2012-03-08  Andreas Schwab  <schwab@linux-m68k.org>

       * m68klinux-nat.c: Include "gdb_proc_service.h".
       (PTRACE_GET_THREAD_AREA): Define.
       (ps_get_thread_area): New function.

Index: gdb-7.4.1/gdb/m68klinux-nat.c
===================================================================
--- gdb-7.4.1.orig/gdb/m68klinux-nat.c	2012-01-06 04:43:19.000000000 +0000
+++ gdb-7.4.1/gdb/m68klinux-nat.c	2012-09-19 22:19:06.000000000 +0000
@@ -51,7 +51,14 @@
 
 /* Prototypes for supply_gregset etc.  */
 #include "gregset.h"
-
+
+/* Defines ps_err_e, struct ps_prochandle.  */
+#include "gdb_proc_service.h"
+
+#ifndef PTRACE_GET_THREAD_AREA
+#define PTRACE_GET_THREAD_AREA 25
+#endif
+
 /* This table must line up with gdbarch_register_name in "m68k-tdep.c".  */
 static const int regmap[] =
 {
@@ -556,6 +563,24 @@
 }
 
 
+/* Fetch the thread-local storage pointer for libthread_db.  */
+
+ps_err_e
+ps_get_thread_area (const struct ps_prochandle *ph,
+                  lwpid_t lwpid, int idx, void **base)
+{
+  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 = (char *) *base - idx;
+
+  return PS_OK;
+}
+
+
 /* Register that we are able to handle GNU/Linux ELF core file
    formats.  */