4 files changed, 938 insertions, 0 deletions
diff --git a/sys/cddl/dev/dtrace/riscv/dtrace_asm.S b/sys/cddl/dev/dtrace/riscv/dtrace_asm.S
new file mode 100644
index 000000000000..eeaf64061675
--- /dev/null
+++ b/sys/cddl/dev/dtrace/riscv/dtrace_asm.S
@@ -0,0 +1,177 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ *
+ * Portions Copyright 2016 Ruslan Bukin <br@bsdpad.com>
+ *
+ * $FreeBSD$
+ */
+/*
+ * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#define _ASM
+#define _LOCORE
+
+#include <sys/cpuvar_defs.h>
+#include <sys/dtrace.h>
+
+#include <machine/riscvreg.h>
+#include <machine/asm.h>
+
+#include "assym.inc"
+
+/*
+void dtrace_membar_producer(void)
+*/
+ENTRY(dtrace_membar_producer)
+	RET
+END(dtrace_membar_producer)
+
+/*
+void dtrace_membar_consumer(void)
+*/
+ENTRY(dtrace_membar_consumer)
+	RET
+END(dtrace_membar_consumer)
+
+/*
+dtrace_icookie_t dtrace_interrupt_disable(void)
+*/
+ENTRY(dtrace_interrupt_disable)
+	csrrci	a0, sstatus, (SSTATUS_SIE)
+	andi	a0, a0, (SSTATUS_SIE)
+	RET
+END(dtrace_interrupt_disable)
+
+/*
+void dtrace_interrupt_enable(dtrace_icookie_t cookie)
+*/
+ENTRY(dtrace_interrupt_enable)
+	csrs	sstatus, a0
+	RET
+END(dtrace_interrupt_enable)
+/*
+uint8_t
+dtrace_fuword8_nocheck(void *addr)
+*/
+ENTRY(dtrace_fuword8_nocheck)
+	lb	a0, 0(a0)
+	RET
+END(dtrace_fuword8_nocheck)
+
+/*
+uint16_t
+dtrace_fuword16_nocheck(void *addr)
+*/
+ENTRY(dtrace_fuword16_nocheck)
+	lh	a0, 0(a0)
+	RET
+END(dtrace_fuword16_nocheck)
+
+/*
+uint32_t
+dtrace_fuword32_nocheck(void *addr)
+*/
+ENTRY(dtrace_fuword32_nocheck)
+	lw	a0, 0(a0)
+	RET
+END(dtrace_fuword32_nocheck)
+
+/*
+uint64_t
+dtrace_fuword64_nocheck(void *addr)
+*/
+ENTRY(dtrace_fuword64_nocheck)
+	ld	a0, 0(a0)
+	RET
+END(dtrace_fuword64_nocheck)
+
+/*
+void
+dtrace_copy(uintptr_t uaddr, uintptr_t kaddr, size_t size)
+*/
+ENTRY(dtrace_copy)
+	beqz	a2, 2f		/* If len == 0 then skip loop */
+1:
+	lb	a4, 0(a0)	/* Load from uaddr */
+	addi	a0, a0, 1
+	sb	a4, 0(a1)	/* Store in kaddr */
+	addi	a1, a1, 1
+	addi	a2, a2, -1	/* len-- */
+	bnez	a2, 1b
+2:
+	RET
+END(dtrace_copy)
+
+/*
+void
+dtrace_copystr(uintptr_t uaddr, uintptr_t kaddr, size_t size,
+    volatile uint16_t *flags)
+XXX: Check for flags?
+*/
+ENTRY(dtrace_copystr)
+	beqz	a2, 2f		/* If len == 0 then skip loop */
+	lb	a4, 0(a0)	/* Load from uaddr */
+	addi	a0, a0, 1
+	sb	a4, 0(a1)	/* Store in kaddr */
+	addi	a1, a1, 1
+	beqz	a4, 2f		/* If == 0 then break */
+	addi	a2, a2, -1	/* len-- */
+	bnez	a2, 1b
+2:
+	RET
+END(dtrace_copystr)
+
+/*
+uintptr_t
+dtrace_caller(int aframes)
+*/
+ENTRY(dtrace_caller)
+	li	a0, -1
+	RET
+END(dtrace_caller)
+
+/*
+uint32_t
+dtrace_cas32(uint32_t *target, uint32_t cmp, uint32_t new)
+*/
+ENTRY(dtrace_cas32)
+1:	lr.w	a3, 0(a0)	/* Load target */
+	bne	a3, a1, 2f	/* *target != cmp ? return */
+	sc.w	a4, a2, 0(a0)	/* Store new to target */
+	bnez	a4, 1b		/* Try again if store not succeed */
+2:	mv	a0, a3		/* Return the value loaded from target */
+	RET
+END(dtrace_cas32)
+
+/*
+void *
+dtrace_casptr(volatile void *target, volatile void *cmp, volatile void *new)
+*/
+ENTRY(dtrace_casptr)
+1:	lr.d	a3, 0(a0)	/* Load target */
+	bne	a3, a1, 2f	/* *target != cmp ? return */
+	sc.d	a4, a2, 0(a0)	/* Store new to target */
+	bnez	a4, 1b		/* Try again if store not succeed */
+2:	mv	a0, a3		/* Return the value loaded from target */
+	RET
+END(dtrace_casptr)
diff --git a/sys/cddl/dev/dtrace/riscv/dtrace_isa.c b/sys/cddl/dev/dtrace/riscv/dtrace_isa.c
new file mode 100644
index 000000000000..955d2cb10f65
--- /dev/null
+++ b/sys/cddl/dev/dtrace/riscv/dtrace_isa.c
@@ -0,0 +1,394 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ *
+ * Portions Copyright 2016 Ruslan Bukin <br@bsdpad.com>
+ *
+ * $FreeBSD$
+ */
+/*
+ * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+#include <sys/cdefs.h>
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/stack.h>
+#include <sys/pcpu.h>
+
+#include <machine/frame.h>
+#include <machine/md_var.h>
+#include <machine/reg.h>
+
+#include <vm/vm.h>
+#include <vm/vm_param.h>
+#include <vm/pmap.h>
+
+#include <machine/atomic.h>
+#include <machine/db_machdep.h>
+#include <machine/md_var.h>
+#include <machine/stack.h>
+#include <ddb/db_sym.h>
+#include <ddb/ddb.h>
+#include <sys/kdb.h>
+
+#include "regset.h"
+
+/*
+ * Wee need some reasonable default to prevent backtrace code
+ * from wandering too far
+ */
+#define	MAX_FUNCTION_SIZE 0x10000
+#define	MAX_PROLOGUE_SIZE 0x100
+#define	MAX_USTACK_DEPTH  2048
+
+uint8_t dtrace_fuword8_nocheck(void *);
+uint16_t dtrace_fuword16_nocheck(void *);
+uint32_t dtrace_fuword32_nocheck(void *);
+uint64_t dtrace_fuword64_nocheck(void *);
+
+void
+dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, int aframes,
+    uint32_t *intrpc)
+{
+	struct unwind_state state;
+	int scp_offset;
+	register_t sp;
+	int depth;
+
+	depth = 0;
+
+	if (intrpc != 0) {
+		pcstack[depth++] = (pc_t) intrpc;
+	}
+
+	aframes++;
+
+	__asm __volatile("mv %0, sp" : "=&r" (sp));
+
+	state.fp = (uint64_t)__builtin_frame_address(0);
+	state.sp = sp;
+	state.pc = (uint64_t)dtrace_getpcstack;
+
+	while (depth < pcstack_limit) {
+		if (unwind_frame(&state))
+			break;
+
+		if (!INKERNEL(state.pc) || !INKERNEL(state.fp))
+			break;
+
+		/*
+		 * NB: Unlike some other architectures, we don't need to
+		 * explicitly insert cpu_dtrace_caller as it appears in the
+		 * normal kernel stack trace rather than a special trap frame.
+		 */
+		if (aframes > 0) {
+			aframes--;
+		} else {
+			pcstack[depth++] = state.pc;
+		}
+
+	}
+
+	for (; depth < pcstack_limit; depth++) {
+		pcstack[depth] = 0;
+	}
+}
+
+static int
+dtrace_getustack_common(uint64_t *pcstack, int pcstack_limit, uintptr_t pc,
+    uintptr_t fp)
+{
+	volatile uint16_t *flags;
+	uintptr_t oldfp;
+	int ret;
+
+	ret = 0;
+	flags = (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;
+
+	ASSERT(pcstack == NULL || pcstack_limit > 0);
+
+	while (pc != 0) {
+		/*
+		 * We limit the number of times we can go around this
+		 * loop to account for a circular stack.
+		 */
+		if (ret++ >= MAX_USTACK_DEPTH) {
+			*flags |= CPU_DTRACE_BADSTACK;
+			cpu_core[curcpu].cpuc_dtrace_illval = fp;
+			break;
+		}
+
+		if (pcstack != NULL) {
+			*pcstack++ = (uint64_t)pc;
+			pcstack_limit--;
+			if (pcstack_limit <= 0)
+				break;
+		}
+
+		if (fp == 0)
+			break;
+
+		pc = dtrace_fuword64((void *)(fp +
+		    offsetof(struct riscv_frame, f_retaddr)));
+		fp = dtrace_fuword64((void *)fp);
+
+		if (fp == oldfp) {
+			*flags |= CPU_DTRACE_BADSTACK;
+			cpu_core[curcpu].cpuc_dtrace_illval = fp;
+			break;
+		}
+	}
+
+	return (ret);
+}
+
+void
+dtrace_getupcstack(uint64_t *pcstack, int pcstack_limit)
+{
+	volatile uint16_t *flags;
+	struct trapframe *tf;
+	uintptr_t pc, sp, fp;
+	proc_t *p;
+	int n;
+
+	p = curproc;
+	flags = (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;
+
+	if (*flags & CPU_DTRACE_FAULT)
+		return;
+
+	if (pcstack_limit <= 0)
+		return;
+
+	/*
+	 * If there's no user context we still need to zero the stack.
+	 */
+	if (p == NULL || (tf = curthread->td_frame) == NULL)
+		goto zero;
+
+	*pcstack++ = (uint64_t)p->p_pid;
+	pcstack_limit--;
+
+	if (pcstack_limit <= 0)
+		return;
+
+	pc = tf->tf_sepc;
+	sp = tf->tf_sp;
+	fp = tf->tf_s[0];
+
+	if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) {
+		/*
+		 * In an entry probe.  The frame pointer has not yet been
+		 * pushed (that happens in the function prologue).  The
+		 * best approach is to add the current pc as a missing top
+		 * of stack and back the pc up to the caller, which is stored
+		 * at the current stack pointer address since the call
+		 * instruction puts it there right before the branch.
+		 */
+
+		*pcstack++ = (uint64_t)pc;
+		pcstack_limit--;
+		if (pcstack_limit <= 0)
+			return;
+
+		pc = tf->tf_ra;
+	}
+
+	n = dtrace_getustack_common(pcstack, pcstack_limit, pc, fp);
+	ASSERT(n >= 0);
+	ASSERT(n <= pcstack_limit);
+
+	pcstack += n;
+	pcstack_limit -= n;
+
+zero:
+	while (pcstack_limit-- > 0)
+		*pcstack++ = 0;
+}
+
+int
+dtrace_getustackdepth(void)
+{
+
+	printf("IMPLEMENT ME: %s\n", __func__);
+
+	return (0);
+}
+
+void
+dtrace_getufpstack(uint64_t *pcstack, uint64_t *fpstack, int pcstack_limit)
+{
+
+	printf("IMPLEMENT ME: %s\n", __func__);
+}
+
+/*ARGSUSED*/
+uint64_t
+dtrace_getarg(int arg, int aframes)
+{
+
+	printf("IMPLEMENT ME: %s\n", __func__);
+
+	return (0);
+}
+
+int
+dtrace_getstackdepth(int aframes)
+{
+	struct unwind_state state;
+	int scp_offset;
+	register_t sp;
+	int depth;
+	int done;
+
+	depth = 1;
+	done = 0;
+
+	__asm __volatile("mv %0, sp" : "=&r" (sp));
+
+	state.fp = (uint64_t)__builtin_frame_address(0);
+	state.sp = sp;
+	state.pc = (uint64_t)dtrace_getstackdepth;
+
+	do {
+		done = unwind_frame(&state);
+		if (!INKERNEL(state.pc) || !INKERNEL(state.fp))
+			break;
+		depth++;
+	} while (!done);
+
+	if (depth < aframes)
+		return (0);
+	else
+		return (depth - aframes);
+}
+
+ulong_t
+dtrace_getreg(struct trapframe *rp, uint_t reg)
+{
+
+	printf("IMPLEMENT ME: %s\n", __func__);
+
+	return (0);
+}
+
+static int
+dtrace_copycheck(uintptr_t uaddr, uintptr_t kaddr, size_t size)
+{
+
+	if (uaddr + size > VM_MAXUSER_ADDRESS || uaddr + size < uaddr) {
+		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
+		cpu_core[curcpu].cpuc_dtrace_illval = uaddr;
+		return (0);
+	}
+
+	return (1);
+}
+
+void
+dtrace_copyin(uintptr_t uaddr, uintptr_t kaddr, size_t size,
+    volatile uint16_t *flags)
+{
+
+	if (dtrace_copycheck(uaddr, kaddr, size))
+		dtrace_copy(uaddr, kaddr, size);
+}
+
+void
+dtrace_copyout(uintptr_t kaddr, uintptr_t uaddr, size_t size,
+    volatile uint16_t *flags)
+{
+
+	if (dtrace_copycheck(uaddr, kaddr, size))
+		dtrace_copy(kaddr, uaddr, size);
+}
+
+void
+dtrace_copyinstr(uintptr_t uaddr, uintptr_t kaddr, size_t size,
+    volatile uint16_t *flags)
+{
+
+	if (dtrace_copycheck(uaddr, kaddr, size))
+		dtrace_copystr(uaddr, kaddr, size, flags);
+}
+
+void
+dtrace_copyoutstr(uintptr_t kaddr, uintptr_t uaddr, size_t size,
+    volatile uint16_t *flags)
+{
+
+	if (dtrace_copycheck(uaddr, kaddr, size))
+		dtrace_copystr(kaddr, uaddr, size, flags);
+}
+
+uint8_t
+dtrace_fuword8(void *uaddr)
+{
+
+	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
+		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
+		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
+		return (0);
+	}
+
+	return (dtrace_fuword8_nocheck(uaddr));
+}
+
+uint16_t
+dtrace_fuword16(void *uaddr)
+{
+
+	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
+		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
+		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
+		return (0);
+	}
+
+	return (dtrace_fuword16_nocheck(uaddr));
+}
+
+uint32_t
+dtrace_fuword32(void *uaddr)
+{
+
+	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
+		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
+		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
+		return (0);
+	}
+
+	return (dtrace_fuword32_nocheck(uaddr));
+}
+
+uint64_t
+dtrace_fuword64(void *uaddr)
+{
+
+	if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
+		DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
+		cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
+		return (0);
+	}
+
+	return (dtrace_fuword64_nocheck(uaddr));
+}
diff --git a/sys/cddl/dev/dtrace/riscv/dtrace_subr.c b/sys/cddl/dev/dtrace/riscv/dtrace_subr.c
new file mode 100644
index 000000000000..ccc6b77090ab
--- /dev/null
+++ b/sys/cddl/dev/dtrace/riscv/dtrace_subr.c
@@ -0,0 +1,316 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ *
+ * Portions Copyright 2016-2018 Ruslan Bukin <br@bsdpad.com>
+ *
+ * $FreeBSD$
+ *
+ */
+/*
+ * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/types.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/kmem.h>
+#include <sys/smp.h>
+#include <sys/dtrace_impl.h>
+#include <sys/dtrace_bsd.h>
+#include <machine/vmparam.h>
+#include <machine/encoding.h>
+#include <machine/riscvreg.h>
+#include <machine/clock.h>
+#include <machine/frame.h>
+#include <machine/trap.h>
+#include <vm/pmap.h>
+
+extern dtrace_id_t	dtrace_probeid_error;
+extern int (*dtrace_invop_jump_addr)(struct trapframe *);
+extern void dtrace_getnanotime(struct timespec *tsp);
+
+int dtrace_invop(uintptr_t, struct trapframe *, uintptr_t);
+void dtrace_invop_init(void);
+void dtrace_invop_uninit(void);
+
+typedef struct dtrace_invop_hdlr {
+	int (*dtih_func)(uintptr_t, struct trapframe *, uintptr_t);
+	struct dtrace_invop_hdlr *dtih_next;
+} dtrace_invop_hdlr_t;
+
+dtrace_invop_hdlr_t *dtrace_invop_hdlr;
+
+int
+dtrace_invop(uintptr_t addr, struct trapframe *frame, uintptr_t eax)
+{
+	dtrace_invop_hdlr_t *hdlr;
+	int rval;
+
+	for (hdlr = dtrace_invop_hdlr; hdlr != NULL; hdlr = hdlr->dtih_next)
+		if ((rval = hdlr->dtih_func(addr, frame, eax)) != 0)
+			return (rval);
+
+	return (0);
+}
+
+void
+dtrace_invop_add(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
+{
+	dtrace_invop_hdlr_t *hdlr;
+
+	hdlr = kmem_alloc(sizeof (dtrace_invop_hdlr_t), KM_SLEEP);
+	hdlr->dtih_func = func;
+	hdlr->dtih_next = dtrace_invop_hdlr;
+	dtrace_invop_hdlr = hdlr;
+}
+
+void
+dtrace_invop_remove(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
+{
+	dtrace_invop_hdlr_t *hdlr, *prev;
+
+	hdlr = dtrace_invop_hdlr;
+	prev = NULL;
+
+	for (;;) {
+		if (hdlr == NULL)
+			panic("attempt to remove non-existent invop handler");
+
+		if (hdlr->dtih_func == func)
+			break;
+
+		prev = hdlr;
+		hdlr = hdlr->dtih_next;
+	}
+
+	if (prev == NULL) {
+		ASSERT(dtrace_invop_hdlr == hdlr);
+		dtrace_invop_hdlr = hdlr->dtih_next;
+	} else {
+		ASSERT(dtrace_invop_hdlr != hdlr);
+		prev->dtih_next = hdlr->dtih_next;
+	}
+
+	kmem_free(hdlr, 0);
+}
+
+/*ARGSUSED*/
+void
+dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
+{
+
+	(*func)(0, (uintptr_t)VM_MIN_KERNEL_ADDRESS);
+}
+
+void
+dtrace_xcall(processorid_t cpu, dtrace_xcall_t func, void *arg)
+{
+	cpuset_t cpus;
+
+	if (cpu == DTRACE_CPUALL)
+		cpus = all_cpus;
+	else
+		CPU_SETOF(cpu, &cpus);
+
+	smp_rendezvous_cpus(cpus, smp_no_rendezvous_barrier, func,
+	    smp_no_rendezvous_barrier, arg);
+}
+
+static void
+dtrace_sync_func(void)
+{
+
+}
+
+void
+dtrace_sync(void)
+{
+
+	dtrace_xcall(DTRACE_CPUALL, (dtrace_xcall_t)dtrace_sync_func, NULL);
+}
+
+/*
+ * DTrace needs a high resolution time function which can
+ * be called from a probe context and guaranteed not to have
+ * instrumented with probes itself.
+ *
+ * Returns nanoseconds since boot.
+ */
+uint64_t
+dtrace_gethrtime()
+{
+	struct timespec curtime;
+
+	nanouptime(&curtime);
+
+	return (curtime.tv_sec * 1000000000UL + curtime.tv_nsec);
+
+}
+
+uint64_t
+dtrace_gethrestime(void)
+{
+	struct timespec current_time;
+
+	dtrace_getnanotime(&current_time);
+
+	return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
+}
+
+/* Function to handle DTrace traps during probes. See riscv/riscv/trap.c */
+int
+dtrace_trap(struct trapframe *frame, u_int type)
+{
+	/*
+	 * A trap can occur while DTrace executes a probe. Before
+	 * executing the probe, DTrace blocks re-scheduling and sets
+	 * a flag in its per-cpu flags to indicate that it doesn't
+	 * want to fault. On returning from the probe, the no-fault
+	 * flag is cleared and finally re-scheduling is enabled.
+	 *
+	 * Check if DTrace has enabled 'no-fault' mode:
+	 *
+	 */
+
+	if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
+		/*
+		 * There are only a couple of trap types that are expected.
+		 * All the rest will be handled in the usual way.
+		 */
+		switch (type) {
+		case EXCP_FAULT_LOAD:
+		case EXCP_FAULT_STORE:
+		case EXCP_FAULT_FETCH:
+			/* Flag a bad address. */
+			cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
+			cpu_core[curcpu].cpuc_dtrace_illval = 0;
+
+			/*
+			 * Offset the instruction pointer to the instruction
+			 * following the one causing the fault.
+			 */
+			frame->tf_sepc += 4;
+
+			return (1);
+		default:
+			/* Handle all other traps in the usual way. */
+			break;
+		}
+	}
+
+	/* Handle the trap in the usual way. */
+	return (0);
+}
+
+void
+dtrace_probe_error(dtrace_state_t *state, dtrace_epid_t epid, int which,
+    int fault, int fltoffs, uintptr_t illval)
+{
+
+	dtrace_probe(dtrace_probeid_error, (uint64_t)(uintptr_t)state,
+	    (uintptr_t)epid,
+	    (uintptr_t)which, (uintptr_t)fault, (uintptr_t)fltoffs);
+}
+
+static int
+match_opcode(uint32_t insn, int match, int mask)  
+{
+
+	if (((insn ^ match) & mask) == 0)
+		return (1);
+
+	return (0);
+}
+
+static int
+dtrace_invop_start(struct trapframe *frame)
+{
+	register_t *sp;
+	uint32_t uimm;
+	uint32_t imm;
+	int invop;
+
+	invop = dtrace_invop(frame->tf_sepc, frame, frame->tf_sepc);
+	if (invop == 0)
+		return (-1);
+
+	if (match_opcode(invop, (MATCH_SD | RS2_RA | RS1_SP),
+	    (MASK_SD | RS2_MASK | RS1_MASK))) {
+		/* Non-compressed store of ra to sp */
+		imm = (invop >> 7) & 0x1f;
+		imm |= ((invop >> 25) & 0x7f) << 5;
+		sp = (register_t *)((uint8_t *)frame->tf_sp + imm);
+		*sp = frame->tf_ra;
+		frame->tf_sepc += INSN_SIZE;
+		return (0);
+	}
+
+	if (match_opcode(invop, (MATCH_JALR | (X_RA << RS1_SHIFT)),
+	    (MASK_JALR | RD_MASK | RS1_MASK | IMM_MASK))) {
+		/* Non-compressed ret */
+		frame->tf_sepc = frame->tf_ra;
+		return (0);
+	}
+
+	if (match_opcode(invop, (MATCH_C_SDSP | RS2_C_RA),
+	    (MASK_C_SDSP | RS2_C_MASK))) {
+		/* 'C'-compressed store of ra to sp */
+		uimm = ((invop >> 10) & 0x7) << 3;
+		uimm |= ((invop >> 7) & 0x7) << 6;
+		sp = (register_t *)((uint8_t *)frame->tf_sp + uimm);
+		*sp = frame->tf_ra;
+		frame->tf_sepc += INSN_C_SIZE;
+		return (0);
+	}
+
+	if (match_opcode(invop, (MATCH_C_JR | (X_RA << RD_SHIFT)),
+	    (MASK_C_JR | RD_MASK))) {
+		/* 'C'-compressed ret */
+		frame->tf_sepc = frame->tf_ra;
+		return (0);
+	}
+
+#ifdef INVARIANTS
+	panic("Instruction %x doesn't match any opcode.", invop);
+#endif
+
+	return (-1);
+}
+
+void
+dtrace_invop_init(void)
+{
+
+	dtrace_invop_jump_addr = dtrace_invop_start;
+}
+
+void
+dtrace_invop_uninit(void)
+{
+
+	dtrace_invop_jump_addr = 0;
+}
diff --git a/sys/cddl/dev/dtrace/riscv/regset.h b/sys/cddl/dev/dtrace/riscv/regset.h
new file mode 100644
index 000000000000..f99b48f8354f
--- /dev/null
+++ b/sys/cddl/dev/dtrace/riscv/regset.h
@@ -0,0 +1,51 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ *
+ * $FreeBSD$ 
+ */
+/*
+ * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*	Copyright (c) 1990, 1991 UNIX System Laboratories, Inc. */
+
+/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T		*/
+/*	All Rights Reserved	*/
+
+#ifndef	_REGSET_H
+#define	_REGSET_H
+
+/*
+ * #pragma ident	"@(#)regset.h	1.11	05/06/08 SMI"
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Place here */
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* _REGSET_H */