/**************************************************************************** * arch/risc-v/src/gap8/gap8_schedulesigaction.c * * Copyright (C) 2018 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Modified for RISC-V: * * Author: hhuysqt <1020988872@qq.com> * * 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 #include "sched/sched.h" #include "riscv_internal.h" #include "riscv_arch.h" /**************************************************************************** * 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 'sigdeliver' 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. * * Assumptions: * Called from critical section * ****************************************************************************/ irqstate_t flags; void up_schedule_sigaction(struct tcb_s *tcb, sig_deliver_t sigdeliver) { // uint32_t int_ctx; 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 g_current_regs=0x%p\n", this_task(), g_current_regs); if (tcb == this_task()) { /* CASE 1: We are not in an interrupt handler and * a task is signaling itself for some reason. */ if (!g_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. * * Hmmm... there looks like a latent bug here: The following * logic would fail in the strange case where we are in an * interrupt handler, the thread is signaling itself, but * a context switch to another task has occurred so that * g_current_regs does not refer to the thread of this_task()! */ else { /* Save the return EPC and STATUS registers. These will be * restored by the signal trampoline after the signals have * been delivered. */ tcb->xcp.sigdeliver = sigdeliver; tcb->xcp.saved_epc = g_current_regs[REG_EPC]; /* Then set up to vector to the trampoline with interrupts * disabled */ g_current_regs[REG_EPC] = (uint32_t)up_sigdeliver; /* And make sure that the saved context in the TCB * is the same as the interrupt return context. */ up_savestate(tcb->xcp.regs); // sinfo("PC/STATUS Saved: %08x/%08x New: %08x/%08x\n", // tcb->xcp.saved_epc, tcb->xcp.saved_int_ctx, // g_current_regs[REG_EPC], g_current_regs[REG_STATUS]); } } /* 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 signaling * some non-running task. */ else { /* Save the return EPC and STATUS registers. These will be * restored by the signal trampoline after the signals have * been delivered. */ tcb->xcp.sigdeliver = sigdeliver; tcb->xcp.saved_epc = tcb->xcp.regs[REG_EPC]; /* Then set up to vector to the trampoline with interrupts * disabled */ tcb->xcp.regs[REG_EPC] = (uint32_t)up_sigdeliver; // sinfo("PC/STATUS Saved: %08x/%08x New: %08x/%08x\n", // tcb->xcp.saved_epc, tcb->xcp.saved_int_ctx, // tcb->xcp.regs[REG_EPC], tcb->xcp.regs[REG_STATUS]); } } }