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/****************************************************************************
* arch/arm/src/armv7-a/crt0.c
*
* Copyright (C) 2014 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 <stdlib.h>
#include <nuttx/addrenv.h>
#ifdef CONFIG_BUILD_KERNEL
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
int main(int argc, char *argv[]);
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: up_signal_handler
*
* Description:
* This function is the user-space, signal handler trampoline function. It
* is called from up_signal_dispatch() in user-mode.
*
* R0-R3, R11 - volatile registers need not be preserved.
* R4-R10 - static registers must be preserved
* R12-R14 - LR and SP must be preserved
*
* Inputs:
* R0 = sighand
* The address user-space signal handling function
* R1-R3 = signo, info, and ucontext
* Standard arguments to be passed to the signal handling function.
*
* Return:
* None. This function does not return in the normal sense. It returns
* via the SYS_signal_handler_return (see svcall.h)
*
****************************************************************************/
#ifndef CONFIG_DISABLE_SIGNALS
static void sig_trampoline(void) naked_function;
static void sig_trampoline(void)
{
__asm__ __volatile__
(
" push {lr}\n" /* Save LR on the stack */
" mov ip, r0\n" /* IP=sighand */
" mov r0, r1\n" /* R0=signo */
" mov r1, r2\n" /* R1=info */
" mov r2, r3\n" /* R2=ucontext */
" blx ip\n" /* Call the signal handler */
" pop {r2}\n" /* Recover LR in R2 */
" mov lr, r2\n" /* Restore LR */
" mov r0, #5\n" /* SYS_signal_handler_return */
" svc #0x900001\n" /* Return from the signal handler */
);
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: _start
*
* Description:
* This function is the low level entry point into the main thread of
* execution of a task. It receives initial control when the task is
* started and calls main entry point of the newly started task.
*
* Input Parameters:
* argc - The number of parameters being passed.
* argv - The parameters being passed. These lie in kernel-space memory
* and will have to be reallocated in user-space memory.
*
* Returned Value:
* This function should not return. It should call the user-mode start-up
* main() function. If that function returns, this function will call
* exit.
*
****************************************************************************/
void _start(int argc, FAR char *argv[])
{
int ret;
#ifndef CONFIG_DISABLE_SIGNALS
/* Initialize the reserved area at the beginning of the .bss/.data region
* that is visible to the RTOS.
*/
ARCH_DATA_RESERVE->ar_sigtramp = (addrenv_sigtramp_t)sig_trampoline;
#endif
/* Call C++ constructors */
/* Setup so that C++ destructors called on task exit */
/* REVISIT: Missing logic */
/* Call the main() entry point passing argc and argv. */
ret = main(argc, argv);
/* Call exit() if/when the main() returns */
exit(ret);
}
#endif /* CONFIG_BUILD_KERNEL */
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