/****************************************************************************
* arch/arm/src/armv7-m/up_initialstate.c
*
* Copyright (C) 2009, 2011-2 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 <string.h>
#include <nuttx/arch.h>
#include "up_internal.h"
#include "up_arch.h"
#include "psr.h"
#include "exc_return.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_initial_state
*
* Description:
* A new thread is being started and a new TCB
* has been created. This function is called to initialize
* the processor specific portions of the new TCB.
*
* This function must setup the intial architecture registers
* and/or stack so that execution will begin at tcb->start
* on the next context switch.
*
****************************************************************************/
void up_initial_state(_TCB *tcb)
{
struct xcptcontext *xcp = &tcb->xcp;
/* Initialize the initial exception register context structure */
memset(xcp, 0, sizeof(struct xcptcontext));
/* Save the initial stack pointer */
xcp->regs[REG_SP] = (uint32_t)tcb->adj_stack_ptr;
/* Save the task entry point (stripping off the thumb bit) */
xcp->regs[REG_PC] = (uint32_t)tcb->start & ~1;
/* Specify thumb mode */
xcp->regs[REG_XPSR] = ARMV7M_XPSR_T;
/* If this task is running PIC, then set the PIC base register to the
* address of the allocated D-Space region.
*/
#ifdef CONFIG_PIC
if (tcb->dspace != NULL)
{
/* Set the PIC base register (probably R10) to the address of the
* alloacated D-Space region.
*/
xcp->regs[REG_PIC] = (uint32_t)tcb->dspace->region;
}
/* Make certain that bit 0 is set in the main entry address. This
* is only an issue when NXFLAT is enabled. NXFLAT doesn't know
* anything about thumb; the addresses that NXFLAT sets are based
* on file header info and won't have bit 0 set.
*/
#ifdef CONFIG_NXFLAT
tcb->entry.main = (main_t)((uint32_t)tcb->entry.main | 1);
#endif
#endif /* CONFIG_PIC */
#ifdef CONFIG_ARMV7M_CMNVECTOR
/* Set privileged- or unprivileged-mode, depending on how NuttX is
* configured and what kind of thread is being started.
*
* If the kernel build is not selected, then all threads run in
* privileged thread mode.
*
* If FPU support is not configured, set the bit that indicates that
* the context does not include the volatile FP registers.
*/
xcp->regs[REG_EXC_RETURN] = EXC_RETURN_BASE | EXC_RETURN_THREAD_MODE;
#ifndef CONFIG_ARCH_FPU
xcp->regs[REG_EXC_RETURN] |= EXC_RETURN_STD_CONTEXT;
#else
xcp->regs[REG_FPSCR] = 0; // XXX initial FPSCR should be configurable
xcp->regs[REG_FPReserved] = 0;
#endif
#ifdef CONFIG_NUTTX_KERNEL
if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL)
{
/* It is a normal task or a pthread. Set user mode */
xcp->regs[REG_EXC_RETURN] = EXC_RETURN_PROCESS_STACK;
}
#endif
#else /* CONFIG_ARMV7M_CMNVECTOR */
/* Set privileged- or unprivileged-mode, depending on how NuttX is
* configured and what kind of thread is being started.
*
* If the kernel build is not selected, then all threads run in
* privileged thread mode.
*/
#ifdef CONFIG_NUTTX_KERNEL
if ((tcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_KERNEL)
{
/* It is a kernel thread.. set privileged thread mode */
xcp->regs[REG_EXC_RETURN] = EXC_RETURN_PRIVTHR;
}
else
{
/* It is a normal task or a pthread. Set user mode */
xcp->regs[REG_EXC_RETURN] = EXC_RETURN_UNPRIVTHR;
}
#endif
#endif /* CONFIG_ARMV7M_CMNVECTOR */
/* Enable or disable interrupts, based on user configuration */
#ifdef CONFIG_SUPPRESS_INTERRUPTS
xcp->regs[REG_PRIMASK] = 1;
#endif
}
