gdb10: Fixes for ARC

Here we add a couple of fixes and improvements for ARC processors.
All except 1 patch are already in the upstream "master" branch
and will be an essential part of GCC 11.x whenever it gets released.

The most important are first 4 patches (0005-0008) which introduce
support of full native GDB support in Linux on ARC.

And the rests are tiny, yet useful improvements.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

1 files changed, 413 insertions, 0 deletions

diff --git a/packages/gdb/10.2/0008-gdb-Add-native-support-for-ARC-in-GNU-Linux.patch b/packages/gdb/10.2/0008-gdb-Add-native-support-for-ARC-in-GNU-Linux.patch
new file mode 100644
index 00000000..7ff7b286
--- /dev/null
+++ b/packages/gdb/10.2/0008-gdb-Add-native-support-for-ARC-in-GNU-Linux.patch
@@ -0,0 +1,413 @@
+From 59a76f39ab17bf00545559c0c655ba89405d478d Mon Sep 17 00:00:00 2001
+From: Anton Kolesov <anton.kolesov@synopsys.com>
+Date: Fri, 14 Feb 2014 11:56:23 +0400
+Subject: [PATCH 09/20] gdb: Add native support for ARC in GNU/Linux
+
+With this patch in place it is possible to build a GDB that
+can run on ARC (GNU/Linux) hosts for debugging ARC targets.
+
+The "arc-linux-nat.c" is a rather small one that mostly deals
+with registers and a few thread related hooks.
+
+v2 [1]:
+- Remove "void" from the input of "_initialize_arc_linux_nat ()"
+
+[1] Tom's remark after the first patch
+https://sourceware.org/pipermail/gdb-patches/2020-November/173223.html
+
+gdb/ChangeLog:
+
+	* Makefile.in (ALLDEPFILES): Add arc-linux-nat.c.
+	* configure.host (host to gdb names): Add arc*-*-linux*.
+	* configure.nat (gdb_host_cpu): Add arc.
+	* arc-linux-nat.c: New.
+
+Will be a part of GDB 11:
+https://sourceware.org/git?p=binutils-gdb.git;a=commit;h=04c9f85efcd8df5fc482ce97c0104cc7dd5d19e6
+---
+ gdb/ChangeLog       |    7 +
+ gdb/Makefile.in     |    1 
+ gdb/arc-linux-nat.c |  320 ++++++++++++++++++++++++++++++++++++++++++++++++++++
+ gdb/configure.host  |    3 
+ gdb/configure.nat   |    4 
+ 5 files changed, 335 insertions(+)
+ create mode 100644 gdb/arc-linux-nat.c
+
+--- a/gdb/ChangeLog
++++ b/gdb/ChangeLog
+@@ -1,3 +1,10 @@
++2020-12-22  Anton Kolesov  <anton.kolesov@synopsys.com>
++
++	* Makefile.in (ALLDEPFILES): Add arc-linux-nat.c.
++	* configure.host (host to gdb names): Add arc*-*-linux*.
++	* configure.nat (gdb_host_cpu): Add arc.
++	* arc-linux-nat.c: New.
++
+ 2020-12-22  Shahab Vahedi  <shahab@synopsys.com>
+ 
+ 	* arc-linux-tdep.c (supply_register): New.
+--- a/gdb/Makefile.in
++++ b/gdb/Makefile.in
+@@ -2136,6 +2136,7 @@
+ 	amd64-obsd-tdep.c \
+ 	amd64-sol2-tdep.c \
+ 	amd64-tdep.c \
++	arc-linux-nat.c \
+ 	arc-tdep.c \
+ 	arm.c \
+ 	arm-bsd-tdep.c \
+--- /dev/null
++++ b/gdb/arc-linux-nat.c
+@@ -0,0 +1,320 @@
++/* Native-dependent code for GNU/Linux ARC.
++
++   Copyright 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 "frame.h"
++#include "inferior.h"
++#include "gdbcore.h"
++#include "regcache.h"
++#include "gdbsupport/gdb_assert.h"
++#include "target.h"
++#include "linux-nat.h"
++#include "nat/gdb_ptrace.h"
++
++#include <stdint.h>
++#include <sys/types.h>
++#include <sys/param.h>
++#include <signal.h>
++#include <sys/user.h>
++#include <sys/ioctl.h>
++#include "gdbsupport/gdb_wait.h"
++#include <fcntl.h>
++#include <sys/procfs.h>
++#include <linux/elf.h>
++
++#include "gregset.h"
++#include "arc-tdep.h"
++#include "arc-linux-tdep.h"
++#include "arch/arc.h"
++
++/* Defines ps_err_e, struct ps_prochandle.  */
++#include "gdb_proc_service.h"
++
++/* Linux starting with 4.12 supports NT_ARC_V2 note type, which adds R30,
++   R58 and R59 registers, which are specific to ARC HS and aren't
++   available in ARC 700.  */
++#if defined (NT_ARC_V2) && defined (__ARCHS__)
++#define ARC_HAS_V2_REGSET
++#endif
++
++class arc_linux_nat_target final : public linux_nat_target
++{
++public:
++  /* Add ARC register access methods.  */
++  void fetch_registers (struct regcache *, int) override;
++  void store_registers (struct regcache *, int) override;
++
++  const struct target_desc *read_description () override;
++
++  /* Handle threads  */
++  void low_prepare_to_resume (struct lwp_info *lp) override;
++};
++
++static arc_linux_nat_target the_arc_linux_nat_target;
++
++/* Read general registers from target process/thread (via ptrace)
++   into REGCACHE.  */
++
++static void
++fetch_gregs (struct regcache *regcache, int regnum)
++{
++  const int tid = get_ptrace_pid (regcache->ptid ());
++  struct iovec iov;
++  gdb_gregset_t regs;
++
++  iov.iov_base = &regs;
++  iov.iov_len = sizeof (gdb_gregset_t);
++
++  if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0)
++    perror_with_name (_("Couldn't get general registers"));
++  else
++    arc_linux_supply_gregset (NULL, regcache, regnum, &regs, 0);
++}
++
++#ifdef ARC_HAS_V2_REGSET
++/* Read ARC v2 registers from target process/thread (via ptrace)
++   into REGCACHE.  */
++
++static void
++fetch_v2_regs (struct regcache *regcache, int regnum)
++{
++  const int tid = get_ptrace_pid (regcache->ptid ());
++  struct iovec iov;
++  bfd_byte v2_buffer[ARC_LINUX_SIZEOF_V2_REGSET];
++
++  iov.iov_base = &v2_buffer;
++  iov.iov_len = ARC_LINUX_SIZEOF_V2_REGSET;
++
++  if (ptrace (PTRACE_GETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0)
++    perror_with_name (_("Couldn't get ARC HS registers"));
++  else
++    arc_linux_supply_v2_regset (NULL, regcache, regnum, v2_buffer, 0);
++}
++#endif
++
++/* Store general registers from REGCACHE into the target process/thread.  */
++
++static void
++store_gregs (const struct regcache *regcache, int regnum)
++{
++  const int tid = get_ptrace_pid (regcache->ptid ());
++  struct iovec iov;
++  gdb_gregset_t regs;
++
++  iov.iov_base = &regs;
++  iov.iov_len = sizeof (gdb_gregset_t);
++
++  if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0)
++    perror_with_name (_("Couldn't get general registers"));
++  else
++    {
++      arc_linux_collect_gregset (NULL, regcache, regnum, regs, 0);
++
++      if (ptrace (PTRACE_SETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0)
++	perror_with_name (_("Couldn't write general registers"));
++    }
++}
++
++#ifdef ARC_HAS_V2_REGSET
++/* Store ARC v2 registers from REGCACHE into the target process/thread.  */
++
++static void
++store_v2_regs (const struct regcache *regcache, int regnum)
++{
++  const int tid = get_ptrace_pid (regcache->ptid ());
++  struct iovec iov;
++  bfd_byte v2_buffer[ARC_LINUX_SIZEOF_V2_REGSET];
++
++  iov.iov_base = &v2_buffer;
++  iov.iov_len = ARC_LINUX_SIZEOF_V2_REGSET;
++
++  if (ptrace (PTRACE_GETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0)
++    perror_with_name (_("Couldn't get ARC HS registers"));
++  else
++    {
++      arc_linux_collect_v2_regset (NULL, regcache, regnum, v2_buffer, 0);
++
++      if (ptrace (PTRACE_SETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0)
++	perror_with_name (_("Couldn't write ARC HS registers"));
++    }
++}
++#endif
++
++/* Target operation: Read REGNUM register (all registers if REGNUM == -1)
++   from target process into REGCACHE.  */
++
++void
++arc_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum)
++{
++
++  if (regnum == -1 || regnum <= ARC_LAST_REGNUM)
++    fetch_gregs (regcache, regnum);
++
++#ifdef ARC_HAS_V2_REGSET
++  if (regnum == -1
++      || regnum == ARC_R30_REGNUM
++      || regnum == ARC_R58_REGNUM
++      || regnum == ARC_R59_REGNUM)
++      fetch_v2_regs (regcache, regnum);
++#endif
++}
++
++/* Target operation: Store REGNUM register (all registers if REGNUM == -1)
++   to the target process from REGCACHE.  */
++
++void
++arc_linux_nat_target::store_registers (struct regcache *regcache, int regnum)
++{
++  if (regnum == -1 || regnum <= ARC_LAST_REGNUM)
++    store_gregs (regcache, regnum);
++
++#ifdef ARC_HAS_V2_REGSET
++  if (regnum == -1
++      || regnum == ARC_R30_REGNUM
++      || regnum == ARC_R58_REGNUM
++      || regnum == ARC_R59_REGNUM)
++    store_v2_regs (regcache, regnum);
++#endif
++}
++
++/* Copy general purpose register(s) from REGCACHE into regset GREGS.
++   This function is exported to proc-service.c  */
++
++void
++fill_gregset (const struct regcache *regcache,
++	      gdb_gregset_t *gregs, int regnum)
++{
++  arc_linux_collect_gregset (NULL, regcache, regnum, gregs, 0);
++}
++
++/* Copy all the general purpose registers from regset GREGS into REGCACHE.
++   This function is exported to proc-service.c.  */
++
++void
++supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregs)
++{
++  arc_linux_supply_gregset (NULL, regcache, -1, gregs, 0);
++}
++
++/* ARC doesn't have separate FP registers.  This function is exported
++   to proc-service.c.  */
++
++void
++fill_fpregset (const struct regcache *regcache,
++	       gdb_fpregset_t *fpregsetp, int regnum)
++{
++  if (arc_debug)
++    debug_printf ("arc-linux-nat: fill_fpregset called.");
++  return;
++}
++
++/* ARC doesn't have separate FP registers.  This function is exported
++   to proc-service.c.  */
++
++void
++supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp)
++{
++  if (arc_debug)
++    debug_printf ("arc-linux-nat: supply_fpregset called.");
++  return;
++}
++
++/* Implement the "read_description" method of linux_nat_target.  */
++
++const struct target_desc *
++arc_linux_nat_target::read_description ()
++{
++  /* This is a native target, hence description is hardcoded.  */
++#ifdef __ARCHS__
++  arc_arch_features features (4, ARC_ISA_ARCV2);
++#else
++  arc_arch_features features (4, ARC_ISA_ARCV1);
++#endif
++  return arc_lookup_target_description (features);
++}
++
++/* As described in arc_linux_collect_gregset(), we need to write resume-PC
++   to ERET.  However by default GDB for native targets doesn't write
++   registers if they haven't been changed.  This is a callback called by
++   generic GDB, and in this callback we have to rewrite PC value so it
++   would force rewrite of register on target.  It seems that the only
++   other arch that utilizes this hook is x86/x86-64 for HW breakpoint
++   support.  But then, AFAIK no other arch has this stop_pc/eret
++   complexity.
++
++   No better way was found, other than this fake write of register value,
++   to force GDB into writing register to target.  Is there any?  */
++
++void
++arc_linux_nat_target::low_prepare_to_resume (struct lwp_info *lwp)
++{
++  /* When new processes and threads are created we do not have the address
++     space for them and calling get_thread_regcache will cause an internal
++     error in GDB.  It looks like that checking for last_resume_kind is the
++     sensible way to determine processes for which we cannot get regcache.
++     Ultimately, a better way would be removing the need for
++     low_prepare_to_resume in the first place.  */
++  if (lwp->last_resume_kind == resume_stop)
++    return;
++
++  struct regcache *regcache = get_thread_regcache (this, lwp->ptid);
++  struct gdbarch *gdbarch = regcache->arch ();
++
++  /* Read current PC value, then write it back.  It is required to call
++     invalidate(), otherwise GDB will note that new value is equal to old
++     value and will skip write.  */
++  ULONGEST new_pc;
++  regcache_cooked_read_unsigned (regcache, gdbarch_pc_regnum (gdbarch),
++				 &new_pc);
++  regcache->invalidate (gdbarch_pc_regnum (gdbarch));
++  regcache_cooked_write_unsigned (regcache, gdbarch_pc_regnum (gdbarch),
++				  new_pc);
++}
++
++/* Fetch the thread-local storage pointer for libthread_db.  Note that
++   this function is not called from GDB, but is called from libthread_db.
++   This is required to debug multithreaded applications with NPTL.  */
++
++ps_err_e
++ps_get_thread_area (struct ps_prochandle *ph, lwpid_t lwpid, int idx,
++		    void **base)
++{
++  if (arc_debug >= 2)
++    debug_printf ("arc-linux-nat: ps_get_thread_area called");
++
++  if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
++    return PS_ERR;
++
++  /* IDX is the bias from the thread pointer to the beginning of the
++     thread descriptor.  It has to be subtracted due to implementation
++     quirks in libthread_db.  */
++  *base = (void *) ((char *) *base - idx);
++
++  return PS_OK;
++}
++
++/* Suppress warning from -Wmissing-prototypes.  */
++void _initialize_arc_linux_nat ();
++void
++_initialize_arc_linux_nat ()
++{
++  /* Register the target.  */
++  linux_target = &the_arc_linux_nat_target;
++  add_inf_child_target (&the_arc_linux_nat_target);
++}
+--- a/gdb/configure.host
++++ b/gdb/configure.host
+@@ -60,6 +60,7 @@
+ 
+ aarch64*)		gdb_host_cpu=aarch64 ;;
+ alpha*)			gdb_host_cpu=alpha ;;
++arc*)			gdb_host_cpu=arc ;;
+ arm*)			gdb_host_cpu=arm ;;
+ hppa*)			gdb_host_cpu=pa ;;
+ i[34567]86*)		gdb_host_cpu=i386 ;;
+@@ -91,6 +92,8 @@
+ 			gdb_host=nbsd ;;
+ alpha*-*-openbsd*)	gdb_host=nbsd ;;
+ 
++arc*-*-linux*)		gdb_host=linux ;;
++
+ arm*-*-freebsd*)	gdb_host=fbsd ;;
+ arm*-*-linux*)		gdb_host=linux ;;
+ arm*-*-netbsdelf* | arm*-*-knetbsd*-gnu)
+--- a/gdb/configure.nat
++++ b/gdb/configure.nat
+@@ -238,6 +238,10 @@
+ 		nat/aarch64-linux.o \
+ 		nat/aarch64-sve-linux-ptrace.o"
+ 		;;
++	    arc)
++		# Host: ARC based machine running GNU/Linux
++		NATDEPFILES="${NATDEPFILES} arc-linux-nat.o"
++		;;
+ 	    arm)
+ 		# Host: ARM based machine running GNU/Linux
+ 		NATDEPFILES="${NATDEPFILES} arm-linux-nat.o \