Index: lib/libthread_db/arch/riscv/libpthread_md.c
===================================================================
--- /dev/null
+++ lib/libthread_db/arch/riscv/libpthread_md.c
@@ -0,0 +1,104 @@
+/*-
+ * Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com>
+ * All rights reserved.
+ *
+ * Portions of this software were developed by SRI International and the
+ * University of Cambridge Computer Laboratory under DARPA/AFRL contract
+ * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
+ *
+ * Portions of this software were developed by the University of Cambridge
+ * Computer Laboratory as part of the CTSRD Project, with support from the
+ * UK Higher Education Innovation Fund (HEIF).
+ *
+ * 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/types.h>
+#include <string.h>
+#include <thread_db.h>
+
+#include "libpthread_db.h"
+
+void
+pt_reg_to_ucontext(const struct reg *r, ucontext_t *uc)
+{
+	mcontext_t *mc;
+
+	mc = &uc->uc_mcontext;
+
+	memcpy(mc->mc_gpregs.gp_t, r->t, sizeof(mc->mc_gpregs.gp_t));
+	memcpy(mc->mc_gpregs.gp_s, r->s, sizeof(mc->mc_gpregs.gp_s));
+	memcpy(mc->mc_gpregs.gp_a, r->a, sizeof(mc->mc_gpregs.gp_a));
+	mc->mc_gpregs.gp_ra = r->ra;
+	mc->mc_gpregs.gp_sp = r->sp;
+	mc->mc_gpregs.gp_gp = r->gp;
+	mc->mc_gpregs.gp_tp = r->tp;
+	mc->mc_gpregs.gp_sepc = r->sepc;
+	mc->mc_gpregs.gp_sstatus = r->sstatus;
+}
+
+void
+pt_ucontext_to_reg(const ucontext_t *uc, struct reg *r)
+{
+	const mcontext_t *mc;
+
+	mc = &uc->uc_mcontext;
+
+	memcpy(r->t, mc->mc_gpregs.gp_t, sizeof(mc->mc_gpregs.gp_t));
+	memcpy(r->s, mc->mc_gpregs.gp_s, sizeof(mc->mc_gpregs.gp_s));
+	memcpy(r->a, mc->mc_gpregs.gp_a, sizeof(mc->mc_gpregs.gp_a));
+	r->ra = mc->mc_gpregs.gp_ra;
+	r->sp = mc->mc_gpregs.gp_sp;
+	r->gp = mc->mc_gpregs.gp_gp;
+	r->tp = mc->mc_gpregs.gp_tp;
+	r->sepc = mc->mc_gpregs.gp_sepc;
+	r->sstatus = mc->mc_gpregs.gp_sstatus;
+}
+
+void
+pt_fpreg_to_ucontext(const struct fpreg *r __unused, ucontext_t *uc __unused)
+{
+
+	/* RISCVTODO */
+}
+
+void
+pt_ucontext_to_fpreg(const ucontext_t *uc __unused, struct fpreg *r __unused)
+{
+
+	/* RISCVTODO */
+}
+
+void
+pt_md_init(void)
+{
+}
+
+int
+pt_reg_sstep(struct reg *reg __unused, int step __unused)
+{
+
+	return (0);
+}