             */
  
            (void)group_addrenv(nexttcb);
  #endif
            /* Update scheduler parameters */
  
            sched_resume_scheduler(nexttcb);
  
            /* Then switch contexts */
  
            up_switchcontext(rtcb->xcp.regs, nexttcb->xcp.regs);
  
            /* up_switchcontext forces a context switch to the task at the
             * head of the ready-to-run list.  It does not 'return' in the
             * normal sense.  When it does return, it is because the blocked
             * task is again ready to run and has execution priority.
             */
          }
      }
  }
  