Index: binutils-gdb/gdb/arch/riscv.c
===================================================================
--- binutils-gdb.orig/gdb/arch/riscv.c
+++ binutils-gdb/gdb/arch/riscv.c
@@ -43,7 +43,7 @@ static std::unordered_map<riscv_gdbarch_
 
 /* See arch/riscv.h.  */
 
-const target_desc *
+target_desc *
 riscv_create_target_description (struct riscv_gdbarch_features features)
 {
   /* Have we seen this feature set before?  If we have return the same
Index: binutils-gdb/gdb/arch/riscv.h
===================================================================
--- binutils-gdb.orig/gdb/arch/riscv.h
+++ binutils-gdb/gdb/arch/riscv.h
@@ -69,7 +69,7 @@ struct riscv_gdbarch_features
 /* Create and return a target description that is compatible with
    FEATURES.  */
 
-const target_desc *riscv_create_target_description
-	(struct riscv_gdbarch_features features);
+target_desc *riscv_create_target_description
+  (struct riscv_gdbarch_features features);
 
 #endif /* ARCH_RISCV_H */
Index: binutils-gdb/gdb/configure.tgt
===================================================================
--- binutils-gdb.orig/gdb/configure.tgt
+++ binutils-gdb/gdb/configure.tgt
@@ -553,6 +553,7 @@ riscv*-*-linux*)
 	# Target: Linux/RISC-V
 	gdb_target_obs="riscv-linux-tdep.o glibc-tdep.o \
  			linux-tdep.o solib-svr4.o symfile-mem.o linux-record.o"
+	build_gdbserver=yes
 	;;
 
 riscv*-*-*)
Index: binutils-gdb/gdb/gdbserver/Makefile.in
===================================================================
--- binutils-gdb.orig/gdb/gdbserver/Makefile.in
+++ binutils-gdb/gdb/gdbserver/Makefile.in
@@ -177,6 +177,7 @@ SFILES = \
 	$(srcdir)/linux-mips-low.c \
 	$(srcdir)/linux-nios2-low.c \
 	$(srcdir)/linux-ppc-low.c \
+	$(srcdir)/linux-riscv-low.c \
 	$(srcdir)/linux-s390-low.c \
 	$(srcdir)/linux-sh-low.c \
 	$(srcdir)/linux-sparc-low.c \
@@ -203,6 +204,7 @@ SFILES = \
 	$(srcdir)/../arch/arm-get-next-pcs.c \
 	$(srcdir)/../arch/arm-linux.c \
 	$(srcdir)/../arch/ppc-linux-common.c \
+	$(srcdir)/../arch/riscv.c \
 	$(srcdir)/../../gdbsupport/btrace-common.c \
 	$(srcdir)/../../gdbsupport/buffer.c \
 	$(srcdir)/../../gdbsupport/cleanups.c \
@@ -236,6 +238,7 @@ SFILES = \
 	$(srcdir)/../nat/linux-personality.c \
 	$(srcdir)/../nat/mips-linux-watch.c \
 	$(srcdir)/../nat/ppc-linux.c \
+	$(srcdir)/../nat/riscv-linux-tdesc.c \
 	$(srcdir)/../nat/fork-inferior.c \
 	$(srcdir)/../target/waitstatus.c
 
Index: binutils-gdb/gdb/gdbserver/configure.srv
===================================================================
--- binutils-gdb.orig/gdb/gdbserver/configure.srv
+++ binutils-gdb/gdb/gdbserver/configure.srv
@@ -267,6 +267,13 @@ case "${target}" in
 			srv_xmlfiles="${srv_xmlfiles} rs6000/power-fpu.xml"
 			srv_lynxos=yes
 			;;
+  riscv*-*-linux*)	srv_tgtobj="arch/riscv.o nat/riscv-linux-tdesc.o"
+			srv_tgtobj="${srv_tgtobj} linux-riscv-low.o"
+			srv_tgtobj="${srv_tgtobj} ${srv_linux_obj}"
+			srv_linux_regsets=yes
+			srv_linux_usrregs=yes
+			srv_linux_thread_db=yes
+			;;
   s390*-*-linux*)	srv_regobj="s390-linux32.o"
 			srv_regobj="${srv_regobj} s390-linux32v1.o"
 			srv_regobj="${srv_regobj} s390-linux32v2.o"
Index: binutils-gdb/gdb/gdbserver/linux-riscv-low.c
===================================================================
--- /dev/null
+++ binutils-gdb/gdb/gdbserver/linux-riscv-low.c
@@ -0,0 +1,274 @@
+/* GNU/Linux/RISC-V specific low level interface, for the remote server
+   for GDB.
+   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/>.  */
+
+#include "server.h"
+
+#include "linux-low.h"
+#include "tdesc.h"
+#include "elf/common.h"
+#include "nat/riscv-linux-tdesc.h"
+#include "opcode/riscv.h"
+
+/* Work around glibc header breakage causing ELF_NFPREG not to be usable.  */
+#ifndef NFPREG
+# define NFPREG 33
+#endif
+
+/* Implementation of linux_target_ops method "arch_setup".  */
+
+static void
+riscv_arch_setup ()
+{
+  static const char *expedite_regs[] = { "sp", "pc", NULL };
+  target_desc *tdesc;
+
+  tdesc = riscv_linux_read_description (lwpid_of (current_thread));
+  if (!tdesc->expedite_regs)
+    init_target_desc (tdesc, expedite_regs);
+  current_process ()->tdesc = tdesc;
+}
+
+/* Collect GPRs from REGCACHE into BUF.  */
+
+static void
+riscv_fill_gregset (struct regcache *regcache, void *buf)
+{
+  const struct target_desc *tdesc = regcache->tdesc;
+  elf_gregset_t *regset = (elf_gregset_t *) buf;
+  int regno = find_regno (tdesc, "zero");
+  int i;
+
+  collect_register_by_name (regcache, "pc", *regset);
+  for (i = 1; i < ARRAY_SIZE (*regset); i++)
+    collect_register (regcache, regno + i, *regset + i);
+}
+
+/* Supply GPRs from BUF into REGCACHE.  */
+
+static void
+riscv_store_gregset (struct regcache *regcache, const void *buf)
+{
+  const elf_gregset_t *regset = (const elf_gregset_t *) buf;
+  const struct target_desc *tdesc = regcache->tdesc;
+  int regno = find_regno (tdesc, "zero");
+  int i;
+
+  supply_register_by_name (regcache, "pc", *regset);
+  supply_register_zeroed (regcache, regno);
+  for (i = 1; i < ARRAY_SIZE (*regset); i++)
+    supply_register (regcache, regno + i, *regset + i);
+}
+
+/* Collect FPRs from REGCACHE into BUF.  */
+
+static void
+riscv_fill_fpregset (struct regcache *regcache, void *buf)
+{
+  const struct target_desc *tdesc = regcache->tdesc;
+  int regno = find_regno (tdesc, "ft0");
+  int flen = register_size (regcache->tdesc, regno);
+  gdb_byte *regbuf = (gdb_byte *) buf;
+  int i;
+
+  for (i = 0; i < ELF_NFPREG - 1; i++, regbuf += flen)
+    collect_register (regcache, regno + i, regbuf);
+  collect_register_by_name (regcache, "fcsr", regbuf);
+}
+
+/* Supply FPRs from BUF into REGCACHE.  */
+
+static void
+riscv_store_fpregset (struct regcache *regcache, const void *buf)
+{
+  const struct target_desc *tdesc = regcache->tdesc;
+  int regno = find_regno (tdesc, "ft0");
+  int flen = register_size (regcache->tdesc, regno);
+  const gdb_byte *regbuf = (const gdb_byte *) buf;
+  int i;
+
+  for (i = 0; i < ELF_NFPREG - 1; i++, regbuf += flen)
+    supply_register (regcache, regno + i, regbuf);
+  supply_register_by_name (regcache, "fcsr", regbuf);
+}
+
+/* RISC-V/Linux regsets.  FPRs are optional and come in different sizes,
+   so define multiple regsets for them marking them all as OPTIONAL_REGS
+   rather than FP_REGS, so that "regsets_fetch_inferior_registers" picks
+   the right one according to size.  */
+static struct regset_info riscv_regsets[] = {
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS,
+    sizeof (elf_gregset_t), GENERAL_REGS,
+    riscv_fill_gregset, riscv_store_gregset },
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET,
+    sizeof (struct __riscv_mc_d_ext_state), OPTIONAL_REGS,
+    riscv_fill_fpregset, riscv_store_fpregset },
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET,
+    sizeof (struct __riscv_mc_f_ext_state), OPTIONAL_REGS,
+    riscv_fill_fpregset, riscv_store_fpregset },
+  NULL_REGSET
+};
+
+/* RISC-V/Linux regset information.  */
+static struct regsets_info riscv_regsets_info =
+  {
+    riscv_regsets, /* regsets */
+    0, /* num_regsets */
+    NULL, /* disabled_regsets */
+  };
+
+/* Definition of linux_target_ops data member "regs_info".  */
+static struct regs_info riscv_regs =
+  {
+    NULL, /* regset_bitmap */
+    NULL, /* usrregs */
+    &riscv_regsets_info,
+  };
+
+/* Implementation of linux_target_ops method "regs_info".  */
+
+static const struct regs_info *
+riscv_regs_info ()
+{
+  return &riscv_regs;
+}
+
+/* Implementation of linux_target_ops method "fetch_register".  */
+
+static int
+riscv_fetch_register (struct regcache *regcache, int regno)
+{
+  const struct target_desc *tdesc = regcache->tdesc;
+
+  if (regno != find_regno (tdesc, "zero"))
+    return 0;
+  supply_register_zeroed (regcache, regno);
+  return 1;
+}
+
+/* Implementation of linux_target_ops method "get_pc".  */
+
+static CORE_ADDR
+riscv_get_pc (struct regcache *regcache)
+{
+  elf_gregset_t regset;
+
+  if (sizeof (regset[0]) == 8)
+    return linux_get_pc_64bit (regcache);
+  else
+    return linux_get_pc_32bit (regcache);
+}
+
+/* Implementation of linux_target_ops method "set_pc".  */
+
+static void
+riscv_set_pc (struct regcache *regcache, CORE_ADDR newpc)
+{
+  elf_gregset_t regset;
+
+  if (sizeof (regset[0]) == 8)
+    linux_set_pc_64bit (regcache, newpc);
+  else
+    linux_set_pc_32bit (regcache, newpc);
+}
+
+/* Correct in either endianness.  */
+static const uint16_t riscv_ibreakpoint[] = { 0x0073, 0x0010 };
+static const uint16_t riscv_cbreakpoint = 0x9002;
+
+/* Implementation of linux_target_ops method "breakpoint_kind_from_pc".  */
+
+static int
+riscv_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
+{
+  union
+    {
+      gdb_byte bytes[2];
+      uint16_t insn;
+    }
+  buf;
+
+  if (target_read_memory (*pcptr, buf.bytes, sizeof (buf.insn)) == 0
+      && riscv_insn_length (buf.insn == sizeof (riscv_ibreakpoint)))
+    return sizeof (riscv_ibreakpoint);
+  else
+    return sizeof (riscv_cbreakpoint);
+}
+
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+riscv_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = kind;
+  switch (kind)
+    {
+      case sizeof (riscv_ibreakpoint):
+	return (const gdb_byte *) &riscv_ibreakpoint;
+      default:
+	return (const gdb_byte *) &riscv_cbreakpoint;
+    }
+}
+
+/* Implementation of linux_target_ops method "breakpoint_at".  */
+
+static int
+riscv_breakpoint_at (CORE_ADDR pc)
+{
+  union
+    {
+      gdb_byte bytes[2];
+      uint16_t insn;
+    }
+  buf;
+
+  if (target_read_memory (pc, buf.bytes, sizeof (buf.insn)) == 0
+      && (buf.insn == riscv_cbreakpoint
+	  || (buf.insn == riscv_ibreakpoint[0]
+	      && target_read_memory (pc + sizeof (buf.insn), buf.bytes,
+				     sizeof (buf.insn)) == 0
+	      && buf.insn == riscv_ibreakpoint[1])))
+    return 1;
+  else
+    return 0;
+}
+
+/* RISC-V/Linux target operations.  */
+struct linux_target_ops the_low_target =
+{
+  riscv_arch_setup,
+  riscv_regs_info,
+  NULL, /* cannot_fetch_register */
+  NULL, /* cannot_store_register */
+  riscv_fetch_register,
+  riscv_get_pc,
+  riscv_set_pc,
+  riscv_breakpoint_kind_from_pc,
+  riscv_sw_breakpoint_from_kind,
+  NULL, /* get_next_pcs */
+  0,    /* decr_pc_after_break */
+  riscv_breakpoint_at,
+};
+
+/* Initialize the RISC-V/Linux target.  */
+
+void
+initialize_low_arch ()
+{
+  initialize_regsets_info (&riscv_regsets_info);
+}
Index: binutils-gdb/gdb/nat/riscv-linux-tdesc.c
===================================================================
--- binutils-gdb.orig/gdb/nat/riscv-linux-tdesc.c
+++ binutils-gdb/gdb/nat/riscv-linux-tdesc.c
@@ -33,7 +33,7 @@
 
 /* Determine XLEN and FLEN and return a corresponding target description.  */
 
-const struct target_desc *
+struct target_desc *
 riscv_linux_read_description (int tid)
 {
   struct riscv_gdbarch_features features;
Index: binutils-gdb/gdb/nat/riscv-linux-tdesc.h
===================================================================
--- binutils-gdb.orig/gdb/nat/riscv-linux-tdesc.h
+++ binutils-gdb/gdb/nat/riscv-linux-tdesc.h
@@ -22,6 +22,6 @@
 struct target_desc;
 
 /* Return a target description for the LWP identified by TID.  */
-const struct target_desc *riscv_linux_read_description (int tid);
+struct target_desc *riscv_linux_read_description (int tid);
 
 #endif /* NAT_RISCV_LINUX_TDESC_H */
