xnu-792.6.76.tar.gz

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

/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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 OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */

#include <mach_rt.h>
#include <mach_kdb.h>
#include <mach_kdp.h>
#include <mach_ldebug.h>
#include <gprof.h>

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

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

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

#include <profiling/profile-mk.h>

#include <i386/mp.h>
#include <i386/mp_events.h>
#include <i386/mp_slave_boot.h>
#include <i386/apic.h>
#include <i386/ipl.h>
#include <i386/fpu.h>
#include <i386/pio.h>
#include <i386/cpuid.h>
#include <i386/proc_reg.h>
#include <i386/machine_cpu.h>
#include <i386/misc_protos.h>
#include <i386/mtrr.h>
#include <i386/postcode.h>
#include <i386/perfmon.h>
#include <i386/cpu_threads.h>
#include <i386/mp_desc.h>

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

/*
 * By default, use high vectors to leave vector space for systems
 * with multiple I/O APIC's. However some systems that boot with
 * local APIC disabled will hang in SMM when vectors greater than
 * 0x5F are used. Those systems are not expected to have I/O APIC
 * so 16 (0x50 - 0x40) vectors for legacy PIC support is perfect.
 */
#define LAPIC_DEFAULT_INTERRUPT_BASE    0xD0
#define LAPIC_REDUCED_INTERRUPT_BASE    0x50
/*
 * Specific lapic interrupts are relative to this base:
 */ 
#define LAPIC_PERFCNT_INTERRUPT         0xB
#define LAPIC_TIMER_INTERRUPT           0xC
#define LAPIC_SPURIOUS_INTERRUPT        0xD     
#define LAPIC_INTERPROCESSOR_INTERRUPT  0xE
#define LAPIC_ERROR_INTERRUPT           0xF

/* Initialize lapic_id so cpu_number() works on non SMP systems */
unsigned long   lapic_id_initdata = 0;
unsigned long   lapic_id = (unsigned long)&lapic_id_initdata;
vm_offset_t     lapic_start;

static i386_intr_func_t lapic_timer_func;
static i386_intr_func_t lapic_pmi_func;

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

/* Base vector for local APIC interrupt sources */
int lapic_interrupt_base = LAPIC_DEFAULT_INTERRUPT_BASE;

void            slave_boot_init(void);

static void     mp_kdp_wait(void);
static void     mp_rendezvous_action(void);

boolean_t       smp_initialized = FALSE;

decl_simple_lock_data(,mp_kdp_lock);

decl_mutex_data(static, mp_cpu_boot_lock);

/* Variables needed for MP rendezvous. */
static void             (*mp_rv_setup_func)(void *arg);
static void             (*mp_rv_action_func)(void *arg);
static void             (*mp_rv_teardown_func)(void *arg);
static void             *mp_rv_func_arg;
static int              mp_rv_ncpus;
static long             mp_rv_waiters[2];
decl_simple_lock_data(,mp_rv_lock);

int             lapic_to_cpu[MAX_CPUS];
int             cpu_to_lapic[MAX_CPUS];

static void
lapic_cpu_map_init(void)
{
        int     i;

        for (i = 0; i < MAX_CPUS; i++) {
                lapic_to_cpu[i] = -1;
                cpu_to_lapic[i] = -1;
        }
}

void
lapic_cpu_map(int apic_id, int cpu)
{
        cpu_to_lapic[cpu] = apic_id;
        lapic_to_cpu[apic_id] = cpu;
}

#ifdef MP_DEBUG
static 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_CPUS; i++) {
                if (lapic_to_cpu[i] == -1)
                        continue;
                kprintf("lapic_to_cpu[%d]: %d\n",
                        i, lapic_to_cpu[i]);
        }
}
#define LAPIC_CPU_MAP_DUMP()    lapic_cpu_map_dump()
#define LAPIC_DUMP()            lapic_dump()
#else
#define LAPIC_CPU_MAP_DUMP()
#define LAPIC_DUMP()
#endif /* MP_DEBUG */

#define LAPIC_REG(reg) \
        (*((volatile int *)(lapic_start + LAPIC_##reg)))
#define LAPIC_REG_OFFSET(reg,off) \
        (*((volatile int *)(lapic_start + LAPIC_##reg + (off))))

#define LAPIC_VECTOR(src) \
        (lapic_interrupt_base + LAPIC_##src##_INTERRUPT)

#define LAPIC_ISR_IS_SET(base,src) \
        (LAPIC_REG_OFFSET(ISR_BASE,((base+LAPIC_##src##_INTERRUPT)/32)*0x10) & \
                (1 <<((base + LAPIC_##src##_INTERRUPT)%32)))

#if GPROF
/*
 * Initialize dummy structs for profiling. These aren't used but
 * allows hertz_tick() to be built with GPROF defined.
 */
struct profile_vars _profile_vars;
struct profile_vars *_profile_vars_cpus[MAX_CPUS] = { &_profile_vars };
#define GPROF_INIT()                                                    \
{                                                                       \
        int     i;                                                      \
                                                                        \
        /* Hack to initialize pointers to unused profiling structs */   \
        for (i = 1; i < MAX_CPUS; i++)                          \
                _profile_vars_cpus[i] = &_profile_vars;                 \
}
#else
#define GPROF_INIT()
#endif /* GPROF */

extern void     master_up(void);

void
smp_init(void)
{
        int             result;
        vm_map_entry_t  entry;
        uint32_t        lo;
        uint32_t        hi;
        boolean_t       is_boot_processor;
        boolean_t       is_lapic_enabled;
        vm_offset_t     lapic_base;

        simple_lock_init(&mp_kdp_lock, 0);
        simple_lock_init(&mp_rv_lock, 0);
        mutex_init(&mp_cpu_boot_lock, 0);
        console_init();

        /* Local APIC? */
        if (!lapic_probe())
                return;

        /* 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;
        lapic_base = (lo &  MSR_IA32_APIC_BASE_BASE);
        kprintf("MSR_IA32_APIC_BASE 0x%x %s %s\n", lapic_base,
                is_lapic_enabled ? "enabled" : "disabled",
                is_boot_processor ? "BSP" : "AP");
        if (!is_boot_processor || !is_lapic_enabled)
                panic("Unexpected local APIC state\n");

        /* Establish a map to the local apic */
        lapic_start = vm_map_min(kernel_map);
        result = vm_map_find_space(kernel_map, &lapic_start,
                                   round_page(LAPIC_SIZE), 0, &entry);
        if (result != KERN_SUCCESS) {
                panic("smp_init: vm_map_find_entry FAILED (err=%d)", result);
        }
        vm_map_unlock(kernel_map);
        pmap_enter(pmap_kernel(),
                        lapic_start,
                        (ppnum_t) i386_btop(lapic_base),
                        VM_PROT_READ|VM_PROT_WRITE,
                        VM_WIMG_USE_DEFAULT,
                        TRUE);
        lapic_id = (unsigned long)(lapic_start + LAPIC_ID);

        if ((LAPIC_REG(VERSION)&LAPIC_VERSION_MASK) != 0x14) {
                printf("Local APIC version not 0x14 as expected\n");
        }

        /* Set up the lapic_id <-> cpu_number map and add this boot processor */
        lapic_cpu_map_init();
        lapic_cpu_map((LAPIC_REG(ID)>>LAPIC_ID_SHIFT)&LAPIC_ID_MASK, 0);

        lapic_init();

        cpu_thread_init();

        if (pmc_init() != KERN_SUCCESS)
                printf("Performance counters not available\n");

        GPROF_INIT();
        DBGLOG_CPU_INIT(master_cpu);

        slave_boot_init();
        master_up();

        smp_initialized = TRUE;

        return;
}


static int
lapic_esr_read(void)
{
        /* write-read register */
        LAPIC_REG(ERROR_STATUS) = 0;
        return LAPIC_REG(ERROR_STATUS);
}

static void 
lapic_esr_clear(void)
{
        LAPIC_REG(ERROR_STATUS) = 0;
        LAPIC_REG(ERROR_STATUS) = 0;
}

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

void
lapic_dump(void)
{
        int     i;

#define BOOL(a) ((a)?' ':'!')

        kprintf("LAPIC %d at 0x%x version 0x%x\n", 
                (LAPIC_REG(ID)>>LAPIC_ID_SHIFT)&LAPIC_ID_MASK,
                lapic_start,
                LAPIC_REG(VERSION)&LAPIC_VERSION_MASK);
        kprintf("Priorities: Task 0x%x  Arbitration 0x%x  Processor 0x%x\n",
                LAPIC_REG(TPR)&LAPIC_TPR_MASK,
                LAPIC_REG(APR)&LAPIC_APR_MASK,
                LAPIC_REG(PPR)&LAPIC_PPR_MASK);
        kprintf("Destination Format 0x%x Logical Destination 0x%x\n",
                LAPIC_REG(DFR)>>LAPIC_DFR_SHIFT,
                LAPIC_REG(LDR)>>LAPIC_LDR_SHIFT);
        kprintf("%cEnabled %cFocusChecking SV 0x%x\n",
                BOOL(LAPIC_REG(SVR)&LAPIC_SVR_ENABLE),
                BOOL(!(LAPIC_REG(SVR)&LAPIC_SVR_FOCUS_OFF)),
                LAPIC_REG(SVR) & LAPIC_SVR_MASK);
        kprintf("LVT_TIMER:   Vector 0x%02x %s %cmasked %s\n",
                LAPIC_REG(LVT_TIMER)&LAPIC_LVT_VECTOR_MASK,
                (LAPIC_REG(LVT_TIMER)&LAPIC_LVT_DS_PENDING)?"SendPending":"Idle",
                BOOL(LAPIC_REG(LVT_TIMER)&LAPIC_LVT_MASKED),
                (LAPIC_REG(LVT_TIMER)&LAPIC_LVT_PERIODIC)?"Periodic":"OneShot");
        kprintf("  Initial Count: 0x%08x \n", LAPIC_REG(TIMER_INITIAL_COUNT));
        kprintf("  Current Count: 0x%08x \n", LAPIC_REG(TIMER_CURRENT_COUNT));
        kprintf("  Divide Config: 0x%08x \n", LAPIC_REG(TIMER_DIVIDE_CONFIG));
        kprintf("LVT_PERFCNT: Vector 0x%02x [%s] %s %cmasked\n",
                LAPIC_REG(LVT_PERFCNT)&LAPIC_LVT_VECTOR_MASK,
                DM[(LAPIC_REG(LVT_PERFCNT)>>LAPIC_LVT_DM_SHIFT)&LAPIC_LVT_DM_MASK],
                (LAPIC_REG(LVT_PERFCNT)&LAPIC_LVT_DS_PENDING)?"SendPending":"Idle",
                BOOL(LAPIC_REG(LVT_PERFCNT)&LAPIC_LVT_MASKED));
        kprintf("LVT_LINT0:   Vector 0x%02x [%s][%s][%s] %s %cmasked\n",
                LAPIC_REG(LVT_LINT0)&LAPIC_LVT_VECTOR_MASK,
                DM[(LAPIC_REG(LVT_LINT0)>>LAPIC_LVT_DM_SHIFT)&LAPIC_LVT_DM_MASK],
                (LAPIC_REG(LVT_LINT0)&LAPIC_LVT_TM_LEVEL)?"Level":"Edge ",
                (LAPIC_REG(LVT_LINT0)&LAPIC_LVT_IP_PLRITY_LOW)?"Low ":"High",
                (LAPIC_REG(LVT_LINT0)&LAPIC_LVT_DS_PENDING)?"SendPending":"Idle",
                BOOL(LAPIC_REG(LVT_LINT0)&LAPIC_LVT_MASKED));
        kprintf("LVT_LINT1:   Vector 0x%02x [%s][%s][%s] %s %cmasked\n",
                LAPIC_REG(LVT_LINT1)&LAPIC_LVT_VECTOR_MASK,
                DM[(LAPIC_REG(LVT_LINT1)>>LAPIC_LVT_DM_SHIFT)&LAPIC_LVT_DM_MASK],
                (LAPIC_REG(LVT_LINT1)&LAPIC_LVT_TM_LEVEL)?"Level":"Edge ",
                (LAPIC_REG(LVT_LINT1)&LAPIC_LVT_IP_PLRITY_LOW)?"Low ":"High",
                (LAPIC_REG(LVT_LINT1)&LAPIC_LVT_DS_PENDING)?"SendPending":"Idle",
                BOOL(LAPIC_REG(LVT_LINT1)&LAPIC_LVT_MASKED));
        kprintf("LVT_ERROR:   Vector 0x%02x %s %cmasked\n",
                LAPIC_REG(LVT_ERROR)&LAPIC_LVT_VECTOR_MASK,
                (LAPIC_REG(LVT_ERROR)&LAPIC_LVT_DS_PENDING)?"SendPending":"Idle",
                BOOL(LAPIC_REG(LVT_ERROR)&LAPIC_LVT_MASKED));
        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_REG_OFFSET(TMR_BASE, i*0x10));
        kprintf("\n");
        kprintf("IRR: 0x");
        for(i=7; i>=0; i--)
                kprintf("%08x",LAPIC_REG_OFFSET(IRR_BASE, i*0x10));
        kprintf("\n");
        kprintf("ISR: 0x");
        for(i=7; i >= 0; i--)
                kprintf("%08x",LAPIC_REG_OFFSET(ISR_BASE, i*0x10));
        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.
                 */
                set_cpu_model();
                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_REG(LVT_LINT0);
                value |= LAPIC_LVT_MASKED;
                LAPIC_REG(LVT_LINT0) = value;
        }

        /* Timer: masked */
        LAPIC_REG(LVT_TIMER) |= LAPIC_LVT_MASKED;

        /* Perfmon: masked */
        LAPIC_REG(LVT_PERFCNT) |= LAPIC_LVT_MASKED;

        /* Error: masked */
        LAPIC_REG(LVT_ERROR) |= LAPIC_LVT_MASKED;

        /* APIC software disabled */
        LAPIC_REG(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);
        set_cpu_model();

        mp_enable_preemption();
}

void
lapic_init(void)
{
        int     value;

        /* Set flat delivery model, logical processor id */
        LAPIC_REG(DFR) = LAPIC_DFR_FLAT;
        LAPIC_REG(LDR) = (get_cpu_number()) << LAPIC_LDR_SHIFT;

        /* Accept all */
        LAPIC_REG(TPR) =  0;

        LAPIC_REG(SVR) = LAPIC_VECTOR(SPURIOUS) | LAPIC_SVR_ENABLE;

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

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

        /* Perfmon: unmasked */
        LAPIC_REG(LVT_PERFCNT) = LAPIC_VECTOR(PERFCNT);

        lapic_esr_clear();

        LAPIC_REG(LVT_ERROR) = LAPIC_VECTOR(ERROR);

}

void
lapic_set_timer_func(i386_intr_func_t func)
{
        lapic_timer_func = func;
}

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

        state = ml_set_interrupts_enabled(FALSE);
        timer_vector = LAPIC_REG(LVT_TIMER);
        timer_vector &= ~(LAPIC_LVT_MASKED|LAPIC_LVT_PERIODIC);;
        timer_vector |= interrupt ? 0 : LAPIC_LVT_MASKED;
        timer_vector |= (mode == periodic) ? LAPIC_LVT_PERIODIC : 0;
        LAPIC_REG(LVT_TIMER) = timer_vector;
        LAPIC_REG(TIMER_DIVIDE_CONFIG) = divisor;
        LAPIC_REG(TIMER_INITIAL_COUNT) = initial_count;
        ml_set_interrupts_enabled(state);
}

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)
{
        boolean_t       state;

        state = ml_set_interrupts_enabled(FALSE);
        if (mode)
                *mode = (LAPIC_REG(LVT_TIMER) & LAPIC_LVT_PERIODIC) ?
                                periodic : one_shot;
        if (divisor)
                *divisor = LAPIC_REG(TIMER_DIVIDE_CONFIG) & LAPIC_TIMER_DIVIDE_MASK;
        if (initial_count)
                *initial_count = LAPIC_REG(TIMER_INITIAL_COUNT);
        if (current_count)
                *current_count = LAPIC_REG(TIMER_CURRENT_COUNT);
        ml_set_interrupts_enabled(state);
} 

void
lapic_set_pmi_func(i386_intr_func_t func)
{
        lapic_pmi_func = func;
}

static inline void
_lapic_end_of_interrupt(void)
{
        LAPIC_REG(EOI) = 0;
}

void
lapic_end_of_interrupt(void)
{
        _lapic_end_of_interrupt();
}

int
lapic_interrupt(int interrupt, void *state)
{
        interrupt -= lapic_interrupt_base;
        if (interrupt < 0)
                return 0;

        switch(interrupt) {
        case LAPIC_PERFCNT_INTERRUPT:
                if (lapic_pmi_func != NULL)
                        (*lapic_pmi_func)(
                                (struct i386_interrupt_state *) state);
                /* Clear interrupt masked */
                LAPIC_REG(LVT_PERFCNT) = LAPIC_VECTOR(PERFCNT);
                _lapic_end_of_interrupt();
                return 1;
        case LAPIC_TIMER_INTERRUPT:
                _lapic_end_of_interrupt();
                if (lapic_timer_func != NULL)
                        (*lapic_timer_func)(
                                (struct i386_interrupt_state *) state);
                return 1;
        case LAPIC_ERROR_INTERRUPT:
                lapic_dump();
                panic("Local APIC error\n");
                _lapic_end_of_interrupt();
                return 1;
        case LAPIC_SPURIOUS_INTERRUPT:
                kprintf("SPIV\n");
                /* No EOI required here */
                return 1;
        case LAPIC_INTERPROCESSOR_INTERRUPT:
                cpu_signal_handler((struct i386_interrupt_state *) state);
                _lapic_end_of_interrupt();
                return 1;
        }
        return 0;
}

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_REG(TIMER_CURRENT_COUNT) == 0) {
                        LAPIC_REG(TIMER_INITIAL_COUNT) = 1;
                }

                kprintf("lapic_smm_restore\n");
        }

        ml_set_interrupts_enabled(state);
}

kern_return_t
intel_startCPU(
        int     slot_num)
{

        int     i = 1000;
        int     lapic = cpu_to_lapic[slot_num];

        assert(lapic != -1);

        DBGLOG_CPU_INIT(slot_num);

        DBG("intel_startCPU(%d) lapic_id=%d\n", slot_num, lapic);
        DBG("IdlePTD(%p): 0x%x\n", &IdlePTD, (int) IdlePTD);

        /* Initialize (or re-initialize) the descriptor tables for this cpu. */
        mp_desc_init(cpu_datap(slot_num), FALSE);

        /* Serialize use of the slave boot stack. */
        mutex_lock(&mp_cpu_boot_lock);

        mp_disable_preemption();
        if (slot_num == get_cpu_number()) {
                mp_enable_preemption();
                mutex_unlock(&mp_cpu_boot_lock);
                return KERN_SUCCESS;
        }

        LAPIC_REG(ICRD) = lapic << LAPIC_ICRD_DEST_SHIFT;
        LAPIC_REG(ICR) = LAPIC_ICR_DM_INIT;
        delay(10000);

        LAPIC_REG(ICRD) = lapic << LAPIC_ICRD_DEST_SHIFT;
        LAPIC_REG(ICR) = LAPIC_ICR_DM_STARTUP|(MP_BOOT>>12);
        delay(200);

        LAPIC_REG(ICRD) = lapic << LAPIC_ICRD_DEST_SHIFT;
        LAPIC_REG(ICR) = LAPIC_ICR_DM_STARTUP|(MP_BOOT>>12);
        delay(200);

#ifdef  POSTCODE_DELAY
        /* Wait much longer if postcodes are displayed for a delay period. */
        i *= 10000;
#endif
        while(i-- > 0) {
                if (cpu_datap(slot_num)->cpu_running)
                        break;
                delay(10000);
        }

        mp_enable_preemption();
        mutex_unlock(&mp_cpu_boot_lock);

        if (!cpu_datap(slot_num)->cpu_running) {
                DBG("Failed to start CPU %02d\n", slot_num);
                printf("Failed to start CPU %02d, rebooting...\n", slot_num);
                delay(1000000);
                cpu_shutdown();
                return KERN_SUCCESS;
        } else {
                DBG("Started CPU %02d\n", slot_num);
                printf("Started CPU %02d\n", slot_num);
                return KERN_SUCCESS;
        }
}

extern char     slave_boot_base[];
extern char     slave_boot_end[];
extern void     pstart(void);

void
slave_boot_init(void)
{
        DBG("V(slave_boot_base)=%p P(slave_boot_base)=%p MP_BOOT=%p sz=0x%x\n",
                slave_boot_base,
                kvtophys((vm_offset_t) slave_boot_base),
                MP_BOOT,
                slave_boot_end-slave_boot_base);

        /*
         * Copy the boot entry code to the real-mode vector area MP_BOOT.
         * This is in page 1 which has been reserved for this purpose by
         * machine_startup() from the boot processor.
         * The slave boot code is responsible for switching to protected
         * mode and then jumping to the common startup, _start().
         */
        bcopy_phys((addr64_t) kvtophys((vm_offset_t) slave_boot_base),
                   (addr64_t) MP_BOOT,
                   slave_boot_end-slave_boot_base);

        /*
         * Zero a stack area above the boot code.
         */
        DBG("bzero_phys 0x%x sz 0x%x\n",MP_BOOTSTACK+MP_BOOT-0x400, 0x400);
        bzero_phys((addr64_t)MP_BOOTSTACK+MP_BOOT-0x400, 0x400);

        /*
         * Set the location at the base of the stack to point to the
         * common startup entry.
         */
        DBG("writing 0x%x at phys 0x%x\n",
                kvtophys((vm_offset_t) &pstart), MP_MACH_START+MP_BOOT);
        ml_phys_write_word(MP_MACH_START+MP_BOOT,
                           kvtophys((vm_offset_t) &pstart));
        
        /* Flush caches */
        __asm__("wbinvd");
}

#if     MP_DEBUG
cpu_signal_event_log_t  *cpu_signal[MAX_CPUS];
cpu_signal_event_log_t  *cpu_handle[MAX_CPUS];

MP_EVENT_NAME_DECL();

#endif  /* MP_DEBUG */

void
cpu_signal_handler(__unused struct i386_interrupt_state *regs)
{
        int             my_cpu;
        volatile int    *my_word;
#if     MACH_KDB && MACH_ASSERT
        int             i=100;
#endif  /* MACH_KDB && MACH_ASSERT */

        mp_disable_preemption();

        my_cpu = cpu_number();
        my_word = &current_cpu_datap()->cpu_signals;

        do {
#if     MACH_KDB && MACH_ASSERT
                if (i-- <= 0)
                    Debugger("cpu_signal_handler");
#endif  /* MACH_KDB && MACH_ASSERT */
#if     MACH_KDP
                if (i_bit(MP_KDP, my_word)) {
                        DBGLOG(cpu_handle,my_cpu,MP_KDP);
                        i_bit_clear(MP_KDP, my_word);
                        mp_kdp_wait();
                } else
#endif  /* MACH_KDP */
                if (i_bit(MP_TLB_FLUSH, my_word)) {
                        DBGLOG(cpu_handle,my_cpu,MP_TLB_FLUSH);
                        i_bit_clear(MP_TLB_FLUSH, my_word);
                        pmap_update_interrupt();
                } else if (i_bit(MP_AST, my_word)) {
                        DBGLOG(cpu_handle,my_cpu,MP_AST);
                        i_bit_clear(MP_AST, my_word);
                        ast_check(cpu_to_processor(my_cpu));
#if     MACH_KDB
                } else if (i_bit(MP_KDB, my_word)) {
                        extern kdb_is_slave[];

                        i_bit_clear(MP_KDB, my_word);
                        kdb_is_slave[my_cpu]++;
                        kdb_kintr();
#endif  /* MACH_KDB */
                } else if (i_bit(MP_RENDEZVOUS, my_word)) {
                        DBGLOG(cpu_handle,my_cpu,MP_RENDEZVOUS);
                        i_bit_clear(MP_RENDEZVOUS, my_word);
                        mp_rendezvous_action();
                }
        } while (*my_word);

        mp_enable_preemption();

}

#ifdef  MP_DEBUG
extern int      max_lock_loops;
#endif  /* MP_DEBUG */
void
cpu_interrupt(int cpu)
{
        boolean_t       state;

        if (smp_initialized) {

                /* Wait for previous interrupt to be delivered... */
#ifdef  MP_DEBUG
                int     pending_busy_count = 0;
                while (LAPIC_REG(ICR) & LAPIC_ICR_DS_PENDING) {
                        if (++pending_busy_count > max_lock_loops)
                                panic("cpus_interrupt() deadlock\n");
#else
                while (LAPIC_REG(ICR) & LAPIC_ICR_DS_PENDING) {
#endif  /* MP_DEBUG */
                        cpu_pause();
                }

                state = ml_set_interrupts_enabled(FALSE);
                LAPIC_REG(ICRD) =
                        cpu_to_lapic[cpu] << LAPIC_ICRD_DEST_SHIFT;
                LAPIC_REG(ICR)  =
                        LAPIC_VECTOR(INTERPROCESSOR) | LAPIC_ICR_DM_FIXED;
                (void) ml_set_interrupts_enabled(state);
        }

}

void
i386_signal_cpu(int cpu, mp_event_t event, mp_sync_t mode)
{
        volatile int    *signals = &cpu_datap(cpu)->cpu_signals;
        uint64_t        tsc_timeout;
        

        if (!cpu_datap(cpu)->cpu_running)
                return;

        DBGLOG(cpu_signal, cpu, event);

        i_bit_set(event, signals);
        cpu_interrupt(cpu);
        if (mode == SYNC) {
           again:
                tsc_timeout = rdtsc64() + (1000*1000*1000);
                while (i_bit(event, signals) && rdtsc64() < tsc_timeout) {
                        cpu_pause();
                }
                if (i_bit(event, signals)) {
                        DBG("i386_signal_cpu(%d, 0x%x, SYNC) timed out\n",
                                cpu, event);
                        goto again;
                }
        }
}

void
i386_signal_cpus(mp_event_t event, mp_sync_t mode)
{
        unsigned int    cpu;
        unsigned int    my_cpu = cpu_number();

        for (cpu = 0; cpu < real_ncpus; cpu++) {
                if (cpu == my_cpu || !cpu_datap(cpu)->cpu_running)
                        continue;
                i386_signal_cpu(cpu, event, mode);
        }
}

int
i386_active_cpus(void)
{
        unsigned int    cpu;
        unsigned int    ncpus = 0;

        for (cpu = 0; cpu < real_ncpus; cpu++) {
                if (cpu_datap(cpu)->cpu_running)
                        ncpus++;
        }
        return(ncpus);
}

/*
 * All-CPU rendezvous:
 *      - CPUs are signalled,
 *      - all execute the setup function (if specified),
 *      - rendezvous (i.e. all cpus reach a barrier),
 *      - all execute the action function (if specified),
 *      - rendezvous again,
 *      - execute the teardown function (if specified), and then
 *      - resume.
 *
 * Note that the supplied external functions _must_ be reentrant and aware
 * that they are running in parallel and in an unknown lock context.
 */

static void
mp_rendezvous_action(void)
{

        /* setup function */
        if (mp_rv_setup_func != NULL)
                mp_rv_setup_func(mp_rv_func_arg);
        /* spin on entry rendezvous */
        atomic_incl(&mp_rv_waiters[0], 1);
        while (*((volatile long *) &mp_rv_waiters[0]) < mp_rv_ncpus)
                cpu_pause();
        /* action function */
        if (mp_rv_action_func != NULL)
                mp_rv_action_func(mp_rv_func_arg);
        /* spin on exit rendezvous */
        atomic_incl(&mp_rv_waiters[1], 1);
        while (*((volatile long *) &mp_rv_waiters[1]) < mp_rv_ncpus)
                cpu_pause();
        /* teardown function */
        if (mp_rv_teardown_func != NULL)
                mp_rv_teardown_func(mp_rv_func_arg);
}

void
mp_rendezvous(void (*setup_func)(void *), 
              void (*action_func)(void *),
              void (*teardown_func)(void *),
              void *arg)
{

        if (!smp_initialized) {
                if (setup_func != NULL)
                        setup_func(arg);
                if (action_func != NULL)
                        action_func(arg);
                if (teardown_func != NULL)
                        teardown_func(arg);
                return;
        }
                
        /* obtain rendezvous lock */
        simple_lock(&mp_rv_lock);

        /* set static function pointers */
        mp_rv_setup_func = setup_func;
        mp_rv_action_func = action_func;
        mp_rv_teardown_func = teardown_func;
        mp_rv_func_arg = arg;

        mp_rv_waiters[0] = 0;           /* entry rendezvous count */
        mp_rv_waiters[1] = 0;           /* exit  rendezvous count */
        mp_rv_ncpus = i386_active_cpus();

        /*
         * signal other processors, which will call mp_rendezvous_action()
         * with interrupts disabled
         */
        i386_signal_cpus(MP_RENDEZVOUS, ASYNC);

        /* call executor function on this cpu */
        mp_rendezvous_action();

        /* release lock */
        simple_unlock(&mp_rv_lock);
}

#if     MACH_KDP
volatile boolean_t      mp_kdp_trap = FALSE;
long                    mp_kdp_ncpus;
boolean_t               mp_kdp_state;


void
mp_kdp_enter(void)
{
        unsigned int    cpu;
        unsigned int    ncpus;
        unsigned int    my_cpu = cpu_number();
        uint64_t        tsc_timeout;

        DBG("mp_kdp_enter()\n");

        /*
         * Here to enter the debugger.
         * In case of races, only one cpu is allowed to enter kdp after
         * stopping others.
         */
        mp_kdp_state = ml_set_interrupts_enabled(FALSE);
        simple_lock(&mp_kdp_lock);
        while (mp_kdp_trap) {
                simple_unlock(&mp_kdp_lock);
                DBG("mp_kdp_enter() race lost\n");
                mp_kdp_wait();
                simple_lock(&mp_kdp_lock);
        }
        mp_kdp_ncpus = 1;       /* self */
        mp_kdp_trap = TRUE;
        simple_unlock(&mp_kdp_lock);

        /* Deliver a nudge to other cpus, counting how many */
        DBG("mp_kdp_enter() signaling other processors\n");
        for (ncpus = 1, cpu = 0; cpu < real_ncpus; cpu++) {
                if (cpu == my_cpu || !cpu_datap(cpu)->cpu_running)
                        continue;
                ncpus++;
                i386_signal_cpu(cpu, MP_KDP, ASYNC); 
        }

        /* Wait other processors to spin. */
        DBG("mp_kdp_enter() waiting for (%d) processors to suspend\n", ncpus);
        tsc_timeout = rdtsc64() + (1000*1000*1000);
        while (*((volatile unsigned int *) &mp_kdp_ncpus) != ncpus
                && rdtsc64() < tsc_timeout) {
                cpu_pause();
        }
        DBG("mp_kdp_enter() %d processors done %s\n",
                mp_kdp_ncpus, (mp_kdp_ncpus == ncpus) ? "OK" : "timed out");
        postcode(MP_KDP_ENTER);
}

static void
mp_kdp_wait(void)
{
        boolean_t       state;

        state = ml_set_interrupts_enabled(TRUE);
        DBG("mp_kdp_wait()\n");
        atomic_incl(&mp_kdp_ncpus, 1);
        while (mp_kdp_trap) {
                cpu_pause();
        }
        atomic_decl(&mp_kdp_ncpus, 1);
        DBG("mp_kdp_wait() done\n");
        (void) ml_set_interrupts_enabled(state);
}

void
mp_kdp_exit(void)
{
        DBG("mp_kdp_exit()\n");
        atomic_decl(&mp_kdp_ncpus, 1);
        mp_kdp_trap = FALSE;

        /* Wait other processors to stop spinning. XXX needs timeout */
        DBG("mp_kdp_exit() waiting for processors to resume\n");
        while (*((volatile long *) &mp_kdp_ncpus) > 0) {
                cpu_pause();
        }
        DBG("mp_kdp_exit() done\n");
        (void) ml_set_interrupts_enabled(mp_kdp_state);
        postcode(0);
}
#endif  /* MACH_KDP */

/*ARGSUSED*/
void
init_ast_check(
        __unused processor_t    processor)
{
}

void
cause_ast_check(
        processor_t     processor)
{
        int     cpu = PROCESSOR_DATA(processor, slot_num);

        if (cpu != cpu_number()) {
                i386_signal_cpu(cpu, MP_AST, ASYNC);
        }
}

/*
 * invoke kdb on slave processors 
 */

void
remote_kdb(void)
{
        unsigned int    my_cpu = cpu_number();
        unsigned int    cpu;
        
        mp_disable_preemption();
        for (cpu = 0; cpu < real_ncpus; cpu++) {
                if (cpu == my_cpu || !cpu_datap(cpu)->cpu_running)
                        continue;
                i386_signal_cpu(cpu, MP_KDB, SYNC);
        }
        mp_enable_preemption();
}

/*
 * Clear kdb interrupt
 */

void
clear_kdb_intr(void)
{
        mp_disable_preemption();
        i_bit_clear(MP_KDB, &current_cpu_datap()->cpu_signals);
        mp_enable_preemption();
}

/*
 * i386_init_slave() is called from pstart.
 * We're in the cpu's interrupt stack with interrupts disabled.
 */
void
i386_init_slave(void)
{
        postcode(I386_INIT_SLAVE);

        /* Ensure that caching and write-through are enabled */
        set_cr0(get_cr0() & ~(CR0_NW|CR0_CD));

        DBG("i386_init_slave() CPU%d: phys (%d) active.\n",
                get_cpu_number(), get_cpu_phys_number());

        lapic_init();

        LAPIC_DUMP();
        LAPIC_CPU_MAP_DUMP();

        mtrr_update_cpu();

        pat_init();

        cpu_init();

        slave_main();

        panic("i386_init_slave() returned from slave_main()");
}

void
slave_machine_init(void)
{
        /*
         * Here in process context.
         */
        DBG("slave_machine_init() CPU%d\n", get_cpu_number());

        init_fpu();

        cpu_thread_init();

        pmc_init();

        cpu_machine_init();

        clock_init();
}

#undef cpu_number()
int cpu_number(void)
{
        return get_cpu_number();
}

#if     MACH_KDB
#include <ddb/db_output.h>

#define TRAP_DEBUG 0 /* Must match interrupt.s and spl.s */


#if     TRAP_DEBUG
#define MTRAPS 100
struct mp_trap_hist_struct {
        unsigned char type;
        unsigned char data[5];
} trap_hist[MTRAPS], *cur_trap_hist = trap_hist,
    *max_trap_hist = &trap_hist[MTRAPS];

void db_trap_hist(void);

/*
 * SPL:
 *      1: new spl
 *      2: old spl
 *      3: new tpr
 *      4: old tpr
 * INT:
 *      1: int vec
 *      2: old spl
 *      3: new spl
 *      4: post eoi tpr
 *      5: exit tpr
 */

void
db_trap_hist(void)
{
        int i,j;
        for(i=0;i<MTRAPS;i++)
            if (trap_hist[i].type == 1 || trap_hist[i].type == 2) {
                    db_printf("%s%s",
                              (&trap_hist[i]>=cur_trap_hist)?"*":" ",
                              (trap_hist[i].type == 1)?"SPL":"INT");
                    for(j=0;j<5;j++)
                        db_printf(" %02x", trap_hist[i].data[j]);
                    db_printf("\n");
            }
                
}
#endif  /* TRAP_DEBUG */

void db_lapic(int cpu);
unsigned int db_remote_read(int cpu, int reg);
void db_ioapic(unsigned int);
void kdb_console(void);

void
kdb_console(void)
{
}

#define BOOLP(a) ((a)?' ':'!')

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

unsigned int
db_remote_read(int cpu, int reg)
{
        return -1;
}

void
db_lapic(int cpu)
{
}

void
db_ioapic(unsigned int ind)
{
}

#endif  /* MACH_KDB */