smpboot_32.c

linux 内核源代码

{
	/*
	 * We don't actually need to load the full TSS,
	 * basically just the stack pointer and the eip.
	 */

	asm volatile(
		"movl %0,%%esp\n\t"
		"jmp *%1"
		:
		:"m" (current->thread.esp),"m" (current->thread.eip));
}

/* Static state in head.S used to set up a CPU */
extern struct {
	void * esp;
	unsigned short ss;
} stack_start;

#ifdef CONFIG_NUMA

/* which logical CPUs are on which nodes */
cpumask_t node_2_cpu_mask[MAX_NUMNODES] __read_mostly =
				{ [0 ... MAX_NUMNODES-1] = CPU_MASK_NONE };
EXPORT_SYMBOL(node_2_cpu_mask);
/* which node each logical CPU is on */
int cpu_2_node[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = 0 };
EXPORT_SYMBOL(cpu_2_node);

/* set up a mapping between cpu and node. */
static inline void map_cpu_to_node(int cpu, int node)
{
	printk("Mapping cpu %d to node %d\n", cpu, node);
	cpu_set(cpu, node_2_cpu_mask[node]);
	cpu_2_node[cpu] = node;
}

/* undo a mapping between cpu and node. */
static inline void unmap_cpu_to_node(int cpu)
{
	int node;

	printk("Unmapping cpu %d from all nodes\n", cpu);
	for (node = 0; node < MAX_NUMNODES; node ++)
		cpu_clear(cpu, node_2_cpu_mask[node]);
	cpu_2_node[cpu] = 0;
}
#else /* !CONFIG_NUMA */

#define map_cpu_to_node(cpu, node)	({})
#define unmap_cpu_to_node(cpu)	({})

#endif /* CONFIG_NUMA */

u8 cpu_2_logical_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = BAD_APICID };

static void map_cpu_to_logical_apicid(void)
{
	int cpu = smp_processor_id();
	int apicid = logical_smp_processor_id();
	int node = apicid_to_node(apicid);

	if (!node_online(node))
		node = first_online_node;

	cpu_2_logical_apicid[cpu] = apicid;
	map_cpu_to_node(cpu, node);
}

static void unmap_cpu_to_logical_apicid(int cpu)
{
	cpu_2_logical_apicid[cpu] = BAD_APICID;
	unmap_cpu_to_node(cpu);
}

static inline void __inquire_remote_apic(int apicid)
{
	int i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
	char *names[] = { "ID", "VERSION", "SPIV" };
	int timeout;
	unsigned long status;

	printk("Inquiring remote APIC #%d...\n", apicid);

	for (i = 0; i < ARRAY_SIZE(regs); i++) {
		printk("... APIC #%d %s: ", apicid, names[i]);

		/*
		 * Wait for idle.
		 */
		status = safe_apic_wait_icr_idle();
		if (status)
			printk("a previous APIC delivery may have failed\n");

		apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(apicid));
		apic_write_around(APIC_ICR, APIC_DM_REMRD | regs[i]);

		timeout = 0;
		do {
			udelay(100);
			status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK;
		} while (status == APIC_ICR_RR_INPROG && timeout++ < 1000);

		switch (status) {
		case APIC_ICR_RR_VALID:
			status = apic_read(APIC_RRR);
			printk("%lx\n", status);
			break;
		default:
			printk("failed\n");
		}
	}
}

#ifdef WAKE_SECONDARY_VIA_NMI
/* 
 * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
 * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
 * won't ... remember to clear down the APIC, etc later.
 */
static int __devinit
wakeup_secondary_cpu(int logical_apicid, unsigned long start_eip)
{
	unsigned long send_status, accept_status = 0;
	int maxlvt;

	/* Target chip */
	apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(logical_apicid));

	/* Boot on the stack */
	/* Kick the second */
	apic_write_around(APIC_ICR, APIC_DM_NMI | APIC_DEST_LOGICAL);

	Dprintk("Waiting for send to finish...\n");
	send_status = safe_apic_wait_icr_idle();

	/*
	 * Give the other CPU some time to accept the IPI.
	 */
	udelay(200);
	/*
	 * Due to the Pentium erratum 3AP.
	 */
	maxlvt = lapic_get_maxlvt();
	if (maxlvt > 3) {
		apic_read_around(APIC_SPIV);
		apic_write(APIC_ESR, 0);
	}
	accept_status = (apic_read(APIC_ESR) & 0xEF);
	Dprintk("NMI sent.\n");

	if (send_status)
		printk("APIC never delivered???\n");
	if (accept_status)
		printk("APIC delivery error (%lx).\n", accept_status);

	return (send_status | accept_status);
}
#endif	/* WAKE_SECONDARY_VIA_NMI */

#ifdef WAKE_SECONDARY_VIA_INIT
static int __devinit
wakeup_secondary_cpu(int phys_apicid, unsigned long start_eip)
{
	unsigned long send_status, accept_status = 0;
	int maxlvt, num_starts, j;

	/*
	 * Be paranoid about clearing APIC errors.
	 */
	if (APIC_INTEGRATED(apic_version[phys_apicid])) {
		apic_read_around(APIC_SPIV);
		apic_write(APIC_ESR, 0);
		apic_read(APIC_ESR);
	}

	Dprintk("Asserting INIT.\n");

	/*
	 * Turn INIT on target chip
	 */
	apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));

	/*
	 * Send IPI
	 */
	apic_write_around(APIC_ICR, APIC_INT_LEVELTRIG | APIC_INT_ASSERT
				| APIC_DM_INIT);

	Dprintk("Waiting for send to finish...\n");
	send_status = safe_apic_wait_icr_idle();

	mdelay(10);

	Dprintk("Deasserting INIT.\n");

	/* Target chip */
	apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));

	/* Send IPI */
	apic_write_around(APIC_ICR, APIC_INT_LEVELTRIG | APIC_DM_INIT);

	Dprintk("Waiting for send to finish...\n");
	send_status = safe_apic_wait_icr_idle();

	atomic_set(&init_deasserted, 1);

	/*
	 * Should we send STARTUP IPIs ?
	 *
	 * Determine this based on the APIC version.
	 * If we don't have an integrated APIC, don't send the STARTUP IPIs.
	 */
	if (APIC_INTEGRATED(apic_version[phys_apicid]))
		num_starts = 2;
	else
		num_starts = 0;

	/*
	 * Paravirt / VMI wants a startup IPI hook here to set up the
	 * target processor state.
	 */
	startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
		         (unsigned long) stack_start.esp);

	/*
	 * Run STARTUP IPI loop.
	 */
	Dprintk("#startup loops: %d.\n", num_starts);

	maxlvt = lapic_get_maxlvt();

	for (j = 1; j <= num_starts; j++) {
		Dprintk("Sending STARTUP #%d.\n",j);
		apic_read_around(APIC_SPIV);
		apic_write(APIC_ESR, 0);
		apic_read(APIC_ESR);
		Dprintk("After apic_write.\n");

		/*
		 * STARTUP IPI
		 */

		/* Target chip */
		apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));

		/* Boot on the stack */
		/* Kick the second */
		apic_write_around(APIC_ICR, APIC_DM_STARTUP
					| (start_eip >> 12));

		/*
		 * Give the other CPU some time to accept the IPI.
		 */
		udelay(300);

		Dprintk("Startup point 1.\n");

		Dprintk("Waiting for send to finish...\n");
		send_status = safe_apic_wait_icr_idle();

		/*
		 * Give the other CPU some time to accept the IPI.
		 */
		udelay(200);
		/*
		 * Due to the Pentium erratum 3AP.
		 */
		if (maxlvt > 3) {
			apic_read_around(APIC_SPIV);
			apic_write(APIC_ESR, 0);
		}
		accept_status = (apic_read(APIC_ESR) & 0xEF);
		if (send_status || accept_status)
			break;
	}
	Dprintk("After Startup.\n");

	if (send_status)
		printk("APIC never delivered???\n");
	if (accept_status)
		printk("APIC delivery error (%lx).\n", accept_status);

	return (send_status | accept_status);
}
#endif	/* WAKE_SECONDARY_VIA_INIT */

extern cpumask_t cpu_initialized;
static inline int alloc_cpu_id(void)
{
	cpumask_t	tmp_map;
	int cpu;
	cpus_complement(tmp_map, cpu_present_map);
	cpu = first_cpu(tmp_map);
	if (cpu >= NR_CPUS)
		return -ENODEV;
	return cpu;
}

#ifdef CONFIG_HOTPLUG_CPU
static struct task_struct * __cpuinitdata cpu_idle_tasks[NR_CPUS];
static inline struct task_struct * __cpuinit alloc_idle_task(int cpu)
{
	struct task_struct *idle;

	if ((idle = cpu_idle_tasks[cpu]) != NULL) {
		/* initialize thread_struct.  we really want to avoid destroy
		 * idle tread
		 */
		idle->thread.esp = (unsigned long)task_pt_regs(idle);
		init_idle(idle, cpu);
		return idle;
	}
	idle = fork_idle(cpu);

	if (!IS_ERR(idle))
		cpu_idle_tasks[cpu] = idle;
	return idle;
}
#else
#define alloc_idle_task(cpu) fork_idle(cpu)
#endif

static int __cpuinit do_boot_cpu(int apicid, int cpu)
/*
 * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
 * (ie clustered apic addressing mode), this is a LOGICAL apic ID.
 * Returns zero if CPU booted OK, else error code from wakeup_secondary_cpu.
 */
{
	struct task_struct *idle;
	unsigned long boot_error;
	int timeout;
	unsigned long start_eip;
	unsigned short nmi_high = 0, nmi_low = 0;

	/*
	 * Save current MTRR state in case it was changed since early boot
	 * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
	 */
	mtrr_save_state();

	/*
	 * We can't use kernel_thread since we must avoid to
	 * reschedule the child.
	 */
	idle = alloc_idle_task(cpu);
	if (IS_ERR(idle))
		panic("failed fork for CPU %d", cpu);

	init_gdt(cpu);
 	per_cpu(current_task, cpu) = idle;
	early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);

	idle->thread.eip = (unsigned long) start_secondary;
	/* start_eip had better be page-aligned! */
	start_eip = setup_trampoline();

	++cpucount;
	alternatives_smp_switch(1);

	/* So we see what's up   */
	printk("Booting processor %d/%d eip %lx\n", cpu, apicid, start_eip);
	/* Stack for startup_32 can be just as for start_secondary onwards */
	stack_start.esp = (void *) idle->thread.esp;

	irq_ctx_init(cpu);

	per_cpu(x86_cpu_to_apicid, cpu) = apicid;
	/*
	 * This grunge runs the startup process for
	 * the targeted processor.
	 */

	atomic_set(&init_deasserted, 0);

	Dprintk("Setting warm reset code and vector.\n");

	store_NMI_vector(&nmi_high, &nmi_low);

	smpboot_setup_warm_reset_vector(start_eip);

	/*
	 * Starting actual IPI sequence...
	 */
	boot_error = wakeup_secondary_cpu(apicid, start_eip);

	if (!boot_error) {
		/*
		 * allow APs to start initializing.
		 */
		Dprintk("Before Callout %d.\n", cpu);
		cpu_set(cpu, cpu_callout_map);
		Dprintk("After Callout %d.\n", cpu);

		/*
		 * Wait 5s total for a response
		 */
		for (timeout = 0; timeout < 50000; timeout++) {
			if (cpu_isset(cpu, cpu_callin_map))
				break;	/* It has booted */
			udelay(100);
		}

		if (cpu_isset(cpu, cpu_callin_map)) {
			/* number CPUs logically, starting from 1 (BSP is 0) */
			Dprintk("OK.\n");
			printk("CPU%d: ", cpu);
			print_cpu_info(&cpu_data(cpu));
			Dprintk("CPU has booted.\n");
		} else {
			boot_error= 1;
			if (*((volatile unsigned char *)trampoline_base)
					== 0xA5)
				/* trampoline started but...? */
				printk("Stuck ??\n");
			else
				/* trampoline code not run */
				printk("Not responding.\n");
			inquire_remote_apic(apicid);
		}
	}

	if (boot_error) {
		/* Try to put things back the way they were before ... */
		unmap_cpu_to_logical_apicid(cpu);
		cpu_clear(cpu, cpu_callout_map); /* was set here (do_boot_cpu()) */
		cpu_clear(cpu, cpu_initialized); /* was set by cpu_init() */
		cpucount--;
	} else {
		per_cpu(x86_cpu_to_apicid, cpu) = apicid;
		cpu_set(cpu, cpu_present_map);
	}

	/* mark "stuck" area as not stuck */
	*((volatile unsigned long *)trampoline_base) = 0;

	return boot_error;
}

#ifdef CONFIG_HOTPLUG_CPU
void cpu_exit_clear(void)
{
	int cpu = raw_smp_processor_id();

	idle_task_exit();