* alpha-linux-tdep.c: New file. Move alpha_linux_sigtramp_offset

to here...
* alpha-tdep.c: ...from here.
* config/alpha/alpha-linux.mt (TDEPFILES): Add alpha-linux-tdep.o.

1 files changed, 98 insertions, 0 deletions

diff --git a/gdb/alpha-linux-tdep.c b/gdb/alpha-linux-tdep.c
new file mode 100644
index 0000000..cb4e9c7
--- /dev/null
+++ b/gdb/alpha-linux-tdep.c
@@ -0,0 +1,98 @@
+/* Target-dependent code for GNU/Linux on Alpha.
+   Copyright 2002 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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "value.h"
+
+#include "alpha-tdep.h"
+
+/* Under GNU/Linux, signal handler invocations can be identified by the
+   designated code sequence that is used to return from a signal
+   handler.  In particular, the return address of a signal handler
+   points to the following sequence (the first instruction is quadword
+   aligned):
+  
+   bis $30,$30,$16
+   addq $31,0x67,$0
+   call_pal callsys 
+      
+   Each instruction has a unique encoding, so we simply attempt to
+   match the instruction the pc is pointing to with any of the above
+   instructions.  If there is a hit, we know the offset to the start
+   of the designated sequence and can then check whether we really are
+   executing in a designated sequence.  If not, -1 is returned,
+   otherwise the offset from the start of the desingated sequence is
+   returned.
+   
+   There is a slight chance of false hits: code could jump into the
+   middle of the designated sequence, in which case there is no
+   guarantee that we are in the middle of a sigreturn syscall.  Don't
+   think this will be a problem in praxis, though.  */
+long
+alpha_linux_sigtramp_offset (CORE_ADDR pc)
+{
+  unsigned int i[3], w;
+  long off;
+
+  if (read_memory_nobpt (pc, (char *) &w, 4) != 0)
+    return -1;
+
+  off = -1;
+  switch (w)
+    {
+    case 0x47de0410:
+      off = 0;
+      break;			/* bis $30,$30,$16 */
+    case 0x43ecf400:
+      off = 4;
+      break;			/* addq $31,0x67,$0 */
+    case 0x00000083:
+      off = 8;
+      break;			/* call_pal callsys */
+    default:
+      return -1;
+    }
+  pc -= off;
+  if (pc & 0x7)
+    {
+      /* designated sequence is not quadword aligned */
+      return -1;
+    }
+  if (read_memory_nobpt (pc, (char *) i, sizeof (i)) != 0)
+    return -1;
+
+  if (i[0] == 0x47de0410 && i[1] == 0x43ecf400 && i[2] == 0x00000083)
+    return off;
+
+  return -1;
+}
+
+static void
+alpha_linux_init_abi (struct gdbarch_info info,
+                      struct gdbarch *gdbarch)
+{
+  /* Place holder. */
+}
+
+void
+_initialize_alpha_linux_tdep (void)
+{
+  alpha_gdbarch_register_os_abi (ALPHA_ABI_LINUX, alpha_linux_init_abi);
+}