Re: [PATCH 2/7][LoongArch] GDB Server support

[Paul Hua via Gdb-patches <gdb-patches@sourceware.org>]

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Sorry, forget the raw patch.

On Sat, Aug 14, 2021 at 4:50 PM Paul Hua <paul.hua.gm@gmail.com> wrote:
>
> Also, send to gdb-patches@sourceware.org
>
> Original message:
> https://sourceware.org/pipermail/binutils/2021-August/117697.html
>
>
> On Sat, Aug 14, 2021 at 4:11 PM Paul Hua <paul.hua.gm@gmail.com> wrote:
> >
> >

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From 25a0318b3c4b9c5f0794de6904616e0678761f73 Mon Sep 17 00:00:00 2001
From: liuzhensong <liuzhensong@loongson.cn>
Date: Sat, 14 Aug 2021 11:32:33 +0800
Subject: [PATCH 2/7] gdbserver: LoongArch GDBServer Port.

  gdbserver/Makefile.in
  gdbserver/configure.srv
  gdbserver/linux-loongarch-low.cc
---
 gdbserver/Makefile.in            |   2 +
 gdbserver/configure.srv          |  15 ++
 gdbserver/linux-loongarch-low.cc | 292 +++++++++++++++++++++++++++++++
 3 files changed, 309 insertions(+)
 create mode 100644 gdbserver/linux-loongarch-low.cc

diff --git a/gdbserver/Makefile.in b/gdbserver/Makefile.in
index 12e9b2777ae..c2a49fbd02d 100644
--- a/gdbserver/Makefile.in
+++ b/gdbserver/Makefile.in
@@ -193,6 +193,7 @@ SFILES = \
 	$(srcdir)/linux-arm-low.cc \
 	$(srcdir)/linux-ia64-low.cc \
 	$(srcdir)/linux-low.cc \
+	$(srcdir)/linux-loongarch-low.cc \
 	$(srcdir)/linux-m68k-low.cc \
 	$(srcdir)/linux-mips-low.cc \
 	$(srcdir)/linux-nios2-low.cc \
@@ -226,6 +227,7 @@ SFILES = \
 	$(srcdir)/../gdb/arch/arm.c \
 	$(srcdir)/../gdb/arch/arm-get-next-pcs.c \
 	$(srcdir)/../gdb/arch/arm-linux.c \
+	$(srcdir)/../gdb/arch/loongarch.c \
 	$(srcdir)/../gdb/arch/ppc-linux-common.c \
 	$(srcdir)/../gdb/arch/riscv.c \
 	$(srcdir)/../gdb/nat/aarch64-mte-linux-ptrace.c \
diff --git a/gdbserver/configure.srv b/gdbserver/configure.srv
index 971f537bffa..2881d85e4d7 100644
--- a/gdbserver/configure.srv
+++ b/gdbserver/configure.srv
@@ -381,6 +381,21 @@ case "${gdbserver_host}" in
 			srv_linux_regsets=yes
 			srv_linux_thread_db=yes
 			;;
+  loongarch*-linux*)	srv_tgtobj="$srv_linux_obj linux-loongarch-low.o"
+			srv_tgtobj="${srv_tgtobj} arch/loongarch.o"
+			srv_tgtobj="${srv_tgtobj} arch/loongarch-linux-nat.o"
+			srv_xmlfiles="loongarch/base32.xml"
+			srv_xmlfiles="${srv_xmlfiles} loongarch/base64.xml"
+			srv_xmlfiles="${srv_xmlfiles} loongarch/fpu32.xml"
+			srv_xmlfiles="${srv_xmlfiles} loongarch/fpu64.xml"
+			srv_xmlfiles="${srv_xmlfiles} loongarch/lbt32.xml"
+			srv_xmlfiles="${srv_xmlfiles} loongarch/lbt64.xml"
+			srv_xmlfiles="${srv_xmlfiles} loongarch/lsx.xml"
+			srv_xmlfiles="${srv_xmlfiles} loongarch/lasx.xml"
+			srv_linux_regsets=yes
+			srv_linux_usrregs=yes
+			srv_linux_thread_db=yes
+			;;
   *)
 			# Who are you?
 			UNSUPPORTED=1
diff --git a/gdbserver/linux-loongarch-low.cc b/gdbserver/linux-loongarch-low.cc
new file mode 100644
index 00000000000..67f1de19074
--- /dev/null
+++ b/gdbserver/linux-loongarch-low.cc
@@ -0,0 +1,292 @@
+/* Copyright (C) 2021 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 "nat/gdb_ptrace.h"
+
+#include "gdb_proc_service.h"
+#include "arch/loongarch.h"
+#include "arch/loongarch-linux-nat.h"
+#include "elf/common.h"
+#include "tdesc.h"
+
+class loongarch_target : public linux_process_target
+{
+public:
+  const regs_info *get_regs_info () override;
+
+  const gdb_byte *sw_breakpoint_from_kind (int kind, int *size) override;
+
+protected:
+  void low_arch_setup () override;
+
+  bool low_cannot_fetch_register (int regno) override;
+
+  bool low_cannot_store_register (int regno) override;
+
+  bool low_fetch_register (regcache *regcache, int regno) override;
+
+  bool low_supports_breakpoints () override;
+
+  CORE_ADDR low_get_pc (regcache *regcache) override;
+
+  void low_set_pc (regcache *regcache, CORE_ADDR newpc) override;
+
+  bool low_breakpoint_at (CORE_ADDR pc) override;
+};
+
+static loongarch_target the_loongarch_target;
+
+static const unsigned int loongarch_breakpoint = 0x002a0005;
+#define loongarch_breakpoint_len 4
+
+void
+loongarch_target::low_arch_setup ()
+{
+  int pid = lwpid_of (current_thread);
+  struct target_desc *tdesc = loongarch_linux_read_description_runtime (pid);
+  init_target_desc (tdesc, loongarch_expedite_regs);
+  current_process ()->tdesc = tdesc;
+}
+
+bool
+loongarch_target::low_cannot_fetch_register (int regno)
+{
+  return false;
+}
+
+bool
+loongarch_target::low_cannot_store_register (int regno)
+{
+  return false;
+}
+
+bool
+loongarch_target::low_fetch_register (regcache *regcache, int regno)
+{
+  const struct target_desc *tdesc = current_process ()->tdesc;
+
+  if (find_regno (tdesc, "r0") == regno)
+    {
+      supply_register_zeroed (regcache, regno);
+      return true;
+    }
+
+  return false;
+}
+
+bool
+loongarch_target::low_supports_breakpoints ()
+{
+  return true;
+}
+
+CORE_ADDR
+loongarch_target::low_get_pc (regcache *regcache)
+{
+  int regno = find_regno (regcache->tdesc, "pc");
+  if (register_size (regcache->tdesc, regno) == 4)
+    {
+      int32_t pc;
+      collect_register (regcache, regno, &pc);
+      return pc;
+    }
+  else
+    {
+      int64_t pc;
+      collect_register (regcache, regno, &pc);
+      return pc;
+    }
+}
+
+void
+loongarch_target::low_set_pc (regcache *regcache, CORE_ADDR pc)
+{
+  supply_register_by_name (regcache, "pc", &pc);
+}
+
+const gdb_byte *
+loongarch_target::sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = loongarch_breakpoint_len;
+  return (const gdb_byte *) &loongarch_breakpoint;
+}
+
+bool
+loongarch_target::low_breakpoint_at (CORE_ADDR where)
+{
+  uint32_t insn;
+
+  read_memory (where, (unsigned char *) &insn, sizeof (insn));
+  if (insn == loongarch_breakpoint)
+    return true;
+
+  return false;
+}
+
+static void
+loongarch_fill_gregset (struct regcache *regcache, void *buf)
+{
+  int i, r = find_regno (regcache->tdesc, "r0");
+
+  for (i = 0; i < 32; i++)
+    collect_register (regcache, r + i, (uint64_t *) buf + i);
+  collect_register_by_name (regcache, "pc", (uint64_t *) buf + 32);
+}
+
+static void
+loongarch_store_gregset (struct regcache *regcache, const void *buf)
+{
+  int i, r = find_regno (regcache->tdesc, "r0");
+
+  supply_register_zeroed (regcache, r);
+  for (i = 1; i < 32; i++)
+    supply_register (regcache, r + i, (const uint64_t *) buf + i);
+  supply_register_by_name (regcache, "pc", (const uint64_t *) buf + 32);
+}
+
+static void
+loongarch_fill_fpregset (struct regcache *regcache, void *buf)
+{
+  int i, f, fcc;
+  f = find_regno (regcache->tdesc, "f0");
+  fcc = find_regno (regcache->tdesc, "fcc0");
+  uint8_t *fccs = (uint8_t *) ((uint64_t *) buf + 32);
+
+  for (i = 0; i < 32; i++)
+    collect_register (regcache, f + i, (uint64_t *) buf + i);
+  for (i = 0; i < 8; i++)
+    collect_register (regcache, fcc + i, fccs + i);
+  collect_register_by_name (regcache, "fcsr", (uint64_t *) buf + 33);
+}
+
+static void
+loongarch_store_fpregset (struct regcache *regcache, const void *buf)
+{
+  int i, f, fcc;
+  f = find_regno (regcache->tdesc, "f0");
+  fcc = find_regno (regcache->tdesc, "fcc0");
+  const uint8_t *fccs = (const uint8_t *) ((const uint64_t *) buf + 32);
+
+  for (i = 0; i < 32; i++)
+    supply_register (regcache, f + i, (const uint64_t *) buf + i);
+  for (i = 0; i < 8; i++)
+    supply_register (regcache, fcc + i, fccs + i);
+  supply_register_by_name (regcache, "fcsr", (const uint64_t *) buf + 33);
+}
+
+static void
+loongarch_fill_lbtregset (struct regcache *regcache, void *buf)
+{
+  int i, scr = find_regno (regcache->tdesc, "scr0");
+
+  for (i = 0; i < 4; i++)
+    collect_register (regcache, scr + i, (uint64_t *) buf + i);
+  collect_register_by_name (regcache, "EFLAG", (uint64_t *) buf + 4);
+  collect_register_by_name (regcache, "x86_top", (uint32_t *) buf + 9);
+}
+
+static void
+loongarch_store_lbtregset (struct regcache *regcache, const void *buf)
+{
+  int i, scr = find_regno (regcache->tdesc, "scr0");
+
+  for (i = 0; i < 4; i++)
+    supply_register (regcache, scr + i, (const uint64_t *) buf + i);
+  supply_register_by_name (regcache, "EFLAG", (const uint64_t *) buf + 4);
+  supply_register_by_name (regcache, "x86_top", (const uint32_t *) buf + 9);
+}
+
+static void
+loongarch_fill_lsxregset (struct regcache *regcache, void *buf)
+{
+  int i, vr = find_regno (regcache->tdesc, "vr0");
+
+  for (i = 0; i < 32; i++)
+    collect_register (regcache, vr + i, (uint64_t *) buf + 2 * i);
+}
+
+static void
+loongarch_store_lsxregset (struct regcache *regcache, const void *buf)
+{
+  int i, vr = find_regno (regcache->tdesc, "vr0");
+
+  for (i = 1; i < 32; i++)
+    supply_register (regcache, vr + i, (const uint64_t *) buf + 2 * i);
+}
+
+static void
+loongarch_fill_lasxregset (struct regcache *regcache, void *buf)
+{
+  int i, xr = find_regno (regcache->tdesc, "xr0");
+
+  for (i = 0; i < 32; i++)
+    collect_register (regcache, xr + i, (uint64_t *) buf + 4 * i);
+}
+
+static void
+loongarch_store_lasxregset (struct regcache *regcache, const void *buf)
+{
+  int i, xr = find_regno (regcache->tdesc, "xr0");
+
+  for (i = 1; i < 32; i++)
+    supply_register (regcache, xr + i, (const uint64_t *) buf + 4 * i);
+}
+
+static struct regset_info loongarch_regsets[] =
+{
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS, 33 * 8, GENERAL_REGS,
+    loongarch_fill_gregset, loongarch_store_gregset },
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET, 34 * 8, FP_REGS,
+    loongarch_fill_fpregset, loongarch_store_fpregset },
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_LARCH_LBT, 5 * 8, EXTENDED_REGS,
+    loongarch_fill_lbtregset, loongarch_store_lbtregset },
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_LARCH_LSX, 32 * 16, EXTENDED_REGS,
+    loongarch_fill_lsxregset, loongarch_store_lsxregset },
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_LARCH_LASX, 32 * 32, EXTENDED_REGS,
+    loongarch_fill_lasxregset, loongarch_store_lasxregset },
+  NULL_REGSET
+};
+
+static struct regsets_info loongarch_regsets_info =
+{
+  loongarch_regsets, 	/* regsets.  */
+  0,		 	/* num_regsets.  */
+  NULL,	      		/* disabled_regsets.  */
+};
+
+static regs_info loongarch_regs_info = { NULL, /* regset_bitmap.  */
+					 NULL, &loongarch_regsets_info };
+
+const regs_info *
+loongarch_target::get_regs_info ()
+{
+  return &loongarch_regs_info;
+}
+
+/* The linux target ops object.  */
+
+linux_process_target *the_linux_target = &the_loongarch_target;
+
+void initialize_low_arch ();
+void
+initialize_low_arch ()
+{
+  initialize_regsets_info (&loongarch_regsets_info);
+}
-- 
2.27.0