text: /****************************************************************************
   * arch/arm/src/common/arm_releasestack.c
   *
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.  The
   * ASF licenses this file to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance with the
   * License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations
   * under the License.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <sched.h>
  #include <debug.h>
  
  #include <nuttx/arch.h>
  #include <nuttx/kmalloc.h>
  
  #include "arm_internal.h"
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: up_release_stack
   *
   * Description:
   *   A task has been stopped. Free all stack related resources retained in
   *   the defunct TCB.
   *
   * Input Parameters:
   *   - 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 either CONFIG_BUILD_PROTECTED or CONFIG_BUILD_KERNEL are 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)
      {
  #ifdef CONFIG_MM_KERNEL_HEAP
        /* Use the kernel allocator if this is a kernel thread */
  
        if (ttype == TCB_FLAG_TTYPE_KERNEL)
          {
            if (kmm_heapmember(dtcb->stack_alloc_ptr))
              {
                kmm_free(dtcb->stack_alloc_ptr);
              }
          }
        else
  #endif
          {
            /* Use the user-space allocator if this is a task or pthread */
  
            if (umm_heapmember(dtcb->stack_alloc_ptr))
              {
                kumm_free(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;
  }
  