| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| /** |
| * This file implements the "no-signals" version of sim. This implementation |
| * does not use signals to perform context switches. This is the less correct |
| * version of sim: the OS tick timer only runs while the idle task is active. |
| * Therefore, a sleeping high-priority task will not preempt a low-priority |
| * task due to a timing event (e.g., delay or callout expired). However, this |
| * version of sim does not suffer from the stability issues that affect the |
| * "signals" implementation. |
| * |
| * To use this version of sim, disable the MCU_NATIVE_USE_SIGNALS syscfg |
| * setting. |
| */ |
| |
| #include "os/mynewt.h" |
| |
| #if !MYNEWT_VAL(MCU_NATIVE_USE_SIGNALS) |
| |
| #include <hal/hal_bsp.h> |
| |
| #ifdef __APPLE__ |
| #define _XOPEN_SOURCE |
| #endif |
| |
| #include <string.h> |
| #include <stdio.h> |
| #include <unistd.h> |
| #include <setjmp.h> |
| #include <signal.h> |
| #include <sys/time.h> |
| #include <assert.h> |
| #include "sim_priv.h" |
| |
| static sigset_t nosigs; |
| static sigset_t suspsigs; /* signals delivered in sigsuspend() */ |
| |
| static int ctx_sw_pending; |
| static int interrupts_enabled = 1; |
| |
| void |
| sim_ctx_sw(struct os_task *next_t) |
| { |
| if (interrupts_enabled) { |
| /* Perform the context switch immediately. */ |
| sim_switch_tasks(); |
| } else { |
| /* Remember that we want to perform a context switch. Perform it when |
| * interrupts are re-enabled. |
| */ |
| ctx_sw_pending = 1; |
| } |
| } |
| |
| /* |
| * Enter a critical section. |
| * |
| * Returns 1 if interrupts were already disabled; 0 otherwise. |
| */ |
| os_sr_t |
| sim_save_sr(void) |
| { |
| if (!interrupts_enabled) { |
| return 1; |
| } |
| |
| interrupts_enabled = 0; |
| return 0; |
| } |
| |
| void |
| sim_restore_sr(os_sr_t osr) |
| { |
| OS_ASSERT_CRITICAL(); |
| assert(osr == 0 || osr == 1); |
| |
| if (osr == 1) { |
| /* Exiting a nested critical section */ |
| return; |
| } |
| |
| if (ctx_sw_pending) { |
| /* A context switch was requested while interrupts were disabled. |
| * Perform it now that interrupts are enabled again. |
| */ |
| ctx_sw_pending = 0; |
| sim_switch_tasks(); |
| } |
| interrupts_enabled = 1; |
| } |
| |
| int |
| sim_in_critical(void) |
| { |
| return !interrupts_enabled; |
| } |
| |
| /** |
| * Unblocks the SIGALRM signal that is delivered by the OS tick timer. |
| */ |
| static void |
| unblock_timer(void) |
| { |
| sigset_t sigs; |
| int rc; |
| |
| sigemptyset(&sigs); |
| sigaddset(&sigs, SIGALRM); |
| |
| rc = sigprocmask(SIG_UNBLOCK, &sigs, NULL); |
| assert(rc == 0); |
| } |
| |
| /** |
| * Blocks the SIGALRM signal that is delivered by the OS tick timer. |
| */ |
| static void |
| block_timer(void) |
| { |
| sigset_t sigs; |
| int rc; |
| |
| sigemptyset(&sigs); |
| sigaddset(&sigs, SIGALRM); |
| |
| rc = sigprocmask(SIG_BLOCK, &sigs, NULL); |
| assert(rc == 0); |
| } |
| |
| static void |
| sig_handler_alrm(int sig) |
| { |
| /* Wake the idle task. */ |
| sigaddset(&suspsigs, sig); |
| } |
| |
| void |
| sim_tick_idle(os_time_t ticks) |
| { |
| int rc; |
| struct itimerval it; |
| |
| OS_ASSERT_CRITICAL(); |
| |
| if (ticks > 0) { |
| /* |
| * Enter tickless regime and set the timer to fire after 'ticks' |
| * worth of time has elapsed. |
| */ |
| it.it_value.tv_sec = ticks / OS_TICKS_PER_SEC; |
| it.it_value.tv_usec = (ticks % OS_TICKS_PER_SEC) * OS_USEC_PER_TICK; |
| it.it_interval.tv_sec = 0; |
| it.it_interval.tv_usec = OS_USEC_PER_TICK; |
| rc = setitimer(ITIMER_REAL, &it, NULL); |
| assert(rc == 0); |
| } |
| |
| unblock_timer(); |
| |
| sigemptyset(&suspsigs); |
| sigsuspend(&nosigs); /* Wait for a signal to wake us up */ |
| |
| block_timer(); |
| |
| /* |
| * Call handlers for signals delivered to the process during sigsuspend(). |
| * The SIGALRM handler is called before any other handlers to ensure that |
| * OS time is always correct. |
| */ |
| if (sigismember(&suspsigs, SIGALRM)) { |
| sim_tick(); |
| } |
| |
| if (ticks > 0) { |
| /* |
| * Enable the periodic timer interrupt. |
| */ |
| it.it_value.tv_sec = 0; |
| it.it_value.tv_usec = OS_USEC_PER_TICK; |
| it.it_interval.tv_sec = 0; |
| it.it_interval.tv_usec = OS_USEC_PER_TICK; |
| rc = setitimer(ITIMER_REAL, &it, NULL); |
| assert(rc == 0); |
| } |
| } |
| |
| void |
| sim_signals_init(void) |
| { |
| sigset_t sigset_alrm; |
| struct sigaction sa; |
| int error; |
| |
| block_timer(); |
| |
| sigemptyset(&nosigs); |
| |
| sigemptyset(&sigset_alrm); |
| sigaddset(&sigset_alrm, SIGALRM); |
| |
| memset(&sa, 0, sizeof sa); |
| sa.sa_handler = sig_handler_alrm; |
| sa.sa_mask = sigset_alrm; |
| sa.sa_flags = SA_RESTART; |
| error = sigaction(SIGALRM, &sa, NULL); |
| assert(error == 0); |
| } |
| |
| void |
| sim_signals_cleanup(void) |
| { |
| int error; |
| struct sigaction sa; |
| |
| memset(&sa, 0, sizeof sa); |
| sa.sa_handler = SIG_DFL; |
| error = sigaction(SIGALRM, &sa, NULL); |
| assert(error == 0); |
| } |
| |
| #endif /* !MYNEWT_VAL(MCU_NATIVE_USE_SIGNALS) */ |