Revision af8f3f514d193eb353f9b6cea503c55d074e6153 authored by Hanjun Guo on 04 January 2015, 10:55:02 UTC, committed by Rafael J. Wysocki on 05 January 2015, 22:32:42 UTC
apic_id in MADT table is the CPU hardware id which identify it self in the system for x86 and ia64, OSPM will use it for SMP init to map APIC ID to logical cpu number in the early boot, when the DSDT/SSDT (ACPI namespace) is scanned later, the ACPI processor driver is probed and the driver will use acpi_id in DSDT to get the apic_id, then map to the logical cpu number which is needed by the processor driver. Before ACPI 5.0, only x86 and ia64 were supported in ACPI spec, so apic_id is used both in arch code and ACPI core which is pretty fine. Since ACPI 5.0, ARM is supported by ACPI and APIC is not available on ARM, this will confuse people when apic_id is both used by x86 and ARM in one function. So convert apic_id to phys_id (which is the original meaning) in ACPI processor dirver to make it arch agnostic, but leave the arch dependent code unchanged, no functional change. Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
1 parent b7392d2
smpboot.c
/*
* Common SMP CPU bringup/teardown functions
*/
#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/kthread.h>
#include <linux/smpboot.h>
#include "smpboot.h"
#ifdef CONFIG_SMP
#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
/*
* For the hotplug case we keep the task structs around and reuse
* them.
*/
static DEFINE_PER_CPU(struct task_struct *, idle_threads);
struct task_struct *idle_thread_get(unsigned int cpu)
{
struct task_struct *tsk = per_cpu(idle_threads, cpu);
if (!tsk)
return ERR_PTR(-ENOMEM);
init_idle(tsk, cpu);
return tsk;
}
void __init idle_thread_set_boot_cpu(void)
{
per_cpu(idle_threads, smp_processor_id()) = current;
}
/**
* idle_init - Initialize the idle thread for a cpu
* @cpu: The cpu for which the idle thread should be initialized
*
* Creates the thread if it does not exist.
*/
static inline void idle_init(unsigned int cpu)
{
struct task_struct *tsk = per_cpu(idle_threads, cpu);
if (!tsk) {
tsk = fork_idle(cpu);
if (IS_ERR(tsk))
pr_err("SMP: fork_idle() failed for CPU %u\n", cpu);
else
per_cpu(idle_threads, cpu) = tsk;
}
}
/**
* idle_threads_init - Initialize idle threads for all cpus
*/
void __init idle_threads_init(void)
{
unsigned int cpu, boot_cpu;
boot_cpu = smp_processor_id();
for_each_possible_cpu(cpu) {
if (cpu != boot_cpu)
idle_init(cpu);
}
}
#endif
#endif /* #ifdef CONFIG_SMP */
static LIST_HEAD(hotplug_threads);
static DEFINE_MUTEX(smpboot_threads_lock);
struct smpboot_thread_data {
unsigned int cpu;
unsigned int status;
struct smp_hotplug_thread *ht;
};
enum {
HP_THREAD_NONE = 0,
HP_THREAD_ACTIVE,
HP_THREAD_PARKED,
};
/**
* smpboot_thread_fn - percpu hotplug thread loop function
* @data: thread data pointer
*
* Checks for thread stop and park conditions. Calls the necessary
* setup, cleanup, park and unpark functions for the registered
* thread.
*
* Returns 1 when the thread should exit, 0 otherwise.
*/
static int smpboot_thread_fn(void *data)
{
struct smpboot_thread_data *td = data;
struct smp_hotplug_thread *ht = td->ht;
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
preempt_disable();
if (kthread_should_stop()) {
__set_current_state(TASK_RUNNING);
preempt_enable();
if (ht->cleanup)
ht->cleanup(td->cpu, cpu_online(td->cpu));
kfree(td);
return 0;
}
if (kthread_should_park()) {
__set_current_state(TASK_RUNNING);
preempt_enable();
if (ht->park && td->status == HP_THREAD_ACTIVE) {
BUG_ON(td->cpu != smp_processor_id());
ht->park(td->cpu);
td->status = HP_THREAD_PARKED;
}
kthread_parkme();
/* We might have been woken for stop */
continue;
}
BUG_ON(td->cpu != smp_processor_id());
/* Check for state change setup */
switch (td->status) {
case HP_THREAD_NONE:
__set_current_state(TASK_RUNNING);
preempt_enable();
if (ht->setup)
ht->setup(td->cpu);
td->status = HP_THREAD_ACTIVE;
continue;
case HP_THREAD_PARKED:
__set_current_state(TASK_RUNNING);
preempt_enable();
if (ht->unpark)
ht->unpark(td->cpu);
td->status = HP_THREAD_ACTIVE;
continue;
}
if (!ht->thread_should_run(td->cpu)) {
preempt_enable_no_resched();
schedule();
} else {
__set_current_state(TASK_RUNNING);
preempt_enable();
ht->thread_fn(td->cpu);
}
}
}
static int
__smpboot_create_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
{
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
struct smpboot_thread_data *td;
if (tsk)
return 0;
td = kzalloc_node(sizeof(*td), GFP_KERNEL, cpu_to_node(cpu));
if (!td)
return -ENOMEM;
td->cpu = cpu;
td->ht = ht;
tsk = kthread_create_on_cpu(smpboot_thread_fn, td, cpu,
ht->thread_comm);
if (IS_ERR(tsk)) {
kfree(td);
return PTR_ERR(tsk);
}
get_task_struct(tsk);
*per_cpu_ptr(ht->store, cpu) = tsk;
if (ht->create) {
/*
* Make sure that the task has actually scheduled out
* into park position, before calling the create
* callback. At least the migration thread callback
* requires that the task is off the runqueue.
*/
if (!wait_task_inactive(tsk, TASK_PARKED))
WARN_ON(1);
else
ht->create(cpu);
}
return 0;
}
int smpboot_create_threads(unsigned int cpu)
{
struct smp_hotplug_thread *cur;
int ret = 0;
mutex_lock(&smpboot_threads_lock);
list_for_each_entry(cur, &hotplug_threads, list) {
ret = __smpboot_create_thread(cur, cpu);
if (ret)
break;
}
mutex_unlock(&smpboot_threads_lock);
return ret;
}
static void smpboot_unpark_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
{
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
if (ht->pre_unpark)
ht->pre_unpark(cpu);
kthread_unpark(tsk);
}
void smpboot_unpark_threads(unsigned int cpu)
{
struct smp_hotplug_thread *cur;
mutex_lock(&smpboot_threads_lock);
list_for_each_entry(cur, &hotplug_threads, list)
smpboot_unpark_thread(cur, cpu);
mutex_unlock(&smpboot_threads_lock);
}
static void smpboot_park_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
{
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
if (tsk && !ht->selfparking)
kthread_park(tsk);
}
void smpboot_park_threads(unsigned int cpu)
{
struct smp_hotplug_thread *cur;
mutex_lock(&smpboot_threads_lock);
list_for_each_entry_reverse(cur, &hotplug_threads, list)
smpboot_park_thread(cur, cpu);
mutex_unlock(&smpboot_threads_lock);
}
static void smpboot_destroy_threads(struct smp_hotplug_thread *ht)
{
unsigned int cpu;
/* We need to destroy also the parked threads of offline cpus */
for_each_possible_cpu(cpu) {
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
if (tsk) {
kthread_stop(tsk);
put_task_struct(tsk);
*per_cpu_ptr(ht->store, cpu) = NULL;
}
}
}
/**
* smpboot_register_percpu_thread - Register a per_cpu thread related to hotplug
* @plug_thread: Hotplug thread descriptor
*
* Creates and starts the threads on all online cpus.
*/
int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread)
{
unsigned int cpu;
int ret = 0;
mutex_lock(&smpboot_threads_lock);
for_each_online_cpu(cpu) {
ret = __smpboot_create_thread(plug_thread, cpu);
if (ret) {
smpboot_destroy_threads(plug_thread);
goto out;
}
smpboot_unpark_thread(plug_thread, cpu);
}
list_add(&plug_thread->list, &hotplug_threads);
out:
mutex_unlock(&smpboot_threads_lock);
return ret;
}
EXPORT_SYMBOL_GPL(smpboot_register_percpu_thread);
/**
* smpboot_unregister_percpu_thread - Unregister a per_cpu thread related to hotplug
* @plug_thread: Hotplug thread descriptor
*
* Stops all threads on all possible cpus.
*/
void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread)
{
get_online_cpus();
mutex_lock(&smpboot_threads_lock);
list_del(&plug_thread->list);
smpboot_destroy_threads(plug_thread);
mutex_unlock(&smpboot_threads_lock);
put_online_cpus();
}
EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread);
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