Biarch support for i386/amd64 gdbserver.

	* Makefile.in (SFILES): Remove linux-i386-low.c, linux-x86-64-low.c.
	Add linux-x86-low.c.
	(linux-i386-low.o, linux-x86-64-low.o): Delete.
	(linux-x86-low.o): Add.
	* linux-x86-64-low.c: Delete.
	* linux-i386-low.c: Delete.
	* linux-x86-low.c: New file.
	* configure.srv (i?86-linux srv_tgtobj): Replace linux-i386-low.o with
	linux-x86-low.o.
	(x86_64-linux srv_tgtobj): Replace linux-x86-64-low.o with
	linux-x86-low.o.
	(x86_64-linux srv_regobj): Add reg-i386-linux.o.
	* linux-low.c: Include ansidecl.h, elf/common.h, elf/external.h.
	(linux_child_pid_to_exec_file): New function.
	(elf_64_header_p, elf_64_file_p): New functions.
	(siginfo_fixup): New function.
	(linux_xfer_siginfo): New local inf_siginfo.  Call siginfo_fixup to
	give target a chance to convert layout.
	* linux-low.h (linux_target_ops): New member siginfo_fixup.
	(linux_child_pid_to_exec_file, elf_64_file_p): Declare.

8 files changed, 790 insertions, 407 deletions

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 022f266..798d4de 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,27 @@
+2009-05-12  Doug Evans  <dje@google.com>
+
+	Biarch support for i386/amd64 gdbserver.
+	* Makefile.in (SFILES): Remove linux-i386-low.c, linux-x86-64-low.c.
+	Add linux-x86-low.c.
+	(linux-i386-low.o, linux-x86-64-low.o): Delete.
+	(linux-x86-low.o): Add.
+	* linux-x86-64-low.c: Delete.
+	* linux-i386-low.c: Delete.
+	* linux-x86-low.c: New file.
+	* configure.srv (i?86-linux srv_tgtobj): Replace linux-i386-low.o with
+	linux-x86-low.o.
+	(x86_64-linux srv_tgtobj): Replace linux-x86-64-low.o with
+	linux-x86-low.o.
+	(x86_64-linux srv_regobj): Add reg-i386-linux.o.
+	* linux-low.c: Include ansidecl.h, elf/common.h, elf/external.h.
+	(linux_child_pid_to_exec_file): New function.
+	(elf_64_header_p, elf_64_file_p): New functions.
+	(siginfo_fixup): New function.
+	(linux_xfer_siginfo): New local inf_siginfo.  Call siginfo_fixup to
+	give target a chance to convert layout.
+	* linux-low.h (linux_target_ops): New member siginfo_fixup.
+	(linux_child_pid_to_exec_file, elf_64_file_p): Declare.
+
 2009-05-07  Doug Evans  <dje@google.com>
 
 	* linux-low.c (regsets_fetch_inferior_registers): Fix memory leak.
diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in
index a62b25b..f395d9e 100644
--- a/gdb/gdbserver/Makefile.in
+++ b/gdb/gdbserver/Makefile.in
@@ -103,7 +103,7 @@ SFILES=	$(srcdir)/gdbreplay.c $(srcdir)/inferiors.c \
 	$(srcdir)/remote-utils.c $(srcdir)/server.c $(srcdir)/target.c \
 	$(srcdir)/thread-db.c $(srcdir)/utils.c \
 	$(srcdir)/linux-arm-low.c $(srcdir)/linux-cris-low.c \
-	$(srcdir)/linux-crisv32-low.c $(srcdir)/linux-i386-low.c \
+	$(srcdir)/linux-crisv32-low.c \
 	$(srcdir)/i387-fp.c \
 	$(srcdir)/linux-ia64-low.c $(srcdir)/linux-low.c \
 	$(srcdir)/linux-m32r-low.c \
@@ -111,7 +111,7 @@ SFILES=	$(srcdir)/gdbreplay.c $(srcdir)/inferiors.c \
 	$(srcdir)/linux-ppc-low.c \
 	$(srcdir)/linux-s390-low.c \
 	$(srcdir)/linux-sh-low.c $(srcdir)/linux-sparc-low.c \
-	$(srcdir)/linux-x86-64-low.c \
+	$(srcdir)/linux-x86-low.c \
 	$(srcdir)/linux-xtensa-low.c \
 	$(srcdir)/win32-arm-low.c $(srcdir)/win32-i386-low.c \
 	$(srcdir)/win32-low.c $(srcdir)/wincecompat.c \
@@ -296,8 +296,6 @@ linux-arm-low.o: linux-arm-low.c $(linux_low_h) $(server_h) \
 	$(gdb_proc_service_h)
 linux-cris-low.o: linux-cris-low.c $(linux_low_h) $(server_h)
 linux-crisv32-low.o: linux-crisv32-low.c $(linux_low_h) $(server_h)
-linux-i386-low.o: linux-i386-low.c $(linux_low_h) $(server_h) \
-	$(gdb_proc_service_h)
 linux-ia64-low.o: linux-ia64-low.c $(linux_low_h) $(server_h)
 linux-m32r-low.o: linux-m32r-low.c $(linux_low_h) $(server_h)
 linux-mips-low.o: linux-mips-low.c $(linux_low_h) $(server_h) \
@@ -305,7 +303,7 @@ linux-mips-low.o: linux-mips-low.c $(linux_low_h) $(server_h) \
 linux-ppc-low.o: linux-ppc-low.c $(linux_low_h) $(server_h)
 linux-s390-low.o: linux-s390-low.c $(linux_low_h) $(server_h)
 linux-sh-low.o: linux-sh-low.c $(linux_low_h) $(server_h)
-linux-x86-64-low.o: linux-x86-64-low.c $(linux_low_h) $(server_h) \
+linux-x86-low.o: linux-x86-low.c $(linux_low_h) $(server_h) \
 	$(gdb_proc_service_h)
 linux-xtensa-low.o: linux-xtensa-low.c xtensa-xtregs.c $(linux_low_h) $(server_h)
 
diff --git a/gdb/gdbserver/configure.srv b/gdb/gdbserver/configure.srv
index 924ac66..e4252af 100644
--- a/gdb/gdbserver/configure.srv
+++ b/gdb/gdbserver/configure.srv
@@ -56,7 +56,7 @@ case "${target}" in
 			srv_tgtobj="win32-low.o win32-i386-low.o"
 			;;
   i[34567]86-*-linux*)	srv_regobj=reg-i386-linux.o
-			srv_tgtobj="linux-low.o linux-i386-low.o i387-fp.o"
+			srv_tgtobj="linux-low.o linux-x86-low.o i387-fp.o"
 			srv_linux_usrregs=yes
 			srv_linux_regsets=yes
 			srv_linux_thread_db=yes
@@ -169,8 +169,9 @@ case "${target}" in
   spu*-*-*)		srv_regobj=reg-spu.o
 			srv_tgtobj="spu-low.o"
 			;;
-  x86_64-*-linux*)	srv_regobj=reg-x86-64-linux.o
-			srv_tgtobj="linux-low.o linux-x86-64-low.o i387-fp.o"
+  x86_64-*-linux*)	srv_regobj="reg-x86-64-linux.o reg-i386-linux.o"
+			srv_tgtobj="linux-low.o linux-x86-low.o i387-fp.o"
+			srv_linux_usrregs=yes # This is for i386 progs.
 			srv_linux_regsets=yes
 			srv_linux_thread_db=yes
 			;;
diff --git a/gdb/gdbserver/linux-i386-low.c b/gdb/gdbserver/linux-i386-low.c
deleted file mode 100644
index a94ce69..0000000
--- a/gdb/gdbserver/linux-i386-low.c
+++ /dev/null
@@ -1,210 +0,0 @@
-/* GNU/Linux/i386 specific low level interface, for the remote server for GDB.
-   Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006,
-   2007, 2008, 2009 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 "i387-fp.h"
-
-#include "gdb_proc_service.h"
-
-#include <sys/ptrace.h>
-
-#ifdef HAVE_SYS_REG_H
-#include <sys/reg.h>
-#endif
-
-#ifndef PTRACE_GET_THREAD_AREA
-#define PTRACE_GET_THREAD_AREA 25
-#endif
-
-/* Defined in auto-generated file reg-i386-linux.c.  */
-void init_registers_i386_linux (void);
-
-
-/* This module only supports access to the general purpose registers.  */
-
-#define i386_num_regs 16
-
-/* This stuff comes from i386-linux-nat.c.  */
-
-/* Mapping between the general-purpose registers in `struct user'
-   format and GDB's register array layout.  */
-static int i386_regmap[] =
-{
-  EAX * 4, ECX * 4, EDX * 4, EBX * 4,
-  UESP * 4, EBP * 4, ESI * 4, EDI * 4,
-  EIP * 4, EFL * 4, CS * 4, SS * 4,
-  DS * 4, ES * 4, FS * 4, GS * 4
-};
-
-/* Called by libthread_db.  */
-
-ps_err_e
-ps_get_thread_area (const struct ps_prochandle *ph,
-		    lwpid_t lwpid, int idx, void **base)
-{
-  unsigned int desc[4];
-
-  if (ptrace (PTRACE_GET_THREAD_AREA, lwpid,
-	      (void *) idx, (unsigned long) &desc) < 0)
-    return PS_ERR;
-
-  *(int *)base = desc[1];
-  return PS_OK;
-}
-
-static int
-i386_cannot_store_register (int regno)
-{
-  return (regno >= i386_num_regs);
-}
-
-static int
-i386_cannot_fetch_register (int regno)
-{
-  return (regno >= i386_num_regs);
-}
-
-
-#ifdef HAVE_PTRACE_GETREGS
-#include <sys/procfs.h>
-#include <sys/ptrace.h>
-
-static void
-i386_fill_gregset (void *buf)
-{
-  int i;
-
-  for (i = 0; i < i386_num_regs; i++)
-    collect_register (i, ((char *) buf) + i386_regmap[i]);
-
-  collect_register_by_name ("orig_eax", ((char *) buf) + ORIG_EAX * 4);
-}
-
-static void
-i386_store_gregset (const void *buf)
-{
-  int i;
-
-  for (i = 0; i < i386_num_regs; i++)
-    supply_register (i, ((char *) buf) + i386_regmap[i]);
-
-  supply_register_by_name ("orig_eax", ((char *) buf) + ORIG_EAX * 4);
-}
-
-static void
-i386_fill_fpregset (void *buf)
-{
-  i387_cache_to_fsave (buf);
-}
-
-static void
-i386_store_fpregset (const void *buf)
-{
-  i387_fsave_to_cache (buf);
-}
-
-static void
-i386_fill_fpxregset (void *buf)
-{
-  i387_cache_to_fxsave (buf);
-}
-
-static void
-i386_store_fpxregset (const void *buf)
-{
-  i387_fxsave_to_cache (buf);
-}
-
-#endif /* HAVE_PTRACE_GETREGS */
-
-struct regset_info target_regsets[] = {
-#ifdef HAVE_PTRACE_GETREGS
-  { PTRACE_GETREGS, PTRACE_SETREGS, sizeof (elf_gregset_t),
-    GENERAL_REGS,
-    i386_fill_gregset, i386_store_gregset },
-# ifdef HAVE_PTRACE_GETFPXREGS
-  { PTRACE_GETFPXREGS, PTRACE_SETFPXREGS, sizeof (elf_fpxregset_t),
-    EXTENDED_REGS,
-    i386_fill_fpxregset, i386_store_fpxregset },
-# endif
-  { PTRACE_GETFPREGS, PTRACE_SETFPREGS, sizeof (elf_fpregset_t),
-    FP_REGS,
-    i386_fill_fpregset, i386_store_fpregset },
-#endif /* HAVE_PTRACE_GETREGS */
-  { 0, 0, -1, -1, NULL, NULL }
-};
-
-static const unsigned char i386_breakpoint[] = { 0xCC };
-#define i386_breakpoint_len 1
-
-extern int debug_threads;
-
-static CORE_ADDR
-i386_get_pc ()
-{
-  unsigned long pc;
-
-  collect_register_by_name ("eip", &pc);
-
-  if (debug_threads)
-    fprintf (stderr, "stop pc (before any decrement) is %08lx\n", pc);
-  return pc;
-}
-
-static void
-i386_set_pc (CORE_ADDR newpc)
-{
-  if (debug_threads)
-    fprintf (stderr, "set pc to %08lx\n", (long) newpc);
-  supply_register_by_name ("eip", &newpc);
-}
-
-static int
-i386_breakpoint_at (CORE_ADDR pc)
-{
-  unsigned char c;
-
-  read_inferior_memory (pc, &c, 1);
-  if (c == 0xCC)
-    return 1;
-
-  return 0;
-}
-
-struct linux_target_ops the_low_target = {
-  init_registers_i386_linux,
-  i386_num_regs,
-  i386_regmap,
-  i386_cannot_fetch_register,
-  i386_cannot_store_register,
-  i386_get_pc,
-  i386_set_pc,
-  i386_breakpoint,
-  i386_breakpoint_len,
-  NULL,
-  1,
-  i386_breakpoint_at,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-};
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 46969b7..d7fd141 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -19,6 +19,9 @@
 
 #include "server.h"
 #include "linux-low.h"
+#include "ansidecl.h" /* For ATTRIBUTE_PACKED, must be bug in external.h.  */
+#include "elf/common.h"
+#include "elf/external.h"
 
 #include <sys/wait.h>
 #include <stdio.h>
@@ -154,6 +157,68 @@ static int linux_event_pipe[2] = { -1, -1 };
 static void send_sigstop (struct inferior_list_entry *entry);
 static void wait_for_sigstop (struct inferior_list_entry *entry);
 
+/* Accepts an integer PID; Returns a string representing a file that
+   can be opened to get info for the child process.
+   Space for the result is malloc'd, caller must free.  */
+
+char *
+linux_child_pid_to_exec_file (int pid)
+{
+  char *name1, *name2;
+
+  name1 = xmalloc (MAXPATHLEN);
+  name2 = xmalloc (MAXPATHLEN);
+  memset (name2, 0, MAXPATHLEN);
+
+  sprintf (name1, "/proc/%d/exe", pid);
+  if (readlink (name1, name2, MAXPATHLEN) > 0)
+    {
+      free (name1);
+      return name2;
+    }
+  else
+    {
+      free (name2);
+      return name1;
+    }
+}
+
+/* Return non-zero if HEADER is a 64-bit ELF file.  */
+
+static int
+elf_64_header_p (const Elf64_External_Ehdr *header)
+{
+  return (header->e_ident[EI_MAG0] == ELFMAG0
+          && header->e_ident[EI_MAG1] == ELFMAG1
+          && header->e_ident[EI_MAG2] == ELFMAG2
+          && header->e_ident[EI_MAG3] == ELFMAG3
+          && header->e_ident[EI_CLASS] == ELFCLASS64);
+}
+
+/* Return non-zero if FILE is a 64-bit ELF file,
+   zero if the file is not a 64-bit ELF file,
+   and -1 if the file is not accessible or doesn't exist.  */
+
+int
+elf_64_file_p (const char *file)
+{
+  Elf64_External_Ehdr header;
+  int fd;
+
+  fd = open (file, O_RDONLY);
+  if (fd < 0)
+    return -1;
+
+  if (read (fd, &header, sizeof (header)) != sizeof (header))
+    {
+      close (fd);
+      return 0;
+    }
+  close (fd);
+
+  return elf_64_header_p (&header);
+}
+
 static void
 delete_lwp (struct lwp_info *lwp)
 {
@@ -2458,6 +2523,8 @@ linux_test_for_tracefork (void)
 
   linux_supports_tracefork_flag = 0;
 
+  return;
+
   /* Use CLONE_VM instead of fork, to support uClinux (no MMU).  */
 #ifdef __ia64__
   child_pid = __clone2 (linux_tracefork_child, stack, STACK_SIZE,
@@ -2786,12 +2853,35 @@ linux_qxfer_osdata (const char *annex,
   return len;
 }
 
+/* Convert a native/host siginfo object, into/from the siginfo in the
+   layout of the inferiors' architecture.  */
+
+static void
+siginfo_fixup (struct siginfo *siginfo, void *inf_siginfo, int direction)
+{
+  int done = 0;
+
+  if (the_low_target.siginfo_fixup != NULL)
+    done = the_low_target.siginfo_fixup (siginfo, inf_siginfo, direction);
+
+  /* If there was no callback, or the callback didn't do anything,
+     then just do a straight memcpy.  */
+  if (!done)
+    {
+      if (direction == 1)
+	memcpy (siginfo, inf_siginfo, sizeof (struct siginfo));
+      else
+	memcpy (inf_siginfo, siginfo, sizeof (struct siginfo));
+    }
+}
+
 static int
 linux_xfer_siginfo (const char *annex, unsigned char *readbuf,
 		    unsigned const char *writebuf, CORE_ADDR offset, int len)
 {
+  int pid;
   struct siginfo siginfo;
-  long pid = -1;
+  char inf_siginfo[sizeof (struct siginfo)];
 
   if (current_inferior == NULL)
     return -1;
@@ -2799,7 +2889,7 @@ linux_xfer_siginfo (const char *annex, unsigned char *readbuf,
   pid = lwpid_of (get_thread_lwp (current_inferior));
 
   if (debug_threads)
-    fprintf (stderr, "%s siginfo for lwp %ld.\n",
+    fprintf (stderr, "%s siginfo for lwp %d.\n",
 	     readbuf != NULL ? "Reading" : "Writing",
 	     pid);
 
@@ -2809,14 +2899,24 @@ linux_xfer_siginfo (const char *annex, unsigned char *readbuf,
   if (ptrace (PTRACE_GETSIGINFO, pid, 0, &siginfo) != 0)
     return -1;
 
+  /* When GDBSERVER is built as a 64-bit application, ptrace writes into
+     SIGINFO an object with 64-bit layout.  Since debugging a 32-bit
+     inferior with a 64-bit GDBSERVER should look the same as debugging it
+     with a 32-bit GDBSERVER, we need to convert it.  */
+  siginfo_fixup (&siginfo, inf_siginfo, 0);
+
   if (offset + len > sizeof (siginfo))
     len = sizeof (siginfo) - offset;
 
   if (readbuf != NULL)
-    memcpy (readbuf, (char *) &siginfo + offset, len);
+    memcpy (readbuf, inf_siginfo + offset, len);
   else
     {
-      memcpy ((char *) &siginfo + offset, writebuf, len);
+      memcpy (inf_siginfo + offset, writebuf, len);
+
+      /* Convert back to ptrace layout before flushing it out.  */
+      siginfo_fixup (&siginfo, inf_siginfo, 1);
+
       if (ptrace (PTRACE_SETSIGINFO, pid, 0, &siginfo) != 0)
 	return -1;
     }
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index fc93a0e..a23945a 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/gdb/gdbserver/linux-low.h
@@ -43,6 +43,8 @@ struct regset_info
 extern struct regset_info target_regsets[];
 #endif
 
+struct siginfo;
+
 struct process_info_private
 {
   /* True if this process has loaded thread_db, and it is active.  */
@@ -75,7 +77,6 @@ struct linux_target_ops
   int breakpoint_len;
   CORE_ADDR (*breakpoint_reinsert_addr) (void);
 
-
   int decr_pc_after_break;
   int (*breakpoint_at) (CORE_ADDR pc);
 
@@ -89,6 +90,12 @@ struct linux_target_ops
      for registers smaller than an xfer unit).  */
   void (*collect_ptrace_register) (int regno, char *buf);
   void (*supply_ptrace_register) (int regno, const char *buf);
+
+  /* Hook to convert from target format to ptrace format and back.
+     Returns true if any conversion was done; false otherwise.
+     If DIRECTION is 1, then copy from INF to NATIVE.
+     If DIRECTION is 0, copy from NATIVE to INF.  */
+  int (*siginfo_fixup) (struct siginfo *native, void *inf, int direction);
 };
 
 extern struct linux_target_ops the_low_target;
@@ -169,6 +176,9 @@ struct lwp_info
 
 extern struct inferior_list all_lwps;
 
+char *linux_child_pid_to_exec_file (int pid);
+int elf_64_file_p (const char *file);
+
 void linux_attach_lwp (unsigned long pid);
 
 int thread_db_init (int use_events);
diff --git a/gdb/gdbserver/linux-x86-64-low.c b/gdb/gdbserver/linux-x86-64-low.c
deleted file mode 100644
index e61daff..0000000
--- a/gdb/gdbserver/linux-x86-64-low.c
+++ /dev/null
@@ -1,184 +0,0 @@
-/* GNU/Linux/x86-64 specific low level interface, for the remote server
-   for GDB.
-   Copyright (C) 2002, 2004, 2005, 2006, 2007, 2008, 2009
-   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 "i387-fp.h"
-
-#include "gdb_proc_service.h"
-
-/* Defined in auto-generated file reg-x86-64-linux.c.  */
-void init_registers_x86_64_linux (void);
-
-#include <sys/reg.h>
-#include <sys/procfs.h>
-#include <sys/ptrace.h>
-
-/* This definition comes from prctl.h, but some kernels may not have it.  */
-#ifndef PTRACE_ARCH_PRCTL
-#define PTRACE_ARCH_PRCTL      30
-#endif
-
-/* The following definitions come from prctl.h, but may be absent
-   for certain configurations.  */
-#ifndef ARCH_GET_FS
-#define ARCH_SET_GS 0x1001
-#define ARCH_SET_FS 0x1002
-#define ARCH_GET_FS 0x1003
-#define ARCH_GET_GS 0x1004
-#endif
-
-static int x86_64_regmap[] = {
-  RAX * 8, RBX * 8, RCX * 8, RDX * 8,
-  RSI * 8, RDI * 8, RBP * 8, RSP * 8,
-  R8 * 8, R9 * 8, R10 * 8, R11 * 8,
-  R12 * 8, R13 * 8, R14 * 8, R15 * 8,
-  RIP * 8, EFLAGS * 8, CS * 8, SS * 8,
-  DS * 8, ES * 8, FS * 8, GS * 8,
-  -1, -1, -1, -1, -1, -1, -1, -1,
-  -1, -1, -1, -1, -1, -1, -1, -1,
-  -1, -1, -1, -1, -1, -1, -1, -1,
-  -1, -1, -1, -1, -1, -1, -1, -1, -1,
-  ORIG_RAX * 8
-};
-
-#define X86_64_NUM_GREGS (sizeof(x86_64_regmap)/sizeof(int))
-
-/* Called by libthread_db.  */
-
-ps_err_e
-ps_get_thread_area (const struct ps_prochandle *ph,
-		    lwpid_t lwpid, int idx, void **base)
-{
-  switch (idx)
-    {
-    case FS:
-      if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_FS) == 0)
-	return PS_OK;
-      break;
-    case GS:
-      if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_GS) == 0)
-	return PS_OK;
-      break;
-    default:
-      return PS_BADADDR;
-    }
-  return PS_ERR;
-}
-
-static void
-x86_64_fill_gregset (void *buf)
-{
-  int i;
-
-  for (i = 0; i < X86_64_NUM_GREGS; i++)
-    if (x86_64_regmap[i] != -1)
-      collect_register (i, ((char *) buf) + x86_64_regmap[i]);
-}
-
-static void
-x86_64_store_gregset (const void *buf)
-{
-  int i;
-
-  for (i = 0; i < X86_64_NUM_GREGS; i++)
-    if (x86_64_regmap[i] != -1)
-      supply_register (i, ((char *) buf) + x86_64_regmap[i]);
-}
-
-static void
-x86_64_fill_fpregset (void *buf)
-{
-  i387_cache_to_fxsave (buf);
-}
-
-static void
-x86_64_store_fpregset (const void *buf)
-{
-  i387_fxsave_to_cache (buf);
-}
-
-struct regset_info target_regsets[] = {
-  { PTRACE_GETREGS, PTRACE_SETREGS, sizeof (elf_gregset_t),
-    GENERAL_REGS,
-    x86_64_fill_gregset, x86_64_store_gregset },
-  { PTRACE_GETFPREGS, PTRACE_SETFPREGS, sizeof (elf_fpregset_t),
-    FP_REGS,
-    x86_64_fill_fpregset, x86_64_store_fpregset },
-  { 0, 0, -1, -1, NULL, NULL }
-};
-
-static const unsigned char x86_64_breakpoint[] = { 0xCC };
-#define x86_64_breakpoint_len 1
-
-extern int debug_threads;
-
-static CORE_ADDR
-x86_64_get_pc ()
-{
-  unsigned long pc;
-
-  collect_register_by_name ("rip", &pc);
-
-  if (debug_threads)
-    fprintf (stderr, "stop pc (before any decrement) is %08lx\n", pc);
-  return pc;
-}
-
-static void
-x86_64_set_pc (CORE_ADDR newpc)
-{
-  if (debug_threads)
-    fprintf (stderr, "set pc to %08lx\n", (long) newpc);
-  supply_register_by_name ("rip", &newpc);
-}
-
-static int
-x86_64_breakpoint_at (CORE_ADDR pc)
-{
-  unsigned char c;
-
-  read_inferior_memory (pc, &c, 1);
-  if (c == 0xCC)
-    return 1;
-
-  return 0;
-}
-
-struct linux_target_ops the_low_target = {
-  init_registers_x86_64_linux,
-  -1,
-  NULL,
-  NULL,
-  NULL,
-  x86_64_get_pc,
-  x86_64_set_pc,
-  x86_64_breakpoint,
-  x86_64_breakpoint_len,
-  NULL,
-  1,
-  x86_64_breakpoint_at,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
-};
diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
new file mode 100644
index 0000000..ffb70dc
--- /dev/null
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -0,0 +1,644 @@
+/* GNU/Linux/x86-64 specific low level interface, for the remote server
+   for GDB.
+   Copyright (C) 2002, 2004, 2005, 2006, 2007, 2008, 2009
+   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 <assert.h>
+#include <signal.h>
+#include "server.h"
+#include "linux-low.h"
+#include "i387-fp.h"
+
+#include "gdb_proc_service.h"
+
+/* NOTE: gdb_proc_service.h may include linux/elf.h.
+   We need Elf32_Phdr.  If we don't get linux/elf.h we could include
+   elf.h like linux-ppc-low.c does.  */
+
+/* Defined in auto-generated file reg-i386-linux.c.  */
+void init_registers_i386_linux (void);
+/* Defined in auto-generated file reg-x86-64-linux.c.  */
+void init_registers_x86_64_linux (void);
+
+#include <sys/reg.h>
+#include <sys/procfs.h>
+#include <sys/ptrace.h>
+
+#ifndef PTRACE_GET_THREAD_AREA
+#define PTRACE_GET_THREAD_AREA 25
+#endif
+
+/* This definition comes from prctl.h, but some kernels may not have it.  */
+#ifndef PTRACE_ARCH_PRCTL
+#define PTRACE_ARCH_PRCTL      30
+#endif
+
+/* The following definitions come from prctl.h, but may be absent
+   for certain configurations.  */
+#ifndef ARCH_GET_FS
+#define ARCH_SET_GS 0x1001
+#define ARCH_SET_FS 0x1002
+#define ARCH_GET_FS 0x1003
+#define ARCH_GET_GS 0x1004
+#endif
+
+#ifdef __x86_64__
+
+/* Mapping between the general-purpose registers in `struct user'
+   format and GDB's register array layout.
+   Note that the transfer layout uses 64-bit regs.  */
+static /*const*/ int i386_regmap[] = 
+{
+  RAX * 8, RCX * 8, RDX * 8, RBX * 8,
+  RSP * 8, RBP * 8, RSI * 8, RDI * 8,
+  RIP * 8, EFLAGS * 8, CS * 8, SS * 8,
+  DS * 8, ES * 8, FS * 8, GS * 8
+};
+
+#define I386_NUM_REGS (sizeof (i386_regmap) / sizeof (i386_regmap[0]))
+
+/* So code below doesn't have to care, i386 or amd64.  */
+#define ORIG_EAX ORIG_RAX
+
+static const int x86_64_regmap[] =
+{
+  RAX * 8, RBX * 8, RCX * 8, RDX * 8,
+  RSI * 8, RDI * 8, RBP * 8, RSP * 8,
+  R8 * 8, R9 * 8, R10 * 8, R11 * 8,
+  R12 * 8, R13 * 8, R14 * 8, R15 * 8,
+  RIP * 8, EFLAGS * 8, CS * 8, SS * 8,
+  DS * 8, ES * 8, FS * 8, GS * 8,
+  -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  ORIG_RAX * 8
+};
+
+#define X86_64_NUM_REGS (sizeof (x86_64_regmap) / sizeof (x86_64_regmap[0]))
+
+#else /* ! __x86_64__ */
+
+/* Mapping between the general-purpose registers in `struct user'
+   format and GDB's register array layout.  */
+static /*const*/ int i386_regmap[] = 
+{
+  EAX * 4, ECX * 4, EDX * 4, EBX * 4,
+  UESP * 4, EBP * 4, ESI * 4, EDI * 4,
+  EIP * 4, EFL * 4, CS * 4, SS * 4,
+  DS * 4, ES * 4, FS * 4, GS * 4
+};
+
+#define I386_NUM_REGS (sizeof (i386_regmap) / sizeof (i386_regmap[0]))
+
+#endif
+
+/* Called by libthread_db.  */
+
+ps_err_e
+ps_get_thread_area (const struct ps_prochandle *ph,
+		    lwpid_t lwpid, int idx, void **base)
+{
+#ifdef __x86_64__
+  int use_64bit = register_size (0) == 8;
+
+  if (use_64bit)
+    {
+      switch (idx)
+	{
+	case FS:
+	  if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_FS) == 0)
+	    return PS_OK;
+	  break;
+	case GS:
+	  if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_GS) == 0)
+	    return PS_OK;
+	  break;
+	default:
+	  return PS_BADADDR;
+	}
+      return PS_ERR;
+    }
+#endif
+
+  {
+    unsigned int desc[4];
+
+    if (ptrace (PTRACE_GET_THREAD_AREA, lwpid,
+		(void *) (intptr_t) idx, (unsigned long) &desc) < 0)
+      return PS_ERR;
+
+    *(int *)base = desc[1];
+    return PS_OK;
+  }
+}
+
+static int
+i386_cannot_store_register (int regno)
+{
+  return regno >= I386_NUM_REGS;
+}
+
+static int
+i386_cannot_fetch_register (int regno)
+{
+  return regno >= I386_NUM_REGS;
+}
+
+static void
+x86_fill_gregset (void *buf)
+{
+  int i;
+
+#ifdef __x86_64__
+  if (register_size (0) == 8)
+    {
+      for (i = 0; i < X86_64_NUM_REGS; i++)
+	if (x86_64_regmap[i] != -1)
+	  collect_register (i, ((char *) buf) + x86_64_regmap[i]);
+      return;
+    }
+#endif
+
+  for (i = 0; i < I386_NUM_REGS; i++)
+    collect_register (i, ((char *) buf) + i386_regmap[i]);
+
+  collect_register_by_name ("orig_eax", ((char *) buf) + ORIG_EAX * 4);
+}
+
+static void
+x86_store_gregset (const void *buf)
+{
+  int i;
+
+#ifdef __x86_64__
+  if (register_size (0) == 8)
+    {
+      for (i = 0; i < X86_64_NUM_REGS; i++)
+	if (x86_64_regmap[i] != -1)
+	  supply_register (i, ((char *) buf) + x86_64_regmap[i]);
+      return;
+    }
+#endif
+
+  for (i = 0; i < I386_NUM_REGS; i++)
+    supply_register (i, ((char *) buf) + i386_regmap[i]);
+
+  supply_register_by_name ("orig_eax", ((char *) buf) + ORIG_EAX * 4);
+}
+
+static void
+x86_fill_fpregset (void *buf)
+{
+#ifdef __x86_64__
+  i387_cache_to_fxsave (buf);
+#else
+  i387_cache_to_fsave (buf);
+#endif
+}
+
+static void
+x86_store_fpregset (const void *buf)
+{
+#ifdef __x86_64__
+  i387_fxsave_to_cache (buf);
+#else
+  i387_fsave_to_cache (buf);
+#endif
+}
+
+#ifndef __x86_64__
+
+static void
+x86_fill_fpxregset (void *buf)
+{
+  i387_cache_to_fxsave (buf);
+}
+
+static void
+x86_store_fpxregset (const void *buf)
+{
+  i387_fxsave_to_cache (buf);
+}
+
+#endif
+
+/* ??? The non-biarch i386 case stores all the i387 regs twice.
+   Once in i387_.*fsave.* and once in i387_.*fxsave.*.
+   This is, presumably, to handle the case where PTRACE_[GS]ETFPXREGS
+   doesn't work.  IWBN to avoid the duplication in the case where it
+   does work.  Maybe the arch_setup routine could check whether it works
+   and update target_regsets accordingly, maybe by moving target_regsets
+   to linux_target_ops and set the right one there, rather than having to
+   modify the target_regsets global.  */
+
+struct regset_info target_regsets[] =
+{
+#ifdef HAVE_PTRACE_GETREGS
+  { PTRACE_GETREGS, PTRACE_SETREGS, sizeof (elf_gregset_t),
+    GENERAL_REGS,
+    x86_fill_gregset, x86_store_gregset },
+# ifndef __x86_64__
+#  ifdef HAVE_PTRACE_GETFPXREGS
+  { PTRACE_GETFPXREGS, PTRACE_SETFPXREGS, sizeof (elf_fpxregset_t),
+    EXTENDED_REGS,
+    x86_fill_fpxregset, x86_store_fpxregset },
+#  endif
+# endif
+  { PTRACE_GETFPREGS, PTRACE_SETFPREGS, sizeof (elf_fpregset_t),
+    FP_REGS,
+    x86_fill_fpregset, x86_store_fpregset },
+#endif /* HAVE_PTRACE_GETREGS */
+  { 0, 0, -1, -1, NULL, NULL }
+};
+
+static CORE_ADDR
+x86_get_pc (void)
+{
+  int use_64bit = register_size (0) == 8;
+
+  if (use_64bit)
+    {
+      unsigned long pc;
+      collect_register_by_name ("rip", &pc);
+      return (CORE_ADDR) pc;
+    }
+  else
+    {
+      unsigned int pc;
+      collect_register_by_name ("eip", &pc);
+      return (CORE_ADDR) pc;
+    }
+}
+
+static void
+x86_set_pc (CORE_ADDR pc)
+{
+  int use_64bit = register_size (0) == 8;
+
+  if (use_64bit)
+    {
+      unsigned long newpc = pc;
+      supply_register_by_name ("rip", &newpc);
+    }
+  else
+    {
+      unsigned int newpc = pc;
+      supply_register_by_name ("eip", &newpc);
+    }
+}
+
+static const unsigned char x86_breakpoint[] = { 0xCC };
+#define x86_breakpoint_len 1
+
+static int
+x86_breakpoint_at (CORE_ADDR pc)
+{
+  unsigned char c;
+
+  read_inferior_memory (pc, &c, 1);
+  if (c == 0xCC)
+    return 1;
+
+  return 0;
+}
+
+/* When GDBSERVER is built as a 64-bit application on linux, the
+   PTRACE_GETSIGINFO data is always presented in 64-bit layout.  Since
+   debugging a 32-bit inferior with a 64-bit GDBSERVER should look the same
+   as debugging it with a 32-bit GDBSERVER, we do the 32-bit <-> 64-bit
+   conversion in-place ourselves.  */
+
+/* These types below (compat_*) define a siginfo type that is layout
+   compatible with the siginfo type exported by the 32-bit userspace
+   support.  */
+
+#ifdef __x86_64__
+
+typedef int compat_int_t;
+typedef unsigned int compat_uptr_t;
+
+typedef int compat_time_t;
+typedef int compat_timer_t;
+typedef int compat_clock_t;
+
+struct compat_timeval
+{
+  compat_time_t tv_sec;
+  int tv_usec;
+};
+
+typedef union compat_sigval
+{
+  compat_int_t sival_int;
+  compat_uptr_t sival_ptr;
+} compat_sigval_t;
+
+typedef struct compat_siginfo
+{
+  int si_signo;
+  int si_errno;
+  int si_code;
+
+  union
+  {
+    int _pad[((128 / sizeof (int)) - 3)];
+
+    /* kill() */
+    struct
+    {
+      unsigned int _pid;
+      unsigned int _uid;
+    } _kill;
+
+    /* POSIX.1b timers */
+    struct
+    {
+      compat_timer_t _tid;
+      int _overrun;
+      compat_sigval_t _sigval;
+    } _timer;
+
+    /* POSIX.1b signals */
+    struct
+    {
+      unsigned int _pid;
+      unsigned int _uid;
+      compat_sigval_t _sigval;
+    } _rt;
+
+    /* SIGCHLD */
+    struct
+    {
+      unsigned int _pid;
+      unsigned int _uid;
+      int _status;
+      compat_clock_t _utime;
+      compat_clock_t _stime;
+    } _sigchld;
+
+    /* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
+    struct
+    {
+      unsigned int _addr;
+    } _sigfault;
+
+    /* SIGPOLL */
+    struct
+    {
+      int _band;
+      int _fd;
+    } _sigpoll;
+  } _sifields;
+} compat_siginfo_t;
+
+#define cpt_si_pid _sifields._kill._pid
+#define cpt_si_uid _sifields._kill._uid
+#define cpt_si_timerid _sifields._timer._tid
+#define cpt_si_overrun _sifields._timer._overrun
+#define cpt_si_status _sifields._sigchld._status
+#define cpt_si_utime _sifields._sigchld._utime
+#define cpt_si_stime _sifields._sigchld._stime
+#define cpt_si_ptr _sifields._rt._sigval.sival_ptr
+#define cpt_si_addr _sifields._sigfault._addr
+#define cpt_si_band _sifields._sigpoll._band
+#define cpt_si_fd _sifields._sigpoll._fd
+
+/* glibc at least up to 2.3.2 doesn't have si_timerid, si_overrun.
+   In their place is si_timer1,si_timer2.  */
+#ifndef si_timerid
+#define si_timerid si_timer1
+#endif
+#ifndef si_overrun
+#define si_overrun si_timer2
+#endif
+
+static void
+compat_siginfo_from_siginfo (compat_siginfo_t *to, siginfo_t *from)
+{
+  memset (to, 0, sizeof (*to));
+
+  to->si_signo = from->si_signo;
+  to->si_errno = from->si_errno;
+  to->si_code = from->si_code;
+
+  if (to->si_code < 0)
+    {
+      to->cpt_si_ptr = (intptr_t) from->si_ptr;
+    }
+  else if (to->si_code == SI_USER)
+    {
+      to->cpt_si_pid = from->si_pid;
+      to->cpt_si_uid = from->si_uid;
+    }
+  else if (to->si_code == SI_TIMER)
+    {
+      to->cpt_si_timerid = from->si_timerid;
+      to->cpt_si_overrun = from->si_overrun;
+      to->cpt_si_ptr = (intptr_t) from->si_ptr;
+    }
+  else
+    {
+      switch (to->si_signo)
+	{
+	case SIGCHLD:
+	  to->cpt_si_pid = from->si_pid;
+	  to->cpt_si_uid = from->si_uid;
+	  to->cpt_si_status = from->si_status;
+	  to->cpt_si_utime = from->si_utime;
+	  to->cpt_si_stime = from->si_stime;
+	  break;
+	case SIGILL:
+	case SIGFPE:
+	case SIGSEGV:
+	case SIGBUS:
+	  to->cpt_si_addr = (intptr_t) from->si_addr;
+	  break;
+	case SIGPOLL:
+	  to->cpt_si_band = from->si_band;
+	  to->cpt_si_fd = from->si_fd;
+	  break;
+	default:
+	  to->cpt_si_pid = from->si_pid;
+	  to->cpt_si_uid = from->si_uid;
+	  to->cpt_si_ptr = (intptr_t) from->si_ptr;
+	  break;
+	}
+    }
+}
+
+static void
+siginfo_from_compat_siginfo (siginfo_t *to, compat_siginfo_t *from)
+{
+  memset (to, 0, sizeof (*to));
+
+  to->si_signo = from->si_signo;
+  to->si_errno = from->si_errno;
+  to->si_code = from->si_code;
+
+  if (to->si_code < 0)
+    {
+      to->si_ptr = (void *) (intptr_t) from->cpt_si_ptr;
+    }
+  else if (to->si_code == SI_USER)
+    {
+      to->si_pid = from->cpt_si_pid;
+      to->si_uid = from->cpt_si_uid;
+    }
+  else if (to->si_code == SI_TIMER)
+    {
+      to->si_timerid = from->cpt_si_timerid;
+      to->si_overrun = from->cpt_si_overrun;
+      to->si_ptr = (void *) (intptr_t) from->cpt_si_ptr;
+    }
+  else
+    {
+      switch (to->si_signo)
+	{
+	case SIGCHLD:
+	  to->si_pid = from->cpt_si_pid;
+	  to->si_uid = from->cpt_si_uid;
+	  to->si_status = from->cpt_si_status;
+	  to->si_utime = from->cpt_si_utime;
+	  to->si_stime = from->cpt_si_stime;
+	  break;
+	case SIGILL:
+	case SIGFPE:
+	case SIGSEGV:
+	case SIGBUS:
+	  to->si_addr = (void *) (intptr_t) from->cpt_si_addr;
+	  break;
+	case SIGPOLL:
+	  to->si_band = from->cpt_si_band;
+	  to->si_fd = from->cpt_si_fd;
+	  break;
+	default:
+	  to->si_pid = from->cpt_si_pid;
+	  to->si_uid = from->cpt_si_uid;
+	  to->si_ptr = (void* ) (intptr_t) from->cpt_si_ptr;
+	  break;
+	}
+    }
+}
+
+#endif /* __x86_64__ */
+
+/* Convert a native/host siginfo object, into/from the siginfo in the
+   layout of the inferiors' architecture.  Returns true if any
+   conversion was done; false otherwise.  If DIRECTION is 1, then copy
+   from INF to NATIVE.  If DIRECTION is 0, copy from NATIVE to
+   INF.  */
+
+static int
+x86_siginfo_fixup (struct siginfo *native, void *inf, int direction)
+{
+#ifdef __x86_64__
+  /* Is the inferior 32-bit?  If so, then fixup the siginfo object.  */
+  if (register_size (0) == 4)
+    {
+      assert (sizeof (struct siginfo) == sizeof (compat_siginfo_t));
+
+      if (direction == 0)
+	compat_siginfo_from_siginfo ((struct compat_siginfo *) inf, native);
+      else
+	siginfo_from_compat_siginfo (native, (struct compat_siginfo *) inf);
+
+      return 1;
+    }
+#endif
+
+  return 0;
+}
+
+/* Return non-zero if the target is 64-bit.  */
+
+static void
+x86_arch_setup (void)
+{
+#ifdef __x86_64__
+  int pid = pid_of (get_thread_lwp (current_inferior));
+  char *file = linux_child_pid_to_exec_file (pid);
+  int use_64bit = elf_64_file_p (file);
+
+  free (file);
+
+  if (use_64bit < 0)
+    {
+      /* This can only happen if /proc/<pid>/exe is unreadable,
+	 but "that can't happen" if we've gotten this far.
+	 Fall through and assume this is a 32-bit program.  */
+    }
+  else if (use_64bit)
+    {
+      init_registers_x86_64_linux ();
+
+      /* Amd64 doesn't have HAVE_LINUX_USRREGS.  */
+      the_low_target.num_regs = -1;
+      the_low_target.regmap = NULL;
+      the_low_target.cannot_fetch_register = NULL;
+      the_low_target.cannot_store_register = NULL;
+
+      /* Amd64 has 16 xmm regs.  */
+      num_xmm_registers = 16;
+
+      return;
+    }
+#endif
+
+  /* Ok we have a 32-bit inferior.  */
+
+  init_registers_i386_linux ();
+
+  the_low_target.num_regs = I386_NUM_REGS;
+  the_low_target.regmap = i386_regmap;
+  the_low_target.cannot_fetch_register = i386_cannot_fetch_register;
+  the_low_target.cannot_store_register = i386_cannot_store_register;
+
+  /* I386 has 8 xmm regs.  */
+  num_xmm_registers = 8;
+}
+
+/* This is initialized assuming an amd64 target.
+   x86_arch_setup will correct it for i386 or amd64 targets.  */
+
+struct linux_target_ops the_low_target =
+{
+  x86_arch_setup,
+  -1,
+  NULL,
+  NULL,
+  NULL,
+  x86_get_pc,
+  x86_set_pc,
+  x86_breakpoint,
+  x86_breakpoint_len,
+  NULL,
+  1,
+  x86_breakpoint_at,
+  NULL,
+  NULL,
+  NULL,
+  NULL,
+  /* collect_ptrace_register/supply_ptrace_register are not needed in the
+     native i386 case (no registers smaller than an xfer unit), and are not
+     used in the biarch case (HAVE_LINUX_USRREGS is not defined).  */
+  NULL,
+  NULL,
+  /* need to fix up i386 siginfo if host is amd64 */
+  x86_siginfo_fixup,
+};