nuttx/arch/sim/src/up_usestack.c

/****************************************************************************
 * arch/sim/src/up_usestack.c
 *
 *   Copyright (C) 2007-2009, 2016 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 <string.h>
#include <debug.h>

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

#include "up_internal.h"

/****************************************************************************
 * Pre-processor Macros
 ****************************************************************************/

/* Use a stack alignment of 16 bytes.  If necessary frame_size must be rounded
 * up to the next boundary
 */

#define STACK_ALIGNMENT     16

/* Stack alignment macros */

#define STACK_ALIGN_MASK    (STACK_ALIGNMENT-1)
#define STACK_ALIGN_DOWN(a) ((a) & ~STACK_ALIGN_MASK)
#define STACK_ALIGN_UP(a)   (((a) + STACK_ALIGN_MASK) & ~STACK_ALIGN_MASK)

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

/****************************************************************************
 * Name: up_use_stack
 *
 * Description:
 *   Setup up stack-related information in the TCB using pre-allocated stack
 *   memory.  This function is called only from task_init() when a task or
 *   kernel thread is started (never for pthreads).
 *
 *   The following TCB fields must be initialized:
 *
 *   - 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.
 *
 * Input Parameters:
 *   - tcb: The TCB of new task
 *   - stack_size:  The allocated stack size.
 *
 *   NOTE:  Unlike up_stack_create() and up_stack_release, this function
 *   does not require the task type (ttype) parameter.  The TCB flags will
 *   always be set to provide the task type to up_use_stack() if it needs
 *   that information.
 *
 ****************************************************************************/

int up_use_stack(FAR struct tcb_s *tcb, FAR void *stack, size_t stack_size)
{
  uintptr_t adj_stack_addr;
  size_t adj_stack_size;

#ifdef CONFIG_TLS
  /* Make certain that the user provided stack is properly aligned */

  DEBUGASSERT(((uintptr_t)stack & TLS_STACK_MASK) == 0);
#endif
  /* Move down to next even word boundary within the pre-allocated stack
   * memory, if necessary.
   */

  adj_stack_size = STACK_ALIGN_DOWN(stack_size);

  /* This is the address of the last word in the allocation.
   * NOTE that stack_alloc_ptr + adj_stack_size may lie one byte
   * outside of the stack.  This is okay for an inital state; the
   * first pushed values will be within the stack allocation.
   */

  adj_stack_addr = STACK_ALIGN_DOWN((uintptr_t)stack + adj_stack_size);

  /* Save the values in the TCB */

  tcb->adj_stack_size  = adj_stack_size;
  tcb->stack_alloc_ptr = stack;
  tcb->adj_stack_ptr   = (FAR void *)adj_stack_addr;

#ifdef CONFIG_TLS
  /* Initialize the TLS data structure */

  memset(stack, 0, sizeof(struct tls_info_s));
#endif

  return OK;
}