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nuttx/sched/init/os_start.c

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/****************************************************************************
* sched/init/os_start.c
*
* Copyright (C) 2007-2014, 2016, 2018 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 <sys/types.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/compiler.h>
#include <nuttx/sched.h>
#include <nuttx/fs/fs.h>
#include <nuttx/net/net.h>
#include <nuttx/lib/lib.h>
#include <nuttx/mm/mm.h>
#include <nuttx/mm/shm.h>
#include <nuttx/kmalloc.h>
#include <nuttx/sched_note.h>
#include <nuttx/syslog/syslog.h>
#include <nuttx/binfmt/binfmt.h>
#include <nuttx/init.h>
#include "sched/sched.h"
#include "signal/signal.h"
#include "wdog/wdog.h"
#include "semaphore/semaphore.h"
#ifndef CONFIG_DISABLE_MQUEUE
# include "mqueue/mqueue.h"
#endif
#ifndef CONFIG_DISABLE_PTHREAD
# include "pthread/pthread.h"
#endif
#include "clock/clock.h"
#include "timer/timer.h"
#include "irq/irq.h"
#ifdef HAVE_TASK_GROUP
# include "group/group.h"
#endif
#include "init/init.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifdef CONFIG_SMP
/* This set of all CPUs */
# define SCHED_ALL_CPUS ((1 << CONFIG_SMP_NCPUS) - 1)
#endif /* CONFIG_SMP */
/****************************************************************************
* Public Data
****************************************************************************/
/* Task Lists ***************************************************************/
/* The state of a task is indicated both by the task_state field of the TCB
* and by a series of task lists. All of these tasks lists are declared
* below. Although it is not always necessary, most of these lists are
* prioritized so that common list handling logic can be used (only the
* g_readytorun, the g_pendingtasks, and the g_waitingforsemaphore lists
* need to be prioritized).
*/
/* This is the list of all tasks that are ready to run. This is a
* prioritized list with head of the list holding the highest priority
* (unassigned) task. In the non-SMP case, the head of this list is the
* currently active task and the tail of this list, the lowest priority
* task, is always the IDLE task.
*/
volatile dq_queue_t g_readytorun;
#ifdef CONFIG_SMP
/* In order to support SMP, the function of the g_readytorun list changes,
* The g_readytorun is still used but in the SMP case it will contain only:
*
* - Only tasks/threads that are eligible to run, but not currently running,
* and
* - Tasks/threads that have not been assigned to a CPU.
*
* Otherwise, the TCB will be retained in an assigned task list,
* g_assignedtasks. As its name suggests, on 'g_assignedtasks queue for CPU
* 'n' would contain only tasks/threads that are assigned to CPU 'n'. Tasks/
* threads would be assigned a particular CPU by one of two mechanisms:
*
* - (Semi-)permanently through an RTOS interfaces such as
* pthread_attr_setaffinity(), or
* - Temporarily through scheduling logic when a previously unassigned task
* is made to run.
*
* Tasks/threads that are assigned to a CPU via an interface like
* pthread_attr_setaffinity() would never go into the g_readytorun list, but
* would only go into the g_assignedtasks[n] list for the CPU 'n' to which
* the thread has been assigned. Hence, the g_readytorun list would hold
* only unassigned tasks/threads.
*
* Like the g_readytorun list in in non-SMP case, each g_assignedtask[] list
* is prioritized: The head of the list is the currently active task on this
* CPU. Tasks after the active task are ready-to-run and assigned to this
* CPU. The tail of this assigned task list, the lowest priority task, is
* always the CPU's IDLE task.
*/
volatile dq_queue_t g_assignedtasks[CONFIG_SMP_NCPUS];
/* g_running_tasks[] holds a references to the running task for each cpu.
* It is valid only when up_interrupt_context() returns true.
*/
FAR struct tcb_s *g_running_tasks[CONFIG_SMP_NCPUS];
#else
FAR struct tcb_s *g_running_tasks[1];
#endif
/* This is the list of all tasks that are ready-to-run, but cannot be placed
* in the g_readytorun list because: (1) They are higher priority than the
* currently active task at the head of the g_readytorun list, and (2) the
* currently active task has disabled pre-emption.
*/
volatile dq_queue_t g_pendingtasks;
/* This is the list of all tasks that are blocked waiting for a semaphore */
volatile dq_queue_t g_waitingforsemaphore;
#ifndef CONFIG_DISABLE_SIGNALS
/* This is the list of all tasks that are blocked waiting for a signal */
volatile dq_queue_t g_waitingforsignal;
#endif
#ifndef CONFIG_DISABLE_MQUEUE
/* This is the list of all tasks that are blocked waiting for a message
* queue to become non-empty.
*/
volatile dq_queue_t g_waitingformqnotempty;
#endif
#ifndef CONFIG_DISABLE_MQUEUE
/* This is the list of all tasks that are blocked waiting for a message
* queue to become non-full.
*/
volatile dq_queue_t g_waitingformqnotfull;
#endif
#ifdef CONFIG_PAGING
/* This is the list of all tasks that are blocking waiting for a page fill */
volatile dq_queue_t g_waitingforfill;
#endif
#ifdef CONFIG_SIG_SIGSTOP_ACTION
/* This is the list of all tasks that have been stopped via SIGSTOP or SIGSTP */
volatile dq_queue_t g_stoppedtasks;
#endif
/* This the list of all tasks that have been initialized, but not yet
* activated. NOTE: This is the only list that is not prioritized.
*/
volatile dq_queue_t g_inactivetasks;
#if (defined(CONFIG_BUILD_PROTECTED) || defined(CONFIG_BUILD_KERNEL)) && \
defined(CONFIG_MM_KERNEL_HEAP)
/* These are lists of delayed memory deallocations that need to be handled
* within the IDLE loop or worker thread. These deallocations get queued
* by sched_kufree and sched_kfree() if the OS needs to deallocate memory
* while it is within an interrupt handler.
*/
volatile sq_queue_t g_delayed_kfree;
#endif
#ifndef CONFIG_BUILD_KERNEL
/* REVISIT: It is not safe to defer user allocation in the kernel mode
* build. Why? Because the correct user context will not be in place
* when these deferred de-allocations are performed. In order to make this
* work, we would need to do something like: (1) move g_delayed_kufree
* into the group structure, then traverse the groups to collect garbage
* on a group-by-group basis.
*/
volatile sq_queue_t g_delayed_kufree;
#endif
/* This is the value of the last process ID assigned to a task */
volatile pid_t g_lastpid;
/* The following hash table is used for two things:
*
* 1. This hash table greatly speeds the determination of a new unique
* process ID for a task, and
* 2. Is used to quickly map a process ID into a TCB.
*
* It has the side effects of using more memory and limiting
* the number of tasks to CONFIG_MAX_TASKS.
*/
struct pidhash_s g_pidhash[CONFIG_MAX_TASKS];
/* This is a table of task lists. This table is indexed by the task stat
* enumeration type (tstate_t) and provides a pointer to the associated
* static task list (if there is one) as well as a a set of attribute flags
* indicating properties of the list, for example, if the list is an
* ordered list or not.
*/
const struct tasklist_s g_tasklisttable[NUM_TASK_STATES] =
{
{ /* TSTATE_TASK_INVALID */
NULL,
0
},
{ /* TSTATE_TASK_PENDING */
&g_pendingtasks,
TLIST_ATTR_PRIORITIZED
},
#ifdef CONFIG_SMP
{ /* TSTATE_TASK_READYTORUN */
&g_readytorun,
TLIST_ATTR_PRIORITIZED
},
{ /* TSTATE_TASK_ASSIGNED */
g_assignedtasks,
TLIST_ATTR_PRIORITIZED | TLIST_ATTR_INDEXED | TLIST_ATTR_RUNNABLE
},
{ /* TSTATE_TASK_RUNNING */
g_assignedtasks,
TLIST_ATTR_PRIORITIZED | TLIST_ATTR_INDEXED | TLIST_ATTR_RUNNABLE
},
#else
{ /* TSTATE_TASK_READYTORUN */
&g_readytorun,
TLIST_ATTR_PRIORITIZED | TLIST_ATTR_RUNNABLE
},
{ /* TSTATE_TASK_RUNNING */
&g_readytorun,
TLIST_ATTR_PRIORITIZED | TLIST_ATTR_RUNNABLE
},
#endif
{ /* TSTATE_TASK_INACTIVE */
&g_inactivetasks,
0
},
{ /* TSTATE_WAIT_SEM */
&g_waitingforsemaphore,
TLIST_ATTR_PRIORITIZED
}
#ifndef CONFIG_DISABLE_SIGNALS
,
{ /* TSTATE_WAIT_SIG */
&g_waitingforsignal,
0
}
#endif
#ifndef CONFIG_DISABLE_MQUEUE
,
{ /* TSTATE_WAIT_MQNOTEMPTY */
&g_waitingformqnotempty,
TLIST_ATTR_PRIORITIZED
},
{ /* TSTATE_WAIT_MQNOTFULL */
&g_waitingformqnotfull,
TLIST_ATTR_PRIORITIZED
}
#endif
#ifdef CONFIG_PAGING
,
{ /* TSTATE_WAIT_PAGEFILL */
&g_waitingforfill,
TLIST_ATTR_PRIORITIZED
}
#endif
#ifdef CONFIG_SIG_SIGSTOP_ACTION
,
{ /* TSTATE_TASK_STOPPED */
&g_stoppedtasks,
0 /* See tcb->prev_state */
},
#endif
};
/* This is the current initialization state. The level of initialization
* is only important early in the start-up sequence when certain OS or
* hardware resources may not yet be available to the kernel logic.
*/
uint8_t g_os_initstate; /* See enum os_initstate_e */
/****************************************************************************
* Private Data
****************************************************************************/
/* This is an array of task control block (TCB) for the IDLE thread of each
* CPU. For the non-SMP case, this is a a single TCB; For the SMP case,
* there is one TCB per CPU. NOTE: The system boots on CPU0 into the IDLE
* task. The IDLE task later starts the other CPUs and spawns the user
* initialization task. That user initialization task is responsible for
* bringing up the rest of the system.
*/
#ifdef CONFIG_SMP
static struct task_tcb_s g_idletcb[CONFIG_SMP_NCPUS];
#else
static struct task_tcb_s g_idletcb[1];
#endif
/* This is the name of the idle task */
#if CONFIG_TASK_NAME_SIZE <= 0 || !defined(CONFIG_SMP)
#ifdef CONFIG_SMP
static const char g_idlename[] = "CPU Idle";
#else
static const char g_idlename[] = "Idle Task";
#endif
#endif
/* This the IDLE idle threads argument list. NOTE: Normally the argument
* list is created on the stack prior to starting the task. We have to
* do things s little differently here for the IDLE tasks.
*/
#ifdef CONFIG_SMP
static FAR char *g_idleargv[CONFIG_SMP_NCPUS][2];
#else
static FAR char *g_idleargv[1][2];
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: os_start
*
* Description:
* This function is called to initialize the operating system and to spawn
* the user initialization thread of execution. This is the initial entry
* point into NuttX
*
* Input Parameters:
* None
*
* Returned Value:
* Does not return.
*
****************************************************************************/
void os_start(void)
{
#ifdef CONFIG_SMP
int cpu;
#else
# define cpu 0
#endif
int i;
sinfo("Entry\n");
/* Boot up is complete */
g_os_initstate = OSINIT_BOOT;
/* Initialize RTOS Data ***************************************************/
/* Initialize all task lists */
dq_init(&g_readytorun);
dq_init(&g_pendingtasks);
dq_init(&g_waitingforsemaphore);
#ifndef CONFIG_DISABLE_SIGNALS
dq_init(&g_waitingforsignal);
#endif
#ifndef CONFIG_DISABLE_MQUEUE
dq_init(&g_waitingformqnotfull);
dq_init(&g_waitingformqnotempty);
#endif
#ifdef CONFIG_PAGING
dq_init(&g_waitingforfill);
#endif
#ifdef CONFIG_SIG_SIGSTOP_ACTION
dq_init(&g_stoppedtasks);
#endif
dq_init(&g_inactivetasks);
#if (defined(CONFIG_BUILD_PROTECTED) || defined(CONFIG_BUILD_KERNEL)) && \
defined(CONFIG_MM_KERNEL_HEAP)
sq_init(&g_delayed_kfree);
#endif
#ifndef CONFIG_BUILD_KERNEL
sq_init(&g_delayed_kufree);
#endif
#ifdef CONFIG_SMP
for (i = 0; i < CONFIG_SMP_NCPUS; i++)
{
dq_init(&g_assignedtasks[i]);
}
#endif
/* Initialize the logic that determine unique process IDs. */
g_lastpid = 0;
for (i = 0; i < CONFIG_MAX_TASKS; i++)
{
g_pidhash[i].tcb = NULL;
g_pidhash[i].pid = INVALID_PROCESS_ID;
}
/* Initialize the IDLE task TCB *******************************************/
#ifdef CONFIG_SMP
for (cpu = 0; cpu < CONFIG_SMP_NCPUS; cpu++, g_lastpid++)
#endif
{
FAR dq_queue_t *tasklist;
int hashndx;
/* Assign the process ID(s) of ZERO to the idle task(s) */
hashndx = PIDHASH(g_lastpid);
g_pidhash[hashndx].tcb = &g_idletcb[cpu].cmn;
g_pidhash[hashndx].pid = g_lastpid;
/* Initialize a TCB for this thread of execution. NOTE: The default
* value for most components of the g_idletcb are zero. The entire
* structure is set to zero. Then only the (potentially) non-zero
* elements are initialized. NOTE: The idle task is the only task in
* that has pid == 0 and sched_priority == 0.
*/
memset((void *)&g_idletcb[cpu], 0, sizeof(struct task_tcb_s));
g_idletcb[cpu].cmn.pid = g_lastpid;
g_idletcb[cpu].cmn.task_state = TSTATE_TASK_RUNNING;
/* Set the entry point. This is only for debug purposes. NOTE: that
* the start_t entry point is not saved. That is acceptable, however,
* becaue it can be used only for restarting a task: The IDLE task
* cannot be restarted.
*/
#ifdef CONFIG_SMP
if (cpu > 0)
{
g_idletcb[cpu].cmn.start = os_idle_trampoline;
g_idletcb[cpu].cmn.entry.main = os_idle_task;
}
else
#endif
{
g_idletcb[cpu].cmn.start = (start_t)os_start;
g_idletcb[cpu].cmn.entry.main = (main_t)os_start;
}
/* Set the task flags to indicate that this is a kernel thread and, if
* configured for SMP, that this task is locked to this CPU.
*/
#ifdef CONFIG_SMP
g_idletcb[cpu].cmn.flags = (TCB_FLAG_TTYPE_KERNEL | TCB_FLAG_NONCANCELABLE |
TCB_FLAG_CPU_LOCKED);
g_idletcb[cpu].cmn.cpu = cpu;
#else
g_idletcb[cpu].cmn.flags = (TCB_FLAG_TTYPE_KERNEL | TCB_FLAG_NONCANCELABLE);
#endif
#ifdef CONFIG_SMP
/* Set the affinity mask to allow the thread to run on all CPUs. No,
* this IDLE thread can only run on its assigned CPU. That is
* enforced by the TCB_FLAG_CPU_LOCKED which overrides the affinity
* mask. This is essential because all tasks inherit the affinity
* mask from their parent and, ultimately, the parent of all tasks is
* the IDLE task.
*/
g_idletcb[cpu].cmn.affinity = SCHED_ALL_CPUS;
#endif
#if CONFIG_TASK_NAME_SIZE > 0
/* Set the IDLE task name */
# ifdef CONFIG_SMP
snprintf(g_idletcb[cpu].cmn.name, CONFIG_TASK_NAME_SIZE, "CPU%d IDLE", cpu);
# else
strncpy(g_idletcb[cpu].cmn.name, g_idlename, CONFIG_TASK_NAME_SIZE);
g_idletcb[cpu].cmn.name[CONFIG_TASK_NAME_SIZE] = '\0';
# endif
#endif
/* Configure the task name in the argument list. The IDLE task does
* not really have an argument list, but this name is still useful
* for things like the NSH PS command.
*
* In the kernel mode build, the arguments are saved on the task's
* stack and there is no support that yet.
*/
#if CONFIG_TASK_NAME_SIZE > 0
g_idleargv[cpu][0] = g_idletcb[cpu].cmn.name;
#else
g_idleargv[cpu][0] = (FAR char *)g_idlename;
#endif /* CONFIG_TASK_NAME_SIZE */
g_idleargv[cpu][1] = NULL;
g_idletcb[cpu].argv = &g_idleargv[cpu][0];
/* Then add the idle task's TCB to the head of the corrent ready to
* run list.
*/
#ifdef CONFIG_SMP
tasklist = TLIST_HEAD(TSTATE_TASK_RUNNING, cpu);
#else
tasklist = TLIST_HEAD(TSTATE_TASK_RUNNING);
#endif
dq_addfirst((FAR dq_entry_t *)&g_idletcb[cpu], tasklist);
/* Mark the idle task as the running task */
g_running_tasks[cpu] = &g_idletcb[cpu].cmn;
/* Initialize the processor-specific portion of the TCB */
up_initial_state(&g_idletcb[cpu].cmn);
}
/* Task lists are initialized */
g_os_initstate = OSINIT_TASKLISTS;
/* Initialize RTOS facilities *********************************************/
/* Initialize the semaphore facility. This has to be done very early
* because many subsystems depend upon fully functional semaphores.
*/
nxsem_initialize();
#if defined(MM_KERNEL_USRHEAP_INIT) || defined(CONFIG_MM_KERNEL_HEAP) || \
defined(CONFIG_MM_PGALLOC)
/* Initialize the memory manager */
{
FAR void *heap_start;
size_t heap_size;
#ifdef MM_KERNEL_USRHEAP_INIT
/* Get the user-mode heap from the platform specific code and configure
* the user-mode memory allocator.
*/
up_allocate_heap(&heap_start, &heap_size);
kumm_initialize(heap_start, heap_size);
#endif
#ifdef CONFIG_MM_KERNEL_HEAP
/* Get the kernel-mode heap from the platform specific code and configure
* the kernel-mode memory allocator.
*/
up_allocate_kheap(&heap_start, &heap_size);
kmm_initialize(heap_start, heap_size);
#endif
#ifdef CONFIG_MM_PGALLOC
/* If there is a page allocator in the configuration, then get the page
* heap information from the platform-specific code and configure the
* page allocator.
*/
up_allocate_pgheap(&heap_start, &heap_size);
mm_pginitialize(heap_start, heap_size);
#endif
}
#endif
/* The memory manager is available */
g_os_initstate = OSINIT_MEMORY;
#if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS)
/* Initialize tasking data structures */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (task_initialize != NULL)
#endif
{
task_initialize();
}
#endif
/* Initialize the interrupt handling subsystem (if included) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (irq_initialize != NULL)
#endif
{
irq_initialize();
}
/* Initialize the watchdog facility (if included in the link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (wd_initialize != NULL)
#endif
{
wd_initialize();
}
/* Initialize the POSIX timer facility (if included in the link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (clock_initialize != NULL)
#endif
{
clock_initialize();
}
#ifndef CONFIG_DISABLE_POSIX_TIMERS
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (timer_initialize != NULL)
#endif
{
timer_initialize();
}
#endif
#ifndef CONFIG_DISABLE_SIGNALS
/* Initialize the signal facility (if in link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (nxsig_initialize != NULL)
#endif
{
nxsig_initialize();
}
#endif
#ifndef CONFIG_DISABLE_MQUEUE
/* Initialize the named message queue facility (if in link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (nxmq_initialize != NULL)
#endif
{
nxmq_initialize();
}
#endif
#ifndef CONFIG_DISABLE_PTHREAD
/* Initialize the thread-specific data facility (if in link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (pthread_initialize != NULL)
#endif
{
pthread_initialize();
}
#endif
#if CONFIG_NFILE_DESCRIPTORS > 0
/* Initialize the file system (needed to support device drivers) */
fs_initialize();
#endif
#ifdef CONFIG_NET
/* Initialize the networking system */
net_initialize();
#endif
/* The processor specific details of running the operating system
* will be handled here. Such things as setting up interrupt
* service routines and starting the clock are some of the things
* that are different for each processor and hardware platform.
*/
up_initialize();
/* Hardware resources are available */
g_os_initstate = OSINIT_HARDWARE;
#ifdef CONFIG_MM_SHM
/* Initialize shared memory support */
shm_initialize();
#endif
/* Initialize the C libraries. This is done last because the libraries
* may depend on the above.
*/
lib_initialize();
#ifndef CONFIG_BINFMT_DISABLE
/* Initialize the binfmt system */
binfmt_initialize();
#endif
/* IDLE Group Initialization **********************************************/
/* Announce that the CPU0 IDLE task has started */
sched_note_start(&g_idletcb[0].cmn);
#ifdef CONFIG_SMP
/* Initialize the IDLE group for the IDLE task of each CPU */
for (cpu = 0; cpu < CONFIG_SMP_NCPUS; cpu++)
#endif
{
#ifdef HAVE_TASK_GROUP
/* Allocate the IDLE group */
DEBUGVERIFY(group_allocate(&g_idletcb[cpu], g_idletcb[cpu].cmn.flags));
#endif
#if CONFIG_NFILE_DESCRIPTORS > 0 || CONFIG_NSOCKET_DESCRIPTORS > 0
#ifdef CONFIG_SMP
if (cpu > 0)
{
/* Clone stdout, stderr, stdin from the CPU0 IDLE task. */
DEBUGVERIFY(group_setuptaskfiles(&g_idletcb[cpu]));
}
else
#endif
{
/* Create stdout, stderr, stdin on the CPU0 IDLE task. These
* will be inherited by all of the threads created by the CPU0
* IDLE task.
*/
DEBUGVERIFY(group_setupidlefiles(&g_idletcb[cpu]));
}
#endif
#ifdef HAVE_TASK_GROUP
/* Complete initialization of the IDLE group. Suppress retention
* of child status in the IDLE group.
*/
DEBUGVERIFY(group_initialize(&g_idletcb[cpu]));
g_idletcb[cpu].cmn.group->tg_flags = GROUP_FLAG_NOCLDWAIT;
#endif
}
/* Start SYSLOG ***********************************************************/
/* Late initialization of the system logging device. Some SYSLOG channel
* must be initialized late in the initialization sequence because it may
* depend on having IDLE task file structures setup.
*/
syslog_initialize(SYSLOG_INIT_LATE);
#ifdef CONFIG_SMP
/* Start all CPUs *********************************************************/
/* A few basic sanity checks */
DEBUGASSERT(this_cpu() == 0 && CONFIG_MAX_TASKS > CONFIG_SMP_NCPUS);
/* Take the memory manager semaphore on this CPU so that it will not be
* available on the other CPUs until we have finished initialization.
*/
DEBUGVERIFY(kmm_trysemaphore());
/* Then start the other CPUs */
DEBUGVERIFY(os_smp_start());
#endif /* CONFIG_SMP */
/* Bring Up the System ****************************************************/
/* The OS is fully initialized and we are beginning multi-tasking */
g_os_initstate = OSINIT_OSREADY;
/* Create initial tasks and bring-up the system */
DEBUGVERIFY(os_bringup());
#ifdef CONFIG_SMP
/* Let other threads have access to the memory manager */
kmm_givesemaphore();
#endif /* CONFIG_SMP */
/* The IDLE Loop **********************************************************/
/* When control is return to this point, the system is idle. */
sinfo("CPU0: Beginning Idle Loop\n");
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. Imaginee 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();
}
}
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