22 files changed, 256 insertions, 28 deletions

diff --git a/sys/cddl/dev/dtrace/amd64/dtrace_subr.c b/sys/cddl/dev/dtrace/amd64/dtrace_subr.c
index 1d81d42..df39d2e 100644
--- a/sys/cddl/dev/dtrace/amd64/dtrace_subr.c
+++ b/sys/cddl/dev/dtrace/amd64/dtrace_subr.c
@@ -246,6 +246,26 @@ static uint64_t	nsec_scale;
 /* See below for the explanation of this macro. */
 #define SCALE_SHIFT	28
 
+static void
+dtrace_gethrtime_init_cpu(void *arg)
+{
+	uintptr_t cpu = (uintptr_t) arg;
+
+	if (cpu == curcpu)
+		tgt_cpu_tsc = rdtsc();
+	else
+		hst_cpu_tsc = rdtsc();
+}
+
+#ifdef EARLY_AP_STARTUP
+static void
+dtrace_gethrtime_init(void *arg)
+{
+	struct pcpu *pc;
+	uint64_t tsc_f;
+	cpuset_t map;
+	int i;
+#else
 /*
  * Get the frequency and scale factor as early as possible so that they can be
  * used for boot-time tracing.
@@ -254,6 +274,7 @@ static void
 dtrace_gethrtime_init_early(void *arg)
 {
 	uint64_t tsc_f;
+#endif
 
 	/*
 	 * Get TSC frequency known at this moment.
@@ -282,27 +303,18 @@ dtrace_gethrtime_init_early(void *arg)
 	 *   (terahertz) values;
 	 */
 	nsec_scale = ((uint64_t)NANOSEC << SCALE_SHIFT) / tsc_f;
+#ifndef EARLY_AP_STARTUP
 }
 SYSINIT(dtrace_gethrtime_init_early, SI_SUB_CPU, SI_ORDER_ANY,
     dtrace_gethrtime_init_early, NULL);
 
 static void
-dtrace_gethrtime_init_cpu(void *arg)
-{
-	uintptr_t cpu = (uintptr_t) arg;
-
-	if (cpu == curcpu)
-		tgt_cpu_tsc = rdtsc();
-	else
-		hst_cpu_tsc = rdtsc();
-}
-
-static void
 dtrace_gethrtime_init(void *arg)
 {
 	struct pcpu *pc;
 	cpuset_t map;
 	int i;
+#endif
 
 	/* The current CPU is the reference one. */
 	sched_pin();
@@ -323,8 +335,13 @@ dtrace_gethrtime_init(void *arg)
 	}
 	sched_unpin();
 }
+#ifdef EARLY_AP_STARTUP
+SYSINIT(dtrace_gethrtime_init, SI_SUB_DTRACE, SI_ORDER_ANY,
+    dtrace_gethrtime_init, NULL);
+#else
 SYSINIT(dtrace_gethrtime_init, SI_SUB_SMP, SI_ORDER_ANY, dtrace_gethrtime_init,
     NULL);
+#endif
 
 /*
  * DTrace needs a high resolution time function which can
diff --git a/sys/cddl/dev/dtrace/dtrace_load.c b/sys/cddl/dev/dtrace/dtrace_load.c
index c49de55..7f7dd79 100644
--- a/sys/cddl/dev/dtrace/dtrace_load.c
+++ b/sys/cddl/dev/dtrace/dtrace_load.c
@@ -22,6 +22,7 @@
  *
  */
 
+#ifndef EARLY_AP_STARTUP
 static void
 dtrace_ap_start(void *dummy)
 {
@@ -41,11 +42,15 @@ dtrace_ap_start(void *dummy)
 }
 
 SYSINIT(dtrace_ap_start, SI_SUB_SMP, SI_ORDER_ANY, dtrace_ap_start, NULL);
+#endif
 
 static void
 dtrace_load(void *dummy)
 {
 	dtrace_provider_id_t id;
+#ifdef EARLY_AP_STARTUP
+	int i;
+#endif
 
 	/* Hook into the trap handler. */
 	dtrace_trap_func = dtrace_trap;
@@ -142,8 +147,14 @@ dtrace_load(void *dummy)
 
 	mutex_enter(&cpu_lock);
 
+#ifdef EARLY_AP_STARTUP
+	CPU_FOREACH(i) {
+		(void) dtrace_cpu_setup(CPU_CONFIG, i);
+	}
+#else
 	/* Setup the boot CPU */
 	(void) dtrace_cpu_setup(CPU_CONFIG, 0);
+#endif
 
 	mutex_exit(&cpu_lock);
 
diff --git a/sys/cddl/dev/dtrace/i386/dtrace_subr.c b/sys/cddl/dev/dtrace/i386/dtrace_subr.c
index a2263ec..b70eab9 100644
--- a/sys/cddl/dev/dtrace/i386/dtrace_subr.c
+++ b/sys/cddl/dev/dtrace/i386/dtrace_subr.c
@@ -248,6 +248,26 @@ static uint64_t	nsec_scale;
 /* See below for the explanation of this macro. */
 #define SCALE_SHIFT	28
 
+static void
+dtrace_gethrtime_init_cpu(void *arg)
+{
+	uintptr_t cpu = (uintptr_t) arg;
+
+	if (cpu == curcpu)
+		tgt_cpu_tsc = rdtsc();
+	else
+		hst_cpu_tsc = rdtsc();
+}
+
+#ifdef EARLY_AP_STARTUP
+static void
+dtrace_gethrtime_init(void *arg)
+{
+	struct pcpu *pc;
+	uint64_t tsc_f;
+	cpuset_t map;
+	int i;
+#else
 /*
  * Get the frequency and scale factor as early as possible so that they can be
  * used for boot-time tracing.
@@ -256,6 +276,7 @@ static void
 dtrace_gethrtime_init_early(void *arg)
 {
 	uint64_t tsc_f;
+#endif
 
 	/*
 	 * Get TSC frequency known at this moment.
@@ -284,27 +305,18 @@ dtrace_gethrtime_init_early(void *arg)
 	 *   (terahertz) values;
 	 */
 	nsec_scale = ((uint64_t)NANOSEC << SCALE_SHIFT) / tsc_f;
+#ifndef EARLY_AP_STARTUP
 }
 SYSINIT(dtrace_gethrtime_init_early, SI_SUB_CPU, SI_ORDER_ANY,
     dtrace_gethrtime_init_early, NULL);
 
 static void
-dtrace_gethrtime_init_cpu(void *arg)
-{
-	uintptr_t cpu = (uintptr_t) arg;
-
-	if (cpu == curcpu)
-		tgt_cpu_tsc = rdtsc();
-	else
-		hst_cpu_tsc = rdtsc();
-}
-
-static void
 dtrace_gethrtime_init(void *arg)
 {
 	cpuset_t map;
 	struct pcpu *pc;
 	int i;
+#endif
 
 	/* The current CPU is the reference one. */
 	sched_pin();
@@ -325,8 +337,13 @@ dtrace_gethrtime_init(void *arg)
 	}
 	sched_unpin();
 }
+#ifdef EARLY_AP_STARTUP
+SYSINIT(dtrace_gethrtime_init, SI_SUB_DTRACE, SI_ORDER_ANY,
+    dtrace_gethrtime_init, NULL);
+#else
 SYSINIT(dtrace_gethrtime_init, SI_SUB_SMP, SI_ORDER_ANY, dtrace_gethrtime_init,
     NULL);
+#endif
 
 /*
  * DTrace needs a high resolution time function which can
diff --git a/sys/cddl/dev/dtrace/powerpc/dtrace_subr.c b/sys/cddl/dev/dtrace/powerpc/dtrace_subr.c
index 3546147..310a553 100644
--- a/sys/cddl/dev/dtrace/powerpc/dtrace_subr.c
+++ b/sys/cddl/dev/dtrace/powerpc/dtrace_subr.c
@@ -218,8 +218,13 @@ dtrace_gethrtime_init(void *arg)
 	}
 	sched_unpin();
 }
-
-SYSINIT(dtrace_gethrtime_init, SI_SUB_SMP, SI_ORDER_ANY, dtrace_gethrtime_init, NULL);
+#ifdef EARLY_AP_STARTUP
+SYSINIT(dtrace_gethrtime_init, SI_SUB_DTRACE, SI_ORDER_ANY,
+    dtrace_gethrtime_init, NULL);
+#else
+SYSINIT(dtrace_gethrtime_init, SI_SUB_SMP, SI_ORDER_ANY, dtrace_gethrtime_init,
+    NULL);
+#endif
 
 /*
  * DTrace needs a high resolution time function which can
diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 51e81f1..45732da 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -223,6 +223,12 @@ options 	SCHED_STATS
 # Mandatory:
 options 	SMP			# Symmetric MultiProcessor Kernel
 
+# EARLY_AP_STARTUP releases the Application Processors earlier in the
+# kernel startup process (before devices are probed) rather than at the
+# end.  This is a temporary option for use during the transition from
+# late to early AP startup.
+options		EARLY_AP_STARTUP
+
 # MAXCPU defines the maximum number of CPUs that can boot in the system.
 # A default value should be already present, for every architecture.
 options 	MAXCPU=32
diff --git a/sys/conf/options b/sys/conf/options
index 6dd51d7..f06a092 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -620,6 +620,7 @@ DEBUG_MEMGUARD		opt_vm.h
 DEBUG_REDZONE		opt_vm.h
 
 # Standard SMP options
+EARLY_AP_STARTUP	opt_global.h
 SMP			opt_global.h
 
 # Size of the kernel message buffer
diff --git a/sys/dev/acpica/acpi.c b/sys/dev/acpica/acpi.c
index b29b3c4..cbba9bf 100644
--- a/sys/dev/acpica/acpi.c
+++ b/sys/dev/acpica/acpi.c
@@ -2856,11 +2856,18 @@ acpi_EnterSleepState(struct acpi_softc *sc, int state)
     stop_all_proc();
     EVENTHANDLER_INVOKE(power_suspend);
 
+#ifdef EARLY_AP_STARTUP
+    MPASS(mp_ncpus == 1 || smp_started);
+    thread_lock(curthread);
+    sched_bind(curthread, 0);
+    thread_unlock(curthread);
+#else
     if (smp_started) {
 	thread_lock(curthread);
 	sched_bind(curthread, 0);
 	thread_unlock(curthread);
     }
+#endif
 
     /*
      * Be sure to hold Giant across DEVICE_SUSPEND/RESUME since non-MPSAFE
@@ -2991,11 +2998,17 @@ backout:
 
     mtx_unlock(&Giant);
 
+#ifdef EARLY_AP_STARTUP
+    thread_lock(curthread);
+    sched_unbind(curthread);
+    thread_unlock(curthread);
+#else
     if (smp_started) {
 	thread_lock(curthread);
 	sched_unbind(curthread);
 	thread_unlock(curthread);
     }
+#endif
 
     resume_all_proc();
 
diff --git a/sys/dev/acpica/acpi_cpu.c b/sys/dev/acpica/acpi_cpu.c
index 218da4e..00c951f 100644
--- a/sys/dev/acpica/acpi_cpu.c
+++ b/sys/dev/acpica/acpi_cpu.c
@@ -439,8 +439,12 @@ acpi_cpu_postattach(void *unused __unused)
     free(devices, M_TEMP);
 
     if (attached) {
+#ifdef EARLY_AP_STARTUP
+	acpi_cpu_startup(NULL);
+#else
 	/* Queue post cpu-probing task handler */
 	AcpiOsExecute(OSL_NOTIFY_HANDLER, acpi_cpu_startup, NULL);
+#endif
     }
 }
 
diff --git a/sys/dev/hwpmc/hwpmc_mod.c b/sys/dev/hwpmc/hwpmc_mod.c
index c0caab6..48bb23e 100644
--- a/sys/dev/hwpmc/hwpmc_mod.c
+++ b/sys/dev/hwpmc/hwpmc_mod.c
@@ -334,7 +334,11 @@ static moduledata_t pmc_mod = {
 	&pmc_syscall_mod
 };
 
+#ifdef EARLY_AP_STARTUP
+DECLARE_MODULE(pmc, pmc_mod, SI_SUB_SYSCALLS, SI_ORDER_ANY);
+#else
 DECLARE_MODULE(pmc, pmc_mod, SI_SUB_SMP, SI_ORDER_ANY);
+#endif
 MODULE_VERSION(pmc, PMC_VERSION);
 
 #ifdef	HWPMC_DEBUG
diff --git a/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c b/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
index bcdf0cb..d0bdfc4 100644
--- a/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
+++ b/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
@@ -519,6 +519,7 @@ vmbus_attach(device_t dev)
 		device_printf(dev, "VMBUS: attach dev: %p\n", dev);
 	vmbus_devp = dev;
 
+#ifndef EARLY_AP_STARTUP
 	/* 
 	 * If the system has already booted and thread
 	 * scheduling is possible indicated by the global
@@ -526,6 +527,7 @@ vmbus_attach(device_t dev)
 	 * initialization directly.
 	 */
 	if (!cold)
+#endif
 		vmbus_bus_init();
 
 	bus_generic_probe(dev);
@@ -538,6 +540,7 @@ vmbus_init(void)
 	if (vm_guest != VM_GUEST_HV)
 		return;
 
+#ifndef EARLY_AP_STARTUP
 	/* 
 	 * If the system has already booted and thread
 	 * scheduling is possible, as indicated by the
@@ -545,6 +548,7 @@ vmbus_init(void)
 	 * initialization directly.
 	 */
 	if (!cold) 
+#endif
 		vmbus_bus_init();
 }
 
@@ -611,6 +615,9 @@ vmbus_modevent(module_t mod, int what, void *arg)
 	switch (what) {
 
 	case MOD_LOAD:
+#ifdef EARLY_AP_STARTUP
+		vmbus_init();
+#endif
 		vmbus_mod_load();
 		break;
 	case MOD_UNLOAD:
@@ -649,6 +656,7 @@ DRIVER_MODULE(vmbus, acpi, vmbus_driver, vmbus_devclass, vmbus_modevent, 0);
 MODULE_DEPEND(vmbus, acpi, 1, 1, 1);
 MODULE_VERSION(vmbus, 1);
 
+#ifndef EARLY_AP_STARTUP
 /* We want to be started after SMP is initialized */
 SYSINIT(vmb_init, SI_SUB_SMP + 1, SI_ORDER_FIRST, vmbus_init, NULL);
-
+#endif
diff --git a/sys/dev/xen/control/control.c b/sys/dev/xen/control/control.c
index a62b2ca..ae13c6c 100644
--- a/sys/dev/xen/control/control.c
+++ b/sys/dev/xen/control/control.c
@@ -202,11 +202,18 @@ xctrl_suspend()
 	stop_all_proc();
 	EVENTHANDLER_INVOKE(power_suspend);
 
+#ifdef EARLY_AP_STARTUP
+	MPASS(mp_ncpus == 1 || smp_started);
+	thread_lock(curthread);
+	sched_bind(curthread, 0);
+	thread_unlock(curthread);
+#else
 	if (smp_started) {
 		thread_lock(curthread);
 		sched_bind(curthread, 0);
 		thread_unlock(curthread);
 	}
+#endif
 	KASSERT((PCPU_GET(cpuid) == 0), ("Not running on CPU#0"));
 
 	/*
@@ -227,6 +234,17 @@ xctrl_suspend()
 	}
 
 #ifdef SMP
+#ifdef EARLY_AP_STARTUP
+	/*
+	 * Suspend other CPUs. This prevents IPIs while we
+	 * are resuming, and will allow us to reset per-cpu
+	 * vcpu_info on resume.
+	 */
+	cpu_suspend_map = all_cpus;
+	CPU_CLR(PCPU_GET(cpuid), &cpu_suspend_map);
+	if (!CPU_EMPTY(&cpu_suspend_map))
+		suspend_cpus(cpu_suspend_map);
+#else
 	CPU_ZERO(&cpu_suspend_map);	/* silence gcc */
 	if (smp_started) {
 		/*
@@ -240,6 +258,7 @@ xctrl_suspend()
 			suspend_cpus(cpu_suspend_map);
 	}
 #endif
+#endif
 
 	/*
 	 * Prevent any races with evtchn_interrupt() handler.
@@ -285,11 +304,17 @@ xctrl_suspend()
 	timecounter->tc_get_timecount(timecounter);
 	inittodr(time_second);
 
+#ifdef EARLY_AP_STARTUP
+	thread_lock(curthread);
+	sched_unbind(curthread);
+	thread_unlock(curthread);
+#else
 	if (smp_started) {
 		thread_lock(curthread);
 		sched_unbind(curthread);
 		thread_unlock(curthread);
 	}
+#endif
 
 	resume_all_proc();
 
diff --git a/sys/geom/eli/g_eli.c b/sys/geom/eli/g_eli.c
index 912a5c5..403d0b6 100644
--- a/sys/geom/eli/g_eli.c
+++ b/sys/geom/eli/g_eli.c
@@ -479,7 +479,9 @@ g_eli_worker(void *arg)
 
 	wr = arg;
 	sc = wr->w_softc;
-#ifdef SMP
+#ifdef EARLY_AP_STARTUP
+	MPASS(!sc->sc_cpubind || smp_started);
+#elif defined(SMP)
 	/* Before sched_bind() to a CPU, wait for all CPUs to go on-line. */
 	if (sc->sc_cpubind) {
 		while (!smp_started)
diff --git a/sys/kern/kern_clock.c b/sys/kern/kern_clock.c
index 1f4b129..17b85bc 100644
--- a/sys/kern/kern_clock.c
+++ b/sys/kern/kern_clock.c
@@ -391,6 +391,10 @@ static void
 initclocks(dummy)
 	void *dummy;
 {
+#ifdef EARLY_AP_STARTUP
+	struct proc *p;
+	struct thread *td;
+#endif
 	register int i;
 
 	/*
@@ -415,6 +419,35 @@ initclocks(dummy)
 	 * sign problems sooner.
 	 */
 	ticks = INT_MAX - (hz * 10 * 60);
+
+#ifdef EARLY_AP_STARTUP
+	/*
+	 * Fixup the tick counts in any blocked or sleeping threads to
+	 * account for the jump above.
+	 */
+	sx_slock(&allproc_lock);
+	FOREACH_PROC_IN_SYSTEM(p) {
+		PROC_LOCK(p);
+		if (p->p_state == PRS_NEW) {
+			PROC_UNLOCK(p);
+			continue;
+		}
+		FOREACH_THREAD_IN_PROC(p, td) {
+			thread_lock(td);
+			if (TD_ON_LOCK(td)) {
+				MPASS(td->td_blktick == 0);
+				td->td_blktick = ticks;
+			}
+			if (TD_ON_SLEEPQ(td)) {
+				MPASS(td->td_slptick == 0);
+				td->td_slptick = ticks;
+			}
+			thread_unlock(td);
+		}
+		PROC_UNLOCK(p);
+	}
+	sx_sunlock(&allproc_lock);
+#endif
 }
 
 /*
diff --git a/sys/kern/kern_clocksource.c b/sys/kern/kern_clocksource.c
index cc7847c..7f7769d 100644
--- a/sys/kern/kern_clocksource.c
+++ b/sys/kern/kern_clocksource.c
@@ -322,9 +322,16 @@ timercb(struct eventtimer *et, void *arg)
 	    curcpu, (int)(now >> 32), (u_int)(now & 0xffffffff));
 
 #ifdef SMP
+#ifdef EARLY_AP_STARTUP
+	MPASS(mp_ncpus == 1 || smp_started);
+#endif
 	/* Prepare broadcasting to other CPUs for non-per-CPU timers. */
 	bcast = 0;
+#ifdef EARLY_AP_STARTUP
+	if ((et->et_flags & ET_FLAGS_PERCPU) == 0) {
+#else
 	if ((et->et_flags & ET_FLAGS_PERCPU) == 0 && smp_started) {
+#endif
 		CPU_FOREACH(cpu) {
 			state = DPCPU_ID_PTR(cpu, timerstate);
 			ET_HW_LOCK(state);
@@ -485,12 +492,17 @@ configtimer(int start)
 			nexttick = next;
 		else
 			nexttick = -1;
+#ifdef EARLY_AP_STARTUP
+		MPASS(mp_ncpus == 1 || smp_started);
+#endif
 		CPU_FOREACH(cpu) {
 			state = DPCPU_ID_PTR(cpu, timerstate);
 			state->now = now;
+#ifndef EARLY_AP_STARTUP
 			if (!smp_started && cpu != CPU_FIRST())
 				state->nextevent = SBT_MAX;
 			else
+#endif
 				state->nextevent = next;
 			if (periodic)
 				state->nexttick = next;
@@ -513,8 +525,13 @@ configtimer(int start)
 	}
 	ET_HW_UNLOCK(DPCPU_PTR(timerstate));
 #ifdef SMP
+#ifdef EARLY_AP_STARTUP
+	/* If timer is global we are done. */
+	if ((timer->et_flags & ET_FLAGS_PERCPU) == 0) {
+#else
 	/* If timer is global or there is no other CPUs yet - we are done. */
 	if ((timer->et_flags & ET_FLAGS_PERCPU) == 0 || !smp_started) {
+#endif
 		critical_exit();
 		return;
 	}
diff --git a/sys/kern/kern_cpu.c b/sys/kern/kern_cpu.c
index 293b940..4e66b13 100644
--- a/sys/kern/kern_cpu.c
+++ b/sys/kern/kern_cpu.c
@@ -259,6 +259,9 @@ cf_set_method(device_t dev, const struct cf_level *level, int priority)
 	CF_MTX_LOCK(&sc->lock);
 
 #ifdef SMP
+#ifdef EARLY_AP_STARTUP
+	MPASS(mp_ncpus == 1 || smp_started);
+#else
 	/*
 	 * If still booting and secondary CPUs not started yet, don't allow
 	 * changing the frequency until they're online.  This is because we
@@ -271,6 +274,7 @@ cf_set_method(device_t dev, const struct cf_level *level, int priority)
 		error = ENXIO;
 		goto out;
 	}
+#endif
 #endif /* SMP */
 
 	/*
diff --git a/sys/net/netisr.c b/sys/net/netisr.c
index 14de112..492a851 100644
--- a/sys/net/netisr.c
+++ b/sys/net/netisr.c
@@ -1119,6 +1119,10 @@ netisr_start_swi(u_int cpuid, struct pcpu *pc)
 static void
 netisr_init(void *arg)
 {
+#ifdef EARLY_AP_STARTUP
+	struct pcpu *pc;
+#endif
+
 	KASSERT(curcpu == 0, ("%s: not on CPU 0", __func__));
 
 	NETISR_LOCK_INIT();
@@ -1149,10 +1153,20 @@ netisr_init(void *arg)
 		netisr_bindthreads = 0;
 	}
 #endif
+
+#ifdef EARLY_AP_STARTUP
+	STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
+		if (nws_count >= netisr_maxthreads)
+			break;
+		netisr_start_swi(pc->pc_cpuid, pc);
+	}
+#else
 	netisr_start_swi(curcpu, pcpu_find(curcpu));
+#endif
 }
 SYSINIT(netisr_init, SI_SUB_SOFTINTR, SI_ORDER_FIRST, netisr_init, NULL);
 
+#ifndef EARLY_AP_STARTUP
 /*
  * Start worker threads for additional CPUs.  No attempt to gracefully handle
  * work reassignment, we don't yet support dynamic reconfiguration.
@@ -1172,6 +1186,7 @@ netisr_start(void *arg)
 	}
 }
 SYSINIT(netisr_start, SI_SUB_SMP, SI_ORDER_MIDDLE, netisr_start, NULL);
+#endif
 
 /*
  * Sysctl monitoring for netisr: query a list of registered protocols.
diff --git a/sys/sys/kernel.h b/sys/sys/kernel.h
index 02628ba..c6dd848 100644
--- a/sys/sys/kernel.h
+++ b/sys/sys/kernel.h
@@ -118,7 +118,10 @@ enum sysinit_sub_id {
 	SI_SUB_SCHED_IDLE	= 0x2600000,	/* required idle procs */
 	SI_SUB_MBUF		= 0x2700000,	/* mbuf subsystem */
 	SI_SUB_INTR		= 0x2800000,	/* interrupt threads */
-	SI_SUB_SOFTINTR		= 0x2800001,	/* start soft interrupt thread */
+#ifdef EARLY_AP_STARTUP
+	SI_SUB_SMP		= 0x2900000,	/* start the APs*/
+#endif
+	SI_SUB_SOFTINTR		= 0x2A00000,	/* start soft interrupt thread */
 	SI_SUB_DEVFS		= 0x2F00000,	/* devfs ready for devices */
 	SI_SUB_INIT_IF		= 0x3000000,	/* prep for net interfaces */
 	SI_SUB_NETGRAPH		= 0x3010000,	/* Let Netgraph initialize */
@@ -154,7 +157,9 @@ enum sysinit_sub_id {
 	SI_SUB_KTHREAD_BUF	= 0xea00000,	/* buffer daemon*/
 	SI_SUB_KTHREAD_UPDATE	= 0xec00000,	/* update daemon*/
 	SI_SUB_KTHREAD_IDLE	= 0xee00000,	/* idle procs*/
+#ifndef EARLY_AP_STARTUP
 	SI_SUB_SMP		= 0xf000000,	/* start the APs*/
+#endif	
 	SI_SUB_RACCTD		= 0xf100000,	/* start racctd*/
 	SI_SUB_LAST		= 0xfffffff	/* final initialization */
 };
diff --git a/sys/x86/isa/clock.c b/sys/x86/isa/clock.c
index cced5e34..fa4ca5b 100644
--- a/sys/x86/isa/clock.c
+++ b/sys/x86/isa/clock.c
@@ -475,8 +475,27 @@ startrtclock()
 void
 cpu_initclocks(void)
 {
+#ifdef EARLY_AP_STARTUP
+	struct thread *td;
+	int i;
 
+	td = curthread;
 	cpu_initclocks_bsp();
+	CPU_FOREACH(i) {
+		if (i == 0)
+			continue;
+		thread_lock(td);
+		sched_bind(td, i);
+		thread_unlock(td);
+		cpu_initclocks_ap();
+	}
+	thread_lock(td);
+	if (sched_is_bound(td))
+		sched_unbind(td);
+	thread_unlock(td);
+#else
+	cpu_initclocks_bsp();
+#endif
 }
 
 static int
diff --git a/sys/x86/x86/intr_machdep.c b/sys/x86/x86/intr_machdep.c
index 36a3441..1bc3038 100644
--- a/sys/x86/x86/intr_machdep.c
+++ b/sys/x86/x86/intr_machdep.c
@@ -77,7 +77,7 @@ static struct mtx intr_table_lock;
 static struct mtx intrcnt_lock;
 static TAILQ_HEAD(pics_head, pic) pics;
 
-#ifdef SMP
+#if defined(SMP) && !defined(EARLY_AP_STARTUP)
 static int assign_cpu;
 #endif
 
@@ -320,11 +320,16 @@ intr_assign_cpu(void *arg, int cpu)
 	struct intsrc *isrc;
 	int error;
 
+#ifdef EARLY_AP_STARTUP
+	MPASS(mp_ncpus == 1 || smp_started);
+	if (cpu != NOCPU) {
+#else
 	/*
 	 * Don't do anything during early boot.  We will pick up the
 	 * assignment once the APs are started.
 	 */
 	if (assign_cpu && cpu != NOCPU) {
+#endif
 		isrc = arg;
 		mtx_lock(&intr_table_lock);
 		error = isrc->is_pic->pic_assign_cpu(isrc, cpu_apic_ids[cpu]);
@@ -502,9 +507,13 @@ intr_next_cpu(void)
 {
 	u_int apic_id;
 
+#ifdef EARLY_AP_STARTUP
+	MPASS(mp_ncpus == 1 || smp_started);
+#else
 	/* Leave all interrupts on the BSP during boot. */
 	if (!assign_cpu)
 		return (PCPU_GET(apic_id));
+#endif
 
 	mtx_lock_spin(&icu_lock);
 	apic_id = cpu_apic_ids[current_cpu];
@@ -546,6 +555,7 @@ intr_add_cpu(u_int cpu)
 	CPU_SET(cpu, &intr_cpus);
 }
 
+#ifndef EARLY_AP_STARTUP
 /*
  * Distribute all the interrupt sources among the available CPUs once the
  * AP's have been launched.
@@ -586,6 +596,7 @@ intr_shuffle_irqs(void *arg __unused)
 }
 SYSINIT(intr_shuffle_irqs, SI_SUB_SMP, SI_ORDER_SECOND, intr_shuffle_irqs,
     NULL);
+#endif
 #else
 /*
  * Always route interrupts to the current processor in the UP case.
diff --git a/sys/x86/x86/local_apic.c b/sys/x86/x86/local_apic.c
index 1a02626..0a77679 100644
--- a/sys/x86/x86/local_apic.c
+++ b/sys/x86/x86/local_apic.c
@@ -749,6 +749,10 @@ native_lapic_enable_pmc(void)
 
 	lvts[APIC_LVT_PMC].lvt_masked = 0;
 
+#ifdef EARLY_AP_STARTUP
+	MPASS(mp_ncpus == 1 || smp_started);
+	smp_rendezvous(NULL, lapic_update_pmc, NULL, NULL);
+#else
 #ifdef SMP
 	/*
 	 * If hwpmc was loaded at boot time then the APs may not be
@@ -760,6 +764,7 @@ native_lapic_enable_pmc(void)
 	else
 #endif
 		lapic_update_pmc(NULL);
+#endif
 	return (1);
 #else
 	return (0);
diff --git a/sys/x86/x86/mca.c b/sys/x86/x86/mca.c
index b3d6066..d005180 100644
--- a/sys/x86/x86/mca.c
+++ b/sys/x86/x86/mca.c
@@ -726,7 +726,11 @@ mca_startup(void *dummy)
 
 	callout_reset(&mca_timer, mca_ticks * hz, mca_periodic_scan, NULL);
 }
+#ifdef EARLY_AP_STARTUP
+SYSINIT(mca_startup, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, mca_startup, NULL);
+#else
 SYSINIT(mca_startup, SI_SUB_SMP, SI_ORDER_ANY, mca_startup, NULL);
+#endif
 
 #ifdef DEV_APIC
 static void
diff --git a/sys/x86/x86/mp_x86.c b/sys/x86/x86/mp_x86.c
index 7ad9b96..d2eb2e9 100644
--- a/sys/x86/x86/mp_x86.c
+++ b/sys/x86/x86/mp_x86.c
@@ -933,8 +933,10 @@ init_secondary_tail(void)
 	while (atomic_load_acq_int(&smp_started) == 0)
 		ia32_pause();
 
+#ifndef EARLY_AP_STARTUP
 	/* Start per-CPU event timers. */
 	cpu_initclocks_ap();
+#endif
 
 	sched_throw(NULL);