xnu-3789.21.4.tar.gz

[apple/xnu.git] / osfmk / i386 / lapic_native.c

/*
 * Copyright (c) 2008-2011 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */

#include <mach/mach_types.h>
#include <mach/kern_return.h>

#include <kern/kern_types.h>
#include <kern/cpu_number.h>
#include <kern/cpu_data.h>
#include <kern/assert.h>
#include <kern/machine.h>
#include <kern/debug.h>

#include <vm/vm_map.h>
#include <vm/vm_kern.h>

#include <i386/lapic.h>
#include <i386/cpuid.h>
#include <i386/proc_reg.h>
#include <i386/machine_cpu.h>
#include <i386/misc_protos.h>
#include <i386/mp.h>
#include <i386/postcode.h>
#include <i386/cpu_threads.h>
#include <i386/machine_routines.h>
#include <i386/tsc.h>
#if CONFIG_MCA
#include <i386/machine_check.h>
#endif

#include <sys/kdebug.h>

#if     MP_DEBUG
#define PAUSE           delay(1000000)
#define DBG(x...)       kprintf(x)
#else
#define DBG(x...)
#define PAUSE
#endif  /* MP_DEBUG */

lapic_ops_table_t       *lapic_ops;     /* Lapic operations switch */

static vm_map_offset_t  lapic_pbase;    /* Physical base memory-mapped regs */
static vm_offset_t      lapic_vbase;    /* Virtual base memory-mapped regs */

static i386_intr_func_t lapic_intr_func[LAPIC_FUNC_TABLE_SIZE];

/* TRUE if local APIC was enabled by the OS not by the BIOS */
static boolean_t lapic_os_enabled = FALSE;

static boolean_t lapic_errors_masked = FALSE;
static uint64_t lapic_last_master_error = 0;
static uint64_t lapic_error_time_threshold = 0;
static unsigned lapic_master_error_count = 0;
static unsigned lapic_error_count_threshold = 5;
static boolean_t lapic_dont_panic = FALSE;

#ifdef MP_DEBUG
void
lapic_cpu_map_dump(void)
{
        int     i;

        for (i = 0; i < MAX_CPUS; i++) {
                if (cpu_to_lapic[i] == -1)
                        continue;
                kprintf("cpu_to_lapic[%d]: %d\n",
                        i, cpu_to_lapic[i]);
        }
        for (i = 0; i < MAX_LAPICIDS; i++) {
                if (lapic_to_cpu[i] == -1)
                        continue;
                kprintf("lapic_to_cpu[%d]: %d\n",
                        i, lapic_to_cpu[i]);
        }
}
#endif /* MP_DEBUG */

static void
legacy_init(void)
{
        int             result;
        vm_map_entry_t  entry;
        vm_map_offset_t lapic_vbase64;
        /* Establish a map to the local apic */

        if (lapic_vbase == 0) {
                lapic_vbase64 = (vm_offset_t)vm_map_min(kernel_map);
                result = vm_map_find_space(kernel_map,
                                           &lapic_vbase64,
                                           round_page(LAPIC_SIZE), 0,
                                           VM_MAKE_TAG(VM_KERN_MEMORY_IOKIT), &entry);
                /* Convert 64-bit vm_map_offset_t to "pointer sized" vm_offset_t
                 */
                lapic_vbase = (vm_offset_t) lapic_vbase64;
                if (result != KERN_SUCCESS) {
                        panic("legacy_init: vm_map_find_entry FAILED (err=%d)", result);
                }
                vm_map_unlock(kernel_map);

                /*
                 * Map in the local APIC non-cacheable, as recommended by Intel
                 * in section 8.4.1 of the "System Programming Guide".
                 * In fact, this is redundant because EFI will have assigned an
                 * MTRR physical range containing the local APIC's MMIO space as
                 * UC and this will override the default PAT setting.
                 */
                pmap_enter(pmap_kernel(),
                                lapic_vbase,
                                (ppnum_t) i386_btop(lapic_pbase),
                                VM_PROT_READ|VM_PROT_WRITE,
                                VM_PROT_NONE,
                                VM_WIMG_IO,
                                TRUE);
        }

        /*
         * Set flat delivery model, logical processor id
         * This should already be the default set.
         */
        LAPIC_WRITE(DFR, LAPIC_DFR_FLAT);
        LAPIC_WRITE(LDR, (get_cpu_number()) << LAPIC_LDR_SHIFT);
}


static uint32_t
legacy_read(lapic_register_t reg)
{
        return  *LAPIC_MMIO(reg);
}

static void
legacy_write(lapic_register_t reg, uint32_t value)
{
        *LAPIC_MMIO(reg) = value;
}

static uint64_t
legacy_read_icr(void)
{
        return (((uint64_t)*LAPIC_MMIO(ICRD)) << 32) | ((uint64_t)*LAPIC_MMIO(ICR));
}

static void
legacy_write_icr(uint32_t dst, uint32_t cmd)
{
        *LAPIC_MMIO(ICRD) = dst << LAPIC_ICRD_DEST_SHIFT;
        *LAPIC_MMIO(ICR) = cmd;
}

static lapic_ops_table_t legacy_ops = {
        legacy_init,
        legacy_read,
        legacy_write,
        legacy_read_icr,
        legacy_write_icr
};

static  boolean_t is_x2apic = FALSE;

static void
x2apic_init(void)
{
        uint32_t        lo;
        uint32_t        hi;

        rdmsr(MSR_IA32_APIC_BASE, lo, hi);
        if ((lo & MSR_IA32_APIC_BASE_EXTENDED) == 0)  {
                lo |= MSR_IA32_APIC_BASE_EXTENDED;
                wrmsr(MSR_IA32_APIC_BASE, lo, hi);
                kprintf("x2APIC mode enabled\n");
        }
}

static uint32_t
x2apic_read(lapic_register_t reg)
{
        uint32_t        lo;
        uint32_t        hi;

        rdmsr(LAPIC_MSR(reg), lo, hi);
        return lo;
}

static void
x2apic_write(lapic_register_t reg, uint32_t value)
{
        wrmsr(LAPIC_MSR(reg), value, 0);
}

static uint64_t
x2apic_read_icr(void)
{
        return rdmsr64(LAPIC_MSR(ICR));;
}

static void
x2apic_write_icr(uint32_t dst, uint32_t cmd)
{
          wrmsr(LAPIC_MSR(ICR), cmd, dst);
}

static lapic_ops_table_t x2apic_ops = {
        x2apic_init,
        x2apic_read,
        x2apic_write,
        x2apic_read_icr,
        x2apic_write_icr
};

void
lapic_init(void)
{
        uint32_t        lo;
        uint32_t        hi;
        boolean_t       is_boot_processor;
        boolean_t       is_lapic_enabled;

        /* Examine the local APIC state */
        rdmsr(MSR_IA32_APIC_BASE, lo, hi);
        is_boot_processor = (lo & MSR_IA32_APIC_BASE_BSP) != 0;
        is_lapic_enabled  = (lo & MSR_IA32_APIC_BASE_ENABLE) != 0;
        is_x2apic         = (lo & MSR_IA32_APIC_BASE_EXTENDED) != 0;
        lapic_pbase = (lo &  MSR_IA32_APIC_BASE_BASE);
        kprintf("MSR_IA32_APIC_BASE 0x%llx %s %s mode %s\n", lapic_pbase,
                is_lapic_enabled ? "enabled" : "disabled",
                is_x2apic ? "extended" : "legacy",
                is_boot_processor ? "BSP" : "AP");
        if (!is_boot_processor || !is_lapic_enabled)
                panic("Unexpected local APIC state\n");

        /*
         * If x2APIC is available and not already enabled, enable it.
         * Unless overriden by boot-arg.
         */
        if (!is_x2apic && (cpuid_features() & CPUID_FEATURE_x2APIC)) {
                PE_parse_boot_argn("-x2apic", &is_x2apic, sizeof(is_x2apic));
                kprintf("x2APIC supported %s be enabled\n",
                        is_x2apic ? "and will" : "but will not");
        }

        lapic_ops = is_x2apic ? &x2apic_ops : &legacy_ops;

        LAPIC_INIT();

        kprintf("ID: 0x%x LDR: 0x%x\n", LAPIC_READ(ID), LAPIC_READ(LDR));
        if ((LAPIC_READ(VERSION)&LAPIC_VERSION_MASK) < 0x14) {
                panic("Local APIC version 0x%x, 0x14 or more expected\n",
                        (LAPIC_READ(VERSION)&LAPIC_VERSION_MASK));
        }

        /* Set up the lapic_id <-> cpu_number map and add this boot processor */
        lapic_cpu_map_init();
        lapic_cpu_map((LAPIC_READ(ID)>>LAPIC_ID_SHIFT)&LAPIC_ID_MASK, 0);
        current_cpu_datap()->cpu_phys_number = cpu_to_lapic[0];
        kprintf("Boot cpu local APIC id 0x%x\n", cpu_to_lapic[0]);
}


static int
lapic_esr_read(void)
{
        /* write-read register */
        LAPIC_WRITE(ERROR_STATUS, 0);
        return LAPIC_READ(ERROR_STATUS);
}

static void 
lapic_esr_clear(void)
{
        LAPIC_WRITE(ERROR_STATUS, 0);
        LAPIC_WRITE(ERROR_STATUS, 0);
}

static const char *DM_str[8] = {
        "Fixed",
        "Lowest Priority",
        "Invalid",
        "Invalid",
        "NMI",
        "Reset",
        "Invalid",
        "ExtINT"};

static const char *TMR_str[] = {
        "OneShot",
        "Periodic",
        "TSC-Deadline",
        "Illegal"
};

void
lapic_dump(void)
{
        int     i;

#define BOOL(a) ((a)?' ':'!')
#define VEC(lvt) \
        LAPIC_READ(lvt)&LAPIC_LVT_VECTOR_MASK
#define DS(lvt) \
        (LAPIC_READ(lvt)&LAPIC_LVT_DS_PENDING)?" SendPending" : "Idle"
#define DM(lvt) \
        DM_str[(LAPIC_READ(lvt)>>LAPIC_LVT_DM_SHIFT)&LAPIC_LVT_DM_MASK]
#define MASK(lvt) \
        BOOL(LAPIC_READ(lvt)&LAPIC_LVT_MASKED)
#define TM(lvt) \
        (LAPIC_READ(lvt)&LAPIC_LVT_TM_LEVEL)? "Level" : "Edge"
#define IP(lvt) \
        (LAPIC_READ(lvt)&LAPIC_LVT_IP_PLRITY_LOW)? "Low " : "High"

        kprintf("LAPIC %d at %p version 0x%x\n", 
                (LAPIC_READ(ID)>>LAPIC_ID_SHIFT)&LAPIC_ID_MASK,
                (void *) lapic_vbase,
                LAPIC_READ(VERSION)&LAPIC_VERSION_MASK);
        kprintf("Priorities: Task 0x%x  Arbitration 0x%x  Processor 0x%x\n",
                LAPIC_READ(TPR)&LAPIC_TPR_MASK,
                LAPIC_READ(APR)&LAPIC_APR_MASK,
                LAPIC_READ(PPR)&LAPIC_PPR_MASK);
        kprintf("Destination Format 0x%x Logical Destination 0x%x\n",
                is_x2apic ? 0 : LAPIC_READ(DFR)>>LAPIC_DFR_SHIFT,
                LAPIC_READ(LDR)>>LAPIC_LDR_SHIFT);
        kprintf("%cEnabled %cFocusChecking SV 0x%x\n",
                BOOL(LAPIC_READ(SVR)&LAPIC_SVR_ENABLE),
                BOOL(!(LAPIC_READ(SVR)&LAPIC_SVR_FOCUS_OFF)),
                LAPIC_READ(SVR) & LAPIC_SVR_MASK);
#if CONFIG_MCA
        if (mca_is_cmci_present())
                kprintf("LVT_CMCI:    Vector 0x%02x [%s] %s %cmasked\n",
                        VEC(LVT_CMCI),
                        DM(LVT_CMCI),
                        DS(LVT_CMCI),
                        MASK(LVT_CMCI));
#endif
        kprintf("LVT_TIMER:   Vector 0x%02x %s %cmasked %s\n",
                VEC(LVT_TIMER),
                DS(LVT_TIMER),
                MASK(LVT_TIMER),
                TMR_str[(LAPIC_READ(LVT_TIMER) >> LAPIC_LVT_TMR_SHIFT)
                                               &  LAPIC_LVT_TMR_MASK]);
        kprintf("  Initial Count: 0x%08x \n", LAPIC_READ(TIMER_INITIAL_COUNT));
        kprintf("  Current Count: 0x%08x \n", LAPIC_READ(TIMER_CURRENT_COUNT));
        kprintf("  Divide Config: 0x%08x \n", LAPIC_READ(TIMER_DIVIDE_CONFIG));
        kprintf("LVT_PERFCNT: Vector 0x%02x [%s] %s %cmasked\n",
                VEC(LVT_PERFCNT),
                DM(LVT_PERFCNT),
                DS(LVT_PERFCNT),
                MASK(LVT_PERFCNT));
        kprintf("LVT_THERMAL: Vector 0x%02x [%s] %s %cmasked\n",
                VEC(LVT_THERMAL),
                DM(LVT_THERMAL),
                DS(LVT_THERMAL),
                MASK(LVT_THERMAL));
        kprintf("LVT_LINT0:   Vector 0x%02x [%s][%s][%s] %s %cmasked\n",
                VEC(LVT_LINT0),
                DM(LVT_LINT0),
                TM(LVT_LINT0),
                IP(LVT_LINT0),
                DS(LVT_LINT0),
                MASK(LVT_LINT0));
        kprintf("LVT_LINT1:   Vector 0x%02x [%s][%s][%s] %s %cmasked\n",
                VEC(LVT_LINT1),
                DM(LVT_LINT1),
                TM(LVT_LINT1),
                IP(LVT_LINT1),
                DS(LVT_LINT1),
                MASK(LVT_LINT1));
        kprintf("LVT_ERROR:   Vector 0x%02x %s %cmasked\n",
                VEC(LVT_ERROR),
                DS(LVT_ERROR),
                MASK(LVT_ERROR));
        kprintf("ESR: %08x \n", lapic_esr_read());
        kprintf("       ");
        for(i=0xf; i>=0; i--)
                kprintf("%x%x%x%x",i,i,i,i);
        kprintf("\n");
        kprintf("TMR: 0x");
        for(i=7; i>=0; i--)
                kprintf("%08x",LAPIC_READ_OFFSET(TMR_BASE, i));
        kprintf("\n");
        kprintf("IRR: 0x");
        for(i=7; i>=0; i--)
                kprintf("%08x",LAPIC_READ_OFFSET(IRR_BASE, i));
        kprintf("\n");
        kprintf("ISR: 0x");
        for(i=7; i >= 0; i--)
                kprintf("%08x",LAPIC_READ_OFFSET(ISR_BASE, i));
        kprintf("\n");
}

boolean_t
lapic_probe(void)
{
        uint32_t        lo;
        uint32_t        hi;

        if (cpuid_features() & CPUID_FEATURE_APIC)
                return TRUE;

        if (cpuid_family() == 6 || cpuid_family() == 15) {
                /*
                 * Mobile Pentiums:
                 * There may be a local APIC which wasn't enabled by BIOS.
                 * So we try to enable it explicitly.
                 */
                rdmsr(MSR_IA32_APIC_BASE, lo, hi);
                lo &= ~MSR_IA32_APIC_BASE_BASE;
                lo |= MSR_IA32_APIC_BASE_ENABLE | LAPIC_START;
                lo |= MSR_IA32_APIC_BASE_ENABLE;
                wrmsr(MSR_IA32_APIC_BASE, lo, hi);

                /*
                 * Re-initialize cpu features info and re-check.
                 */
                cpuid_set_info();
                /* We expect this codepath will never be traversed
                 * due to EFI enabling the APIC. Reducing the APIC
                 * interrupt base dynamically is not supported.
                 */
                if (cpuid_features() & CPUID_FEATURE_APIC) {
                        printf("Local APIC discovered and enabled\n");
                        lapic_os_enabled = TRUE;
                        lapic_interrupt_base = LAPIC_REDUCED_INTERRUPT_BASE;
                        return TRUE;
                }
        }

        return FALSE;
}

void
lapic_shutdown(void)
{
        uint32_t lo;
        uint32_t hi;
        uint32_t value;

        /* Shutdown if local APIC was enabled by OS */
        if (lapic_os_enabled == FALSE)
                return;

        mp_disable_preemption();

        /* ExtINT: masked */
        if (get_cpu_number() == master_cpu) {
                value = LAPIC_READ(LVT_LINT0);
                value |= LAPIC_LVT_MASKED;
                LAPIC_WRITE(LVT_LINT0, value);
        }

        /* Error: masked */
        LAPIC_WRITE(LVT_ERROR, LAPIC_READ(LVT_ERROR) | LAPIC_LVT_MASKED);

        /* Timer: masked */
        LAPIC_WRITE(LVT_TIMER, LAPIC_READ(LVT_TIMER) | LAPIC_LVT_MASKED);

        /* Perfmon: masked */
        LAPIC_WRITE(LVT_PERFCNT, LAPIC_READ(LVT_PERFCNT) | LAPIC_LVT_MASKED);

        /* APIC software disabled */
        LAPIC_WRITE(SVR, LAPIC_READ(SVR) & ~LAPIC_SVR_ENABLE);

        /* Bypass the APIC completely and update cpu features */
        rdmsr(MSR_IA32_APIC_BASE, lo, hi);
        lo &= ~MSR_IA32_APIC_BASE_ENABLE;
        wrmsr(MSR_IA32_APIC_BASE, lo, hi);
        cpuid_set_info();

        mp_enable_preemption();
}

void
lapic_configure(void)
{
        int     value;

        if (lapic_error_time_threshold == 0 && cpu_number() == 0) {
                nanoseconds_to_absolutetime(NSEC_PER_SEC >> 2, &lapic_error_time_threshold);
                if (!PE_parse_boot_argn("lapic_dont_panic", &lapic_dont_panic, sizeof(lapic_dont_panic))) {
                        lapic_dont_panic = FALSE;
                }
        }

        /* Accept all */
        LAPIC_WRITE(TPR, 0);

        LAPIC_WRITE(SVR, LAPIC_VECTOR(SPURIOUS) | LAPIC_SVR_ENABLE);

        /* ExtINT */
        if (get_cpu_number() == master_cpu) {
                value = LAPIC_READ(LVT_LINT0);
                value &= ~LAPIC_LVT_MASKED;
                value |= LAPIC_LVT_DM_EXTINT;
                LAPIC_WRITE(LVT_LINT0, value);
        }

        /* Timer: unmasked, one-shot */
        LAPIC_WRITE(LVT_TIMER, LAPIC_VECTOR(TIMER));

        /* Perfmon: unmasked */
        LAPIC_WRITE(LVT_PERFCNT, LAPIC_VECTOR(PERFCNT));

        /* Thermal: unmasked */
        LAPIC_WRITE(LVT_THERMAL, LAPIC_VECTOR(THERMAL));

#if CONFIG_MCA
        /* CMCI, if available */
        if (mca_is_cmci_present())
                LAPIC_WRITE(LVT_CMCI, LAPIC_VECTOR(CMCI));
#endif

        if (((cpu_number() == master_cpu) && lapic_errors_masked == FALSE) ||
                (cpu_number() != master_cpu)) {
                lapic_esr_clear();
                LAPIC_WRITE(LVT_ERROR, LAPIC_VECTOR(ERROR));
        }
}

void
lapic_set_timer(
        boolean_t               interrupt_unmasked,
        lapic_timer_mode_t      mode,
        lapic_timer_divide_t    divisor,
        lapic_timer_count_t     initial_count)
{
        uint32_t        timer_vector;

        mp_disable_preemption();
        timer_vector = LAPIC_READ(LVT_TIMER);
        timer_vector &= ~(LAPIC_LVT_MASKED|LAPIC_LVT_PERIODIC);;
        timer_vector |= interrupt_unmasked ? 0 : LAPIC_LVT_MASKED;
        timer_vector |= (mode == periodic) ? LAPIC_LVT_PERIODIC : 0;
        LAPIC_WRITE(LVT_TIMER, timer_vector);
        LAPIC_WRITE(TIMER_DIVIDE_CONFIG, divisor);
        LAPIC_WRITE(TIMER_INITIAL_COUNT, initial_count);
        mp_enable_preemption();
}

void
lapic_config_timer(
        boolean_t               interrupt_unmasked,
        lapic_timer_mode_t      mode,
        lapic_timer_divide_t    divisor)
{
        uint32_t        timer_vector;

        mp_disable_preemption();
        timer_vector = LAPIC_READ(LVT_TIMER);
        timer_vector &= ~(LAPIC_LVT_MASKED |
                          LAPIC_LVT_PERIODIC |
                          LAPIC_LVT_TSC_DEADLINE);
        timer_vector |= interrupt_unmasked ? 0 : LAPIC_LVT_MASKED;
        timer_vector |= (mode == periodic) ? LAPIC_LVT_PERIODIC : 0;
        LAPIC_WRITE(LVT_TIMER, timer_vector);
        LAPIC_WRITE(TIMER_DIVIDE_CONFIG, divisor);
        mp_enable_preemption();
}

/*
 * Configure TSC-deadline timer mode. The lapic interrupt is always unmasked.
 */
void
lapic_config_tsc_deadline_timer(void)
{
        uint32_t        timer_vector;

        DBG("lapic_config_tsc_deadline_timer()\n");
        mp_disable_preemption();
        timer_vector = LAPIC_READ(LVT_TIMER);
        timer_vector &= ~(LAPIC_LVT_MASKED |
                          LAPIC_LVT_PERIODIC);
        timer_vector |= LAPIC_LVT_TSC_DEADLINE;
        LAPIC_WRITE(LVT_TIMER, timer_vector);

        /* Serialize writes per Intel OSWG */
        do {
                lapic_set_tsc_deadline_timer(rdtsc64() + (1ULL<<32));
        } while (lapic_get_tsc_deadline_timer() == 0);
        lapic_set_tsc_deadline_timer(0);

        mp_enable_preemption();
        DBG("lapic_config_tsc_deadline_timer() done\n");
}

void
lapic_set_timer_fast(
        lapic_timer_count_t     initial_count)
{
        LAPIC_WRITE(LVT_TIMER, LAPIC_READ(LVT_TIMER) & ~LAPIC_LVT_MASKED);
        LAPIC_WRITE(TIMER_INITIAL_COUNT, initial_count);
}

void
lapic_set_tsc_deadline_timer(uint64_t deadline)
{
        /* Don't bother disarming: wrmsr64(MSR_IA32_TSC_DEADLINE, 0); */
        wrmsr64(MSR_IA32_TSC_DEADLINE, deadline);
}

uint64_t
lapic_get_tsc_deadline_timer(void)
{
        return rdmsr64(MSR_IA32_TSC_DEADLINE);
}

void
lapic_get_timer(
        lapic_timer_mode_t      *mode,
        lapic_timer_divide_t    *divisor,
        lapic_timer_count_t     *initial_count,
        lapic_timer_count_t     *current_count)
{
        mp_disable_preemption();
        if (mode)
                *mode = (LAPIC_READ(LVT_TIMER) & LAPIC_LVT_PERIODIC) ?
                                periodic : one_shot;
        if (divisor)
                *divisor = LAPIC_READ(TIMER_DIVIDE_CONFIG) & LAPIC_TIMER_DIVIDE_MASK;
        if (initial_count)
                *initial_count = LAPIC_READ(TIMER_INITIAL_COUNT);
        if (current_count)
                *current_count = LAPIC_READ(TIMER_CURRENT_COUNT);
        mp_enable_preemption();
} 

static inline void
_lapic_end_of_interrupt(void)
{
        LAPIC_WRITE(EOI, 0);
}

void
lapic_end_of_interrupt(void)
{
        _lapic_end_of_interrupt();
}

void lapic_unmask_perfcnt_interrupt(void) {
        LAPIC_WRITE(LVT_PERFCNT, LAPIC_VECTOR(PERFCNT));
}

void lapic_set_perfcnt_interrupt_mask(boolean_t mask) {
        uint32_t m = (mask ? LAPIC_LVT_MASKED : 0);
        LAPIC_WRITE(LVT_PERFCNT, LAPIC_VECTOR(PERFCNT) | m);
}

void
lapic_set_intr_func(int vector, i386_intr_func_t func)
{
        if (vector > lapic_interrupt_base)
                vector -= lapic_interrupt_base;

        switch (vector) {
        case LAPIC_NMI_INTERRUPT:
        case LAPIC_INTERPROCESSOR_INTERRUPT:
        case LAPIC_TIMER_INTERRUPT:
        case LAPIC_THERMAL_INTERRUPT:
        case LAPIC_PERFCNT_INTERRUPT:
        case LAPIC_CMCI_INTERRUPT:
        case LAPIC_PM_INTERRUPT:
                lapic_intr_func[vector] = func;
                break;
        default:
                panic("lapic_set_intr_func(%d,%p) invalid vector\n",
                        vector, func);
        }
}

void    lapic_set_pmi_func(i386_intr_func_t func) {
        lapic_set_intr_func(LAPIC_VECTOR(PERFCNT), func);
}

int
lapic_interrupt(int interrupt_num, x86_saved_state_t *state)
{
        int     retval = 0;
        int     esr = -1;

        interrupt_num -= lapic_interrupt_base;
        if (interrupt_num < 0) {
                if (interrupt_num == (LAPIC_NMI_INTERRUPT - lapic_interrupt_base) &&
                    lapic_intr_func[LAPIC_NMI_INTERRUPT] != NULL) {
                        retval = (*lapic_intr_func[LAPIC_NMI_INTERRUPT])(state);
                        return retval;
                }
                else
                        return 0;
        }

        switch(interrupt_num) {
        case LAPIC_TIMER_INTERRUPT:
        case LAPIC_THERMAL_INTERRUPT:
        case LAPIC_INTERPROCESSOR_INTERRUPT:
        case LAPIC_PM_INTERRUPT:
                if (lapic_intr_func[interrupt_num] != NULL)
                        (void) (*lapic_intr_func[interrupt_num])(state);
                _lapic_end_of_interrupt();
                retval = 1;
                break;
        case LAPIC_PERFCNT_INTERRUPT:
                /* If a function has been registered, invoke it.  Otherwise,
                 * pass up to IOKit.
                 */
                if (lapic_intr_func[interrupt_num] != NULL) {
                        (void) (*lapic_intr_func[interrupt_num])(state);
                        /* Unmask the interrupt since we don't expect legacy users
                         * to be responsible for it.
                         */
                        lapic_unmask_perfcnt_interrupt();
                        _lapic_end_of_interrupt();
                        retval = 1;
                }
                break;
        case LAPIC_CMCI_INTERRUPT:
                if (lapic_intr_func[interrupt_num] != NULL)
                        (void) (*lapic_intr_func[interrupt_num])(state);
                /* return 0 for plaform expert to handle */
                break;
        case LAPIC_ERROR_INTERRUPT:
                /* We treat error interrupts on APs as fatal.
                 * The current interrupt steering scheme directs most
                 * external interrupts to the BSP (HPET interrupts being
                 * a notable exception); hence, such an error
                 * on an AP may signify LVT corruption (with "may" being
                 * the operative word). On the BSP, we adopt a more
                 * lenient approach, in the interests of enhancing
                 * debuggability and reducing fragility.
                 * If "lapic_error_count_threshold" error interrupts
                 * occur within "lapic_error_time_threshold" absolute
                 * time units, we mask the error vector and log. The
                 * error interrupts themselves are likely
                 * side effects of issues which are beyond the purview of
                 * the local APIC interrupt handler, however. The Error
                 * Status Register value (the illegal destination
                 * vector code is one observed in practice) indicates
                 * the immediate cause of the error.
                 */
                esr = lapic_esr_read();
                lapic_dump();

                if ((debug_boot_arg && (lapic_dont_panic == FALSE)) ||
                        cpu_number() != master_cpu) {
                        panic("Local APIC error, ESR: %d\n", esr);
                }

                if (cpu_number() == master_cpu) {
                        uint64_t abstime = mach_absolute_time();
                        if ((abstime - lapic_last_master_error) < lapic_error_time_threshold) {
                                if (lapic_master_error_count++ > lapic_error_count_threshold) {
                                        lapic_errors_masked = TRUE;
                                        LAPIC_WRITE(LVT_ERROR, LAPIC_READ(LVT_ERROR) | LAPIC_LVT_MASKED);
                                        printf("Local APIC: errors masked\n");
                                }
                        }
                        else {
                                lapic_last_master_error = abstime;
                                lapic_master_error_count = 0;
                        }
                        printf("Local APIC error on master CPU, ESR: %d, error count this run: %d\n", esr, lapic_master_error_count);
                }

                _lapic_end_of_interrupt();
                retval = 1;
                break;
        case LAPIC_SPURIOUS_INTERRUPT:
                kprintf("SPIV\n");
                /* No EOI required here */
                retval = 1;
                break;
        case LAPIC_PMC_SW_INTERRUPT: 
                {
                }
                break;
        case LAPIC_KICK_INTERRUPT:
                _lapic_end_of_interrupt();
                retval = 1;
                break;
        }

        return retval;
}

void
lapic_smm_restore(void)
{
        boolean_t state;

        if (lapic_os_enabled == FALSE)
                return;

        state = ml_set_interrupts_enabled(FALSE);

        if (LAPIC_ISR_IS_SET(LAPIC_REDUCED_INTERRUPT_BASE, TIMER)) {
                /*
                 * Bogus SMI handler enables interrupts but does not know about
                 * local APIC interrupt sources. When APIC timer counts down to
                 * zero while in SMM, local APIC will end up waiting for an EOI
                 * but no interrupt was delivered to the OS.
                 */
                _lapic_end_of_interrupt();

                /*
                 * timer is one-shot, trigger another quick countdown to trigger
                 * another timer interrupt.
                 */
                if (LAPIC_READ(TIMER_CURRENT_COUNT) == 0) {
                        LAPIC_WRITE(TIMER_INITIAL_COUNT, 1);
                }

                kprintf("lapic_smm_restore\n");
        }

        ml_set_interrupts_enabled(state);
}

void
lapic_send_ipi(int cpu, int vector)
{
        boolean_t       state;

        if (vector < lapic_interrupt_base)
                vector += lapic_interrupt_base;

        state = ml_set_interrupts_enabled(FALSE);

        /* Wait for pending outgoing send to complete */
        while (LAPIC_READ_ICR() & LAPIC_ICR_DS_PENDING) {
                cpu_pause();
        }

        LAPIC_WRITE_ICR(cpu_to_lapic[cpu], vector | LAPIC_ICR_DM_FIXED);

        (void) ml_set_interrupts_enabled(state);
}

/*
 * The following interfaces are privately exported to AICPM.
 */

boolean_t
lapic_is_interrupt_pending(void)
{
        int             i;

        for (i = 0; i < 8; i += 1) {
                if ((LAPIC_READ_OFFSET(IRR_BASE, i) != 0) ||
                    (LAPIC_READ_OFFSET(ISR_BASE, i) != 0))
                        return (TRUE);
        }

        return (FALSE);
}

boolean_t
lapic_is_interrupting(uint8_t vector)
{
        int             i;
        int             bit;
        uint32_t        irr;
        uint32_t        isr;

        i = vector / 32;
        bit = 1 << (vector % 32);

        irr = LAPIC_READ_OFFSET(IRR_BASE, i);
        isr = LAPIC_READ_OFFSET(ISR_BASE, i);

        if ((irr | isr) & bit)
                return (TRUE);

        return (FALSE);
}

void
lapic_interrupt_counts(uint64_t intrs[256])
{
        int             i;
        int             j;
        int             bit;
        uint32_t        irr;
        uint32_t        isr;

        if (intrs == NULL)
                return;

        for (i = 0; i < 8; i += 1) {
                irr = LAPIC_READ_OFFSET(IRR_BASE, i);
                isr = LAPIC_READ_OFFSET(ISR_BASE, i);

                if ((isr | irr) == 0)
                        continue;

                for (j = (i == 0) ? 16 : 0; j < 32; j += 1) {
                        bit = (32 * i) + j;
                        if ((isr | irr) & (1 << j))
                                intrs[bit] += 1;
                }
        }
}

void
lapic_disable_timer(void)
{
        uint32_t        lvt_timer;

        /*
         * If we're in deadline timer mode,
         * simply clear the deadline timer, otherwise
         * mask the timer interrupt and clear the countdown.
         */
        lvt_timer = LAPIC_READ(LVT_TIMER);
        if (lvt_timer & LAPIC_LVT_TSC_DEADLINE) {
                wrmsr64(MSR_IA32_TSC_DEADLINE, 0);
        } else {
                LAPIC_WRITE(LVT_TIMER, lvt_timer | LAPIC_LVT_MASKED);
                LAPIC_WRITE(TIMER_INITIAL_COUNT, 0);
                lvt_timer = LAPIC_READ(LVT_TIMER);
        }
}

/* SPI returning the CMCI vector */
uint8_t
lapic_get_cmci_vector(void)
{
        uint8_t cmci_vector = 0;
#if CONFIG_MCA
        /* CMCI, if available */
        if (mca_is_cmci_present())
                cmci_vector = LAPIC_VECTOR(CMCI);
#endif
        return cmci_vector;
}

#if DEVELOPMENT || DEBUG
extern void lapic_trigger_MC(void);
void
lapic_trigger_MC(void)
{
        /* A 64-bit access to any register will do it. */
        volatile uint64_t dummy = *(volatile uint64_t *) (volatile void *) LAPIC_MMIO(ID);
        dummy++;
}
#endif