Ports/gdb: Add basic ptrace based native target for SerenityOS/i386

This patch adds a ptrace based gdb backend, which is then enlightended
to known how to read the serenity i386 registers via ptrace.

This is just a basic implementation to get the port bootstrapped.

Ports/gdb/patches/basic-ptrace-i386-native-target.patch

@@ -0,0 +1,421 @@
+From 581bbef892960b1533aa9d9918f5eeee4bff9cce Mon Sep 17 00:00:00 2001
+From: Brian Gianforcaro <b.gianfo@gmail.com>
+Date: Tue, 28 Dec 2021 04:35:47 -0800
+Subject: [PATCH 2/3] serenity: Add basic ptrace based native target for
+ SerenityOS/i386
+
+---
+ gdb/configure.host       |   3 ++
+ gdb/configure.nat        |  11 +++++
+ gdb/configure.tgt        |   4 ++
+ gdb/i386-serenity-nat.c  | 101 +++++++++++++++++++++++++++++++++++++++
+ gdb/i386-serenity-tdep.c |  43 +++++++++++++++++
+ gdb/i386-serenity-tdep.h |   8 ++++
+ gdb/osabi.c              |   1 +
+ gdb/osabi.h              |   1 +
+ gdb/serenity-nat.c       |  13 +++++
+ gdb/serenity-nat.h       |  34 +++++++++++++
+ gdb/serenity-tdep.c      |  28 +++++++++++
+ gdb/serenity-tdep.h      |  24 ++++++++++
+ 12 files changed, 271 insertions(+)
+ create mode 100644 gdb/i386-serenity-nat.c
+ create mode 100644 gdb/i386-serenity-tdep.c
+ create mode 100644 gdb/i386-serenity-tdep.h
+ create mode 100644 gdb/serenity-nat.c
+ create mode 100644 gdb/serenity-nat.h
+ create mode 100644 gdb/serenity-tdep.c
+ create mode 100644 gdb/serenity-tdep.h
+
+diff --git a/gdb/configure.host b/gdb/configure.host
+index e94a19b..06b87ca 100644
+--- a/gdb/configure.host
++++ b/gdb/configure.host
+@@ -85,6 +85,7 @@ case "${host}" in
+ *-*-darwin*)		gdb_host=darwin ;;
+ 
+ aarch64*-*-linux*)	gdb_host=linux ;;
++aarch64*-*-serenity*)	gdb_host=serenity ;;
+ aarch64*-*-freebsd*)	gdb_host=fbsd ;;
+ 
+ alpha*-*-linux*)	gdb_host=alpha-linux ;;
+@@ -117,6 +118,7 @@ i[34567]86-*-linux*)	gdb_host=linux ;;
+ i[34567]86-*-gnu*)	gdb_host=i386gnu ;;
+ i[3456]86-*-nto*) 	gdb_host=nto ;;
+ i[34567]86-*-openbsd*)	gdb_host=obsd ;;
++i[34567]86-*-serenity*)	gdb_host=serenity ;;
+ i[34567]86-*-solaris2* | x86_64-*-solaris2*)
+ 			gdb_host=sol2 ;;
+ i[34567]86-*-cygwin*)	gdb_host=cygwin ;;
+@@ -185,6 +187,7 @@ x86_64-*-mingw*)        gdb_host=mingw64
+ 			gdb_host_obs=mingw-hdep.o
+ 			;;
+ x86_64-*-cygwin*)	gdb_host=cygwin64 ;;
++x86_64-*-serenity*)	gdb_host=serenity ;;
+ m32r*-*-linux*)          gdb_host=linux ;;
+ 
+ xtensa*-*-linux*)	gdb_host=linux ;;
+diff --git a/gdb/configure.nat b/gdb/configure.nat
+index e34cccf..38b687e 100644
+--- a/gdb/configure.nat
++++ b/gdb/configure.nat
+@@ -86,6 +86,9 @@ case ${gdb_host} in
+     darwin)
+ 	NATDEPFILES='fork-child.o nat/fork-inferior.o darwin-nat.o \
+ 	    darwin-nat-info.o'
++    ;;
++    serenity)
++	NATDEPFILES='fork-child.o nat/fork-inferior.o inf-ptrace.o'
+ 	;;
+     sol2)
+ 	NATDEPFILES='fork-child.o nat/fork-inferior.o \
+@@ -477,6 +480,14 @@ case ${gdb_host} in
+ 		;;
+ 	esac
+ 	;;
++    serenity)
++	case ${gdb_host_cpu} in
++	    i386)
++		# Host: SerenityOS/x86_64 ELF
++		NATDEPFILES="${NATDEPFILES} amd64-nat.o serenity-nat.o i386-serenity-nat.o"
++		;;
++	esac
++	;;
+     sol2)
+ 	case ${gdb_host_cpu} in
+ 	    i386)
+diff --git a/gdb/configure.tgt b/gdb/configure.tgt
+index 97a5a57..886542f 100644
+--- a/gdb/configure.tgt
++++ b/gdb/configure.tgt
+@@ -291,6 +291,10 @@ i[34567]86-*-nto*)
+ 	gdb_target_obs="solib-svr4.o \
+ 			i386-nto-tdep.o nto-tdep.o"
+ 	;;
++i[34567]86-*-serenity*)
++	# Target: SerenityOS/i386
++	gdb_target_obs="i386-serenity-tdep.o serenity-tdep.o"
++	;;
+ i[34567]86-*-solaris2* | x86_64-*-solaris2*)
+ 	# Target: Solaris x86_64
+ 	gdb_target_obs="${i386_tobjs} ${amd64_tobjs} \
+diff --git a/gdb/i386-serenity-nat.c b/gdb/i386-serenity-nat.c
+new file mode 100644
+index 0000000..034252a
+--- /dev/null
++++ b/gdb/i386-serenity-nat.c
+@@ -0,0 +1,101 @@
++/* Native-dependent code for SerenityOS/i386.
++
++   Copyright (C) 2002-2021 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 "defs.h"
++#include "gdbcore.h"
++#include "regcache.h"
++#include "regset.h"
++#include "target.h"
++
++#include <sys/arch/i386/regs.h>
++#include <sys/ptrace.h>
++
++#include "i386-tdep.h"
++#include "serenity-nat.h"
++
++/* Register maps.  */
++
++static const struct regcache_map_entry i386_serenity_gregmap[] =
++{
++    { 1, I386_EAX_REGNUM, 0 }, 
++    { 1, I386_ECX_REGNUM, 0 }, 
++    { 1, I386_EDX_REGNUM, 0 }, 
++    { 1, I386_EBX_REGNUM, 0 }, 
++    { 1, I386_ESP_REGNUM, 0 }, 
++    { 1, I386_EBP_REGNUM, 0 }, 
++    { 1, I386_ESI_REGNUM, 0 }, 
++    { 1, I386_EDI_REGNUM, 0 }, 
++    { 1, I386_EIP_REGNUM, 0 }, 
++    { 1, I386_EFLAGS_REGNUM, 0 }, 
++    { 1, I386_CS_REGNUM, 0 }, 
++    { 1, I386_SS_REGNUM, 0 }, 
++    { 1, I386_DS_REGNUM, 0 }, 
++    { 1, I386_ES_REGNUM, 0 }, 
++    { 1, I386_FS_REGNUM, 0 }, 
++    { 1, I386_GS_REGNUM, 0 }, 
++    { 0 },
++};
++
++const struct regset i386_serenity_gregset =
++{
++    i386_serenity_gregmap, regcache_supply_regset, regcache_collect_regset
++};
++
++class i386_serenity_nat_target final : public serenity_nat_target
++{
++  void fetch_registers (struct regcache* cache, int regnum) override
++  {
++    if (regnum == -1) {
++      pid_t pid = get_ptrace_pid (cache->ptid ());
++      PtraceRegisters regs;
++
++      if (ptrace (PT_GETREGS, pid, &regs, 0) == -1)
++        perror_with_name (_("Couldn't get registers"));
++
++      cache->supply_regset (&i386_serenity_gregset, regnum, &regs,
++              sizeof (regs));
++    }
++  };
++
++  void store_registers (struct regcache* cache, int regnum) override
++  {
++    if (regnum == -1) {
++      pid_t pid = get_ptrace_pid (cache->ptid ());
++      PtraceRegisters regs {};
++
++      if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
++        perror_with_name (_("Couldn't get registers"));
++
++      cache->collect_regset (&i386_serenity_gregset, regnum, &regs,
++			       sizeof (regs));
++
++      if (ptrace (PT_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
++        perror_with_name (_("Couldn't write registers"));
++    }
++  };
++};
++
++static i386_serenity_nat_target the_i386_serenity_nat_target;
++
++void _initialize_i386_serenity_nat ();
++void
++_initialize_i386_serenity_nat ()
++{
++  add_inf_child_target (&the_i386_serenity_nat_target);
++}
+diff --git a/gdb/i386-serenity-tdep.c b/gdb/i386-serenity-tdep.c
+new file mode 100644
+index 0000000..d384061
+--- /dev/null
++++ b/gdb/i386-serenity-tdep.c
+@@ -0,0 +1,43 @@
++/* Target-dependent code for SerenityOS/i386.
++
++   Copyright (C) 2003-2021 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 "defs.h"
++#include "arch-utils.h"
++#include "gdbcore.h"
++#include "osabi.h"
++#include "regcache.h"
++
++#include "serenity-tdep.h"
++
++
++/* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
++static void
++i386_serenity_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
++{
++  /* Generic SerenityOS support.  */
++  serenity_init_abi (info, gdbarch);
++}
++
++void _initialize_i386_serenity_tdep ();
++void
++_initialize_i386_serenity_tdep ()
++{
++  gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_SERENITYOS,
++			  i386_serenity_init_abi);
++}
+diff --git a/gdb/i386-serenity-tdep.h b/gdb/i386-serenity-tdep.h
+new file mode 100644
+index 0000000..4ee3fba
+--- /dev/null
++++ b/gdb/i386-serenity-tdep.h
+@@ -0,0 +1,8 @@
++/* Target-dependent code for SernityOS i386. */
++
++#ifndef I386_SERENITY_TDEP_H
++#define I386_SERENITY_TDEP_H
++
++//extern const struct regset i386_serenity_gregset;
++
++#endif /* i386-serenity-tdep.h */
+diff --git a/gdb/osabi.c b/gdb/osabi.c
+index aabf895..28789e8 100644
+--- a/gdb/osabi.c
++++ b/gdb/osabi.c
+@@ -82,6 +82,7 @@ static const struct osabi_names gdb_osabi_names[] =
+   { "Newlib", NULL },
+   { "SDE", NULL },
+   { "PikeOS", NULL },
++  { "SerenityOS", NULL },
+ 
+   { "<invalid>", NULL }
+ };
+diff --git a/gdb/osabi.h b/gdb/osabi.h
+index 1ecbed4..73c5549 100644
+--- a/gdb/osabi.h
++++ b/gdb/osabi.h
+@@ -46,6 +46,7 @@ enum gdb_osabi
+   GDB_OSABI_NEWLIB,
+   GDB_OSABI_SDE,
+   GDB_OSABI_PIKEOS,
++  GDB_OSABI_SERENITYOS,
+ 
+   GDB_OSABI_INVALID		/* keep this last */
+ };
+diff --git a/gdb/serenity-nat.c b/gdb/serenity-nat.c
+new file mode 100644
+index 0000000..ff740d4
+--- /dev/null
++++ b/gdb/serenity-nat.c
+@@ -0,0 +1,13 @@
++/* Native-dependent code for SerenityOS  */
++
++#include "defs.h"
++#include "gdbthread.h"
++#include "inferior.h"
++#include "target.h"
++
++#include <sys/types.h>
++#include <sys/ptrace.h>
++#include "gdbsupport/gdb_wait.h"
++
++#include "inf-child.h"
++#include "serenity-nat.h"
+\ No newline at end of file
+diff --git a/gdb/serenity-nat.h b/gdb/serenity-nat.h
+new file mode 100644
+index 0000000..ac3cfaa
+--- /dev/null
++++ b/gdb/serenity-nat.h
+@@ -0,0 +1,34 @@
++/* Native-dependent code for SerenityOS.  */
++
++#ifndef SERENITYOS_NAT_H
++#define SERENITYOS_NAT_H
++
++#include "inf-ptrace.h"
++
++/* A prototype generic Serenity target.
++   A concrete instance should override it with local methods. 
++*/
++
++class serenity_nat_target : public inf_ptrace_target
++{
++#if 0 
++  /* Override some methods to support threads.  */
++  std::string pid_to_str (ptid_t) override;
++  void update_thread_list () override;
++  ptid_t wait (ptid_t, struct target_waitstatus *, target_wait_flags) override;
++
++#ifdef PT_GET_PROCESS_STATE
++  void follow_fork (bool, bool) override;
++
++  int insert_fork_catchpoint (int) override;
++
++  int remove_fork_catchpoint (int) override;
++
++  void post_startup_inferior (ptid_t) override;
++
++  void post_attach (int) override;
++#endif
++#endif
++};
++
++#endif /* serenity-nat.h */
+diff --git a/gdb/serenity-tdep.c b/gdb/serenity-tdep.c
+new file mode 100644
+index 0000000..45981b2
+--- /dev/null
++++ b/gdb/serenity-tdep.c
+@@ -0,0 +1,28 @@
++/* Target-dependent code for SerenityOS, architecture-independent.
++
++   Copyright (C) 2002-2021 Free Software Foundation, Inc.
++
++   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 "arch-utils.h"
++#include "gdbcore.h"
++
++#include "serenity-tdep.h"
++
++void serenity_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
++{
++    /* NOP for now */
++}
+diff --git a/gdb/serenity-tdep.h b/gdb/serenity-tdep.h
+new file mode 100644
+index 0000000..43048c6
+--- /dev/null
++++ b/gdb/serenity-tdep.h
+@@ -0,0 +1,24 @@
++/* Target-dependent code for SerenityOS, architecture independent.
++
++   Copyright (C) 2009-2021 Free Software Foundation, Inc.
++
++   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 SERENITY_TDEP_H
++#define SERENITY_TDEP_H
++
++extern void serenity_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch);
++
++#endif /* serenity-tdep.h */
+-- 
+2.32.0
+