/**************************************************************************** * sched/init/os_smpstart.c * * Copyright (C) 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 #include #include #include "group/group.h" #include "sched/sched.h" #include "init/init.h" #ifdef CONFIG_SMP /**************************************************************************** * Private Types ****************************************************************************/ struct os_tcballoc_s { struct task_tcb_s tcb; /* IDLE task TCB */ FAR char *idleargv[2]; /* Argument list */ }; /**************************************************************************** * Private Data ****************************************************************************/ #if CONFIG_TASK_NAME_SIZE < 1 static const char g_idlename[] = "CPUn Idle" #endif /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: os_idle_trampoline * * Description: * This is the common start-up logic for the IDLE task for CPUs 1 through * (CONFIG_SMP_NCPUS-1). Having a start-up function such as this for the * IDLE is not really an architectural necessity. It is used only for * symmetry with now other threads are started (see task_start() and * pthread_start()). * * Input Parameters: * None. * * Returned Value: * This function does not return. * ****************************************************************************/ void os_idle_trampoline(void) { #ifdef CONFIG_SCHED_INSTRUMENTATION FAR struct tcb_s *tcb = this_task(); /* Announce that the IDLE task has started */ sched_note_start(tcb); #endif /* Then transfer control to the IDLE task */ (void)os_idle_task(0, NULL); /* The IDLE task should never return */ DEBUGPANIC(); } /**************************************************************************** * Name: os_idle_task * * Description: * This is the common IDLE task for CPUs 1 through (CONFIG_SMP_NCPUS-1). * It is equivalent to the CPU 0 IDLE logic in os_start.c * * Input Parameters: * Standard task arguments. * * Returned Value: * This function does not return. * ****************************************************************************/ int os_idle_task(int argc, FAR char *argv[]) { /* Enter the IDLE loop */ sinfo("CPU%d: Beginning Idle Loop\n", this_cpu()); for (; ; ) { /* Perform garbage collection (if it is not being done by the worker * thread). This cleans-up memory de-allocations that were queued * because they could not be freed in that execution context (for * example, if the memory was freed from an interrupt handler). */ #ifndef CONFIG_SCHED_WORKQUEUE /* We must have exclusive access to the memory manager to do this * BUT the idle task cannot wait on a semaphore. So we only do * the cleanup now if we can get the semaphore -- this should be * possible because if the IDLE thread is running, no other task is! * * WARNING: This logic could have undesirable side-effects if priority * inheritance is enabled. Imagine the possible issues if the * priority of the IDLE thread were to get boosted! Moral: If you * use priority inheritance, then you should also enable the work * queue so that is done in a safer context. */ if (sched_have_garbage() && kmm_trysemaphore() == 0) { sched_garbage_collection(); kmm_givesemaphore(); } #endif /* Perform any processor-specific idle state operations */ up_idle(); } } /**************************************************************************** * Name: os_smp_start * * Description: * In an SMP configuration, only one CPU is initially active (CPU 0). * System initialization occurs on that single thread. At the completion * of the initialization of the OS, just before beginning normal * multitasking, the additional CPUs would be started by calling this * function. * * Input Parameters: * None * * Returned Value: * Zero on success; a negated errno value on failure. * * Assumption: * Runs before the full initialization sequence has completed. Runs after * all OS facilities are set up, but before multi-tasking has been started. * ****************************************************************************/ int os_smp_start(void) { int ret; int cpu; /* Create a stack for all CPU IDLE threads (except CPU0 which already has * a stack). */ for (cpu = 1; cpu < CONFIG_SMP_NCPUS; cpu++) { FAR struct tcb_s *tcb = current_task(cpu); DEBUGASSERT(tcb != NULL); ret = up_cpu_idlestack(cpu, tcb, CONFIG_SMP_IDLETHREAD_STACKSIZE); if (ret < 0) { serr("ERROR: Failed to allocate stack for CPU%d\n", cpu); return ret; } /* Reinitialize the processor-specific portion of the TCB. This is * the second time this has been called for this CPU, but the stack * was not yet initialized on the first call so we need to do it * again. */ up_initial_state(tcb); /* Set the task flags to indicate that this is a kernel thread and that * this task is locked to this CPU. */ tcb->flags = (TCB_FLAG_TTYPE_KERNEL | TCB_FLAG_NONCANCELABLE | TCB_FLAG_CPU_LOCKED); tcb->cpu = cpu; } /* Then start all of the other CPUs after we have completed the memory * allocations. CPU0 is already running. */ for (cpu = 1; cpu < CONFIG_SMP_NCPUS; cpu++) { /* Start the CPU */ ret = up_cpu_start(cpu); if (ret < 0) { serr("ERROR: Failed to start CPU%d: %d\n", cpu, ret); return ret; } } return OK; } #endif /* CONFIG_SMP */