/**************************************************************************** * arch/arm/src/armv6-m/up_schedulesigaction.c * * Copyright (C) 2013-2016 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include "psr.h" #include "exc_return.h" #include "sched/sched.h" #include "up_internal.h" #include "up_arch.h" #ifndef CONFIG_DISABLE_SIGNALS /**************************************************************************** * Pre-processor 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(struct tcb_s *tcb, sig_deliver_t sigdeliver) { irqstate_t flags; sinfo("tcb=0x%p sigdeliver=0x%p\n", tcb, sigdeliver); /* Make sure that interrupts are disabled */ flags = enter_critical_section(); /* Refuse to handle nested signal actions */ if (!tcb->xcp.sigdeliver) { /* First, handle some special cases when the signal is being delivered * to the currently executing task. */ sinfo("rtcb=0x%p CURRENT_REGS=0x%p\n", this_task(), CURRENT_REGS); if (tcb == this_task()) { /* 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 { /* Save the return PC, CPSR, and PRIMASK registers (and * perhaps the LR). These will be restored by the signal * trampoline after the signal has been delivered. */ tcb->xcp.sigdeliver = sigdeliver; tcb->xcp.saved_pc = CURRENT_REGS[REG_PC]; tcb->xcp.saved_primask = CURRENT_REGS[REG_PRIMASK]; tcb->xcp.saved_xpsr = CURRENT_REGS[REG_XPSR]; #ifdef CONFIG_BUILD_PROTECTED tcb->xcp.saved_lr = CURRENT_REGS[REG_LR]; #endif /* Then set up to vector to the trampoline with interrupts * disabled. The kernel-space trampoline must run in * privileged thread mode. */ CURRENT_REGS[REG_PC] = (uint32_t)up_sigdeliver; CURRENT_REGS[REG_PRIMASK] = 1; CURRENT_REGS[REG_XPSR] = ARMV6M_XPSR_T; #ifdef CONFIG_BUILD_PROTECTED CURRENT_REGS[REG_LR] = EXC_RETURN_PRIVTHR; #endif /* And make sure that the saved context in the TCB is the same * as the interrupt return context. */ up_savestate(tcb->xcp.regs); } } /* Otherwise, we are (1) signalling 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 { /* Save the return PS, CPSR and PRIMASK register (a perhaps also * the LR). These will be restored by the signal trampoline after * the signal has been delivered. */ tcb->xcp.sigdeliver = sigdeliver; tcb->xcp.saved_pc = tcb->xcp.regs[REG_PC]; tcb->xcp.saved_primask = tcb->xcp.regs[REG_PRIMASK]; tcb->xcp.saved_xpsr = tcb->xcp.regs[REG_XPSR]; #ifdef CONFIG_BUILD_PROTECTED tcb->xcp.saved_lr = tcb->xcp.regs[REG_LR]; #endif /* Then set up to vector to the trampoline with interrupts * disabled. We must already be in privileged thread mode to be * here. */ tcb->xcp.regs[REG_PC] = (uint32_t)up_sigdeliver; tcb->xcp.regs[REG_PRIMASK] = 1; tcb->xcp.regs[REG_XPSR] = ARMV6M_XPSR_T; #ifdef CONFIG_BUILD_PROTECTED tcb->xcp.regs[REG_LR] = EXC_RETURN_PRIVTHR; #endif } } leave_critical_section(flags); } #endif /* !CONFIG_DISABLE_SIGNALS */