| /* |
| * 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 "signals" version of sim. This implementation uses |
| * signals to perform context switches. This is the more correct version of |
| * sim: the OS tick timer will cause a high-priority task to preempt a |
| * low-priority task. Unfortunately, there are stability issues because a task |
| * can be preempted while it is in the middle of a system call, potentially |
| * causing deadlock or memory corruption. |
| * |
| * To use this version of sim, enable the MCU_NATIVE_USE_SIGNALS syscfg |
| * setting. |
| */ |
| |
| #include "os/mynewt.h" |
| |
| #if MYNEWT_VAL(MCU_NATIVE_USE_SIGNALS) |
| |
| #include "sim_priv.h" |
| |
| #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> |
| |
| static bool suspended; /* process is blocked in sigsuspend() */ |
| static sigset_t suspsigs; /* signals delivered in sigsuspend() */ |
| static sigset_t allsigs; |
| static sigset_t nosigs; |
| |
| void |
| sim_ctx_sw(struct os_task *next_t) |
| { |
| /* |
| * gdb will stop execution of the program on most signals (e.g. SIGUSR1) |
| * whereas it passes SIGURG to the process without any special settings. |
| */ |
| kill(sim_pid, SIGURG); |
| } |
| |
| static void |
| ctxsw_handler(int sig) |
| { |
| OS_ASSERT_CRITICAL(); |
| |
| /* |
| * Just record that this handler was called when the process was blocked. |
| * The handler will be called after sigsuspend() returns in the correct |
| * order. |
| */ |
| if (suspended) { |
| sigaddset(&suspsigs, sig); |
| } else { |
| sim_switch_tasks(); |
| } |
| } |
| |
| /* |
| * Disable signals and enter a critical section. |
| * |
| * Returns 1 if signals were already blocked and 0 otherwise. |
| */ |
| os_sr_t |
| sim_save_sr(void) |
| { |
| int error; |
| sigset_t omask; |
| |
| error = sigprocmask(SIG_BLOCK, &allsigs, &omask); |
| assert(error == 0); |
| |
| /* |
| * If any one of the signals in 'allsigs' is present in 'omask' then |
| * we are already inside a critical section. |
| */ |
| return (sigismember(&omask, SIGALRM)); |
| } |
| |
| void |
| sim_restore_sr(os_sr_t osr) |
| { |
| int error; |
| |
| OS_ASSERT_CRITICAL(); |
| assert(osr == 0 || osr == 1); |
| |
| if (osr == 1) { |
| /* Exiting a nested critical section */ |
| return; |
| } |
| |
| error = sigprocmask(SIG_UNBLOCK, &allsigs, NULL); |
| assert(error == 0); |
| } |
| |
| int |
| sim_in_critical(void) |
| { |
| int error; |
| sigset_t omask; |
| |
| error = sigprocmask(SIG_SETMASK, NULL, &omask); |
| assert(error == 0); |
| |
| /* |
| * If any one of the signals in 'allsigs' is present in 'omask' then |
| * we are already inside a critical section. |
| */ |
| return (sigismember(&omask, SIGALRM)); |
| } |
| |
| static void |
| timer_handler(int sig) |
| { |
| OS_ASSERT_CRITICAL(); |
| |
| /* |
| * Just record that this handler was called when the process was blocked. |
| * The handler will be called after sigsuspend() returns in the proper |
| * order. |
| */ |
| if (suspended) { |
| sigaddset(&suspsigs, sig); |
| } else { |
| sim_tick(); |
| } |
| } |
| |
| static struct { |
| int num; |
| void (*handler)(int sig); |
| } signals[] = { |
| { SIGALRM, timer_handler }, |
| { SIGURG, ctxsw_handler }, |
| }; |
| |
| #define NUMSIGS (sizeof(signals)/sizeof(signals[0])) |
| |
| void |
| sim_tick_idle(os_time_t ticks) |
| { |
| int i, rc, sig; |
| struct itimerval it; |
| void (*handler)(int sig); |
| |
| 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); |
| } |
| |
| suspended = true; |
| sigemptyset(&suspsigs); |
| sigsuspend(&nosigs); /* Wait for a signal to wake us up */ |
| suspended = false; |
| |
| /* |
| * 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(); |
| } |
| for (i = 0; i < NUMSIGS; i++) { |
| sig = signals[i].num; |
| handler = signals[i].handler; |
| if (sig != SIGALRM && sigismember(&suspsigs, sig)) { |
| handler(sig); |
| } |
| } |
| |
| 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) |
| { |
| int i, error; |
| struct sigaction sa; |
| |
| sigemptyset(&nosigs); |
| sigemptyset(&allsigs); |
| for (i = 0; i < NUMSIGS; i++) { |
| sigaddset(&allsigs, signals[i].num); |
| } |
| |
| for (i = 0; i < NUMSIGS; i++) { |
| memset(&sa, 0, sizeof sa); |
| sa.sa_handler = signals[i].handler; |
| sa.sa_mask = allsigs; |
| sa.sa_flags = SA_RESTART; |
| error = sigaction(signals[i].num, &sa, NULL); |
| assert(error == 0); |
| } |
| |
| /* |
| * We use SIGALRM as a proxy for 'allsigs' to check if we are inside |
| * a critical section (for e.g. see sim_in_critical()). Make sure |
| * that SIGALRM is indeed present in 'allsigs'. |
| */ |
| assert(sigismember(&allsigs, SIGALRM)); |
| } |
| |
| void |
| sim_signals_cleanup(void) |
| { |
| int i, error; |
| struct sigaction sa; |
| |
| for (i = 0; i < NUMSIGS; i++) { |
| memset(&sa, 0, sizeof sa); |
| sa.sa_handler = SIG_DFL; |
| error = sigaction(signals[i].num, &sa, NULL); |
| assert(error == 0); |
| } |
| } |
| |
| #endif /* MYNEWT_VAL(MCU_NATIVE_USE_SIGNALS) */ |