diff options
Diffstat (limited to 'nuttx/arch/arm/src/common/up_usestack.c')
-rw-r--r-- | nuttx/arch/arm/src/common/up_usestack.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/nuttx/arch/arm/src/common/up_usestack.c b/nuttx/arch/arm/src/common/up_usestack.c new file mode 100644 index 000000000..f46be0cc9 --- /dev/null +++ b/nuttx/arch/arm/src/common/up_usestack.c @@ -0,0 +1,155 @@ +/**************************************************************************** + * arch/arm/src/common/up_usestack.c + * + * Copyright (C) 2007-2009 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 <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; +} |