Re: GDB m68k debug multi-thread application fails: capability not available [PATCH 1/2] gdb-6.6-m68k-pthread.patch

[lars71dk]

Add the ps_get_thread_area function to m68k to provide debugging of
programs linked to libpthread. The code was copied from the MIPS
implementations in gdb and gdbserver.

diff -ur gdb-6.6.orig/gdb/gdbserver/linux-m68k-low.c 
gdb-6.6/gdb/gdbserver/linux-m68k-low.c
--- /home/davidw/tmp/gdb-6.6.orig/gdb/gdbserver/linux-m68k-low.c        
2011-06-23 09:09:53.977584261 -0500
+++ gdb-6.6/gdb/gdbserver/linux-m68k-low.c      2011-06-23 09:44:41.434490495 
-0500
@@ -153,6 +153,26 @@
   return 0;
 }
 
+#include <asm/ptrace.h>
+#include "gdb_proc_service.h"
+
+/* 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 = (void *) ((char *)*base - idx);
+
+  return PS_OK;
+}
+
 struct linux_target_ops the_low_target = {
   m68k_num_regs,
   m68k_regmap,
diff -ur gdb-6.6.orig/gdb/m68klinux-nat.c gdb-6.6/gdb/m68klinux-nat.c
--- /home/davidw/tmp/gdb-6.6.orig/gdb/m68klinux-nat.c   2011-06-23 
09:09:54.167562142 -0500
+++ gdb-6.6/gdb/m68klinux-nat.c 2011-06-23 09:41:10.319081266 -0500
@@ -67,6 +67,26 @@
   45, 46, 47
 };
 
+#include <asm/ptrace.h>
+#include "gdb_proc_service.h"
+
+/* 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 = (void *) ((char *)*base - idx);
+
+  return PS_OK;
+}
+
 /* Which ptrace request retrieves which registers?
    These apply to the corresponding SET requests as well.  */
 #define NUM_GREGS (18)