pc64/apic/lapic.c

/*
 * Copyright (c) 1996, by Steve Passe
 * All rights reserved.
 *
 * 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. The name of the developer may NOT be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 * $FreeBSD: src/sys/i386/i386/mpapic.c,v 1.37.2.7 2003/01/25 02:31:47 peter Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/machintr.h>
#include <machine/globaldata.h>
#include <machine/smp.h>
#include <machine/md_var.h>
#include <machine/pmap.h>
#include <machine_base/apic/lapic.h>
#include <machine_base/apic/ioapic.h>
#include <machine_base/apic/ioapic_abi.h>
#include <machine_base/apic/apicvar.h>
#include <machine_base/icu/icu_var.h>
#include <machine/segments.h>
#include <sys/thread2.h>

#include <machine/cputypes.h>
#include <machine/intr_machdep.h>

extern int naps;

volatile lapic_t *lapic;

static void	lapic_timer_calibrate(void);
static void	lapic_timer_set_divisor(int);
static void	lapic_timer_fixup_handler(void *);
static void	lapic_timer_restart_handler(void *);

void		lapic_timer_process(void);
void		lapic_timer_process_frame(struct intrframe *);
void		lapic_timer_always(struct intrframe *);

static int	lapic_timer_enable = 1;
TUNABLE_INT("hw.lapic_timer_enable", &lapic_timer_enable);

static void	lapic_timer_intr_reload(struct cputimer_intr *, sysclock_t);
static void	lapic_timer_intr_enable(struct cputimer_intr *);
static void	lapic_timer_intr_restart(struct cputimer_intr *);
static void	lapic_timer_intr_pmfixup(struct cputimer_intr *);

static struct cputimer_intr lapic_cputimer_intr = {
	.freq = 0,
	.reload = lapic_timer_intr_reload,
	.enable = lapic_timer_intr_enable,
	.config = cputimer_intr_default_config,
	.restart = lapic_timer_intr_restart,
	.pmfixup = lapic_timer_intr_pmfixup,
	.initclock = cputimer_intr_default_initclock,
	.next = SLIST_ENTRY_INITIALIZER,
	.name = "lapic",
	.type = CPUTIMER_INTR_LAPIC,
	.prio = CPUTIMER_INTR_PRIO_LAPIC,
	.caps = CPUTIMER_INTR_CAP_NONE
};

static int		lapic_timer_divisor_idx = -1;
static const uint32_t	lapic_timer_divisors[] = {
	APIC_TDCR_2,	APIC_TDCR_4,	APIC_TDCR_8,	APIC_TDCR_16,
	APIC_TDCR_32,	APIC_TDCR_64,	APIC_TDCR_128,	APIC_TDCR_1
};
#define APIC_TIMER_NDIVISORS (int)(NELEM(lapic_timer_divisors))

/*
 * APIC ID <-> CPU ID mapping structures.
 */
int	cpu_id_to_apic_id[NAPICID];
int	apic_id_to_cpu_id[NAPICID];
int	lapic_enable = 1;

/*
 * Enable LAPIC, configure interrupts.
 */
void
lapic_init(boolean_t bsp)
{
	uint32_t timer;
	u_int   temp;

	/*
	 * Install vectors
	 *
	 * Since IDT is shared between BSP and APs, these vectors
	 * only need to be installed once; we do it on BSP.
	 */
	if (bsp) {
		/* Install a 'Spurious INTerrupt' vector */
		setidt(XSPURIOUSINT_OFFSET, Xspuriousint,
		    SDT_SYSIGT, SEL_KPL, 0);

		/* Install a timer vector */
		setidt(XTIMER_OFFSET, Xtimer,
		    SDT_SYSIGT, SEL_KPL, 0);

#ifdef SMP
		/* Install an inter-CPU IPI for TLB invalidation */
		setidt(XINVLTLB_OFFSET, Xinvltlb,
		    SDT_SYSIGT, SEL_KPL, 0);

		/* Install an inter-CPU IPI for IPIQ messaging */
		setidt(XIPIQ_OFFSET, Xipiq,
		    SDT_SYSIGT, SEL_KPL, 0);

		/* Install an inter-CPU IPI for CPU stop/restart */
		setidt(XCPUSTOP_OFFSET, Xcpustop,
		    SDT_SYSIGT, SEL_KPL, 0);
#endif
	}

	/*
	 * Setup LINT0 as ExtINT on the BSP.  This is theoretically an
	 * aggregate interrupt input from the 8259.  The INTA cycle
	 * will be routed to the external controller (the 8259) which
	 * is expected to supply the vector.
	 *
	 * Must be setup edge triggered, active high.
	 *
	 * Disable LINT0 on BSP, if I/O APIC is enabled.
	 *
	 * Disable LINT0 on the APs.  It doesn't matter what delivery
	 * mode we use because we leave it masked.
	 */
	temp = lapic->lvt_lint0;
	temp &= ~(APIC_LVT_MASKED | APIC_LVT_TRIG_MASK |
		  APIC_LVT_POLARITY_MASK | APIC_LVT_DM_MASK);
	if (bsp) {
		temp |= APIC_LVT_DM_EXTINT;
		if (ioapic_enable)
			temp |= APIC_LVT_MASKED;
	} else {
		temp |= APIC_LVT_DM_FIXED | APIC_LVT_MASKED;
	}
	lapic->lvt_lint0 = temp;

	/*
	 * Setup LINT1 as NMI.
	 *
	 * Must be setup edge trigger, active high.
	 *
	 * Enable LINT1 on BSP, if I/O APIC is enabled.
	 *
	 * Disable LINT1 on the APs.
	 */
	temp = lapic->lvt_lint1;
	temp &= ~(APIC_LVT_MASKED | APIC_LVT_TRIG_MASK |
		  APIC_LVT_POLARITY_MASK | APIC_LVT_DM_MASK);
	temp |= APIC_LVT_MASKED | APIC_LVT_DM_NMI;
	if (bsp && ioapic_enable)
		temp &= ~APIC_LVT_MASKED;
	lapic->lvt_lint1 = temp;

	/*
	 * Mask the LAPIC error interrupt, LAPIC performance counter
	 * interrupt.
	 */
	lapic->lvt_error = lapic->lvt_error | APIC_LVT_MASKED;
	lapic->lvt_pcint = lapic->lvt_pcint | APIC_LVT_MASKED;

	/*
	 * Set LAPIC timer vector and mask the LAPIC timer interrupt.
	 */
	timer = lapic->lvt_timer;
	timer &= ~APIC_LVTT_VECTOR;
	timer |= XTIMER_OFFSET;
	timer |= APIC_LVTT_MASKED;
	lapic->lvt_timer = timer;

	/*
	 * Set the Task Priority Register as needed.   At the moment allow
	 * interrupts on all cpus (the APs will remain CLId until they are
	 * ready to deal).
	 */
	temp = lapic->tpr;
	temp &= ~APIC_TPR_PRIO;		/* clear priority field */
	lapic->tpr = temp;

	/*
	 * Enable the LAPIC
	 */
	temp = lapic->svr;
	temp |= APIC_SVR_ENABLE;	/* enable the LAPIC */
	temp &= ~APIC_SVR_FOCUS_DISABLE; /* enable lopri focus processor */

	/*
	 * Set the spurious interrupt vector.  The low 4 bits of the vector
	 * must be 1111.
	 */
	if ((XSPURIOUSINT_OFFSET & 0x0F) != 0x0F)
		panic("bad XSPURIOUSINT_OFFSET: 0x%08x", XSPURIOUSINT_OFFSET);
	temp &= ~APIC_SVR_VECTOR;
	temp |= XSPURIOUSINT_OFFSET;

	lapic->svr = temp;

	/*
	 * Pump out a few EOIs to clean out interrupts that got through
	 * before we were able to set the TPR.
	 */
	lapic->eoi = 0;
	lapic->eoi = 0;
	lapic->eoi = 0;

	if (bsp) {
		lapic_timer_calibrate();
		if (lapic_timer_enable) {
			cputimer_intr_register(&lapic_cputimer_intr);
			cputimer_intr_select(&lapic_cputimer_intr, 0);
		}
	} else {
		lapic_timer_set_divisor(lapic_timer_divisor_idx);
	}

	if (bootverbose)
		apic_dump("apic_initialize()");
}

static void
lapic_timer_set_divisor(int divisor_idx)
{
	KKASSERT(divisor_idx >= 0 && divisor_idx < APIC_TIMER_NDIVISORS);
	lapic->dcr_timer = lapic_timer_divisors[divisor_idx];
}

static void
lapic_timer_oneshot(u_int count)
{
	uint32_t value;

	value = lapic->lvt_timer;
	value &= ~APIC_LVTT_PERIODIC;
	lapic->lvt_timer = value;
	lapic->icr_timer = count;
}

static void
lapic_timer_oneshot_quick(u_int count)
{
	lapic->icr_timer = count;
}

static void
lapic_timer_calibrate(void)
{
	sysclock_t value;

	/* Try to calibrate the local APIC timer. */
	for (lapic_timer_divisor_idx = 0;
	     lapic_timer_divisor_idx < APIC_TIMER_NDIVISORS;
	     lapic_timer_divisor_idx++) {
		lapic_timer_set_divisor(lapic_timer_divisor_idx);
		lapic_timer_oneshot(APIC_TIMER_MAX_COUNT);
		DELAY(2000000);
		value = APIC_TIMER_MAX_COUNT - lapic->ccr_timer;
		if (value != APIC_TIMER_MAX_COUNT)
			break;
	}
	if (lapic_timer_divisor_idx >= APIC_TIMER_NDIVISORS)
		panic("lapic: no proper timer divisor?!\n");
	lapic_cputimer_intr.freq = value / 2;

	kprintf("lapic: divisor index %d, frequency %u Hz\n",
		lapic_timer_divisor_idx, lapic_cputimer_intr.freq);
}

static void
lapic_timer_process_oncpu(struct globaldata *gd, struct intrframe *frame)
{
	sysclock_t count;

	gd->gd_timer_running = 0;

	count = sys_cputimer->count();
	if (TAILQ_FIRST(&gd->gd_systimerq) != NULL)
		systimer_intr(&count, 0, frame);
}

void
lapic_timer_process(void)
{
	lapic_timer_process_oncpu(mycpu, NULL);
}

void
lapic_timer_process_frame(struct intrframe *frame)
{
	lapic_timer_process_oncpu(mycpu, frame);
}

/*
 * This manual debugging code is called unconditionally from Xtimer
 * (the lapic timer interrupt) whether the current thread is in a
 * critical section or not) and can be useful in tracking down lockups.
 *
 * NOTE: MANUAL DEBUG CODE
 */
#if 0
static int saveticks[SMP_MAXCPU];
static int savecounts[SMP_MAXCPU];
#endif

void
lapic_timer_always(struct intrframe *frame)
{
#if 0
	globaldata_t gd = mycpu;
	int cpu = gd->gd_cpuid;
	char buf[64];
	short *gptr;
	int i;

	if (cpu <= 20) {
		gptr = (short *)0xFFFFFFFF800b8000 + 80 * cpu;
		*gptr = ((*gptr + 1) & 0x00FF) | 0x0700;
		++gptr;

		ksnprintf(buf, sizeof(buf), " %p %16s %d %16s ",
		    (void *)frame->if_rip, gd->gd_curthread->td_comm, ticks,
		    gd->gd_infomsg);
		for (i = 0; buf[i]; ++i) {
			gptr[i] = 0x0700 | (unsigned char)buf[i];
		}
	}
#if 0
	if (saveticks[gd->gd_cpuid] != ticks) {
		saveticks[gd->gd_cpuid] = ticks;
		savecounts[gd->gd_cpuid] = 0;
	}
	++savecounts[gd->gd_cpuid];
	if (savecounts[gd->gd_cpuid] > 2000 && panicstr == NULL) {
		panic("cpud %d panicing on ticks failure",
			gd->gd_cpuid);
	}
	for (i = 0; i < ncpus; ++i) {
		int delta;
		if (saveticks[i] && panicstr == NULL) {
			delta = saveticks[i] - ticks;
			if (delta < -10 || delta > 10) {
				panic("cpu %d panicing on cpu %d watchdog",
				      gd->gd_cpuid, i);
			}
		}
	}
#endif
#endif
}

static void
lapic_timer_intr_reload(struct cputimer_intr *cti, sysclock_t reload)
{
	struct globaldata *gd = mycpu;

	reload = (int64_t)reload * cti->freq / sys_cputimer->freq;
	if (reload < 2)
		reload = 2;

	if (gd->gd_timer_running) {
		if (reload < lapic->ccr_timer)
			lapic_timer_oneshot_quick(reload);
	} else {
		gd->gd_timer_running = 1;
		lapic_timer_oneshot_quick(reload);
	}
}

static void
lapic_timer_intr_enable(struct cputimer_intr *cti __unused)
{
	uint32_t timer;

	timer = lapic->lvt_timer;
	timer &= ~(APIC_LVTT_MASKED | APIC_LVTT_PERIODIC);
	lapic->lvt_timer = timer;

	lapic_timer_fixup_handler(NULL);
}

static void
lapic_timer_fixup_handler(void *arg)
{
	int *started = arg;

	if (started != NULL)
		*started = 0;

	if (cpu_vendor_id == CPU_VENDOR_AMD) {
		/*
		 * Detect the presence of C1E capability mostly on latest
		 * dual-cores (or future) k8 family.  This feature renders
		 * the local APIC timer dead, so we disable it by reading
		 * the Interrupt Pending Message register and clearing both
		 * C1eOnCmpHalt (bit 28) and SmiOnCmpHalt (bit 27).
		 *
		 * Reference:
		 *   "BIOS and Kernel Developer's Guide for AMD NPT
		 *    Family 0Fh Processors"
		 *   #32559 revision 3.00
		 */
		if ((cpu_id & 0x00000f00) == 0x00000f00 &&
		    (cpu_id & 0x0fff0000) >= 0x00040000) {
			uint64_t msr;

			msr = rdmsr(0xc0010055);
			if (msr & 0x18000000) {
				struct globaldata *gd = mycpu;

				kprintf("cpu%d: AMD C1E detected\n",
					gd->gd_cpuid);
				wrmsr(0xc0010055, msr & ~0x18000000ULL);

				/*
				 * We are kinda stalled;
				 * kick start again.
				 */
				gd->gd_timer_running = 1;
				lapic_timer_oneshot_quick(2);

				if (started != NULL)
					*started = 1;
			}
		}
	}
}

static void
lapic_timer_restart_handler(void *dummy __unused)
{
	int started;

	lapic_timer_fixup_handler(&started);
	if (!started) {
		struct globaldata *gd = mycpu;

		gd->gd_timer_running = 1;
		lapic_timer_oneshot_quick(2);
	}
}

/*
 * This function is called only by ACPI-CA code currently:
 * - AMD C1E fixup.  AMD C1E only seems to happen after ACPI
 *   module controls PM.  So once ACPI-CA is attached, we try
 *   to apply the fixup to prevent LAPIC timer from hanging.
 */
static void
lapic_timer_intr_pmfixup(struct cputimer_intr *cti __unused)
{
#ifdef SMP
	lwkt_send_ipiq_mask(smp_active_mask,
			    lapic_timer_fixup_handler, NULL);
#else
	lapic_timer_fixup_handler(NULL);
#endif
}

static void
lapic_timer_intr_restart(struct cputimer_intr *cti __unused)
{
#ifdef SMP
	lwkt_send_ipiq_mask(smp_active_mask, lapic_timer_restart_handler, NULL);
#else
	lapic_timer_restart_handler(NULL);
#endif
}


/*
 * dump contents of local APIC registers
 */
void
apic_dump(char* str)
{
	kprintf("SMP: CPU%d %s:\n", mycpu->gd_cpuid, str);
	kprintf("     lint0: 0x%08x lint1: 0x%08x TPR: 0x%08x SVR: 0x%08x\n",
		lapic->lvt_lint0, lapic->lvt_lint1, lapic->tpr, lapic->svr);
}

#ifdef SMP

/*
 * Inter Processor Interrupt functions.
 */

/*
 * Send APIC IPI 'vector' to 'destType' via 'deliveryMode'.
 *
 *  destType is 1 of: APIC_DEST_SELF, APIC_DEST_ALLISELF, APIC_DEST_ALLESELF
 *  vector is any valid SYSTEM INT vector
 *  delivery_mode is 1 of: APIC_DELMODE_FIXED, APIC_DELMODE_LOWPRIO
 *
 * WARNINGS!
 *
 * We now implement a per-cpu interlock (gd->gd_npoll) to prevent more than
 * one IPI from being sent to any given cpu at a time.  Thus we no longer
 * have to process incoming IPIs while waiting for the status to clear.
 * No deadlock should be possible.
 *
 * We now physically disable interrupts for the lapic ICR operation.  If
 * we do not do this then it looks like an EOI sent to the lapic (which
 * occurs even with a critical section) can interfere with the command
 * register ready status and cause an IPI to be lost.
 *
 * e.g. an interrupt can occur, issue the EOI, IRET, and cause the command
 * register to busy just before we write to icr_lo, resulting in a lost
 * issuance.  This only appears to occur on Intel cpus and is not
 * documented.  It could simply be that cpus are so fast these days that
 * it was always an issue, but is only now rearing its ugly head.  This
 * is conjecture.
 */
int
apic_ipi(int dest_type, int vector, int delivery_mode)
{
	unsigned long rflags;
	u_long  icr_lo;

	rflags = read_rflags();
	cpu_disable_intr();
	while ((lapic->icr_lo & APIC_DELSTAT_MASK) != 0) {
		cpu_pause();
	}
	icr_lo = (lapic->icr_lo & APIC_ICRLO_RESV_MASK) | dest_type |
		delivery_mode | vector;
	lapic->icr_lo = icr_lo;
	write_rflags(rflags);

	return 0;
}

void
single_apic_ipi(int cpu, int vector, int delivery_mode)
{
	unsigned long rflags;
	u_long  icr_lo;
	u_long  icr_hi;

	rflags = read_rflags();
	cpu_disable_intr();
	while ((lapic->icr_lo & APIC_DELSTAT_MASK) != 0) {
		cpu_pause();
	}
	icr_hi = lapic->icr_hi & ~APIC_ID_MASK;
	icr_hi |= (CPUID_TO_APICID(cpu) << 24);
	lapic->icr_hi = icr_hi;

	/* build ICR_LOW */
	icr_lo = (lapic->icr_lo & APIC_ICRLO_RESV_MASK) |
		 APIC_DEST_DESTFLD | delivery_mode | vector;

	/* write APIC ICR */
	lapic->icr_lo = icr_lo;
	write_rflags(rflags);
}

#if 0

/*
 * Returns 0 if the apic is busy, 1 if we were able to queue the request.
 *
 * NOT WORKING YET!  The code as-is may end up not queueing an IPI at all
 * to the target, and the scheduler does not 'poll' for IPI messages.
 */
int
single_apic_ipi_passive(int cpu, int vector, int delivery_mode)
{
	u_long  icr_lo;
	u_long  icr_hi;

	crit_enter();
	if ((lapic->icr_lo & APIC_DELSTAT_MASK) != 0) {
	    crit_exit();
	    return(0);
	}
	icr_hi = lapic->icr_hi & ~APIC_ID_MASK;
	icr_hi |= (CPUID_TO_APICID(cpu) << 24);
	lapic->icr_hi = icr_hi;

	/* build IRC_LOW */
	icr_lo = (lapic->icr_lo & APIC_RESV2_MASK)
	    | APIC_DEST_DESTFLD | delivery_mode | vector;

	/* write APIC ICR */
	lapic->icr_lo = icr_lo;
	crit_exit();
	return(1);
}

#endif

/*
 * Send APIC IPI 'vector' to 'target's via 'delivery_mode'.
 *
 * target is a bitmask of destination cpus.  Vector is any
 * valid system INT vector.  Delivery mode may be either
 * APIC_DELMODE_FIXED or APIC_DELMODE_LOWPRIO.
 */
void
selected_apic_ipi(cpumask_t target, int vector, int delivery_mode)
{
	crit_enter();
	while (target) {
		int n = BSFCPUMASK(target);
		target &= ~CPUMASK(n);
		single_apic_ipi(n, vector, delivery_mode);
	}
	crit_exit();
}

#endif	/* SMP */

/*
 * Timer code, in development...
 *  - suggested by rgrimes@gndrsh.aac.dev.com
 */
int
get_apic_timer_frequency(void)
{
	return(lapic_cputimer_intr.freq);
}

/*
 * Load a 'downcount time' in uSeconds.
 */
void
set_apic_timer(int us)
{
	u_int count;

	/*
	 * When we reach here, lapic timer's frequency
	 * must have been calculated as well as the
	 * divisor (lapic->dcr_timer is setup during the
	 * divisor calculation).
	 */
	KKASSERT(lapic_cputimer_intr.freq != 0 &&
		 lapic_timer_divisor_idx >= 0);

	count = ((us * (int64_t)lapic_cputimer_intr.freq) + 999999) / 1000000;
	lapic_timer_oneshot(count);
}


/*
 * Read remaining time in timer.
 */
int
read_apic_timer(void)
{
#if 0
	/** XXX FIXME: we need to return the actual remaining time,
         *         for now we just return the remaining count.
         */
#else
	return lapic->ccr_timer;
#endif
}


/*
 * Spin-style delay, set delay time in uS, spin till it drains.
 */
void
u_sleep(int count)
{
	set_apic_timer(count);
	while (read_apic_timer())
		 /* spin */ ;
}

int
lapic_unused_apic_id(int start)
{
	int i;

	for (i = start; i < NAPICID; ++i) {
		if (APICID_TO_CPUID(i) == -1)
			return i;
	}
	return NAPICID;
}

void
lapic_map(vm_paddr_t lapic_addr)
{
	lapic = pmap_mapdev_uncacheable(lapic_addr, sizeof(struct LAPIC));
}

static TAILQ_HEAD(, lapic_enumerator) lapic_enumerators =
	TAILQ_HEAD_INITIALIZER(lapic_enumerators);

int
lapic_config(void)
{
	struct lapic_enumerator *e;
	int error, i, ap_max;

	KKASSERT(lapic_enable);

	for (i = 0; i < NAPICID; ++i)
		APICID_TO_CPUID(i) = -1;

	TAILQ_FOREACH(e, &lapic_enumerators, lapic_link) {
		error = e->lapic_probe(e);
		if (!error)
			break;
	}
	if (e == NULL) {
		kprintf("LAPIC: Can't find LAPIC\n");
		return ENXIO;
	}

	e->lapic_enumerate(e);

	ap_max = MAXCPU - 1;
	TUNABLE_INT_FETCH("hw.ap_max", &ap_max);
	if (ap_max > MAXCPU - 1)
		ap_max = MAXCPU - 1;

	if (naps > ap_max) {
		kprintf("LAPIC: Warning use only %d out of %d "
			"available APs\n",
			ap_max, naps);
		naps = ap_max;
	}

	return 0;
}

void
lapic_enumerator_register(struct lapic_enumerator *ne)
{
	struct lapic_enumerator *e;

	TAILQ_FOREACH(e, &lapic_enumerators, lapic_link) {
		if (e->lapic_prio < ne->lapic_prio) {
			TAILQ_INSERT_BEFORE(e, ne, lapic_link);
			return;
		}
	}
	TAILQ_INSERT_TAIL(&lapic_enumerators, ne, lapic_link);
}

void
lapic_set_cpuid(int cpu_id, int apic_id)
{
	CPUID_TO_APICID(cpu_id) = apic_id;
	APICID_TO_CPUID(apic_id) = cpu_id;
}

void
lapic_fixup_noioapic(void)
{
	u_int   temp;

	/* Only allowed on BSP */
	KKASSERT(mycpuid == 0);
	KKASSERT(!ioapic_enable);

	temp = lapic->lvt_lint0;
	temp &= ~APIC_LVT_MASKED;
	lapic->lvt_lint0 = temp;

	temp = lapic->lvt_lint1;
	temp |= APIC_LVT_MASKED;
	lapic->lvt_lint1 = temp;
}

static void
lapic_sysinit(void *dummy __unused)
{
	if (lapic_enable) {
		int error;

		error = lapic_config();
		if (error)
			lapic_enable = 0;
	}

	if (lapic_enable) {
		/* Initialize BSP's local APIC */
		lapic_init(TRUE);
	} else if (ioapic_enable) {
		ioapic_enable = 0;
		icu_reinit_noioapic();
	}
}
SYSINIT(lapic, SI_BOOT2_LAPIC, SI_ORDER_FIRST, lapic_sysinit, NULL)