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/****************************************************************************
* arch/arm/src/common/up_usestack.c
*
* Copyright (C) 2007-2009 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 <sched.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/arch.h>
#include "up_internal.h"
/****************************************************************************
* Pre-processor Macros
****************************************************************************/
/* ARM requires at least a 4-byte stack alignment. For use with EABI and
* floating point, the stack must be aligned to 8-byte addresses.
*/
#ifndef CONFIG_STACK_ALIGNMENT
/* The symbol __ARM_EABI__ is defined by GCC if EABI is being used. If you
* are not using GCC, make sure that CONFIG_STACK_ALIGNMENT is set correctly!
*/
# ifdef __ARM_EABI__
# define CONFIG_STACK_ALIGNMENT 8
# else
# define CONFIG_STACK_ALIGNMENT 4
# endif
#endif
/* Stack alignment macros */
#define STACK_ALIGN_MASK (CONFIG_STACK_ALIGNMENT-1)
#define STACK_ALIGN_DOWN(a) ((a) & ~STACK_ALIGN_MASK)
#define STACK_ALIGN_UP(a) (((a) + STACK_ALIGN_MASK) & ~STACK_ALIGN_MASK)
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Global Functions
****************************************************************************/
/****************************************************************************
* Name: up_use_stack
*
* Description:
* Setup up stack-related information in the TCB
* using pre-allocated stack memory
*
* 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 allocated stack size.
*
****************************************************************************/
int up_use_stack(_TCB *tcb, void *stack, size_t stack_size)
{
size_t top_of_stack;
size_t size_of_stack;
if (tcb->stack_alloc_ptr)
{
sched_free(tcb->stack_alloc_ptr);
}
/* Save the stack allocation */
tcb->stack_alloc_ptr = stack;
/* The ARM 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 ARM stack must be aligned; 4 byte alignment for OABI and 8-byte
* alignment for EABI. If necessary top_of_stack must be rounded down
* to the next boundary
*/
top_of_stack = STACK_ALIGN_DOWN(top_of_stack);
/* The size of the stack in bytes is then the difference between
* the top and the bottom of the stack (+4 because if the top
* is the same as the bottom, then the size is one 32-bit element).
* The size need not be aligned.
*/
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;
return OK;
}
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