diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 7c0a0aefbc..1a837eda8d 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -1205,6 +1205,7 @@ HFILES_NO_SRCDIR = \
 	arc-tdep.h \
 	arch-utils.h \
 	arm-linux-tdep.h \
+	arm-nbsd-tdep.h \
 	arm-tdep.h \
 	auto-load.h \
 	auxv.h \
diff --git a/gdb/arm-nbsd-nat.c b/gdb/arm-nbsd-nat.c
index 04fedd4be3..cb31462737 100644
--- a/gdb/arm-nbsd-nat.c
+++ b/gdb/arm-nbsd-nat.c
@@ -31,6 +31,7 @@
 #include <machine/frame.h>
 
 #include "arm-tdep.h"
+#include "arm-nbsd-tdep.h"
 #include "aarch32-tdep.h"
 #include "inf-ptrace.h"
 
@@ -45,28 +46,6 @@ public:
 
 static arm_netbsd_nat_target the_arm_netbsd_nat_target;
 
-static void
-arm_supply_gregset (struct regcache *regcache, struct reg *gregset)
-{
-  int regno;
-  CORE_ADDR r_pc;
-
-  /* Integer registers.  */
-  for (regno = ARM_A1_REGNUM; regno < ARM_SP_REGNUM; regno++)
-    regcache->raw_supply (regno, (char *) &gregset->r[regno]);
-
-  regcache->raw_supply (ARM_SP_REGNUM, (char *) &gregset->r_sp);
-  regcache->raw_supply (ARM_LR_REGNUM, (char *) &gregset->r_lr);
-  /* This is ok: we're running native...  */
-  r_pc = gdbarch_addr_bits_remove (regcache->arch (), gregset->r_pc);
-  regcache->raw_supply (ARM_PC_REGNUM, (char *) &r_pc);
-
-  if (arm_apcs_32)
-    regcache->raw_supply (ARM_PS_REGNUM, (char *) &gregset->r_cpsr);
-  else
-    regcache->raw_supply (ARM_PS_REGNUM, (char *) &gregset->r_pc);
-}
-
 static void
 arm_supply_vfpregset (struct regcache *regcache, struct fpreg *fpregset)
 {
@@ -95,57 +74,8 @@ fetch_register (struct regcache *regcache, int regno)
       warning (_("unable to fetch general register"));
       return;
     }
-
-  switch (regno)
-    {
-    case ARM_SP_REGNUM:
-      regcache->raw_supply (ARM_SP_REGNUM, (char *) &inferior_registers.r_sp);
-      break;
-
-    case ARM_LR_REGNUM:
-      regcache->raw_supply (ARM_LR_REGNUM, (char *) &inferior_registers.r_lr);
-      break;
-
-    case ARM_PC_REGNUM:
-      /* This is ok: we're running native...  */
-      inferior_registers.r_pc = gdbarch_addr_bits_remove
-				  (regcache->arch (),
-				   inferior_registers.r_pc);
-      regcache->raw_supply (ARM_PC_REGNUM, (char *) &inferior_registers.r_pc);
-      break;
-
-    case ARM_PS_REGNUM:
-      if (arm_apcs_32)
-	regcache->raw_supply (ARM_PS_REGNUM,
-			      (char *) &inferior_registers.r_cpsr);
-      else
-	regcache->raw_supply (ARM_PS_REGNUM,
-			      (char *) &inferior_registers.r_pc);
-      break;
-
-    default:
-      regcache->raw_supply (regno, (char *) &inferior_registers.r[regno]);
-      break;
-    }
-}
-
-static void
-fetch_regs (struct regcache *regcache)
-{
-  struct reg inferior_registers;
-  int ret;
-  int regno;
-
-  ret = ptrace (PT_GETREGS, regcache->ptid ().pid (),
-		(PTRACE_TYPE_ARG3) &inferior_registers, 0);
-
-  if (ret < 0)
-    {
-      warning (_("unable to fetch general registers"));
-      return;
-    }
-
-  arm_supply_gregset (regcache, &inferior_registers);
+  arm_nbsd_supply_gregset (nullptr, regcache, regno, &inferior_registers,
+			   sizeof (inferior_registers));
 }
 
 static void
@@ -207,7 +137,7 @@ arm_netbsd_nat_target::fetch_registers (struct regcache *regcache, int regno)
     }
   else
     {
-      fetch_regs (regcache);
+      fetch_register (regcache, -1);
       fetch_fp_regs (regcache);
     }
 }
@@ -416,56 +346,9 @@ arm_netbsd_nat_target::read_description ()
   return arm_read_description (ARM_FP_TYPE_VFPV3);
 }
 
-static void
-fetch_elfcore_registers (struct regcache *regcache,
-			 gdb_byte *core_reg_sect, unsigned core_reg_size,
-			 int which, CORE_ADDR ignore)
-{
-  struct reg gregset;
-  struct fpreg fparegset;
-
-  switch (which)
-    {
-    case 0:	/* Integer registers.  */
-      if (core_reg_size != sizeof (struct reg))
-	warning (_("wrong size of register set in core file"));
-      else
-	{
-	  /* The memcpy may be unnecessary, but we can't really be sure
-	     of the alignment of the data in the core file.  */
-	  memcpy (&gregset, core_reg_sect, sizeof (gregset));
-	  arm_supply_gregset (regcache, &gregset);
-	}
-      break;
-
-    case 2:
-      /* cbiesinger/2020-02-12 -- as far as I can tell, ARM/NetBSD does
-         not write any floating point registers into the core file (tested
-	 with NetBSD 9.1_RC1).  When it does, this block will need to read them,
-	 and the arm-netbsd gdbarch will need a core_read_description function
-	 to return the right description for them.  */
-      break;
-
-    default:
-      /* Don't know what kind of register request this is; just ignore it.  */
-      break;
-    }
-}
-
-static struct core_fns arm_netbsd_elfcore_fns =
-{
-  bfd_target_elf_flavour,		/* core_flavour.  */
-  default_check_format,			/* check_format.  */
-  default_core_sniffer,			/* core_sniffer.  */
-  fetch_elfcore_registers,		/* core_read_registers.  */
-  NULL
-};
-
 void _initialize_arm_netbsd_nat ();
 void
 _initialize_arm_netbsd_nat ()
 {
   add_inf_child_target (&the_arm_netbsd_nat_target);
-
-  deprecated_add_core_fns (&arm_netbsd_elfcore_fns);
 }
diff --git a/gdb/arm-nbsd-tdep.c b/gdb/arm-nbsd-tdep.c
index 2642024022..689c4b6219 100644
--- a/gdb/arm-nbsd-tdep.c
+++ b/gdb/arm-nbsd-tdep.c
@@ -21,7 +21,9 @@
 #include "osabi.h"
 
 #include "arch/arm.h"
+#include "arm-nbsd-tdep.h"
 #include "arm-tdep.h"
+#include "regset.h"
 #include "solib-svr4.h"
 
 /* Description of the longjmp buffer.  */
@@ -35,6 +37,70 @@ static const gdb_byte arm_nbsd_arm_be_breakpoint[] = {0xe6, 0x00, 0x00, 0x11};
 static const gdb_byte arm_nbsd_thumb_le_breakpoint[] = {0xfe, 0xde};
 static const gdb_byte arm_nbsd_thumb_be_breakpoint[] = {0xde, 0xfe};
 
+/* This matches struct reg from NetBSD's sys/arch/arm/include/reg.h */
+struct arm_nbsd_reg {
+  uint32_t reg[13];
+  uint32_t sp;
+  uint32_t lr;
+  uint32_t pc;
+  uint32_t cpsr;
+};
+
+void
+arm_nbsd_supply_gregset (const struct regset *regset, struct regcache *regcache,
+			 int regnum, const void *gregs, size_t len)
+{
+  const arm_nbsd_reg *gregset = static_cast<const arm_nbsd_reg *>(gregs);
+  gdb_assert (len >= sizeof (arm_nbsd_reg));
+
+  /* Integer registers.  */
+  for (int i = ARM_A1_REGNUM; i < ARM_SP_REGNUM; i++)
+    if (regnum == -1 || regnum == i)
+      regcache->raw_supply (i, (char *) &gregset->reg[i]);
+
+  if (regnum == -1 || regnum == ARM_SP_REGNUM)
+    regcache->raw_supply (ARM_SP_REGNUM, (char *) &gregset->sp);
+  if (regnum == -1 || regnum == ARM_LR_REGNUM)
+    regcache->raw_supply (ARM_LR_REGNUM, (char *) &gregset->lr);
+  if (regnum == -1 || regnum == ARM_PC_REGNUM)
+    {
+      CORE_ADDR r_pc = gdbarch_addr_bits_remove (regcache->arch (), gregset->pc);
+      regcache->raw_supply (ARM_PC_REGNUM, (char *) &r_pc);
+    }
+
+  if (regnum == -1 || regnum == ARM_PS_REGNUM)
+    {
+      if (arm_apcs_32)
+	regcache->raw_supply (ARM_PS_REGNUM, (char *) &gregset->cpsr);
+      else
+	regcache->raw_supply (ARM_PS_REGNUM, (char *) &gregset->pc);
+    }
+}
+
+static const struct regset arm_nbsd_regset = {
+  nullptr,
+  arm_nbsd_supply_gregset,
+  /* We don't need a collect function because we only use this reading registers
+     (via iterate_over_regset_sections and fetch_regs/fetch_register).  */
+  nullptr,
+  0
+};
+
+static void
+arm_nbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
+				       iterate_over_regset_sections_cb *cb,
+				       void *cb_data,
+				       const struct regcache *regcache)
+{
+  cb (".reg", sizeof (arm_nbsd_reg), sizeof (arm_nbsd_reg), &arm_nbsd_regset,
+      NULL, cb_data);
+  /* cbiesinger/2020-02-12 -- as far as I can tell, ARM/NetBSD does
+     not write any floating point registers into the core file (tested
+     with NetBSD 9.1_RC1).  When it does, this function will need to read them,
+     and the arm-netbsd gdbarch will need a core_read_description function
+     to return the right description for them.  */
+}
+
 static void
 arm_netbsd_init_abi_common (struct gdbarch_info info,
 			    struct gdbarch *gdbarch)
@@ -66,10 +132,12 @@ arm_netbsd_init_abi_common (struct gdbarch_info info,
   tdep->jb_pc = ARM_NBSD_JB_PC;
   tdep->jb_elt_size = ARM_NBSD_JB_ELEMENT_SIZE;
 
+  set_gdbarch_iterate_over_regset_sections
+    (gdbarch, arm_nbsd_iterate_over_regset_sections);
   /* Single stepping.  */
   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 }
-  
+
 static void
 arm_netbsd_elf_init_abi (struct gdbarch_info info,
 			 struct gdbarch *gdbarch)
diff --git a/gdb/arm-nbsd-tdep.h b/gdb/arm-nbsd-tdep.h
new file mode 100644
index 0000000000..1b35395031
--- /dev/null
+++ b/gdb/arm-nbsd-tdep.h
@@ -0,0 +1,27 @@
+/* NetBSD/ARM support.
+
+   Copyright (C) 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/>.  */
+
+#ifndef ARM_NBSD_TDEP_H
+#define ARM_NBSD_TDEP_H
+
+void arm_nbsd_supply_gregset
+  (const struct regset *regset, struct regcache *regcache,
+   int regnum, const void *gregs, size_t len);
+
+#endif
