Index: gdb/aarch64-obsd-nat.c
--- gdb/aarch64-obsd-nat.c.orig
+++ gdb/aarch64-obsd-nat.c
@@ -0,0 +1,162 @@
+/* Native-dependent code for OpenBSD/aarch64.
+
+   Copyright (C) 2017-2020 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "gdbarch.h"
+#include "regcache.h"
+#include "target.h"
+
+#include <sys/types.h>
+#include <sys/ptrace.h>
+#include <machine/reg.h>
+
+#include "aarch64-tdep.h"
+#include "aarch64-obsd-tdep.h"
+#include "inf-ptrace.h"
+#include "obsd-nat.h"
+
+struct aarch64_obsd_nat_target final : public obsd_nat_target
+{
+  void fetch_registers (struct regcache *, int) override;
+  void store_registers (struct regcache *, int) override;
+
+  const struct target_desc *read_description () override;
+};
+
+static aarch64_obsd_nat_target the_aarch64_obsd_nat_target;
+
+/* Determine if PT_GETREGS fetches REGNUM.  */
+
+static bool
+getregs_supplies (int regnum)
+{
+  return (regnum >= AARCH64_X0_REGNUM && regnum <= AARCH64_CPSR_REGNUM);
+}
+
+/* Determine if PT_GETFPREGS fetches REGNUM.  */
+
+static bool
+getfpregs_supplies (int regnum)
+{
+  return (regnum >= AARCH64_V0_REGNUM && regnum <= AARCH64_FPCR_REGNUM);
+}
+
+/* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
+   for all registers.  */
+
+void
+aarch64_obsd_nat_target::fetch_registers (struct regcache *regcache,
+					  int regnum)
+{
+#ifdef PT_PACMASK
+  struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
+#endif
+  pid_t pid = get_ptrace_pid (regcache->ptid ());
+
+  if (regnum == -1 || getregs_supplies (regnum))
+    {
+      struct reg regs;
+
+      if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
+	perror_with_name (_("Couldn't get registers"));
+
+      regcache->supply_regset (&aarch64_obsd_gregset, regnum, &regs,
+			       sizeof (regs));
+    }
+
+  if (regnum == -1 || getfpregs_supplies (regnum))
+    {
+      struct fpreg fpregs;
+
+      if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
+	perror_with_name (_("Couldn't get floating point status"));
+
+      regcache->supply_regset (&aarch64_obsd_fpregset, regnum, &fpregs,
+			       sizeof (fpregs));
+    }
+
+#ifdef PT_PACMASK
+  if (tdep->has_pauth())
+    {
+      int cmask_num = AARCH64_PAUTH_CMASK_REGNUM (tdep->pauth_reg_base);
+      int dmask_num = AARCH64_PAUTH_DMASK_REGNUM (tdep->pauth_reg_base);
+      register_t pacmask[2];
+
+      if (regnum == -1 || regnum == cmask_num || regnum == dmask_num)
+	{
+	  if (ptrace (PT_PACMASK, pid, (PTRACE_TYPE_ARG3) &pacmask,
+		      sizeof (pacmask)) == -1)
+	    perror_with_name (_("Couldn't get PAC mask"));
+
+	  regcache->raw_supply (cmask_num, &pacmask[0]);
+	  regcache->raw_supply (dmask_num, &pacmask[1]);
+	}
+    }
+#endif
+}
+
+/* Store register REGNUM back into the inferior.  If REGNUM is -1, do
+   this for all registers.  */
+
+void
+aarch64_obsd_nat_target::store_registers (struct regcache *regcache,
+					  int regnum)
+{
+  pid_t pid = get_ptrace_pid (regcache->ptid ());
+
+  if (regnum == -1 || getregs_supplies (regnum))
+    {
+      struct reg regs;
+
+      if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
+	perror_with_name (_("Couldn't get registers"));
+
+      regcache->collect_regset (&aarch64_obsd_gregset, regnum, &regs,
+			       sizeof (regs));
+
+      if (ptrace (PT_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
+	perror_with_name (_("Couldn't write registers"));
+    }
+
+  if (regnum == -1 || getfpregs_supplies (regnum))
+    {
+      struct fpreg fpregs;
+
+      if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
+	perror_with_name (_("Couldn't get floating point status"));
+
+      regcache->collect_regset (&aarch64_obsd_fpregset, regnum, &fpregs,
+				sizeof (fpregs));
+
+      if (ptrace (PT_SETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
+	perror_with_name (_("Couldn't write floating point status"));
+    }
+}
+
+const struct target_desc *
+aarch64_obsd_nat_target::read_description ()
+{
+  return aarch64_read_description(0, true);
+}
+
+void
+_initialize_aarch64_obsd_nat (void)
+{
+  add_inf_child_target (&the_aarch64_obsd_nat_target);
+}