smpboot.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 959 行 · 第 1/2 页

	 *
	 * 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;

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

	maxlvt = 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_rip >> 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");
		timeout = 0;
		do {
			Dprintk("+");
			udelay(100);
			send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
		} while (send_status && (timeout++ < 1000));

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

	return (send_status | accept_status);
}

static void __init do_boot_cpu (int apicid)
{
	struct task_struct *idle;
	unsigned long boot_error;
	int timeout, cpu;
	unsigned long start_rip;

	cpu = ++cpucount;
	/*
	 * We can't use kernel_thread since we must avoid to
	 * reschedule the child.
	 */
	idle = fork_idle(cpu);
	if (IS_ERR(idle))
		panic("failed fork for CPU %d", cpu);
	x86_cpu_to_apicid[cpu] = apicid;

	cpu_pda[cpu].pcurrent = idle;

	start_rip = setup_trampoline();

	init_rsp = idle->thread.rsp; 
	per_cpu(init_tss,cpu).rsp0 = init_rsp;
	initial_code = start_secondary;
	clear_ti_thread_flag(idle->thread_info, TIF_FORK);

	printk(KERN_INFO "Booting processor %d/%d rip %lx rsp %lx\n", cpu, apicid, 
	       start_rip, init_rsp);

	/*
	 * This grunge runs the startup process for
	 * the targeted processor.
	 */

	atomic_set(&init_deasserted, 0);

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

	CMOS_WRITE(0xa, 0xf);
	local_flush_tlb();
	Dprintk("1.\n");
	*((volatile unsigned short *) phys_to_virt(0x469)) = start_rip >> 4;
	Dprintk("2.\n");
	*((volatile unsigned short *) phys_to_virt(0x467)) = start_rip & 0xf;
	Dprintk("3.\n");

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

	/*
	 * Status is now clean
	 */
	boot_error = 0;

	/*
	 * Starting actual IPI sequence...
	 */
	boot_error = wakeup_secondary_via_INIT(apicid, start_rip); 

	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");
			print_cpu_info(&cpu_data[cpu]);
			Dprintk("CPU has booted.\n");
		} else {
			boot_error = 1;
			if (*((volatile unsigned char *)phys_to_virt(SMP_TRAMPOLINE_BASE))
					== 0xA5)
				/* trampoline started but...? */
				printk("Stuck ??\n");
			else
				/* trampoline code not run */
				printk("Not responding.\n");
#if APIC_DEBUG
			inquire_remote_apic(apicid);
#endif
		}
	}
	if (boot_error) {
		cpu_clear(cpu, cpu_callout_map); /* was set here (do_boot_cpu()) */
		clear_bit(cpu, &cpu_initialized); /* was set by cpu_init() */
		cpucount--;
	}
}

cycles_t cacheflush_time;
unsigned long cache_decay_ticks;

static void smp_tune_scheduling (void)
{
	int cachesize;       /* kB   */
	unsigned long bandwidth = 1000; /* MB/s */
	/*
	 * Rough estimation for SMP scheduling, this is the number of
	 * cycles it takes for a fully memory-limited process to flush
	 * the SMP-local cache.
	 *
	 * (For a P5 this pretty much means we will choose another idle
	 *  CPU almost always at wakeup time (this is due to the small
	 *  L1 cache), on PIIs it's around 50-100 usecs, depending on
	 *  the cache size)
	 */

	if (!cpu_khz) {
		/*
		 * this basically disables processor-affinity
		 * scheduling on SMP without a TSC.
		 */
		cacheflush_time = 0;
		return;
	} else {
		cachesize = boot_cpu_data.x86_cache_size;
		if (cachesize == -1) {
			cachesize = 16; /* Pentiums, 2x8kB cache */
			bandwidth = 100;
		}

		cacheflush_time = (cpu_khz>>10) * (cachesize<<10) / bandwidth;
	}

	cache_decay_ticks = (long)cacheflush_time/cpu_khz * HZ / 1000;

	printk(KERN_INFO "per-CPU timeslice cutoff: %ld.%02ld usecs.\n",
		(long)cacheflush_time/(cpu_khz/1000),
		((long)cacheflush_time*100/(cpu_khz/1000)) % 100);
	printk(KERN_INFO "task migration cache decay timeout: %ld msecs.\n",
		(cache_decay_ticks + 1) * 1000 / HZ);
}

/*
 * Cycle through the processors sending APIC IPIs to boot each.
 */

static void __init smp_boot_cpus(unsigned int max_cpus)
{
	unsigned apicid, cpu, bit, kicked;

	nmi_watchdog_default();

	/*
	 * Setup boot CPU information
	 */
	smp_store_cpu_info(0); /* Final full version of the data */
	printk(KERN_INFO "CPU%d: ", 0);
	print_cpu_info(&cpu_data[0]);

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

	if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
		printk("weird, boot CPU (#%d) not listed by the BIOS.\n",
		       hard_smp_processor_id());
		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
	}

	/*
	 * If we couldn't find an SMP configuration at boot time,
	 * get out of here now!
	 */
	if (!smp_found_config) {
		printk(KERN_NOTICE "SMP motherboard not detected.\n");
		io_apic_irqs = 0;
		cpu_online_map = cpumask_of_cpu(0);
		phys_cpu_present_map = physid_mask_of_physid(0);
		if (APIC_init_uniprocessor())
			printk(KERN_NOTICE "Local APIC not detected."
					   " Using dummy APIC emulation.\n");
		goto smp_done;
	}

	/*
	 * Should not be necessary because the MP table should list the boot
	 * CPU too, but we do it for the sake of robustness anyway.
	 */
	if (!physid_isset(boot_cpu_id, phys_cpu_present_map)) {
		printk(KERN_NOTICE "weird, boot CPU (#%d) not listed by the BIOS.\n",
								 boot_cpu_id);
		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
	}

	/*
	 * If we couldn't find a local APIC, then get out of here now!
	 */
	if (APIC_INTEGRATED(apic_version[boot_cpu_id]) && !cpu_has_apic) {
		printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
			boot_cpu_id);
		printk(KERN_ERR "... forcing use of dummy APIC emulation. (tell your hw vendor)\n");
		io_apic_irqs = 0;
		cpu_online_map = cpumask_of_cpu(0);
		phys_cpu_present_map = physid_mask_of_physid(0);
		disable_apic = 1;
		goto smp_done;
	}

	verify_local_APIC();

	/*
	 * If SMP should be disabled, then really disable it!
	 */
	if (!max_cpus) {
		smp_found_config = 0;
		printk(KERN_INFO "SMP mode deactivated, forcing use of dummy APIC emulation.\n");
		io_apic_irqs = 0;
		cpu_online_map = cpumask_of_cpu(0);
		phys_cpu_present_map = physid_mask_of_physid(0);
		disable_apic = 1;
		goto smp_done;
	}

	connect_bsp_APIC();
	setup_local_APIC();

	if (GET_APIC_ID(apic_read(APIC_ID)) != boot_cpu_id)
		BUG();

	x86_cpu_to_apicid[0] = boot_cpu_id;

	/*
	 * Now scan the CPU present map and fire up the other CPUs.
	 */
	Dprintk("CPU present map: %lx\n", physids_coerce(phys_cpu_present_map));

	kicked = 1;
	for (bit = 0; kicked < NR_CPUS && bit < MAX_APICS; bit++) {
		apicid = cpu_present_to_apicid(bit);
		/*
		 * Don't even attempt to start the boot CPU!
		 */
		if (apicid == boot_cpu_id || (apicid == BAD_APICID))
			continue;

		if (!physid_isset(apicid, phys_cpu_present_map))
			continue;
		if ((max_cpus >= 0) && (max_cpus <= cpucount+1))
			continue;

		do_boot_cpu(apicid);
		++kicked;
	}

	/*
	 * Cleanup possible dangling ends...
	 */
	{
		/*
		 * Install writable page 0 entry to set BIOS data area.
		 */
		local_flush_tlb();

		/*
		 * Paranoid:  Set warm reset code and vector here back
		 * to default values.
		 */
		CMOS_WRITE(0, 0xf);

		*((volatile int *) phys_to_virt(0x467)) = 0;
	}

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

	Dprintk("Before bogomips.\n");
	if (!cpucount) {
		printk(KERN_INFO "Only one processor found.\n");
	} else {
		unsigned long bogosum = 0;
		for (cpu = 0; cpu < NR_CPUS; cpu++)
			if (cpu_isset(cpu, cpu_callout_map))
				bogosum += cpu_data[cpu].loops_per_jiffy;
		printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
			cpucount+1,
			bogosum/(500000/HZ),
			(bogosum/(5000/HZ))%100);
		Dprintk("Before bogocount - setting activated=1.\n");
	}

	/*
	 * Construct cpu_sibling_map[], so that we can tell the
	 * sibling CPU efficiently.
	 */
	for (cpu = 0; cpu < NR_CPUS; cpu++)
		cpus_clear(cpu_sibling_map[cpu]);

	for (cpu = 0; cpu < NR_CPUS; cpu++) {
		int siblings = 0;
		int i;
		if (!cpu_isset(cpu, cpu_callout_map))
			continue;

		if (smp_num_siblings > 1) {
			for (i = 0; i < NR_CPUS; i++) {
				if (!cpu_isset(i, cpu_callout_map))
					continue;
				if (phys_proc_id[cpu] == phys_proc_id[i]) {
					siblings++;
					cpu_set(i, cpu_sibling_map[cpu]);
				}
			}
		} else { 
			siblings++;
			cpu_set(cpu, cpu_sibling_map[cpu]);
		}

		if (siblings != smp_num_siblings) {
			printk(KERN_WARNING 
	       "WARNING: %d siblings found for CPU%d, should be %d\n", 
			       siblings, cpu, smp_num_siblings);
			smp_num_siblings = siblings;
		}       
	}

	Dprintk("Boot done.\n");

	/*
	 * Here we can be sure that there is an IO-APIC in the system. Let's
	 * go and set it up:
	 */
	if (!skip_ioapic_setup && nr_ioapics)
		setup_IO_APIC();
	else
		nr_ioapics = 0;

	setup_boot_APIC_clock();

	/*
	 * Synchronize the TSC with the AP
	 */
	if (cpu_has_tsc && cpucount)
		synchronize_tsc_bp();

 smp_done:
	time_init_smp();
}

/* These are wrappers to interface to the new boot process.  Someone
   who understands all this stuff should rewrite it properly. --RR 15/Jul/02 */
void __init smp_prepare_cpus(unsigned int max_cpus)
{
	smp_boot_cpus(max_cpus);
}

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

int __devinit __cpu_up(unsigned int cpu)
{
	/* This only works at boot for x86.  See "rewrite" above. */
	if (cpu_isset(cpu, smp_commenced_mask)) {
		local_irq_enable();
		return -ENOSYS;
	}

	/* In case one didn't come up */
	if (!cpu_isset(cpu, cpu_callin_map)) {
		local_irq_enable();
		return -EIO;
	}
	local_irq_enable();

	/* Unleash the CPU! */
	Dprintk("waiting for cpu %d\n", cpu);

	cpu_set(cpu, smp_commenced_mask);
	while (!cpu_isset(cpu, cpu_online_map))
		mb();
	return 0;
}

void __init smp_cpus_done(unsigned int max_cpus)
{
#ifdef CONFIG_X86_IO_APIC
	setup_ioapic_dest();
#endif
	zap_low_mappings();
}