diff --git a/sys/dev/hwpmc/hwpmc_arm64.c b/sys/dev/hwpmc/hwpmc_arm64.c
index 6b98fb46e7f1..84a8791287f7 100644
--- a/sys/dev/hwpmc/hwpmc_arm64.c
+++ b/sys/dev/hwpmc/hwpmc_arm64.c
@@ -1,596 +1,599 @@
 /*-
  * Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com>
  * All rights reserved.
  *
  * This software was developed by the University of Cambridge Computer
  * Laboratory with support from ARM Ltd.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/pmc.h>
 #include <sys/pmckern.h>
 
 #include <machine/pmc_mdep.h>
 #include <machine/cpu.h>
 
 static int arm64_npmcs;
 
 struct arm64_event_code_map {
 	enum pmc_event	pe_ev;
 	uint8_t		pe_code;
 };
 
 /*
  * Per-processor information.
  */
 struct arm64_cpu {
 	struct pmc_hw   *pc_arm64pmcs;
 };
 
 static struct arm64_cpu **arm64_pcpu;
 
 /*
  * Interrupt Enable Set Register
  */
 static __inline void
 arm64_interrupt_enable(uint32_t pmc)
 {
 	uint32_t reg;
 
 	reg = (1 << pmc);
 	WRITE_SPECIALREG(pmintenset_el1, reg);
 
 	isb();
 }
 
 /*
  * Interrupt Clear Set Register
  */
 static __inline void
 arm64_interrupt_disable(uint32_t pmc)
 {
 	uint32_t reg;
 
 	reg = (1 << pmc);
 	WRITE_SPECIALREG(pmintenclr_el1, reg);
 
 	isb();
 }
 
 /*
  * Counter Set Enable Register
  */
 static __inline void
 arm64_counter_enable(unsigned int pmc)
 {
 	uint32_t reg;
 
 	reg = (1 << pmc);
 	WRITE_SPECIALREG(pmcntenset_el0, reg);
 
 	isb();
 }
 
 /*
  * Counter Clear Enable Register
  */
 static __inline void
 arm64_counter_disable(unsigned int pmc)
 {
 	uint32_t reg;
 
 	reg = (1 << pmc);
 	WRITE_SPECIALREG(pmcntenclr_el0, reg);
 
 	isb();
 }
 
 /*
  * Performance Monitors Control Register
  */
 static uint32_t
 arm64_pmcr_read(void)
 {
 	uint32_t reg;
 
 	reg = READ_SPECIALREG(pmcr_el0);
 
 	return (reg);
 }
 
 static void
 arm64_pmcr_write(uint32_t reg)
 {
 
 	WRITE_SPECIALREG(pmcr_el0, reg);
 
 	isb();
 }
 
 /*
  * Performance Count Register N
  */
 static uint32_t
 arm64_pmcn_read(unsigned int pmc)
 {
 
 	KASSERT(pmc < arm64_npmcs, ("%s: illegal PMC number %d", __func__, pmc));
 
 	WRITE_SPECIALREG(pmselr_el0, pmc);
 
 	isb();
 
 	return (READ_SPECIALREG(pmxevcntr_el0));
 }
 
 static void
 arm64_pmcn_write(unsigned int pmc, uint32_t reg)
 {
 
 	KASSERT(pmc < arm64_npmcs, ("%s: illegal PMC number %d", __func__, pmc));
 
 	WRITE_SPECIALREG(pmselr_el0, pmc);
 	WRITE_SPECIALREG(pmxevcntr_el0, reg);
 
 	isb();
 }
 
 static int
 arm64_allocate_pmc(int cpu, int ri, struct pmc *pm,
   const struct pmc_op_pmcallocate *a)
 {
 	uint32_t caps, config;
 	struct arm64_cpu *pac;
 	enum pmc_event pe;
 
 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 	    ("[arm64,%d] illegal CPU value %d", __LINE__, cpu));
 	KASSERT(ri >= 0 && ri < arm64_npmcs,
 	    ("[arm64,%d] illegal row index %d", __LINE__, ri));
 
 	pac = arm64_pcpu[cpu];
 
 	caps = a->pm_caps;
 	if (a->pm_class != PMC_CLASS_ARMV8) {
 		return (EINVAL);
 	}
 	pe = a->pm_ev;
 
 	/* Adjust the config value if needed. */
 	config = (uint32_t)pe;
 	if ((a->pm_md.pm_md_flags & PM_MD_RAW_EVENT) == 0) {
 		config -= PMC_EV_ARMV8_FIRST;
 		if (config > (PMC_EV_ARMV8_LAST - PMC_EV_ARMV8_FIRST))
 			return (EINVAL);
 	}
 	pm->pm_md.pm_arm64.pm_arm64_evsel = config;
 	PMCDBG2(MDP, ALL, 2, "arm64-allocate ri=%d -> config=0x%x", ri, config);
 
 	return (0);
 }
 
 
 static int
 arm64_read_pmc(int cpu, int ri, pmc_value_t *v)
 {
 	pmc_value_t tmp;
 	struct pmc *pm;
 	register_t s;
 	int reg;
 
 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 	    ("[arm64,%d] illegal CPU value %d", __LINE__, cpu));
 	KASSERT(ri >= 0 && ri < arm64_npmcs,
 	    ("[arm64,%d] illegal row index %d", __LINE__, ri));
 
 	pm  = arm64_pcpu[cpu]->pc_arm64pmcs[ri].phw_pmc;
 
 	/*
 	 * Ensure we don't get interrupted while updating the overflow count.
 	 */
 	s = intr_disable();
 	tmp = arm64_pmcn_read(ri);
 	reg = (1 << ri);
 	if ((READ_SPECIALREG(pmovsclr_el0) & reg) != 0) {
 		/* Clear Overflow Flag */
 		WRITE_SPECIALREG(pmovsclr_el0, reg);
 		if (!PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
 			pm->pm_pcpu_state[cpu].pps_overflowcnt++;
 
 		/* Reread counter in case we raced. */
 		tmp = arm64_pmcn_read(ri);
 	}
 	tmp += 0x100000000llu * pm->pm_pcpu_state[cpu].pps_overflowcnt;
 	intr_restore(s);
 
 	PMCDBG2(MDP, REA, 2, "arm64-read id=%d -> %jd", ri, tmp);
 	if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
 		*v = ARMV8_PERFCTR_VALUE_TO_RELOAD_COUNT(tmp);
 	else
 		*v = tmp;
 
 	return (0);
 }
 
 static int
 arm64_write_pmc(int cpu, int ri, pmc_value_t v)
 {
 	struct pmc *pm;
 
 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 	    ("[arm64,%d] illegal CPU value %d", __LINE__, cpu));
 	KASSERT(ri >= 0 && ri < arm64_npmcs,
 	    ("[arm64,%d] illegal row-index %d", __LINE__, ri));
 
 	pm  = arm64_pcpu[cpu]->pc_arm64pmcs[ri].phw_pmc;
 
 	if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
 		v = ARMV8_RELOAD_COUNT_TO_PERFCTR_VALUE(v);
 
 	PMCDBG3(MDP, WRI, 1, "arm64-write cpu=%d ri=%d v=%jx", cpu, ri, v);
 
 	pm->pm_pcpu_state[cpu].pps_overflowcnt = v >> 32;
 	arm64_pmcn_write(ri, v);
 
 	return (0);
 }
 
 static int
 arm64_config_pmc(int cpu, int ri, struct pmc *pm)
 {
 	struct pmc_hw *phw;
 
 	PMCDBG3(MDP, CFG, 1, "cpu=%d ri=%d pm=%p", cpu, ri, pm);
 
 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 	    ("[arm64,%d] illegal CPU value %d", __LINE__, cpu));
 	KASSERT(ri >= 0 && ri < arm64_npmcs,
 	    ("[arm64,%d] illegal row-index %d", __LINE__, ri));
 
 	phw = &arm64_pcpu[cpu]->pc_arm64pmcs[ri];
 
 	KASSERT(pm == NULL || phw->phw_pmc == NULL,
 	    ("[arm64,%d] pm=%p phw->pm=%p hwpmc not unconfigured",
 	    __LINE__, pm, phw->phw_pmc));
 
 	phw->phw_pmc = pm;
 
 	return (0);
 }
 
 static int
 arm64_start_pmc(int cpu, int ri)
 {
 	struct pmc_hw *phw;
 	uint32_t config;
 	struct pmc *pm;
 
 	phw    = &arm64_pcpu[cpu]->pc_arm64pmcs[ri];
 	pm     = phw->phw_pmc;
 	config = pm->pm_md.pm_arm64.pm_arm64_evsel;
 
 	/*
 	 * Configure the event selection.
 	 */
 	WRITE_SPECIALREG(pmselr_el0, ri);
 	WRITE_SPECIALREG(pmxevtyper_el0, config);
 
 	isb();
 
 	/*
 	 * Enable the PMC.
 	 */
 	arm64_interrupt_enable(ri);
 	arm64_counter_enable(ri);
 
 	return (0);
 }
 
 static int
 arm64_stop_pmc(int cpu, int ri)
 {
 	struct pmc_hw *phw;
 	struct pmc *pm;
 
 	phw    = &arm64_pcpu[cpu]->pc_arm64pmcs[ri];
 	pm     = phw->phw_pmc;
 
 	/*
 	 * Disable the PMCs.
 	 */
 	arm64_counter_disable(ri);
 	arm64_interrupt_disable(ri);
 
 	return (0);
 }
 
 static int
 arm64_release_pmc(int cpu, int ri, struct pmc *pmc)
 {
 	struct pmc_hw *phw;
 
 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 	    ("[arm64,%d] illegal CPU value %d", __LINE__, cpu));
 	KASSERT(ri >= 0 && ri < arm64_npmcs,
 	    ("[arm64,%d] illegal row-index %d", __LINE__, ri));
 
 	phw = &arm64_pcpu[cpu]->pc_arm64pmcs[ri];
 	KASSERT(phw->phw_pmc == NULL,
 	    ("[arm64,%d] PHW pmc %p non-NULL", __LINE__, phw->phw_pmc));
 
 	return (0);
 }
 
 static int
 arm64_intr(struct trapframe *tf)
 {
 	struct arm64_cpu *pc;
 	int retval, ri;
 	struct pmc *pm;
 	int error;
 	int reg, cpu;
 
 	cpu = curcpu;
 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 	    ("[arm64,%d] CPU %d out of range", __LINE__, cpu));
 
+	PMCDBG3(MDP,INT,1, "cpu=%d tf=%p um=%d", cpu, (void *)tf,
+	    TRAPF_USERMODE(tf));
+
 	retval = 0;
 	pc = arm64_pcpu[cpu];
 
 	for (ri = 0; ri < arm64_npmcs; ri++) {
 		pm = arm64_pcpu[cpu]->pc_arm64pmcs[ri].phw_pmc;
 		if (pm == NULL)
 			continue;
 		/* Check if counter is overflowed */
 		reg = (1 << ri);
 		if ((READ_SPECIALREG(pmovsclr_el0) & reg) == 0)
 			continue;
 		/* Clear Overflow Flag */
 		WRITE_SPECIALREG(pmovsclr_el0, reg);
 
 		isb();
 
 		retval = 1; /* Found an interrupting PMC. */
 
 		if (!PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm))) {
 			pm->pm_pcpu_state[cpu].pps_overflowcnt += 1;
 			continue;
 		}
 
 		if (pm->pm_state != PMC_STATE_RUNNING)
 			continue;
 
 		error = pmc_process_interrupt(PMC_HR, pm, tf);
 		if (error)
 			arm64_stop_pmc(cpu, ri);
 
 		/* Reload sampling count */
 		arm64_write_pmc(cpu, ri, pm->pm_sc.pm_reloadcount);
 	}
 
 	return (retval);
 }
 
 static int
 arm64_describe(int cpu, int ri, struct pmc_info *pi, struct pmc **ppmc)
 {
 	char arm64_name[PMC_NAME_MAX];
 	struct pmc_hw *phw;
 	int error;
 
 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 	    ("[arm64,%d], illegal CPU %d", __LINE__, cpu));
 	KASSERT(ri >= 0 && ri < arm64_npmcs,
 	    ("[arm64,%d] row-index %d out of range", __LINE__, ri));
 
 	phw = &arm64_pcpu[cpu]->pc_arm64pmcs[ri];
 	snprintf(arm64_name, sizeof(arm64_name), "ARMV8-%d", ri);
 	if ((error = copystr(arm64_name, pi->pm_name, PMC_NAME_MAX,
 	    NULL)) != 0)
 		return (error);
 	pi->pm_class = PMC_CLASS_ARMV8;
 	if (phw->phw_state & PMC_PHW_FLAG_IS_ENABLED) {
 		pi->pm_enabled = TRUE;
 		*ppmc = phw->phw_pmc;
 	} else {
 		pi->pm_enabled = FALSE;
 		*ppmc = NULL;
 	}
 
 	return (0);
 }
 
 static int
 arm64_get_config(int cpu, int ri, struct pmc **ppm)
 {
 
 	*ppm = arm64_pcpu[cpu]->pc_arm64pmcs[ri].phw_pmc;
 
 	return (0);
 }
 
 /*
  * XXX don't know what we should do here.
  */
 static int
 arm64_switch_in(struct pmc_cpu *pc, struct pmc_process *pp)
 {
 
 	return (0);
 }
 
 static int
 arm64_switch_out(struct pmc_cpu *pc, struct pmc_process *pp)
 {
 
 	return (0);
 }
 
 static int
 arm64_pcpu_init(struct pmc_mdep *md, int cpu)
 {
 	struct arm64_cpu *pac;
 	struct pmc_hw  *phw;
 	struct pmc_cpu *pc;
 	uint64_t pmcr;
 	int first_ri;
 	int i;
 
 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 	    ("[arm64,%d] wrong cpu number %d", __LINE__, cpu));
 	PMCDBG1(MDP, INI, 1, "arm64-init cpu=%d", cpu);
 
 	arm64_pcpu[cpu] = pac = malloc(sizeof(struct arm64_cpu), M_PMC,
 	    M_WAITOK | M_ZERO);
 
 	pac->pc_arm64pmcs = malloc(sizeof(struct pmc_hw) * arm64_npmcs,
 	    M_PMC, M_WAITOK | M_ZERO);
 	pc = pmc_pcpu[cpu];
 	first_ri = md->pmd_classdep[PMC_MDEP_CLASS_INDEX_ARMV8].pcd_ri;
 	KASSERT(pc != NULL, ("[arm64,%d] NULL per-cpu pointer", __LINE__));
 
 	for (i = 0, phw = pac->pc_arm64pmcs; i < arm64_npmcs; i++, phw++) {
 		phw->phw_state    = PMC_PHW_FLAG_IS_ENABLED |
 		    PMC_PHW_CPU_TO_STATE(cpu) | PMC_PHW_INDEX_TO_STATE(i);
 		phw->phw_pmc      = NULL;
 		pc->pc_hwpmcs[i + first_ri] = phw;
 	}
 
 	/* Enable unit */
 	pmcr = arm64_pmcr_read();
 	pmcr |= PMCR_E;
 	arm64_pmcr_write(pmcr);
 
 	return (0);
 }
 
 static int
 arm64_pcpu_fini(struct pmc_mdep *md, int cpu)
 {
 	uint32_t pmcr;
 
 	pmcr = arm64_pmcr_read();
 	pmcr &= ~PMCR_E;
 	arm64_pmcr_write(pmcr);
 
 	return (0);
 }
 
 struct pmc_mdep *
 pmc_arm64_initialize()
 {
 	struct pmc_mdep *pmc_mdep;
 	struct pmc_classdep *pcd;
 	int idcode, impcode;
 	int reg;
 	uint64_t midr;
 
 	reg = arm64_pmcr_read();
 	arm64_npmcs = (reg & PMCR_N_MASK) >> PMCR_N_SHIFT;
 	impcode = (reg & PMCR_IMP_MASK) >> PMCR_IMP_SHIFT;
 	idcode = (reg & PMCR_IDCODE_MASK) >> PMCR_IDCODE_SHIFT;
 
 	PMCDBG1(MDP, INI, 1, "arm64-init npmcs=%d", arm64_npmcs);
 
 	/*
 	 * Write the CPU model to kern.hwpmc.cpuid.
 	 *
 	 * We zero the variant and revision fields.
 	 *
 	 * TODO: how to handle differences between cores due to big.LITTLE?
 	 * For now, just use MIDR from CPU 0.
 	 */
 	midr = (uint64_t)(pcpu_find(0)->pc_midr);
 	midr &= ~(CPU_VAR_MASK | CPU_REV_MASK);
 	snprintf(pmc_cpuid, sizeof(pmc_cpuid), "0x%016lx", midr);
 
 	/*
 	 * Allocate space for pointers to PMC HW descriptors and for
 	 * the MDEP structure used by MI code.
 	 */
 	arm64_pcpu = malloc(sizeof(struct arm64_cpu *) * pmc_cpu_max(),
 		M_PMC, M_WAITOK | M_ZERO);
 
 	/* Just one class */
 	pmc_mdep = pmc_mdep_alloc(1);
 
 	switch(impcode) {
 	case PMCR_IMP_ARM:
 		switch (idcode) {
 		case PMCR_IDCODE_CORTEX_A76:
 		case PMCR_IDCODE_NEOVERSE_N1:
 			pmc_mdep->pmd_cputype = PMC_CPU_ARMV8_CORTEX_A76;
 			break;
 		case PMCR_IDCODE_CORTEX_A57:
 		case PMCR_IDCODE_CORTEX_A72:
 			pmc_mdep->pmd_cputype = PMC_CPU_ARMV8_CORTEX_A57;
 			break;
 		default:
 		case PMCR_IDCODE_CORTEX_A53:
 			pmc_mdep->pmd_cputype = PMC_CPU_ARMV8_CORTEX_A53;
 			break;
 		}
 		break;
 	default:
 		pmc_mdep->pmd_cputype = PMC_CPU_ARMV8_CORTEX_A53;
 		break;
 	}
 
 	pcd = &pmc_mdep->pmd_classdep[PMC_MDEP_CLASS_INDEX_ARMV8];
 	pcd->pcd_caps  = ARMV8_PMC_CAPS;
 	pcd->pcd_class = PMC_CLASS_ARMV8;
 	pcd->pcd_num   = arm64_npmcs;
 	pcd->pcd_ri    = pmc_mdep->pmd_npmc;
 	pcd->pcd_width = 32;
 
 	pcd->pcd_allocate_pmc   = arm64_allocate_pmc;
 	pcd->pcd_config_pmc     = arm64_config_pmc;
 	pcd->pcd_pcpu_fini      = arm64_pcpu_fini;
 	pcd->pcd_pcpu_init      = arm64_pcpu_init;
 	pcd->pcd_describe       = arm64_describe;
 	pcd->pcd_get_config     = arm64_get_config;
 	pcd->pcd_read_pmc       = arm64_read_pmc;
 	pcd->pcd_release_pmc    = arm64_release_pmc;
 	pcd->pcd_start_pmc      = arm64_start_pmc;
 	pcd->pcd_stop_pmc       = arm64_stop_pmc;
 	pcd->pcd_write_pmc      = arm64_write_pmc;
 
 	pmc_mdep->pmd_intr       = arm64_intr;
 	pmc_mdep->pmd_switch_in  = arm64_switch_in;
 	pmc_mdep->pmd_switch_out = arm64_switch_out;
 
 	pmc_mdep->pmd_npmc   += arm64_npmcs;
 
 	return (pmc_mdep);
 }
 
 void
 pmc_arm64_finalize(struct pmc_mdep *md)
 {
 
 }