arch/arm/src/common/arm_releasestack.c

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

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

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

          kumm_free(dtcb->stack_alloc_ptr);
        }
    }

  /* Mark the stack freed */

  dtcb->flags &= ~TCB_FLAG_FREE_STACK;
  dtcb->stack_alloc_ptr = NULL;
  dtcb->stack_base_ptr = NULL;
  dtcb->adj_stack_size = 0;
}