smpboot.c

h内核

	return 0;
}

struct pt_regs * __devinit idle_regs(struct pt_regs *regs)
{
	return NULL;
}

struct create_idle {
	struct task_struct *idle;
	struct completion done;
	int cpu;
};

void
do_fork_idle(void *_c_idle)
{
	struct create_idle *c_idle = _c_idle;

	c_idle->idle = fork_idle(c_idle->cpu);
	complete(&c_idle->done);
}

static int __devinit
do_boot_cpu (int sapicid, int cpu)
{
	int timeout;
	struct create_idle c_idle = {
		.cpu	= cpu,
		.done	= COMPLETION_INITIALIZER(c_idle.done),
	};
	DECLARE_WORK(work, do_fork_idle, &c_idle);
	/*
	 * We can't use kernel_thread since we must avoid to reschedule the child.
	 */
	if (!keventd_up() || current_is_keventd())
		work.func(work.data);
	else {
		schedule_work(&work);
		wait_for_completion(&c_idle.done);
	}

	if (IS_ERR(c_idle.idle))
		panic("failed fork for CPU %d", cpu);
	task_for_booting_cpu = c_idle.idle;

	Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);

	platform_send_ipi(cpu, ap_wakeup_vector, IA64_IPI_DM_INT, 0);

	/*
	 * Wait 10s total for the AP to start
	 */
	Dprintk("Waiting on callin_map ...");
	for (timeout = 0; timeout < 100000; timeout++) {
		if (cpu_isset(cpu, cpu_callin_map))
			break;  /* It has booted */
		udelay(100);
	}
	Dprintk("\n");

	if (!cpu_isset(cpu, cpu_callin_map)) {
		printk(KERN_ERR "Processor 0x%x/0x%x is stuck.\n", cpu, sapicid);
		ia64_cpu_to_sapicid[cpu] = -1;
		cpu_clear(cpu, cpu_online_map);  /* was set in smp_callin() */
		return -EINVAL;
	}
	return 0;
}

static int __init
decay (char *str)
{
	int ticks;
	get_option (&str, &ticks);
	cache_decay_ticks = ticks;
	return 1;
}

__setup("decay=", decay);

/*
 * # of ticks an idle task is considered cache-hot.  Highly application-dependent.  There
 * are apps out there which are known to suffer significantly with values >= 4.
 */
unsigned long cache_decay_ticks = 10;	/* equal to MIN_TIMESLICE */

static void
smp_tune_scheduling (void)
{
	printk(KERN_INFO "task migration cache decay timeout: %ld msecs.\n",
	       (cache_decay_ticks + 1) * 1000 / HZ);
}

/*
 * Initialize the logical CPU number to SAPICID mapping
 */
void __init
smp_build_cpu_map (void)
{
	int sapicid, cpu, i;
	int boot_cpu_id = hard_smp_processor_id();

	for (cpu = 0; cpu < NR_CPUS; cpu++) {
		ia64_cpu_to_sapicid[cpu] = -1;
#ifdef CONFIG_HOTPLUG_CPU
		cpu_set(cpu, cpu_possible_map);
#endif
	}

	ia64_cpu_to_sapicid[0] = boot_cpu_id;
	cpus_clear(cpu_present_map);
	cpu_set(0, cpu_present_map);
	cpu_set(0, cpu_possible_map);
	for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) {
		sapicid = smp_boot_data.cpu_phys_id[i];
		if (sapicid == boot_cpu_id)
			continue;
		cpu_set(cpu, cpu_present_map);
		cpu_set(cpu, cpu_possible_map);
		ia64_cpu_to_sapicid[cpu] = sapicid;
		cpu++;
	}
}

#ifdef CONFIG_NUMA

/* on which node is each logical CPU (one cacheline even for 64 CPUs) */
u8 cpu_to_node_map[NR_CPUS] __cacheline_aligned;
EXPORT_SYMBOL(cpu_to_node_map);
/* which logical CPUs are on which nodes */
cpumask_t node_to_cpu_mask[MAX_NUMNODES] __cacheline_aligned;

/*
 * Build cpu to node mapping and initialize the per node cpu masks.
 */
void __init
build_cpu_to_node_map (void)
{
	int cpu, i, node;

	for(node=0; node<MAX_NUMNODES; node++)
		cpus_clear(node_to_cpu_mask[node]);
	for(cpu = 0; cpu < NR_CPUS; ++cpu) {
		/*
		 * All Itanium NUMA platforms I know use ACPI, so maybe we
		 * can drop this ifdef completely.                    [EF]
		 */
#ifdef CONFIG_ACPI_NUMA
		node = -1;
		for (i = 0; i < NR_CPUS; ++i)
			if (cpu_physical_id(cpu) == node_cpuid[i].phys_id) {
				node = node_cpuid[i].nid;
				break;
			}
#else
#		error Fixme: Dunno how to build CPU-to-node map.
#endif
		cpu_to_node_map[cpu] = (node >= 0) ? node : 0;
		if (node >= 0)
			cpu_set(cpu, node_to_cpu_mask[node]);
	}
}

#endif /* CONFIG_NUMA */

/*
 * Cycle through the APs sending Wakeup IPIs to boot each.
 */
void __init
smp_prepare_cpus (unsigned int max_cpus)
{
	int boot_cpu_id = hard_smp_processor_id();

	/*
	 * Initialize the per-CPU profiling counter/multiplier
	 */

	smp_setup_percpu_timer();

	/*
	 * We have the boot CPU online for sure.
	 */
	cpu_set(0, cpu_online_map);
	cpu_set(0, cpu_callin_map);

	local_cpu_data->loops_per_jiffy = loops_per_jiffy;
	ia64_cpu_to_sapicid[0] = boot_cpu_id;

	printk(KERN_INFO "Boot processor id 0x%x/0x%x\n", 0, boot_cpu_id);

	current_thread_info()->cpu = 0;
	smp_tune_scheduling();

	/*
	 * If SMP should be disabled, then really disable it!
	 */
	if (!max_cpus) {
		printk(KERN_INFO "SMP mode deactivated.\n");
		cpus_clear(cpu_online_map);
		cpus_clear(cpu_present_map);
		cpus_clear(cpu_possible_map);
		cpu_set(0, cpu_online_map);
		cpu_set(0, cpu_present_map);
		cpu_set(0, cpu_possible_map);
		return;
	}
}

void __devinit smp_prepare_boot_cpu(void)
{
	cpu_set(smp_processor_id(), cpu_online_map);
	cpu_set(smp_processor_id(), cpu_callin_map);
}

#ifdef CONFIG_HOTPLUG_CPU
extern void fixup_irqs(void);
/* must be called with cpucontrol mutex held */
static int __devinit cpu_enable(unsigned int cpu)
{
	per_cpu(cpu_state,cpu) = CPU_UP_PREPARE;
	wmb();

	while (!cpu_online(cpu))
		cpu_relax();
	return 0;
}

int __cpu_disable(void)
{
	int cpu = smp_processor_id();

	/*
	 * dont permit boot processor for now
	 */
	if (cpu == 0)
		return -EBUSY;

	fixup_irqs();
	local_flush_tlb_all();
	printk ("Disabled cpu %u\n", smp_processor_id());
	return 0;
}

void __cpu_die(unsigned int cpu)
{
	unsigned int i;

	for (i = 0; i < 100; i++) {
		/* They ack this in play_dead by setting CPU_DEAD */
		if (per_cpu(cpu_state, cpu) == CPU_DEAD)
		{
			/*
			 * TBD: Enable this when physical removal
			 * or when we put the processor is put in
			 * SAL_BOOT_RENDEZ mode
			 * cpu_clear(cpu, cpu_callin_map);
			 */
			return;
		}
		msleep(100);
	}
 	printk(KERN_ERR "CPU %u didn't die...\n", cpu);
}
#else /* !CONFIG_HOTPLUG_CPU */
static int __devinit cpu_enable(unsigned int cpu)
{
	return 0;
}

int __cpu_disable(void)
{
	return -ENOSYS;
}

void __cpu_die(unsigned int cpu)
{
	/* We said "no" in __cpu_disable */
	BUG();
}
#endif /* CONFIG_HOTPLUG_CPU */

void
smp_cpus_done (unsigned int dummy)
{
	int cpu;
	unsigned long bogosum = 0;

	/*
	 * Allow the user to impress friends.
	 */

	for (cpu = 0; cpu < NR_CPUS; cpu++)
		if (cpu_online(cpu))
			bogosum += cpu_data(cpu)->loops_per_jiffy;

	printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
	       (int)num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100);
}

int __devinit
__cpu_up (unsigned int cpu)
{
	int ret;
	int sapicid;

	sapicid = ia64_cpu_to_sapicid[cpu];
	if (sapicid == -1)
		return -EINVAL;

	/*
	 * Already booted.. just enable and get outa idle lool
	 */
	if (cpu_isset(cpu, cpu_callin_map))
	{
		cpu_enable(cpu);
		local_irq_enable();
		while (!cpu_isset(cpu, cpu_online_map))
			mb();
		return 0;
	}
	/* Processor goes to start_secondary(), sets online flag */
	ret = do_boot_cpu(sapicid, cpu);
	if (ret < 0)
		return ret;

	return 0;
}

/*
 * Assume that CPU's have been discovered by some platform-dependent interface.  For
 * SoftSDV/Lion, that would be ACPI.
 *
 * Setup of the IPI irq handler is done in irq.c:init_IRQ_SMP().
 */
void __init
init_smp_config(void)
{
	struct fptr {
		unsigned long fp;
		unsigned long gp;
	} *ap_startup;
	long sal_ret;

	/* Tell SAL where to drop the AP's.  */
	ap_startup = (struct fptr *) start_ap;
	sal_ret = ia64_sal_set_vectors(SAL_VECTOR_OS_BOOT_RENDEZ,
				       ia64_tpa(ap_startup->fp), ia64_tpa(ap_startup->gp), 0, 0, 0, 0);
	if (sal_ret < 0)
		printk(KERN_ERR "SMP: Can't set SAL AP Boot Rendezvous: %s\n",
		       ia64_sal_strerror(sal_ret));
}