xnu-3789.1.32.tar.gz

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

/*
 * Copyright (c) 2000-2012 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_rt.h>
#include <mach_kdp.h>
#include <kdp/kdp_internal.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/timer_queue.h>
#include <kern/processor.h>
#include <kern/cpu_number.h>
#include <kern/cpu_data.h>
#include <kern/assert.h>
#include <kern/machine.h>
#include <kern/pms.h>
#include <kern/misc_protos.h>
#include <kern/timer_call.h>
#include <kern/kalloc.h>
#include <kern/queue.h>
#include <prng/random.h>

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

#include <profiling/profile-mk.h>

#include <i386/bit_routines.h>
#include <i386/proc_reg.h>
#include <i386/cpu_threads.h>
#include <i386/mp_desc.h>
#include <i386/misc_protos.h>
#include <i386/trap.h>
#include <i386/postcode.h>
#include <i386/machine_routines.h>
#include <i386/mp.h>
#include <i386/mp_events.h>
#include <i386/lapic.h>
#include <i386/cpuid.h>
#include <i386/fpu.h>
#include <i386/machine_cpu.h>
#include <i386/pmCPU.h>
#if CONFIG_MCA
#include <i386/machine_check.h>
#endif
#include <i386/acpi.h>

#include <chud/chud_xnu.h>
#include <chud/chud_xnu_private.h>

#include <sys/kdebug.h>

#include <console/serial_protos.h>

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

/* Debugging/test trace events: */
#define	TRACE_MP_TLB_FLUSH		MACHDBG_CODE(DBG_MACH_MP, 0)
#define	TRACE_MP_CPUS_CALL		MACHDBG_CODE(DBG_MACH_MP, 1)
#define	TRACE_MP_CPUS_CALL_LOCAL	MACHDBG_CODE(DBG_MACH_MP, 2)
#define	TRACE_MP_CPUS_CALL_ACTION	MACHDBG_CODE(DBG_MACH_MP, 3)
#define	TRACE_MP_CPUS_CALL_NOBUF	MACHDBG_CODE(DBG_MACH_MP, 4)
#define	TRACE_MP_CPU_FAST_START		MACHDBG_CODE(DBG_MACH_MP, 5)
#define	TRACE_MP_CPU_START		MACHDBG_CODE(DBG_MACH_MP, 6)
#define	TRACE_MP_CPU_DEACTIVATE		MACHDBG_CODE(DBG_MACH_MP, 7)

#define ABS(v)		(((v) > 0)?(v):-(v))

void 		slave_boot_init(void);
void		i386_cpu_IPI(int cpu);

#if MACH_KDP
static void	mp_kdp_wait(boolean_t flush, boolean_t isNMI);
#endif /* MACH_KDP */

static boolean_t	mp_safe_spin_lock(usimple_lock_t lock);
#if MACH_KDP
static boolean_t	cpu_signal_pending(int cpu, mp_event_t event);
#endif /* MACH_KDP */
static int		NMIInterruptHandler(x86_saved_state_t *regs);

boolean_t 		smp_initialized = FALSE;
uint32_t 		TSC_sync_margin = 0xFFF;
volatile boolean_t	force_immediate_debugger_NMI = FALSE;
volatile boolean_t	pmap_tlb_flush_timeout = FALSE;
decl_simple_lock_data(,mp_kdp_lock);

decl_simple_lock_data(,debugger_callback_lock);
struct debugger_callback *debugger_callback = NULL;

decl_lck_mtx_data(static, mp_cpu_boot_lock);
lck_mtx_ext_t	mp_cpu_boot_lock_ext;

/* Variables needed for MP rendezvous. */
decl_simple_lock_data(,mp_rv_lock);
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 volatile int	mp_rv_ncpus;
			/* Cache-aligned barriers: */
static volatile long	mp_rv_entry    __attribute__((aligned(64)));
static volatile long	mp_rv_exit     __attribute__((aligned(64)));
static volatile long	mp_rv_complete __attribute__((aligned(64)));

volatile	uint64_t	debugger_entry_time;
volatile	uint64_t	debugger_exit_time;
#if MACH_KDP
#include <kdp/kdp.h>
extern int kdp_snapshot;
static struct _kdp_xcpu_call_func {
	kdp_x86_xcpu_func_t func;
	void     *arg0, *arg1;
	volatile long     ret;
	volatile uint16_t cpu;
} kdp_xcpu_call_func = {
	.cpu  = KDP_XCPU_NONE
};

#endif

/* Variables needed for MP broadcast. */
static void        (*mp_bc_action_func)(void *arg);
static void        *mp_bc_func_arg;
static int     	mp_bc_ncpus;
static volatile long   mp_bc_count;
decl_lck_mtx_data(static, mp_bc_lock);
lck_mtx_ext_t	mp_bc_lock_ext;
static	volatile int 	debugger_cpu = -1;
volatile long	 NMIPI_acks = 0;
volatile long	 NMI_count = 0;

extern void	NMI_cpus(void);

static void	mp_cpus_call_init(void); 
static void	mp_cpus_call_action(void); 
static void	mp_call_PM(void);

static boolean_t	mp_cpus_call_wait_timeout = FALSE;

char		mp_slave_stack[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE))); // Temp stack for slave init

/* PAL-related routines */
boolean_t i386_smp_init(int nmi_vector, i386_intr_func_t nmi_handler, 
		int ipi_vector, i386_intr_func_t ipi_handler);
void i386_start_cpu(int lapic_id, int cpu_num);
void i386_send_NMI(int cpu);

#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 */

static lck_grp_t 	smp_lck_grp;
static lck_grp_attr_t	smp_lck_grp_attr;

#define NUM_CPU_WARM_CALLS	20
struct timer_call	cpu_warm_call_arr[NUM_CPU_WARM_CALLS];
queue_head_t 		cpu_warm_call_list;
decl_simple_lock_data(static, cpu_warm_lock);

typedef struct cpu_warm_data {
	timer_call_t 	cwd_call;
	uint64_t	cwd_deadline;
	int		cwd_result;
} *cpu_warm_data_t;

static void		cpu_prewarm_init(void);
static void 		cpu_warm_timer_call_func(call_entry_param_t p0, call_entry_param_t p1);
static void 		_cpu_warm_setup(void *arg);
static timer_call_t 	grab_warm_timer_call(void);
static void		free_warm_timer_call(timer_call_t call);

void
smp_init(void)
{
	simple_lock_init(&mp_kdp_lock, 0);
	simple_lock_init(&mp_rv_lock, 0);
	simple_lock_init(&debugger_callback_lock, 0);
	lck_grp_attr_setdefault(&smp_lck_grp_attr);
	lck_grp_init(&smp_lck_grp, "i386_smp", &smp_lck_grp_attr);
	lck_mtx_init_ext(&mp_cpu_boot_lock, &mp_cpu_boot_lock_ext, &smp_lck_grp, LCK_ATTR_NULL);
	lck_mtx_init_ext(&mp_bc_lock, &mp_bc_lock_ext, &smp_lck_grp, LCK_ATTR_NULL);
	console_init();

	if(!i386_smp_init(LAPIC_NMI_INTERRUPT, NMIInterruptHandler, 
				LAPIC_VECTOR(INTERPROCESSOR), cpu_signal_handler))
		return;

	cpu_thread_init();

	GPROF_INIT();
	DBGLOG_CPU_INIT(master_cpu);

	mp_cpus_call_init();
	mp_cpus_call_cpu_init(master_cpu);

	if (PE_parse_boot_argn("TSC_sync_margin",
					&TSC_sync_margin, sizeof(TSC_sync_margin))) {
		kprintf("TSC sync Margin 0x%x\n", TSC_sync_margin);
	} else if (cpuid_vmm_present()) {
		kprintf("TSC sync margin disabled\n");
		TSC_sync_margin = 0;
	}
	smp_initialized = TRUE;

	cpu_prewarm_init();

	return;
}

typedef struct {
	int			target_cpu;
	int			target_lapic;
	int			starter_cpu;
} processor_start_info_t;
static processor_start_info_t	start_info	  __attribute__((aligned(64)));

/* 
 * Cache-alignment is to avoid cross-cpu false-sharing interference.
 */
static volatile long		tsc_entry_barrier __attribute__((aligned(64)));
static volatile long		tsc_exit_barrier  __attribute__((aligned(64)));
static volatile uint64_t	tsc_target	  __attribute__((aligned(64)));

/*
 * Poll a CPU to see when it has marked itself as running.
 */
static void
mp_wait_for_cpu_up(int slot_num, unsigned int iters, unsigned int usecdelay)
{
	while (iters-- > 0) {
		if (cpu_datap(slot_num)->cpu_running)
			break;
		delay(usecdelay);
	}
}

/*
 * Quickly bring a CPU back online which has been halted.
 */
kern_return_t
intel_startCPU_fast(int slot_num)
{
	kern_return_t	rc;

	/*
	 * Try to perform a fast restart
	 */
	rc = pmCPUExitHalt(slot_num);
	if (rc != KERN_SUCCESS)
		/*
		 * The CPU was not eligible for a fast restart.
		 */
		return(rc);

	KERNEL_DEBUG_CONSTANT(
		TRACE_MP_CPU_FAST_START | DBG_FUNC_START,
		slot_num, 0, 0, 0, 0);

	/*
	 * Wait until the CPU is back online.
	 */
	mp_disable_preemption();
    
	/*
	 * We use short pauses (1us) for low latency.  30,000 iterations is
	 * longer than a full restart would require so it should be more
	 * than long enough.
	 */

	mp_wait_for_cpu_up(slot_num, 30000, 1);
	mp_enable_preemption();

	KERNEL_DEBUG_CONSTANT(
		TRACE_MP_CPU_FAST_START | DBG_FUNC_END,
		slot_num, cpu_datap(slot_num)->cpu_running, 0, 0, 0);

	/*
	 * Check to make sure that the CPU is really running.  If not,
	 * go through the slow path.
	 */
	if (cpu_datap(slot_num)->cpu_running)
		return(KERN_SUCCESS);
	else
		return(KERN_FAILURE);
}

static void
started_cpu(void)
{
	/* Here on the started cpu with cpu_running set TRUE */

	if (TSC_sync_margin &&
	    start_info.target_cpu == cpu_number()) {
		/*
		 * I've just started-up, synchronize again with the starter cpu
		 * and then snap my TSC.
		 */
		tsc_target   = 0;
		atomic_decl(&tsc_entry_barrier, 1);
		while (tsc_entry_barrier != 0)
			;	/* spin for starter and target at barrier */
		tsc_target = rdtsc64();
		atomic_decl(&tsc_exit_barrier, 1);
	}
}

static void
start_cpu(void *arg)
{
	int			i = 1000;
	processor_start_info_t	*psip = (processor_start_info_t *) arg;

	/* Ignore this if the current processor is not the starter */
	if (cpu_number() != psip->starter_cpu)
		return;

	DBG("start_cpu(%p) about to start cpu %d, lapic %d\n",
		arg, psip->target_cpu, psip->target_lapic);

	KERNEL_DEBUG_CONSTANT(
		TRACE_MP_CPU_START | DBG_FUNC_START,
		psip->target_cpu,
		psip->target_lapic, 0, 0, 0);

	i386_start_cpu(psip->target_lapic, psip->target_cpu);

#ifdef	POSTCODE_DELAY
	/* Wait much longer if postcodes are displayed for a delay period. */
	i *= 10000;
#endif
	DBG("start_cpu(%p) about to wait for cpu %d\n",
		arg, psip->target_cpu);

	mp_wait_for_cpu_up(psip->target_cpu, i*100, 100);

	KERNEL_DEBUG_CONSTANT(
		TRACE_MP_CPU_START | DBG_FUNC_END,
		psip->target_cpu,
		cpu_datap(psip->target_cpu)->cpu_running, 0, 0, 0);

	if (TSC_sync_margin &&
	    cpu_datap(psip->target_cpu)->cpu_running) {
		/*
		 * Compare the TSC from the started processor with ours.
		 * Report and log/panic if it diverges by more than
		 * TSC_sync_margin (TSC_SYNC_MARGIN) ticks. This margin
		 * can be overriden by boot-arg (with 0 meaning no checking).
		 */
		uint64_t	tsc_starter;
		int64_t		tsc_delta;
		atomic_decl(&tsc_entry_barrier, 1);
		while (tsc_entry_barrier != 0)
			;	/* spin for both processors at barrier */
		tsc_starter = rdtsc64();
		atomic_decl(&tsc_exit_barrier, 1);
		while (tsc_exit_barrier != 0)
			;	/* spin for target to store its TSC */
		tsc_delta = tsc_target - tsc_starter;
		kprintf("TSC sync for cpu %d: 0x%016llx delta 0x%llx (%lld)\n",
			psip->target_cpu, tsc_target, tsc_delta, tsc_delta);
		if (ABS(tsc_delta) > (int64_t) TSC_sync_margin) { 
#if DEBUG
			panic(
#else
			printf(
#endif
				"Unsynchronized  TSC for cpu %d: "
					"0x%016llx, delta 0x%llx\n",
				psip->target_cpu, tsc_target, tsc_delta);
		}
	}
}

kern_return_t
intel_startCPU(
	int	slot_num)
{
	int		lapic = cpu_to_lapic[slot_num];
	boolean_t	istate;

	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) (uintptr_t)IdlePTD);

	/*
	 * Initialize (or re-initialize) the descriptor tables for this cpu.
	 * Propagate processor mode to slave.
	 */
	cpu_desc_init64(cpu_datap(slot_num));

	/* Serialize use of the slave boot stack, etc. */
	lck_mtx_lock(&mp_cpu_boot_lock);

	istate = ml_set_interrupts_enabled(FALSE);
	if (slot_num == get_cpu_number()) {
		ml_set_interrupts_enabled(istate);
		lck_mtx_unlock(&mp_cpu_boot_lock);
		return KERN_SUCCESS;
	}

	start_info.starter_cpu  = cpu_number();
	start_info.target_cpu   = slot_num;
	start_info.target_lapic = lapic;
	tsc_entry_barrier = 2;
	tsc_exit_barrier = 2;

	/*
	 * Perform the processor startup sequence with all running
	 * processors rendezvous'ed. This is required during periods when
	 * the cache-disable bit is set for MTRR/PAT initialization.
	 */
	mp_rendezvous_no_intrs(start_cpu, (void *) &start_info);

	start_info.target_cpu = 0;

	ml_set_interrupts_enabled(istate);
	lck_mtx_unlock(&mp_cpu_boot_lock);

	if (!cpu_datap(slot_num)->cpu_running) {
		kprintf("Failed to start CPU %02d\n", slot_num);
		printf("Failed to start CPU %02d, rebooting...\n", slot_num);
		delay(1000000);
		halt_cpu();
		return KERN_SUCCESS;
	} else {
		kprintf("Started cpu %d (lapic id %08x)\n", slot_num, lapic);
		return KERN_SUCCESS;
	}
}

#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 */

/*
 * Note: called with NULL state when polling for TLB flush and cross-calls.
 */
int
cpu_signal_handler(x86_saved_state_t *regs)
{
#if	!MACH_KDP
#pragma unused (regs)
#endif /* !MACH_KDP */
	int		my_cpu;
	volatile int	*my_word;

	SCHED_STATS_IPI(current_processor());

	my_cpu = cpu_number();
	my_word = &cpu_data_ptr[my_cpu]->cpu_signals;
	/* Store the initial set of signals for diagnostics. New
	 * signals could arrive while these are being processed
	 * so it's no more than a hint.
	 */

	cpu_data_ptr[my_cpu]->cpu_prior_signals = *my_word;

	do {
#if	MACH_KDP
		if (i_bit(MP_KDP, my_word)) {
			DBGLOG(cpu_handle,my_cpu,MP_KDP);
			i_bit_clear(MP_KDP, my_word);
/* Ensure that the i386_kernel_state at the base of the
 * current thread's stack (if any) is synchronized with the
 * context at the moment of the interrupt, to facilitate
 * access through the debugger.
 */
			sync_iss_to_iks(regs);
			if (pmsafe_debug && !kdp_snapshot)
				pmSafeMode(&current_cpu_datap()->lcpu, PM_SAFE_FL_SAFE);
			mp_kdp_wait(TRUE, FALSE);
			if (pmsafe_debug && !kdp_snapshot)
				pmSafeMode(&current_cpu_datap()->lcpu, PM_SAFE_FL_NORMAL);
		} 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_CHUD, my_word)) {
			DBGLOG(cpu_handle,my_cpu,MP_CHUD);
			i_bit_clear(MP_CHUD, my_word);
			chudxnu_cpu_signal_handler();
		} else if (i_bit(MP_CALL, my_word)) {
			DBGLOG(cpu_handle,my_cpu,MP_CALL);
			i_bit_clear(MP_CALL, my_word);
			mp_cpus_call_action();
		} else if (i_bit(MP_CALL_PM, my_word)) {
			DBGLOG(cpu_handle,my_cpu,MP_CALL_PM);
			i_bit_clear(MP_CALL_PM, my_word);
			mp_call_PM();
		}
		if (regs == NULL) {
			/* Called to poll only for cross-calls and TLB flush */
			break;
		} 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));
		}
	} while (*my_word);

	return 0;
}

extern void kprintf_break_lock(void);
static int
NMIInterruptHandler(x86_saved_state_t *regs)
{
	void 		*stackptr;

	if (panic_active() && !panicDebugging) {
		if (pmsafe_debug)
			pmSafeMode(&current_cpu_datap()->lcpu, PM_SAFE_FL_SAFE);
		for(;;)
			cpu_pause();
	}

	atomic_incl(&NMIPI_acks, 1);
	atomic_incl(&NMI_count, 1);
	sync_iss_to_iks_unconditionally(regs);
	__asm__ volatile("movq %%rbp, %0" : "=m" (stackptr));

	if (cpu_number() == debugger_cpu)
		goto NMExit;

	if (spinlock_timed_out) {
		char pstr[192];
		snprintf(&pstr[0], sizeof(pstr), "Panic(CPU %d): NMIPI for spinlock acquisition timeout, spinlock: %p, spinlock owner: %p, current_thread: %p, spinlock_owner_cpu: 0x%x\n", cpu_number(), spinlock_timed_out, (void *) spinlock_timed_out->interlock.lock_data, current_thread(), spinlock_owner_cpu);
		panic_i386_backtrace(stackptr, 64, &pstr[0], TRUE, regs);
	} else if (mp_cpus_call_wait_timeout) {
		char pstr[192];
		snprintf(&pstr[0], sizeof(pstr), "Panic(CPU %d): Unresponsive processor, this CPU timed-out during cross-call\n", cpu_number());
		panic_i386_backtrace(stackptr, 64, &pstr[0], TRUE, regs);
	} else if (pmap_tlb_flush_timeout == TRUE) {
		char pstr[128];
		snprintf(&pstr[0], sizeof(pstr), "Panic(CPU %d): Unresponsive processor (this CPU did not acknowledge interrupts) TLB state:0x%x\n", cpu_number(), current_cpu_datap()->cpu_tlb_invalid);
		panic_i386_backtrace(stackptr, 48, &pstr[0], TRUE, regs);
	} 

#if MACH_KDP
	if (pmsafe_debug && !kdp_snapshot)
		pmSafeMode(&current_cpu_datap()->lcpu, PM_SAFE_FL_SAFE);
	current_cpu_datap()->cpu_NMI_acknowledged = TRUE;
	i_bit_clear(MP_KDP, &current_cpu_datap()->cpu_signals);
	if (pmap_tlb_flush_timeout ||
	    spinlock_timed_out ||
	    mp_cpus_call_wait_timeout ||
	    panic_active()) {
		mp_kdp_wait(FALSE, TRUE);
	} else if (!mp_kdp_trap &&
		   !mp_kdp_is_NMI &&
		   virtualized && (debug_boot_arg & DB_NMI)) {
		/*
		 * Under a VMM with the debug boot-arg set, drop into kdp.
		 * Since an NMI is involved, there's a risk of contending with
		 * a panic. And side-effects of NMIs may result in entry into, 
		 * and continuing from, the debugger being unreliable.
		 */
		if (__sync_bool_compare_and_swap(&mp_kdp_is_NMI, FALSE, TRUE)) {
			kprintf_break_lock();
			kprintf("Debugger entry requested by NMI\n");
			kdp_i386_trap(T_DEBUG, saved_state64(regs), 0, 0);
			printf("Debugger entry requested by NMI\n");
			mp_kdp_is_NMI = FALSE;
		} else {
			mp_kdp_wait(FALSE, FALSE);
		}
	} else {
		mp_kdp_wait(FALSE, FALSE);
	}
	if (pmsafe_debug && !kdp_snapshot)
		pmSafeMode(&current_cpu_datap()->lcpu, PM_SAFE_FL_NORMAL);
#endif
NMExit:	
	return 1;
}


/*
 * cpu_interrupt is really just to be used by the scheduler to
 * get a CPU's attention it may not always issue an IPI.  If an
 * IPI is always needed then use i386_cpu_IPI.
 */
void
cpu_interrupt(int cpu)
{
	boolean_t did_IPI = FALSE;

	if (smp_initialized
	    && pmCPUExitIdle(cpu_datap(cpu))) {
		i386_cpu_IPI(cpu);
		did_IPI = TRUE;
	}

	KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_REMOTE_AST), cpu, did_IPI, 0, 0, 0);
}

/*
 * Send a true NMI via the local APIC to the specified CPU.
 */
void
cpu_NMI_interrupt(int cpu)
{
	if (smp_initialized) {
		i386_send_NMI(cpu);
	}
}

void
NMI_cpus(void)
{
	unsigned int	cpu;
	boolean_t	intrs_enabled;
	uint64_t	tsc_timeout;

	intrs_enabled = ml_set_interrupts_enabled(FALSE);

	for (cpu = 0; cpu < real_ncpus; cpu++) {
		if (!cpu_datap(cpu)->cpu_running)
			continue;
		cpu_datap(cpu)->cpu_NMI_acknowledged = FALSE;
		cpu_NMI_interrupt(cpu);
		tsc_timeout = !machine_timeout_suspended() ?
				rdtsc64() + (1000 * 1000 * 1000 * 10ULL) :
				~0ULL;
		while (!cpu_datap(cpu)->cpu_NMI_acknowledged) {
			handle_pending_TLB_flushes();
			cpu_pause();
			if (rdtsc64() > tsc_timeout)
				panic("NMI_cpus() timeout cpu %d", cpu);
		}
		cpu_datap(cpu)->cpu_NMI_acknowledged = FALSE;
	}

	ml_set_interrupts_enabled(intrs_enabled);
}

static void	(* volatile mp_PM_func)(void) = NULL;

static void
mp_call_PM(void)
{
	assert(!ml_get_interrupts_enabled());

	if (mp_PM_func != NULL)
		mp_PM_func();
}

void
cpu_PM_interrupt(int cpu)
{
	assert(!ml_get_interrupts_enabled());

	if (mp_PM_func != NULL) {
		if (cpu == cpu_number())
			mp_PM_func();
		else
			i386_signal_cpu(cpu, MP_CALL_PM, ASYNC);
	}
}

void
PM_interrupt_register(void (*fn)(void))
{
	mp_PM_func = fn;
}

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;

	if (event == MP_TLB_FLUSH)
	        KERNEL_DEBUG(TRACE_MP_TLB_FLUSH | DBG_FUNC_START, cpu, 0, 0, 0, 0);

	DBGLOG(cpu_signal, cpu, event);
	
	i_bit_set(event, signals);
	i386_cpu_IPI(cpu);
	if (mode == SYNC) {
	   again:
		tsc_timeout = !machine_timeout_suspended() ?
					rdtsc64() + (1000*1000*1000) :
					~0ULL;
		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;
		}
	}
	if (event == MP_TLB_FLUSH)
	        KERNEL_DEBUG(TRACE_MP_TLB_FLUSH | DBG_FUNC_END, cpu, 0, 0, 0, 0);
}

/*
 * Helper function called when busy-waiting: panic if too long
 * a TSC-based time has elapsed since the start of the spin.
 */
static boolean_t
mp_spin_timeout(uint64_t tsc_start)
{
	uint64_t	tsc_timeout;

	cpu_pause();
	if (machine_timeout_suspended())
		return FALSE;

	/*
	 * The timeout is 4 * the spinlock timeout period
	 * unless we have serial console printing (kprintf) enabled
	 * in which case we allow an even greater margin.
	 */
	tsc_timeout = disable_serial_output ? LockTimeOutTSC << 2
					    : LockTimeOutTSC << 4;
	return  (rdtsc64() > tsc_start + tsc_timeout);
}

/*
 * Helper function to take a spinlock while ensuring that incoming IPIs
 * are still serviced if interrupts are masked while we spin.
 * Returns current interrupt state.
 */
static boolean_t
mp_safe_spin_lock(usimple_lock_t lock)
{
	if (ml_get_interrupts_enabled()) {
		simple_lock(lock);
		return TRUE;
	} else {
		uint64_t tsc_spin_start = rdtsc64();
		while (!simple_lock_try(lock)) {
			cpu_signal_handler(NULL);
			if (mp_spin_timeout(tsc_spin_start)) {
				uint32_t lock_cpu;
				uintptr_t lowner = (uintptr_t)
						   lock->interlock.lock_data;
				spinlock_timed_out = lock;
				lock_cpu = spinlock_timeout_NMI(lowner);
				panic("mp_safe_spin_lock() timed out,"
				      " lock: %p, owner thread: 0x%lx,"
				      " current_thread: %p, owner on CPU 0x%x",
				      lock, lowner,
				      current_thread(), lock_cpu);
			}
		}
		return FALSE;
	} 
}

/*
 * 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(__unused void *null)
{
	boolean_t	intrs_enabled;
	uint64_t	tsc_spin_start;

	/* setup function */
	if (mp_rv_setup_func != NULL)
		mp_rv_setup_func(mp_rv_func_arg);

	intrs_enabled = ml_get_interrupts_enabled();

	/* spin on entry rendezvous */
	atomic_incl(&mp_rv_entry, 1);
	tsc_spin_start = rdtsc64();

	while (mp_rv_entry < mp_rv_ncpus) {
		/* poll for pesky tlb flushes if interrupts disabled */
		if (!intrs_enabled)
			handle_pending_TLB_flushes();
		if (mp_spin_timeout(tsc_spin_start)) {
			panic("mp_rv_action() entry: %ld of %d responses, start: 0x%llx, cur: 0x%llx", mp_rv_entry, mp_rv_ncpus, tsc_spin_start, rdtsc64());
		}
	}

	/* action function */
	if (mp_rv_action_func != NULL)
		mp_rv_action_func(mp_rv_func_arg);

	/* spin on exit rendezvous */
	atomic_incl(&mp_rv_exit, 1);
	tsc_spin_start = rdtsc64();
	while (mp_rv_exit < mp_rv_ncpus) {
		if (!intrs_enabled)
			handle_pending_TLB_flushes();
		if (mp_spin_timeout(tsc_spin_start))
			panic("mp_rv_action() exit: %ld of %d responses, start: 0x%llx, cur: 0x%llx", mp_rv_exit, mp_rv_ncpus, tsc_spin_start, rdtsc64());
	}

	/* teardown function */
	if (mp_rv_teardown_func != NULL)
		mp_rv_teardown_func(mp_rv_func_arg);

	/* Bump completion count */
	atomic_incl(&mp_rv_complete, 1);
}

void
mp_rendezvous(void (*setup_func)(void *), 
	      void (*action_func)(void *),
	      void (*teardown_func)(void *),
	      void *arg)
{
	uint64_t	tsc_spin_start;

	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 */
	(void) mp_safe_spin_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_entry    = 0;
	mp_rv_exit     = 0;
	mp_rv_complete = 0;

	/*
	 * signal other processors, which will call mp_rendezvous_action()
	 * with interrupts disabled
	 */
	mp_rv_ncpus = mp_cpus_call(CPUMASK_OTHERS, NOSYNC, &mp_rendezvous_action, NULL) + 1;

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

	/*
	 * Spin for everyone to complete.
	 * This is necessary to ensure that all processors have proceeded
	 * from the exit barrier before we release the rendezvous structure.
	 */
	tsc_spin_start = rdtsc64();
	while (mp_rv_complete < mp_rv_ncpus) {
		if (mp_spin_timeout(tsc_spin_start))
			panic("mp_rendezvous() timeout: %ld of %d responses, start: 0x%llx, cur: 0x%llx", mp_rv_complete, mp_rv_ncpus, tsc_spin_start, rdtsc64());
	}
	
	/* Tidy up */
	mp_rv_setup_func = NULL;
	mp_rv_action_func = NULL;
	mp_rv_teardown_func = NULL;
	mp_rv_func_arg = NULL;

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

void
mp_rendezvous_break_lock(void)
{
	simple_lock_init(&mp_rv_lock, 0);
}

static void
setup_disable_intrs(__unused void * param_not_used)
{
	/* disable interrupts before the first barrier */
	boolean_t intr = ml_set_interrupts_enabled(FALSE);

	current_cpu_datap()->cpu_iflag = intr;
	DBG("CPU%d: %s\n", get_cpu_number(), __FUNCTION__);
}

static void
teardown_restore_intrs(__unused void * param_not_used)
{
	/* restore interrupt flag following MTRR changes */
	ml_set_interrupts_enabled(current_cpu_datap()->cpu_iflag);
	DBG("CPU%d: %s\n", get_cpu_number(), __FUNCTION__);
}

/*
 * A wrapper to mp_rendezvous() to call action_func() with interrupts disabled.
 * This is exported for use by kexts.
 */
void
mp_rendezvous_no_intrs(
	      void (*action_func)(void *),
	      void *arg)
{
	mp_rendezvous(setup_disable_intrs,
		      action_func,
		      teardown_restore_intrs,
		      arg);	
}


typedef struct {
	queue_chain_t	link;			/* queue linkage */
	void		(*func)(void *,void *);	/* routine to call */
	void		*arg0;			/* routine's 1st arg */
	void		*arg1;			/* routine's 2nd arg */
	cpumask_t	*maskp;			/* completion response mask */
} mp_call_t;


typedef struct {
	queue_head_t		queue;
	decl_simple_lock_data(,	lock);
} mp_call_queue_t;
#define MP_CPUS_CALL_BUFS_PER_CPU	MAX_CPUS
static mp_call_queue_t	mp_cpus_call_freelist;
static mp_call_queue_t	mp_cpus_call_head[MAX_CPUS];

static inline boolean_t
mp_call_head_lock(mp_call_queue_t *cqp)
{
	boolean_t	intrs_enabled;

	intrs_enabled = ml_set_interrupts_enabled(FALSE);
	simple_lock(&cqp->lock);

	return intrs_enabled;
}

void
mp_cpus_NMIPI(cpumask_t cpu_mask) {
	unsigned int cpu, cpu_bit;
	uint64_t deadline;

	for (cpu = 0, cpu_bit = 1; cpu < real_ncpus; cpu++, cpu_bit <<= 1) {
		if (cpu_mask & cpu_bit)
			cpu_NMI_interrupt(cpu);
	}
	deadline = mach_absolute_time() + (LockTimeOut);
	while (mach_absolute_time() < deadline)
		cpu_pause();
}

#if MACH_ASSERT
static inline boolean_t
mp_call_head_is_locked(mp_call_queue_t *cqp)
{
	return !ml_get_interrupts_enabled() &&
		hw_lock_held((hw_lock_t)&cqp->lock);
}
#endif

static inline void
mp_call_head_unlock(mp_call_queue_t *cqp, boolean_t intrs_enabled)
{
	simple_unlock(&cqp->lock);
	ml_set_interrupts_enabled(intrs_enabled);
}

static inline mp_call_t *
mp_call_alloc(void)
{
	mp_call_t	*callp = NULL;
	boolean_t	intrs_enabled;
	mp_call_queue_t	*cqp = &mp_cpus_call_freelist;

	intrs_enabled = mp_call_head_lock(cqp);
	if (!queue_empty(&cqp->queue))
		queue_remove_first(&cqp->queue, callp, typeof(callp), link);
	mp_call_head_unlock(cqp, intrs_enabled);

	return callp;
}

static inline void
mp_call_free(mp_call_t *callp)
{
	boolean_t	intrs_enabled;
	mp_call_queue_t	*cqp = &mp_cpus_call_freelist;

	intrs_enabled = mp_call_head_lock(cqp);
	queue_enter_first(&cqp->queue, callp, typeof(callp), link);
	mp_call_head_unlock(cqp, intrs_enabled);
}

static inline mp_call_t *
mp_call_dequeue_locked(mp_call_queue_t *cqp)
{
	mp_call_t	*callp = NULL;

	assert(mp_call_head_is_locked(cqp));
	if (!queue_empty(&cqp->queue))
		queue_remove_first(&cqp->queue, callp, typeof(callp), link);
	return callp;
}

static inline void
mp_call_enqueue_locked(
	mp_call_queue_t	*cqp,
	mp_call_t	*callp)
{
	queue_enter(&cqp->queue, callp, typeof(callp), link);
}

/* Called on the boot processor to initialize global structures */
static void
mp_cpus_call_init(void)
{
	mp_call_queue_t	*cqp = &mp_cpus_call_freelist;

	DBG("mp_cpus_call_init()\n");
	simple_lock_init(&cqp->lock, 0);
	queue_init(&cqp->queue);
}

/*
 * Called at processor registration to add call buffers to the free list
 * and to initialize the per-cpu call queue.
 */
void
mp_cpus_call_cpu_init(int cpu)
{
	int		i;
	mp_call_queue_t	*cqp = &mp_cpus_call_head[cpu];
	mp_call_t	*callp;

	simple_lock_init(&cqp->lock, 0);
	queue_init(&cqp->queue);
	for (i = 0; i < MP_CPUS_CALL_BUFS_PER_CPU; i++) {
		callp = (mp_call_t *) kalloc(sizeof(mp_call_t));
		mp_call_free(callp);
	}

	DBG("mp_cpus_call_init(%d) done\n", cpu);
}

/*
 * This is called from cpu_signal_handler() to process an MP_CALL signal.
 * And also from i386_deactivate_cpu() when a cpu is being taken offline.
 */
static void
mp_cpus_call_action(void)
{
	mp_call_queue_t	*cqp;
	boolean_t	intrs_enabled;
	mp_call_t	*callp;
	mp_call_t	call;

	assert(!ml_get_interrupts_enabled());
	cqp = &mp_cpus_call_head[cpu_number()];
	intrs_enabled = mp_call_head_lock(cqp);
	while ((callp = mp_call_dequeue_locked(cqp)) != NULL) {
		/* Copy call request to the stack to free buffer */
		call = *callp;
		mp_call_free(callp);
		if (call.func != NULL) {
			mp_call_head_unlock(cqp, intrs_enabled);
			KERNEL_DEBUG_CONSTANT(
				TRACE_MP_CPUS_CALL_ACTION,
				VM_KERNEL_UNSLIDE(call.func), VM_KERNEL_UNSLIDE_OR_PERM(call.arg0),
				VM_KERNEL_UNSLIDE_OR_PERM(call.arg1), VM_KERNEL_ADDRPERM(call.maskp), 0);
			call.func(call.arg0, call.arg1);
			(void) mp_call_head_lock(cqp);
		}
		if (call.maskp != NULL)
			i_bit_set(cpu_number(), call.maskp);
	}
	mp_call_head_unlock(cqp, intrs_enabled);
}

/*
 * mp_cpus_call() runs a given function on cpus specified in a given cpu mask.
 * Possible modes are:
 *  SYNC:   function is called serially on target cpus in logical cpu order
 *	    waiting for each call to be acknowledged before proceeding
 *  ASYNC:  function call is queued to the specified cpus
 *	    waiting for all calls to complete in parallel before returning
 *  NOSYNC: function calls are queued
 *	    but we return before confirmation of calls completing. 
 * The action function may be NULL.
 * The cpu mask may include the local cpu. Offline cpus are ignored.
 * The return value is the number of cpus on which the call was made or queued.
 */
cpu_t
mp_cpus_call(
	cpumask_t	cpus,
	mp_sync_t	mode,
        void		(*action_func)(void *),
        void		*arg)
{
	return mp_cpus_call1(
			cpus,
			mode,
			(void (*)(void *,void *))action_func,
			arg,
			NULL,
			NULL);
}

static void
mp_cpus_call_wait(boolean_t	intrs_enabled,
		  cpumask_t	cpus_called,
		  cpumask_t	*cpus_responded)
{
	mp_call_queue_t		*cqp;
	uint64_t		tsc_spin_start;

	assert(ml_get_interrupts_enabled() == 0 || get_preemption_level() != 0);
	cqp = &mp_cpus_call_head[cpu_number()];

	tsc_spin_start = rdtsc64();
	while (*cpus_responded != cpus_called) {
		if (!intrs_enabled) {
			/* Sniffing w/o locking */
			if (!queue_empty(&cqp->queue))
				mp_cpus_call_action();
			cpu_signal_handler(NULL);
		}
		if (mp_spin_timeout(tsc_spin_start)) {
			cpumask_t	cpus_unresponsive;

			mp_cpus_call_wait_timeout = TRUE;
			cpus_unresponsive = cpus_called & ~(*cpus_responded);
			mp_cpus_NMIPI(cpus_unresponsive);
			panic("mp_cpus_call_wait() timeout, cpus: 0x%llx",
				cpus_unresponsive);
		}
	}
}

cpu_t
mp_cpus_call1(
	cpumask_t	cpus,
	mp_sync_t	mode,
        void		(*action_func)(void *, void *),
        void		*arg0,
        void		*arg1,
	cpumask_t	*cpus_calledp)
{
	cpu_t		cpu = 0;
	boolean_t	intrs_enabled = FALSE;
	boolean_t	call_self = FALSE;
	cpumask_t	cpus_called = 0;
	cpumask_t	cpus_responded = 0;
	long 		cpus_call_count = 0;
	uint64_t	tsc_spin_start;
	boolean_t	topo_lock;

	KERNEL_DEBUG_CONSTANT(
		TRACE_MP_CPUS_CALL | DBG_FUNC_START,
		cpus, mode, VM_KERNEL_UNSLIDE(action_func), VM_KERNEL_UNSLIDE_OR_PERM(arg0), VM_KERNEL_UNSLIDE_OR_PERM(arg1));

	if (!smp_initialized) {
		if ((cpus & CPUMASK_SELF) == 0)
			goto out;
		if (action_func != NULL) {
			intrs_enabled = ml_set_interrupts_enabled(FALSE);
			action_func(arg0, arg1);
			ml_set_interrupts_enabled(intrs_enabled);
		}
		call_self = TRUE;
		goto out;
	}

	/*
	 * Queue the call for each non-local requested cpu.
	 * This is performed under the topo lock to prevent changes to
	 * cpus online state and to prevent concurrent rendezvouses --
	 * although an exception is made if we're calling only the master
	 * processor since that always remains active. Note: this exception
	 * is expected for longterm timer nosync cross-calls to the master cpu.
	 */ 
	mp_disable_preemption();
	intrs_enabled = ml_get_interrupts_enabled();
	topo_lock = (cpus != cpu_to_cpumask(master_cpu));
	if (topo_lock) {
		ml_set_interrupts_enabled(FALSE);
		(void) mp_safe_spin_lock(&x86_topo_lock);
	}
	for (cpu = 0; cpu < (cpu_t) real_ncpus; cpu++) {
		if (((cpu_to_cpumask(cpu) & cpus) == 0) ||
		    !cpu_datap(cpu)->cpu_running)
			continue;
		tsc_spin_start = rdtsc64();
		if (cpu == (cpu_t) cpu_number()) {
			/*
			 * We don't IPI ourself and if calling asynchronously,
			 * we defer our call until we have signalled all others.
			 */
			call_self = TRUE;
			if (mode == SYNC && action_func != NULL) {
				KERNEL_DEBUG_CONSTANT(
					TRACE_MP_CPUS_CALL_LOCAL,
					VM_KERNEL_UNSLIDE(action_func),
					VM_KERNEL_UNSLIDE_OR_PERM(arg0), VM_KERNEL_UNSLIDE_OR_PERM(arg1), 0, 0);
				action_func(arg0, arg1);
			}
		} else {
			/*
			 * Here to queue a call to cpu and IPI.
			 */
			mp_call_t	*callp = NULL;
			mp_call_queue_t	*cqp = &mp_cpus_call_head[cpu];
			boolean_t	intrs_inner;

		queue_call:
			if (callp == NULL)
				callp = mp_call_alloc();
			intrs_inner = mp_call_head_lock(cqp);
			if (callp == NULL) {
				mp_call_head_unlock(cqp, intrs_inner);
				KERNEL_DEBUG_CONSTANT(
					TRACE_MP_CPUS_CALL_NOBUF,
					cpu, 0, 0, 0, 0);
				if (!intrs_inner) {
					/* Sniffing w/o locking */
					if (!queue_empty(&cqp->queue))
						mp_cpus_call_action();
					handle_pending_TLB_flushes();
				}
				if (mp_spin_timeout(tsc_spin_start))
					panic("mp_cpus_call1() timeout start: 0x%llx, cur: 0x%llx",
					      tsc_spin_start, rdtsc64());
				goto queue_call;
			}
			callp->maskp = (mode == NOSYNC) ? NULL : &cpus_responded;
			callp->func = action_func;
			callp->arg0 = arg0;
			callp->arg1 = arg1;
			mp_call_enqueue_locked(cqp, callp);
			cpus_call_count++;
			cpus_called |= cpu_to_cpumask(cpu);
			i386_signal_cpu(cpu, MP_CALL, ASYNC);
			mp_call_head_unlock(cqp, intrs_inner);
			if (mode == SYNC) {
				mp_cpus_call_wait(intrs_inner, cpus_called, &cpus_responded);
			}
		}
	}
	if (topo_lock) {
		simple_unlock(&x86_topo_lock);
		ml_set_interrupts_enabled(intrs_enabled);
	}

	/* Call locally if mode not SYNC */
	if (mode != SYNC && call_self ) {
		KERNEL_DEBUG_CONSTANT(
			TRACE_MP_CPUS_CALL_LOCAL,
			VM_KERNEL_UNSLIDE(action_func), VM_KERNEL_UNSLIDE_OR_PERM(arg0), VM_KERNEL_UNSLIDE_OR_PERM(arg1), 0, 0);
		if (action_func != NULL) {
			ml_set_interrupts_enabled(FALSE);
			action_func(arg0, arg1);
			ml_set_interrupts_enabled(intrs_enabled);
		}
	}

	/* For ASYNC, now wait for all signaled cpus to complete their calls */
	if (mode == ASYNC)
		mp_cpus_call_wait(intrs_enabled, cpus_called, &cpus_responded);

	/* Safe to allow pre-emption now */
	mp_enable_preemption();

out:
	if (call_self){
		cpus_called |= cpu_to_cpumask(cpu);
		cpus_call_count++;
	}

	if (cpus_calledp)
		*cpus_calledp = cpus_called;

	KERNEL_DEBUG_CONSTANT(
		TRACE_MP_CPUS_CALL | DBG_FUNC_END,
		cpus_call_count, cpus_called, 0, 0, 0);

	return (cpu_t) cpus_call_count;
}


static void
mp_broadcast_action(__unused void *null)
{
   /* call action function */
   if (mp_bc_action_func != NULL)
       mp_bc_action_func(mp_bc_func_arg);

   /* if we're the last one through, wake up the instigator */
   if (atomic_decl_and_test(&mp_bc_count, 1))
       thread_wakeup(((event_t)(uintptr_t) &mp_bc_count));
}

/*
 * mp_broadcast() runs a given function on all active cpus.
 * The caller blocks until the functions has run on all cpus.
 * The caller will also block if there is another pending braodcast.
 */
void
mp_broadcast(
         void (*action_func)(void *),
         void *arg)
{
   if (!smp_initialized) {
       if (action_func != NULL)
	           action_func(arg);
       return;
   }
       
   /* obtain broadcast lock */
   lck_mtx_lock(&mp_bc_lock);

   /* set static function pointers */
   mp_bc_action_func = action_func;
   mp_bc_func_arg = arg;

   assert_wait((event_t)(uintptr_t)&mp_bc_count, THREAD_UNINT);

   /*
    * signal other processors, which will call mp_broadcast_action()
    */
   mp_bc_count = real_ncpus;				/* assume max possible active */
   mp_bc_ncpus = mp_cpus_call(CPUMASK_OTHERS, NOSYNC, *mp_broadcast_action, NULL) + 1;
   atomic_decl(&mp_bc_count, real_ncpus - mp_bc_ncpus);	/* subtract inactive */

   /* call executor function on this cpu */
   mp_broadcast_action(NULL);

   /* block for other cpus to have run action_func */
   if (mp_bc_ncpus > 1)
       thread_block(THREAD_CONTINUE_NULL);
   else
       clear_wait(current_thread(), THREAD_AWAKENED);
       
   /* release lock */
   lck_mtx_unlock(&mp_bc_lock);
}

void
mp_cpus_kick(cpumask_t cpus)
{
	cpu_t		cpu;
	boolean_t	intrs_enabled = FALSE;

	intrs_enabled = ml_set_interrupts_enabled(FALSE);
	mp_safe_spin_lock(&x86_topo_lock);

	for (cpu = 0; cpu < (cpu_t) real_ncpus; cpu++) {
		if ((cpu == (cpu_t) cpu_number())
			|| ((cpu_to_cpumask(cpu) & cpus) == 0)
			|| (!cpu_datap(cpu)->cpu_running))
		{
				continue;
		}

		lapic_send_ipi(cpu, LAPIC_VECTOR(KICK));
	}

	simple_unlock(&x86_topo_lock);
	ml_set_interrupts_enabled(intrs_enabled);
}

void
i386_activate_cpu(void)
{
	cpu_data_t	*cdp = current_cpu_datap();

	assert(!ml_get_interrupts_enabled());

	if (!smp_initialized) {
		cdp->cpu_running = TRUE;
		return;
	}

	simple_lock(&x86_topo_lock);
	cdp->cpu_running = TRUE;
	started_cpu();
	simple_unlock(&x86_topo_lock);
	flush_tlb_raw();
}

void
i386_deactivate_cpu(void)
{
	cpu_data_t	*cdp = current_cpu_datap();

	assert(!ml_get_interrupts_enabled());
 
	KERNEL_DEBUG_CONSTANT(
		TRACE_MP_CPU_DEACTIVATE | DBG_FUNC_START,
		0, 0, 0, 0, 0);

	simple_lock(&x86_topo_lock);
	cdp->cpu_running = FALSE;
	simple_unlock(&x86_topo_lock);

	/*
	 * Move all of this cpu's timers to the master/boot cpu,
	 * and poke it in case there's a sooner deadline for it to schedule.
	 */
	timer_queue_shutdown(&cdp->rtclock_timer.queue);
	mp_cpus_call(cpu_to_cpumask(master_cpu), ASYNC, timer_queue_expire_local, NULL);

	/*
	 * Open an interrupt window
	 * and ensure any pending IPI or timer is serviced
	 */
	mp_disable_preemption();
	ml_set_interrupts_enabled(TRUE);

	while (cdp->cpu_signals && x86_lcpu()->rtcDeadline != EndOfAllTime)
		cpu_pause();
	/*
	 * Ensure there's no remaining timer deadline set
	 * - AICPM may have left one active.
	 */
	setPop(0);

	ml_set_interrupts_enabled(FALSE);
	mp_enable_preemption();

	KERNEL_DEBUG_CONSTANT(
		TRACE_MP_CPU_DEACTIVATE | DBG_FUNC_END,
		0, 0, 0, 0, 0);
}

int	pmsafe_debug	= 1;

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


void
mp_kdp_enter(void)
{
	unsigned int	cpu;
	unsigned int	ncpus = 0;
	unsigned int	my_cpu;
	uint64_t	tsc_timeout;

	DBG("mp_kdp_enter()\n");

#if DEBUG
	if (!smp_initialized)
		simple_lock_init(&mp_kdp_lock, 0);
#endif

	/*
	 * 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);
	my_cpu = cpu_number();

	if (my_cpu == (unsigned) debugger_cpu) {
		kprintf("\n\nRECURSIVE DEBUGGER ENTRY DETECTED\n\n");
		kdp_reset();
		return;
	}

	cpu_datap(my_cpu)->debugger_entry_time = mach_absolute_time();
	simple_lock(&mp_kdp_lock);

	if (pmsafe_debug && !kdp_snapshot)
	    pmSafeMode(&current_cpu_datap()->lcpu, PM_SAFE_FL_SAFE);

	while (mp_kdp_trap) {
		simple_unlock(&mp_kdp_lock);
		DBG("mp_kdp_enter() race lost\n");
#if MACH_KDP
		mp_kdp_wait(TRUE, FALSE);
#endif
		simple_lock(&mp_kdp_lock);
	}
	debugger_cpu = my_cpu;
	ncpus = 1;
	mp_kdp_ncpus = 1;	/* self */
	mp_kdp_trap = TRUE;
	debugger_entry_time = cpu_datap(my_cpu)->debugger_entry_time;
	simple_unlock(&mp_kdp_lock);

	/*
	 * Deliver a nudge to other cpus, counting how many
	 */
	DBG("mp_kdp_enter() signaling other processors\n");
	if (force_immediate_debugger_NMI == FALSE) {
		for (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 synchronize
		 */
		DBG("mp_kdp_enter() waiting for (%d) processors to suspend\n", ncpus);

		/*
		 * This timeout is rather arbitrary; we don't want to NMI
		 * processors that are executing at potentially
		 * "unsafe-to-interrupt" points such as the trampolines,
		 * but neither do we want to lose state by waiting too long.
		 */
		tsc_timeout = rdtsc64() + (LockTimeOutTSC);

		while (mp_kdp_ncpus != ncpus && rdtsc64() < tsc_timeout) {
			/*
			 * A TLB shootdown request may be pending--this would
			 * result in the requesting processor waiting in
			 * PMAP_UPDATE_TLBS() until this processor deals with it.
			 * Process it, so it can now enter mp_kdp_wait()
			 */
			handle_pending_TLB_flushes();
			cpu_pause();
		}
		/* If we've timed out, and some processor(s) are still unresponsive,
		 * interrupt them with an NMI via the local APIC.
		 */
		if (mp_kdp_ncpus != ncpus) {
			DBG("mp_kdp_enter() timed-out on cpu %d, NMI-ing\n", my_cpu);
			for (cpu = 0; cpu < real_ncpus; cpu++) {
				if (cpu == my_cpu || !cpu_datap(cpu)->cpu_running)
					continue;
				if (cpu_signal_pending(cpu, MP_KDP))
					cpu_NMI_interrupt(cpu);
			}
			/* Wait again for the same timeout */
			tsc_timeout = rdtsc64() + (LockTimeOutTSC);
			while (mp_kdp_ncpus != ncpus && rdtsc64() < tsc_timeout) {
				handle_pending_TLB_flushes();
				cpu_pause();
			}
			if (mp_kdp_ncpus != ncpus) {
				panic("mp_kdp_enter() timed-out waiting after NMI");
			}
		}
	}
	else
		for (cpu = 0; cpu < real_ncpus; cpu++) {
			if (cpu == my_cpu || !cpu_datap(cpu)->cpu_running)
				continue;
			cpu_NMI_interrupt(cpu);
		}

	DBG("mp_kdp_enter() %d processors done %s\n",
	    (int)mp_kdp_ncpus, (mp_kdp_ncpus == ncpus) ? "OK" : "timed out");
	
	postcode(MP_KDP_ENTER);
}

static boolean_t
cpu_signal_pending(int cpu, mp_event_t event)
{
	volatile int	*signals = &cpu_datap(cpu)->cpu_signals;
	boolean_t retval = FALSE;

	if (i_bit(event, signals))
		retval = TRUE;
	return retval;
}

long kdp_x86_xcpu_invoke(const uint16_t lcpu, kdp_x86_xcpu_func_t func,
			 void *arg0, void *arg1)
{
	if (lcpu > (real_ncpus - 1))
		return -1;

        if (func == NULL)
		return -1;

	kdp_xcpu_call_func.func = func;
        kdp_xcpu_call_func.ret  = -1;
	kdp_xcpu_call_func.arg0 = arg0;
	kdp_xcpu_call_func.arg1 = arg1;
	kdp_xcpu_call_func.cpu  = lcpu;
	DBG("Invoking function %p on CPU %d\n", func, (int32_t)lcpu);
	while (kdp_xcpu_call_func.cpu != KDP_XCPU_NONE)
		cpu_pause();
        return kdp_xcpu_call_func.ret;
}

static void
kdp_x86_xcpu_poll(void)
{
	if ((uint16_t)cpu_number() == kdp_xcpu_call_func.cpu) {
            kdp_xcpu_call_func.ret = 
		    kdp_xcpu_call_func.func(kdp_xcpu_call_func.arg0,
					    kdp_xcpu_call_func.arg1,
					    cpu_number());
		kdp_xcpu_call_func.cpu = KDP_XCPU_NONE;
	}
}

static void
mp_kdp_wait(boolean_t flush, boolean_t isNMI)
{
	DBG("mp_kdp_wait()\n");
	/* If an I/O port has been specified as a debugging aid, issue a read */
	panic_io_port_read();
	current_cpu_datap()->debugger_ipi_time = mach_absolute_time();
#if CONFIG_MCA
	/* If we've trapped due to a machine-check, save MCA registers */
	mca_check_save();
#endif

	atomic_incl((volatile long *)&mp_kdp_ncpus, 1);
	while (mp_kdp_trap || (isNMI == TRUE)) {
	        /*
		 * A TLB shootdown request may be pending--this would result
		 * in the requesting processor waiting in PMAP_UPDATE_TLBS()
		 * until this processor handles it.
		 * Process it, so it can now enter mp_kdp_wait()
		 */
		if (flush)
			handle_pending_TLB_flushes();

		kdp_x86_xcpu_poll();
		cpu_pause();
	}

	atomic_decl((volatile long *)&mp_kdp_ncpus, 1);
	DBG("mp_kdp_wait() done\n");
}

void
mp_kdp_exit(void)
{
	DBG("mp_kdp_exit()\n");
	debugger_cpu = -1;
	atomic_decl((volatile long *)&mp_kdp_ncpus, 1);

	debugger_exit_time = mach_absolute_time();

	mp_kdp_trap = FALSE;
	mfence();

	/* Wait other processors to stop spinning. XXX needs timeout */
	DBG("mp_kdp_exit() waiting for processors to resume\n");
	while (mp_kdp_ncpus > 0) {
	        /*
		 * a TLB shootdown request may be pending... this would result in the requesting
		 * processor waiting in PMAP_UPDATE_TLBS() until this processor deals with it.
		 * Process it, so it can now enter mp_kdp_wait()
		 */
	        handle_pending_TLB_flushes();

		cpu_pause();
	}

	if (pmsafe_debug && !kdp_snapshot)
	    pmSafeMode(&current_cpu_datap()->lcpu, PM_SAFE_FL_NORMAL);

	debugger_exit_time = mach_absolute_time();

	DBG("mp_kdp_exit() done\n");
	(void) ml_set_interrupts_enabled(mp_kdp_state);
	postcode(0);
}

#define TRAP_DEBUGGER __asm__ volatile("int3")

kern_return_t
DebuggerWithCallback(kern_return_t (*callback) (void*),
					 void *callback_context,
					 boolean_t proceed_on_sync_failure)
{
	simple_lock(&debugger_callback_lock);

	struct debugger_callback callback_buf = {
		.callback = callback,
		.callback_context = callback_context,
		.proceed_on_sync_failure = proceed_on_sync_failure,
		.error = KERN_FAILURE
	};

	assert(debugger_callback == NULL);
	debugger_callback = &callback_buf;

	TRAP_DEBUGGER;

	debugger_callback = NULL;

	simple_unlock(&debugger_callback_lock);

	return callback_buf.error;
}

#endif	/* MACH_KDP */

boolean_t
mp_recent_debugger_activity(void) {
	uint64_t abstime = mach_absolute_time();
	return (((abstime - debugger_entry_time) < LastDebuggerEntryAllowance) ||
	    ((abstime - debugger_exit_time) < LastDebuggerEntryAllowance));
}

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

void
cause_ast_check(
	processor_t	processor)
{
	int	cpu = processor->cpu_id;

	if (cpu != cpu_number()) {
		i386_signal_cpu(cpu, MP_AST, ASYNC);
		KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_REMOTE_AST), cpu, 1, 0, 0, 0);
	}
}

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

	if (param == FULL_SLAVE_INIT) {
		/*
		 * Cold start
		 */
		clock_init();
	}
	cpu_machine_init();	/* Interrupts enabled hereafter */
}

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

static void
cpu_prewarm_init()
{
	int i;

	simple_lock_init(&cpu_warm_lock, 0);
	queue_init(&cpu_warm_call_list);
	for (i = 0; i < NUM_CPU_WARM_CALLS; i++) {
		enqueue_head(&cpu_warm_call_list, (queue_entry_t)&cpu_warm_call_arr[i]);
	}
}

static timer_call_t
grab_warm_timer_call()
{
	spl_t x;
	timer_call_t call = NULL;

	x = splsched();
	simple_lock(&cpu_warm_lock);
	if (!queue_empty(&cpu_warm_call_list)) {
		call = (timer_call_t) dequeue_head(&cpu_warm_call_list);
	}
	simple_unlock(&cpu_warm_lock);
	splx(x);

	return call;
}

static void
free_warm_timer_call(timer_call_t call)
{
	spl_t x;

	x = splsched();
	simple_lock(&cpu_warm_lock);
	enqueue_head(&cpu_warm_call_list, (queue_entry_t)call);
	simple_unlock(&cpu_warm_lock);
	splx(x);
}

/*
 * Runs in timer call context (interrupts disabled).
 */
static void
cpu_warm_timer_call_func(
		call_entry_param_t p0,
		__unused call_entry_param_t p1)
{
	free_warm_timer_call((timer_call_t)p0);
	return;
}

/*
 * Runs with interrupts disabled on the CPU we wish to warm (i.e. CPU 0).
 */
static void
_cpu_warm_setup(
		void *arg)
{
	cpu_warm_data_t cwdp = (cpu_warm_data_t)arg;

	timer_call_enter(cwdp->cwd_call, cwdp->cwd_deadline, TIMER_CALL_SYS_CRITICAL | TIMER_CALL_LOCAL);
	cwdp->cwd_result = 0;

	return;
}

/*
 * Not safe to call with interrupts disabled.
 */
kern_return_t
ml_interrupt_prewarm(
	uint64_t 	deadline)
{
	struct cpu_warm_data cwd;
	timer_call_t call;
	cpu_t ct;

	if (ml_get_interrupts_enabled() == FALSE) {
		panic("%s: Interrupts disabled?\n", __FUNCTION__);
	}

	/* 
	 * If the platform doesn't need our help, say that we succeeded. 
	 */
	if (!ml_get_interrupt_prewake_applicable()) {
		return KERN_SUCCESS;
	}

	/*
	 * Grab a timer call to use.
	 */
	call = grab_warm_timer_call();
	if (call == NULL) {
		return KERN_RESOURCE_SHORTAGE;
	}

	timer_call_setup(call, cpu_warm_timer_call_func, call);
	cwd.cwd_call = call;
	cwd.cwd_deadline = deadline;
	cwd.cwd_result = 0;

	/*
	 * For now, non-local interrupts happen on the master processor.
	 */
	ct = mp_cpus_call(cpu_to_cpumask(master_cpu), SYNC, _cpu_warm_setup, &cwd);
	if (ct == 0) {
		free_warm_timer_call(call);
		return KERN_FAILURE;
	} else {
		return cwd.cwd_result;
	}
}

#if DEBUG || DEVELOPMENT
void
kernel_spin(uint64_t spin_ns)
{
	boolean_t	istate;
	uint64_t	spin_abs;
	uint64_t	deadline;

	kprintf("kernel_spin(%llu) spinning uninterruptibly\n", spin_ns);
	istate = ml_set_interrupts_enabled(FALSE);
	nanoseconds_to_absolutetime(spin_ns, &spin_abs);
	deadline = mach_absolute_time() + spin_ns;
	while (mach_absolute_time() < deadline)
		cpu_pause();
	ml_set_interrupts_enabled(istate);
	kprintf("kernel_spin() continuing\n");
}
#endif