/****************************************************************************
* common/up_schedulesigaction.c
*
* Copyright (C) 2008-2010 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/arch.h>
#include <arch/irq.h>
#include "os_internal.h"
#include "up_internal.h"
#ifndef CONFIG_DISABLE_SIGNALS
/****************************************************************************
* Private Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_schedule_sigaction
*
* Description:
* This function is called by the OS when one or more
* signal handling actions have been queued for execution.
* The architecture specific code must configure things so
* that the 'igdeliver' callback is executed on the thread
* specified by 'tcb' as soon as possible.
*
* This function may be called from interrupt handling logic.
*
* This operation should not cause the task to be unblocked
* nor should it cause any immediate execution of sigdeliver.
* Typically, a few cases need to be considered:
*
* (1) This function may be called from an interrupt handler
* During interrupt processing, all xcptcontext structures
* should be valid for all tasks. That structure should
* be modified to invoke sigdeliver() either on return
* from (this) interrupt or on some subsequent context
* switch to the recipient task.
* (2) If not in an interrupt handler and the tcb is NOT
* the currently executing task, then again just modify
* the saved xcptcontext structure for the recipient
* task so it will invoke sigdeliver when that task is
* later resumed.
* (3) If not in an interrupt handler and the tcb IS the
* currently executing task -- just call the signal
* handler now.
*
****************************************************************************/
void up_schedule_sigaction(FAR _TCB *tcb, sig_deliver_t sigdeliver)
{
/* Refuse to handle nested signal actions */
dbg("tcb=0x%p sigdeliver=0x%06x\n", tcb, (uint32_t)sigdeliver);
if (!tcb->xcp.sigdeliver)
{
irqstate_t flags;
/* Make sure that interrupts are disabled */
flags = irqsave();
/* First, handle some special cases when the signal is
* being delivered to the currently executing task.
*/
dbg("rtcb=0x%p current_regs=0x%p\n", g_readytorun.head, current_regs);
if (tcb == (FAR _TCB*)g_readytorun.head)
{
/* CASE 1: We are not in an interrupt handler and
* a task is signalling itself for some reason.
*/
if (!current_regs)
{
/* In this case just deliver the signal now. */
sigdeliver(tcb);
}
/* CASE 2: We are in an interrupt handler AND the interrupted
* task is the same as the one that must receive the signal, then
* we will have to modify the return state as well as the state
* in the TCB.
*/
else
{
FAR uint32_t *current_pc = (FAR uint32_t*)¤t_regs[REG_PC];
/* Save the return address and interrupt state. These will be
* restored by the signal trampoline after the signals have
* been delivered.
*/
tcb->xcp.sigdeliver = sigdeliver;
tcb->xcp.saved_pc = *current_pc;
tcb->xcp.saved_i = current_regs[REG_FLAGS];
/* Then set up to vector to the trampoline with interrupts
* disabled
*/
*current_pc = (uint32_t)up_sigdeliver;
current_regs[REG_FLAGS] = 0;
/* And make sure that the saved context in the TCB is the
* same as the interrupt return context.
*/
up_copystate(tcb->xcp.regs, current_regs);
}
}
/* Otherwise, we are (1) signaling a task is not running from an
* interrupt handler or (2) we are not in an interrupt handler
* and the running task is signalling some non-running task.
*/
else
{
FAR uint32_t *saved_pc = (FAR uint32_t*)&tcb->xcp.regs[REG_PC];
/* Save the return lr and cpsr and one scratch register
* These will be restored by the signal trampoline after
* the signals have been delivered.
*/
tcb->xcp.sigdeliver = sigdeliver;
tcb->xcp.saved_pc = *saved_pc;
tcb->xcp.saved_i = tcb->xcp.regs[REG_FLAGS];
/* Then set up to vector to the trampoline with interrupts
* disabled
*/
*saved_pc = (uint32_t)up_sigdeliver;
tcb->xcp.regs[REG_FLAGS] = 0;
}
irqrestore(flags);
}
}
#endif /* CONFIG_DISABLE_SIGNALS */
