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/****************************************************************************
* arch/avr/src/avr/up_sigdeliver.c
*
* Copyright (C) 2011 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 <stdint.h>
#include <sched.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <arch/board/board.h>
#include "os_internal.h"
#include "up_internal.h"
#include "up_arch.h"
#ifndef CONFIG_DISABLE_SIGNALS
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_sigdeliver
*
* Description:
* This is the a signal handling trampoline. When a signal action was
* posted. The task context was mucked with and forced to branch to this
* location with interrupts disabled.
*
****************************************************************************/
void up_sigdeliver(void)
{
struct tcb_s *rtcb = (struct tcb_s*)g_readytorun.head;
uint8_t regs[XCPTCONTEXT_REGS];
sig_deliver_t sigdeliver;
/* Save the errno. This must be preserved throughout the signal handling
* so that the user code final gets the correct errno value (probably EINTR).
*/
int saved_errno = rtcb->pterrno;
up_ledon(LED_SIGNAL);
sdbg("rtcb=%p sigdeliver=%p sigpendactionq.head=%p\n",
rtcb, rtcb->xcp.sigdeliver, rtcb->sigpendactionq.head);
ASSERT(rtcb->xcp.sigdeliver != NULL);
/* Save the real return state on the stack. */
up_copystate(regs, rtcb->xcp.regs);
regs[REG_PCL] = rtcb->xcp.saved_pcl;
regs[REG_PCH] = rtcb->xcp.saved_pch;
regs[REG_SREG] = rtcb->xcp.saved_sreg;
/* Get a local copy of the sigdeliver function pointer. We do this so that
* we can nullify the sigdeliver function pointer in the TCB and accept
* more signal deliveries while processing the current pending signals.
*/
sigdeliver = rtcb->xcp.sigdeliver;
rtcb->xcp.sigdeliver = NULL;
/* Then restore the task interrupt state */
irqrestore(regs[REG_SREG]);
/* Deliver the signals */
sigdeliver(rtcb);
/* Output any debug messages BEFORE restoring errno (because they may
* alter errno), then disable interrupts again and restore the original
* errno that is needed by the user logic (it is probably EINTR).
*/
sdbg("Resuming\n");
(void)irqsave();
rtcb->pterrno = saved_errno;
/* Then restore the correct state for this thread of execution. This is an
* unusual case that must be handled by up_fullcontextresore. This case is
* unusal in two ways:
*
* 1. It is not a context switch between threads. Rather, up_fullcontextrestore
* must behave more it more like a longjmp within the same task, using
* he same stack.
* 2. In this case, up_fullcontextrestore is called with r12 pointing to
* a register save area on the stack to be destroyed. This is
* dangerous because there is the very real possibility that the new
* stack pointer might overlap with the register save area and hat stack
* usage in up_fullcontextrestore might corrupt the register save data
* before the state is restored. At present, there does not appear to
* be any stack overlap problems. If there were, then adding 3 words
* to the size of register save structure size will protect its contents.
*/
up_ledoff(LED_SIGNAL);
up_fullcontextrestore(regs);
}
#endif /* !CONFIG_DISABLE_SIGNALS */
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