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/****************************************************************************
* arch/x86/src/i486/up_createstack.c
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 <stdlib.h>
#include <sched.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/arch.h>
#include <arch/board/board.h>
#include "up_arch.h"
#include "up_internal.h"
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Global 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:
* 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.
*
****************************************************************************/
int up_create_stack(_TCB *tcb, size_t stack_size)
{
if (tcb->stack_alloc_ptr && tcb->adj_stack_size != stack_size)
{
sched_free(tcb->stack_alloc_ptr);
tcb->stack_alloc_ptr = NULL;
}
if (!tcb->stack_alloc_ptr)
{
#ifdef CONFIG_DEBUG
tcb->stack_alloc_ptr = (uint32_t*)zalloc(stack_size);
#else
tcb->stack_alloc_ptr = (uint32_t*)malloc(stack_size);
#endif
}
if (tcb->stack_alloc_ptr)
{
size_t top_of_stack;
size_t size_of_stack;
/* The i486 uses a push-down stack: the stack grows toward lower
* addresses in memory. The stack pointer register, points to the
* lowest, valid work address (the "top" of the stack). Items on
* the stack are referenced as positive word offsets from sp.
*/
top_of_stack = (uint32_t)tcb->stack_alloc_ptr + stack_size - 4;
/* The i486 stack must be aligned at word (4 byte) boundaries. If
* necessary top_of_stack must be rounded down to the next boundary
*/
top_of_stack &= ~3;
size_of_stack = top_of_stack - (uint32_t)tcb->stack_alloc_ptr + 4;
/* Save the adjusted stack values in the _TCB */
tcb->adj_stack_ptr = (uint32_t*)top_of_stack;
tcb->adj_stack_size = size_of_stack;
up_ledon(LED_STACKCREATED);
return OK;
}
return ERROR;
}
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