gdb: backport xtensa NPTL support to 7.10.1

These changes allow debugging multithreaded NPTL xtensa applications and
inspect TLS variables.

Backported from: 40045d91812b25c88c8275b8c08d27c234b68ba8
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gdb/7.10.1/0004-xtensa-implement-NPTL-helpers.patch

@@ -0,0 +1,267 @@
+From d4eb69fc4b50f9a0babd70b28d0601b40f31bd0f Mon Sep 17 00:00:00 2001
+From: Max Filippov <jcmvbkbc@gmail.com>
+Date: Thu, 2 Jul 2015 15:10:58 +0300
+Subject: [PATCH] xtensa: implement NPTL helpers
+
+These changes allow debugging multithreaded NPTL xtensa applications.
+
+2015-08-20  Max Filippov  <jcmvbkbc@gmail.com>
+gdb/gdbserver/
+	* configure.srv (xtensa*-*-linux*): Add srv_linux_thread_db=yes.
+	* linux-xtensa-low.c (arch/xtensa.h gdb_proc_service.h): New
+	#includes.
+	(ps_get_thread_area): New function.
+
+2015-08-20  Max Filippov  <jcmvbkbc@gmail.com>
+gdb/
+	* arch/xtensa.h: New file.
+	* xtensa-linux-nat.c (gdb_proc_service.h): New #include.
+	(ps_get_thread_area): New function.
+	* xtensa-linux-tdep.c (xtensa_linux_init_abi): Add call to
+	set_gdbarch_fetch_tls_load_module_address to enable TLS support.
+	* xtensa-tdep.c (osabi.h): New #include.
+	(xtensa_gdbarch_init): Call gdbarch_init_osabi to register
+	xtensa-specific hooks.
+	* xtensa-tdep.h (struct xtensa_elf_gregset_t): Add threadptr
+	member and move the structure to arch/xtensa.h.
+
+Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
+---
+Backported from: 40045d91812b25c88c8275b8c08d27c234b68ba8
+Changes to ChangeLog files are dropped.
+
+ gdb/arch/xtensa.h                | 46 ++++++++++++++++++++++++++++++++++++++++
+ gdb/gdbserver/configure.srv      |  1 +
+ gdb/gdbserver/linux-xtensa-low.c | 21 ++++++++++++++++++
+ gdb/xtensa-linux-nat.c           | 22 ++++++++++++++++++
+ gdb/xtensa-linux-tdep.c          |  4 ++++
+ gdb/xtensa-tdep.c                |  4 ++++
+ gdb/xtensa-tdep.h                | 24 ++------------------
+ 7 files changed, 100 insertions(+), 22 deletions(-)
+ create mode 100644 gdb/arch/xtensa.h
+
+diff --git a/gdb/arch/xtensa.h b/gdb/arch/xtensa.h
+new file mode 100644
+index 0000000..fe96584
+--- /dev/null
++++ b/gdb/arch/xtensa.h
+@@ -0,0 +1,46 @@
++/* Common Target-dependent code for the Xtensa port of GDB, the GNU debugger.
++
++   Copyright (C) 2003-2015 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 XTENSA_H
++#define XTENSA_H
++
++/* Xtensa ELF core file register set representation ('.reg' section).
++   Copied from target-side ELF header <xtensa/elf.h>.  */
++
++typedef uint32_t xtensa_elf_greg_t;
++
++typedef struct
++{
++  xtensa_elf_greg_t pc;
++  xtensa_elf_greg_t ps;
++  xtensa_elf_greg_t lbeg;
++  xtensa_elf_greg_t lend;
++  xtensa_elf_greg_t lcount;
++  xtensa_elf_greg_t sar;
++  xtensa_elf_greg_t windowstart;
++  xtensa_elf_greg_t windowbase;
++  xtensa_elf_greg_t threadptr;
++  xtensa_elf_greg_t reserved[7+48];
++  xtensa_elf_greg_t ar[64];
++} xtensa_elf_gregset_t;
++
++#define XTENSA_ELF_NGREG (sizeof (xtensa_elf_gregset_t) \
++			  / sizeof (xtensa_elf_greg_t))
++
++#endif
+diff --git a/gdb/gdbserver/configure.srv b/gdb/gdbserver/configure.srv
+index 0b18d1d..320c26a 100644
+--- a/gdb/gdbserver/configure.srv
++++ b/gdb/gdbserver/configure.srv
+@@ -352,6 +352,7 @@ case "${target}" in
+   xtensa*-*-linux*)	srv_regobj=reg-xtensa.o
+ 			srv_tgtobj="$srv_linux_obj linux-xtensa-low.o"
+ 			srv_linux_regsets=yes
++			srv_linux_thread_db=yes
+ 			;;
+   tilegx-*-linux*)	srv_regobj=reg-tilegx.o
+ 			srv_regobj="${srv_regobj} reg-tilegx32.o"
+diff --git a/gdb/gdbserver/linux-xtensa-low.c b/gdb/gdbserver/linux-xtensa-low.c
+index 4daccee..debe467 100644
+--- a/gdb/gdbserver/linux-xtensa-low.c
++++ b/gdb/gdbserver/linux-xtensa-low.c
+@@ -26,6 +26,8 @@ extern const struct target_desc *tdesc_xtensa;
+ 
+ #include <asm/ptrace.h>
+ #include <xtensa-config.h>
++#include "arch/xtensa.h"
++#include "gdb_proc_service.h"
+ 
+ #include "xtensa-xtregs.c"
+ 
+@@ -179,6 +181,25 @@ xtensa_breakpoint_at (CORE_ADDR where)
+ 		  xtensa_breakpoint, xtensa_breakpoint_len) == 0;
+ }
+ 
++/* Called by libthread_db.  */
++
++ps_err_e
++ps_get_thread_area (const struct ps_prochandle *ph,
++                    lwpid_t lwpid, int idx, void **base)
++{
++  xtensa_elf_gregset_t regs;
++
++  if (ptrace (PTRACE_GETREGS, lwpid, NULL, &regs) != 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 *) regs.threadptr - idx);
++
++  return PS_OK;
++}
++
+ static struct regsets_info xtensa_regsets_info =
+   {
+     xtensa_regsets, /* regsets */
+diff --git a/gdb/xtensa-linux-nat.c b/gdb/xtensa-linux-nat.c
+index 77ad3e0..5538d5b 100644
+--- a/gdb/xtensa-linux-nat.c
++++ b/gdb/xtensa-linux-nat.c
+@@ -37,6 +37,9 @@
+ #include "gregset.h"
+ #include "xtensa-tdep.h"
+ 
++/* Defines ps_err_e, struct ps_prochandle.  */
++#include "gdb_proc_service.h"
++
+ /* Extended register set depends on hardware configs.
+    Keeping these definitions separately allows to introduce
+    hardware-specific overlays.  */
+@@ -280,6 +283,25 @@ xtensa_linux_store_inferior_registers (struct target_ops *ops,
+     store_xtregs (regcache, regnum);
+ }
+ 
++/* Called by libthread_db.  */
++
++ps_err_e
++ps_get_thread_area (const struct ps_prochandle *ph,
++                    lwpid_t lwpid, int idx, void **base)
++{
++  xtensa_elf_gregset_t regs;
++
++  if (ptrace (PTRACE_GETREGS, lwpid, NULL, &regs) != 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 *) regs.threadptr - idx);
++
++  return PS_OK;
++}
++
+ void _initialize_xtensa_linux_nat (void);
+ 
+ void
+diff --git a/gdb/xtensa-linux-tdep.c b/gdb/xtensa-linux-tdep.c
+index 61ea9b0..99e0d3e 100644
+--- a/gdb/xtensa-linux-tdep.c
++++ b/gdb/xtensa-linux-tdep.c
+@@ -106,6 +106,10 @@ xtensa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+ 				      xtensa_linux_gdb_signal_from_target);
+   set_gdbarch_gdb_signal_to_target (gdbarch,
+ 				    xtensa_linux_gdb_signal_to_target);
++
++  /* Enable TLS support.  */
++  set_gdbarch_fetch_tls_load_module_address (gdbarch,
++                                             svr4_fetch_objfile_link_map);
+ }
+ 
+ /* Provide a prototype to silence -Wmissing-prototypes.  */
+diff --git a/gdb/xtensa-tdep.c b/gdb/xtensa-tdep.c
+index 55e7d98..4b693ed 100644
+--- a/gdb/xtensa-tdep.c
++++ b/gdb/xtensa-tdep.c
+@@ -28,6 +28,7 @@
+ #include "value.h"
+ #include "dis-asm.h"
+ #include "inferior.h"
++#include "osabi.h"
+ #include "floatformat.h"
+ #include "regcache.h"
+ #include "reggroups.h"
+@@ -3273,6 +3274,9 @@ xtensa_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
+   set_solib_svr4_fetch_link_map_offsets
+     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
+ 
++  /* Hook in the ABI-specific overrides, if they have been registered.  */
++  gdbarch_init_osabi (info, gdbarch);
++
+   return gdbarch;
+ }
+ 
+diff --git a/gdb/xtensa-tdep.h b/gdb/xtensa-tdep.h
+index caa2988..5b28cab 100644
+--- a/gdb/xtensa-tdep.h
++++ b/gdb/xtensa-tdep.h
+@@ -18,6 +18,8 @@
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+ 
+ 
++#include "arch/xtensa.h"
++
+ /* XTENSA_TDEP_VERSION can/should be changed along with XTENSA_CONFIG_VERSION
+    whenever the "tdep" structure changes in an incompatible way.  */
+ 
+@@ -81,28 +83,6 @@ typedef enum
+ } xtensa_target_flags_t;
+ 
+ 
+-/* Xtensa ELF core file register set representation ('.reg' section).
+-   Copied from target-side ELF header <xtensa/elf.h>.  */
+-
+-typedef uint32_t xtensa_elf_greg_t;
+-
+-typedef struct
+-{
+-  xtensa_elf_greg_t pc;
+-  xtensa_elf_greg_t ps;
+-  xtensa_elf_greg_t lbeg;
+-  xtensa_elf_greg_t lend;
+-  xtensa_elf_greg_t lcount;
+-  xtensa_elf_greg_t sar;
+-  xtensa_elf_greg_t windowstart;
+-  xtensa_elf_greg_t windowbase;
+-  xtensa_elf_greg_t reserved[8+48];
+-  xtensa_elf_greg_t ar[64];
+-} xtensa_elf_gregset_t;
+-
+-#define XTENSA_ELF_NGREG (sizeof (xtensa_elf_gregset_t) \
+-			  / sizeof (xtensa_elf_greg_t))
+-
+ /*  Mask.  */
+ 
+ typedef struct 
+-- 
+1.8.1.4
+