text: /****************************************************************************
   * arch/sim/src/up_createstack.c
   *
   *   Copyright (C) 2007-2009, 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 <sys/types.h>
  #include <stdint.h>
  
  #include <nuttx/arch.h>
  #include <nuttx/kmalloc.h>
  
  #include "up_internal.h"
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  /****************************************************************************
   * Private Data
   ****************************************************************************/
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: up_create_stack
   *
   * Description:
   *   Allocate a stack for a new thread and setup up stack-related information
   *   in the TCB.
   *
   *   The following TCB fields must be initialized by this function:
   *
   *   - adj_stack_size: Stack size after adjustment for hardware, processor,
   *     etc.  This value is retained only for debug purposes.
   *   - stack_alloc_ptr: Pointer to allocated stack
   *   - adj_stack_ptr: Adjusted stack_alloc_ptr for HW.  The initial value of
   *     the stack pointer.
   *
   * Inputs:
   *   - tcb: The TCB of new task
   *   - stack_size:  The requested stack size.  At least this much
   *     must be allocated.
   *   - 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 contexts where the TCB may not be fully
   *     initialized when up_create_stack is called.
   *
   ****************************************************************************/
  
  int up_create_stack(FAR struct tcb_s *tcb, size_t stack_size, uint8_t ttype)
  {
    uint32_t *stack_alloc_ptr;
    int ret = ERROR;
  
    /* Move up to next even word boundary if necessary */
  
    size_t adj_stack_size = (stack_size + 3) & ~3;
    size_t adj_stack_words = adj_stack_size >> 2;
  
    /* Allocate the memory for the stack */
  
    stack_alloc_ptr = (uint32_t*)kumm_malloc(adj_stack_size);
  
    /* Was the allocation successful? */
  
    if (stack_alloc_ptr)
      {
        /* This is the address of the last word in the allocation */
  
        size_t *adj_stack_ptr = &stack_alloc_ptr[adj_stack_words - 1];
  
        /* Save the values in the TCB */
  
        tcb->adj_stack_size  = adj_stack_size;
        tcb->stack_alloc_ptr = stack_alloc_ptr;
        tcb->adj_stack_ptr   = adj_stack_ptr;
        ret = OK;
      }
  
    return ret;
  }
  