Index: gdb/ppc64-obsd-nat.c
--- gdb/ppc64-obsd-nat.c.orig
+++ gdb/ppc64-obsd-nat.c
@@ -0,0 +1,219 @@
+/* Native-dependent code for OpenBSD/powerpc64.
+
+   Copyright (C) 2004-2020 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 "gdbcore.h"
+#include "inferior.h"
+#include "regcache.h"
+
+#include <sys/types.h>
+#include <sys/ptrace.h>
+#include <sys/signal.h>
+#include <machine/frame.h>
+#include <machine/pcb.h>
+#include <machine/reg.h>
+
+#include "ppc-tdep.h"
+#include "ppc64-tdep.h"
+#include "ppc64-obsd-tdep.h"
+#include "inf-ptrace.h"
+#include "obsd-nat.h"
+#include "bsd-kvm.h"
+
+struct ppc64_obsd_nat_target final : public obsd_nat_target
+{
+  void fetch_registers (struct regcache *, int) override;
+  void store_registers (struct regcache *, int) override;
+};
+
+static ppc64_obsd_nat_target the_ppc64_obsd_nat_target;
+
+#if 0
+
+/* Returns true if PT_GETFPREGS fetches this register.  */
+
+static int
+getfpregs_supplies (struct gdbarch *gdbarch, int regnum)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
+     point registers.  Traditionally, GDB's register set has still
+     listed the floating point registers for such machines, so this
+     code is harmless.  However, the new E500 port actually omits the
+     floating point registers entirely from the register set --- they
+     don't even have register numbers assigned to them.
+
+     It's not clear to me how best to update this code, so this assert
+     will alert the first person to encounter the NetBSD/E500
+     combination to the problem.  */
+  gdb_assert (ppc_floating_point_unit_p (gdbarch));
+
+  return ((regnum >= tdep->ppc_fp0_regnum
+           && regnum < tdep->ppc_fp0_regnum + ppc_num_fprs)
+	  || regnum == tdep->ppc_fpscr_regnum);
+}
+
+#endif
+
+/* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
+   for all registers.  */
+
+void
+ppc64_obsd_nat_target::fetch_registers (struct regcache *regcache, int regnum)
+{
+  struct reg regs;
+
+  if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
+	      (PTRACE_TYPE_ARG3) &regs, 0) == -1)
+    perror_with_name (_("Couldn't get registers"));
+
+  ppc64obsd_supply_gregset (&ppc64obsd_gregset, regcache, -1,
+			    &regs, sizeof regs);
+
+#if 0
+  if (regnum == -1
+      || getfpregs_supplies (regcache->arch (), regnum))
+    {
+      struct fpreg fpregs;
+
+      if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
+		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
+	perror_with_name (_("Couldn't get floating point status"));
+
+      ppc64obsd_supply_fpregset (&ppc64obsd_fpregset, regcache, -1,
+				 &fpregs, sizeof fpregs);
+    }
+#endif
+}
+
+/* Store register REGNUM back into the inferior.  If REGNUM is -1, do
+   this for all registers.  */
+
+void
+ppc64_obsd_nat_target::store_registers (struct regcache *regcache, int regnum)
+{
+  struct reg regs;
+
+  if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
+	      (PTRACE_TYPE_ARG3) &regs, 0) == -1)
+    perror_with_name (_("Couldn't get registers"));
+
+  ppc64obsd_collect_gregset (&ppc64obsd_gregset, regcache,
+			     regnum, &regs, sizeof regs);
+
+  if (ptrace (PT_SETREGS, get_ptrace_pid (inferior_ptid),
+	      (PTRACE_TYPE_ARG3) &regs, 0) == -1)
+    perror_with_name (_("Couldn't write registers"));
+
+#if 0
+  if (regnum == -1
+      || getfpregs_supplies (regcache->arch (), regnum))
+    {
+      struct fpreg fpregs;
+
+      if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
+		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
+	perror_with_name (_("Couldn't get floating point status"));
+
+      ppc64obsd_collect_fpregset (&ppc64obsd_fpregset, regcache,
+				  regnum, &fpregs, sizeof fpregs);
+
+      if (ptrace (PT_SETFPREGS, get_ptrace_pid (inferior_ptid),
+		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
+	perror_with_name (_("Couldn't write floating point status"));
+    }
+#endif
+}
+
+
+#if 0
+
+static int
+ppc64obsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
+{
+  struct gdbarch *gdbarch = regcache->arch ();
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  struct switchframe sf;
+  struct callframe cf;
+  int i, regnum;
+
+  /* The following is true for OpenBSD 3.7:
+
+     The pcb contains %r1 (the stack pointer) at the point of the
+     context switch in cpu_switch().  At that point we have a stack
+     frame as described by `struct switchframe', and below that a call
+     frame as described by `struct callframe'.  From this information
+     we reconstruct the register state as it would look when we are in
+     cpu_switch().  */
+
+  /* The stack pointer shouldn't be zero.  */
+  if (pcb->pcb_sp == 0)
+    return 0;
+
+  read_memory (pcb->pcb_sp, (gdb_byte *)&sf, sizeof sf);
+  regcache->raw_supply (gdbarch_sp_regnum (gdbarch), &sf.sp);
+  regcache->raw_supply (tdep->ppc_cr_regnum, &sf.cr);
+  regcache->raw_supply (tdep->ppc_gp0_regnum + 2, &sf.fixreg2);
+  for (i = 0, regnum = tdep->ppc_gp0_regnum + 13; i < 19; i++, regnum++)
+    regcache->raw_supply (regnum, &sf.fixreg[i]);
+
+  read_memory (sf.sp, (gdb_byte *)&cf, sizeof cf);
+  regcache->raw_supply (gdbarch_pc_regnum (gdbarch), &cf.lr);
+  regcache->raw_supply (tdep->ppc_gp0_regnum + 30, &cf.r30);
+  regcache->raw_supply (tdep->ppc_gp0_regnum + 31, &cf.r31);
+
+  return 1;
+}
+
+#endif
+
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+void _initialize_ppc64obsd_nat (void);
+
+void
+_initialize_ppc64obsd_nat (void)
+{
+  add_inf_child_target (&the_ppc64_obsd_nat_target);
+
+  /* General-purpose registers.  */
+  ppc64obsd_reg_offsets.r0_offset = offsetof (struct reg, r_reg[0]);
+  ppc64obsd_reg_offsets.gpr_size = 8;
+  ppc64obsd_reg_offsets.xr_size = 8;
+  ppc64obsd_reg_offsets.pc_offset = offsetof (struct reg, r_pc);
+  ppc64obsd_reg_offsets.ps_offset = offsetof (struct reg, r_ps);
+  ppc64obsd_reg_offsets.cr_offset = offsetof (struct reg, r_cr);
+  ppc64obsd_reg_offsets.lr_offset = offsetof (struct reg, r_lr);
+  ppc64obsd_reg_offsets.ctr_offset = offsetof (struct reg, r_ctr);
+  ppc64obsd_reg_offsets.xer_offset = offsetof (struct reg, r_xer);
+  ppc64obsd_reg_offsets.mq_offset = -1;
+
+  /* Floating-point registers.  */
+  ppc64obsd_reg_offsets.f0_offset = -1;
+  ppc64obsd_reg_offsets.fpscr_offset = -1;
+  ppc64obsd_fpreg_offsets.f0_offset = -1;
+  ppc64obsd_fpreg_offsets.fpscr_offset = -1;
+  ppc64obsd_fpreg_offsets.fpscr_size = 8;
+
+#if 0
+  /* Support debugging kernel virtual memory images.  */
+  bsd_kvm_add_target (ppc64obsd_supply_pcb);
+#endif
+}