141 lines
4.9 KiB
C
141 lines
4.9 KiB
C
/****************************************************************************
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* arch/arm/src/armv7-a/arm_initialstate.c
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*
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* Copyright (C) 2013-2014 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <string.h>
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#include <nuttx/arch.h>
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#include "arm.h"
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#include "up_internal.h"
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#include "up_arch.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: up_initial_state
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*
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* Description:
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* A new thread is being started and a new TCB has been created. This
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* function is called to initialize the processor specific portions of
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* the new TCB.
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*
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* This function must setup the initial architecture registers and/or
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* stack so that execution will begin at tcb->start on the next context
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* switch.
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*
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****************************************************************************/
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void up_initial_state(struct tcb_s *tcb)
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{
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struct xcptcontext *xcp = &tcb->xcp;
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uint32_t cpsr;
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/* Initialize the initial exception register context structure */
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memset(xcp, 0, sizeof(struct xcptcontext));
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/* Save the initial stack pointer */
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xcp->regs[REG_SP] = (uint32_t)tcb->adj_stack_ptr;
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/* Save the task entry point */
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xcp->regs[REG_PC] = (uint32_t)tcb->start;
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/* If this task is running PIC, then set the PIC base register to the
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* address of the allocated D-Space region.
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*/
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#ifdef CONFIG_PIC
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if (tcb->dspace != NULL)
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{
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/* Set the PIC base register (probably R10) to the address of the
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* alloacated D-Space region.
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*/
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xcp->regs[REG_PIC] = (uint32_t)tcb->dspace->region;
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}
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#endif
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/* Set supervisor-mode and disable FIQs, regardless of how NuttX is
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* configured and of what kind of thread is being started. That is
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* because all threads, even user-mode threads will start in kernel
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* trampoline at task_start() or pthread_start(). The thread's
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* privileges will be dropped before transitioning to user code.
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*/
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cpsr = PSR_MODE_SVC;
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/* Enable or disable interrupts, based on user configuration */
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#ifdef CONFIG_SUPPRESS_INTERRUPTS
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/* Disable interrupts (both IRQs and FIQs) */
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cpsr |= (PSR_I_BIT | PSR_F_BIT);
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#else /* CONFIG_SUPPRESS_INTERRUPTS */
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/* Leave IRQs enabled (Also FIQs if CONFIG_ARMV7A_DECODEFIQ is selected) */
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#ifndef CONFIG_ARMV7A_DECODEFIQ
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cpsr |= PSR_F_BIT;
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#endif /* !CONFIG_ARMV7A_DECODEFIQ */
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#endif /* CONFIG_SUPPRESS_INTERRUPTS */
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xcp->regs[REG_CPSR] = cpsr;
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}
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