nuttx/arch/xtensa/src/common/xtensa_releasestack.c

/****************************************************************************
 *  arch/xtensa/src/common/xtensa_releasestack.c
 *
 *   Copyright (C) 2011, 2013 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 <debug.h>

#include <nuttx/arch.h>
#include <nuttx/kmalloc.h>

#include "up_internal.h"

/****************************************************************************
 * Private Types
 ****************************************************************************/

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: up_release_stack
 *
 * Description:
 *   A task has been stopped. Free all stack related resources retained in
 *   the defunct TCB.
 *
 * Input Parmeters
 *   - dtcb:  The TCB containing information about the stack to be released
 *   - ttype:  The thread type.  This may be one of following (defined in
 *     include/nuttx/sched.h):
 *
 *       TCB_FLAG_TTYPE_TASK     Normal user task
 *       TCB_FLAG_TTYPE_PTHREAD  User pthread
 *       TCB_FLAG_TTYPE_KERNEL   Kernel thread
 *
 *     This thread type is normally available in the flags field of the TCB,
 *     however, there are certain error recovery contexts where the TCB may
 *     not be fully initialized when up_release_stack is called.
 *
 *     If CONFIG_BUILD_KERNEL is defined, then this thread type may affect
 *     how the stack is freed.  For example, kernel thread stacks may have
 *     been allocated from protected kernel memory.  Stacks for user tasks
 *     and threads must have come from memory that is accessible to user
 *     code.
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

void up_release_stack(FAR struct tcb_s *dtcb, uint8_t ttype)
{
  /* Is there a stack allocated? */

  if (dtcb->stack_alloc_ptr)
    {
#if defined(CONFIG_BUILD_KERNEL) && defined(CONFIG_MM_KERNEL_HEAP)
      /* Use the kernel allocator if this is a kernel thread */

      if (ttype == TCB_FLAG_TTYPE_KERNEL)
        {
          sched_kfree(dtcb->stack_alloc_ptr);
        }
      else
#endif
        {
          /* Use the user-space allocator if this is a task or pthread */

          sched_ufree(dtcb->stack_alloc_ptr);
        }

      /* Mark the stack freed */

      dtcb->stack_alloc_ptr = NULL;
    }

  /* The size of the allocated stack is now zero */

  dtcb->adj_stack_size = 0;
}