1 files changed, 76 insertions, 0 deletions
diff --git a/backends/ppc64_unwind.c b/backends/ppc64_unwind.c
new file mode 100644
index 00000000..4fa0b5a9
--- /dev/null
+++ b/backends/ppc64_unwind.c
@@ -0,0 +1,76 @@
+/* Get previous frame state for an existing frame state.
+   Copyright (C) 2017 Red Hat, Inc.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * 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
+
+   or both in parallel, as here.
+
+   elfutils 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 copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#define BACKEND ppc64_
+
+#define LR_REG 65 /* Not 108, see ppc_dwarf_to_regno.  */
+#define SP_REG  1
+
+#define LR_OFFSET 16
+
+#include "libebl_CPU.h"
+
+/* Simplistic fallback frame unwinder. SP points to the backchain (contains
+   address of previous stack pointer). At SP offset 16 is the LR save area
+   (contains the value of the previous LR).  */
+
+bool
+EBLHOOK(unwind) (Ebl *ebl __attribute__ ((unused)),
+		 Dwarf_Addr pc __attribute__ ((unused)),
+                 ebl_tid_registers_t *setfunc, ebl_tid_registers_get_t *getfunc,
+                 ebl_pid_memory_read_t *readfunc, void *arg,
+                 bool *signal_framep __attribute__ ((unused)))
+{
+  Dwarf_Word sp, newSp, lr, newLr;
+
+  /* Stack pointer points to the backchain which contains the previous sp.  */
+  if (! getfunc (SP_REG, 1, &sp, arg))
+    sp = 0;
+
+  /* Link register contains previous program counter.  */
+  if (! getfunc (LR_REG, 1, &lr, arg)
+      || lr == 0
+      || ! setfunc (-1, 1, &lr, arg))
+    return false;
+
+  if (! readfunc(sp, &newSp, arg))
+    newSp = 0;
+
+  if (! readfunc(newSp + LR_OFFSET, &newLr, arg))
+    newLr = 0;
+
+  setfunc(SP_REG, 1, &newSp, arg);
+  setfunc(LR_REG, 1, &newLr, arg);
+
+  /* Sanity check the stack grows down.  */
+  return newSp > sp;
+}