Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / sh / kernel / return_address.c

diff --git a/kernel/arch/sh/kernel/return_address.c b/kernel/arch/sh/kernel/return_address.c
new file mode 100644 (file)
index 0000000..5124aeb
--- /dev/null
+++ b/kernel/arch/sh/kernel/return_address.c
@@ -0,0 +1,59 @@
+/*
+ * arch/sh/kernel/return_address.c
+ *
+ * Copyright (C) 2009  Matt Fleming
+ * Copyright (C) 2009  Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <asm/dwarf.h>
+
+#ifdef CONFIG_DWARF_UNWINDER
+
+void *return_address(unsigned int depth)
+{
+       struct dwarf_frame *frame;
+       unsigned long ra;
+       int i;
+
+       for (i = 0, frame = NULL, ra = 0; i <= depth; i++) {
+               struct dwarf_frame *tmp;
+
+               tmp = dwarf_unwind_stack(ra, frame);
+               if (!tmp)
+                       return NULL;
+
+               if (frame)
+                       dwarf_free_frame(frame);
+
+               frame = tmp;
+
+               if (!frame || !frame->return_addr)
+                       break;
+
+               ra = frame->return_addr;
+       }
+
+       /* Failed to unwind the stack to the specified depth. */
+       WARN_ON(i != depth + 1);
+
+       if (frame)
+               dwarf_free_frame(frame);
+
+       return (void *)ra;
+}
+
+#else
+
+void *return_address(unsigned int depth)
+{
+       return NULL;
+}
+
+#endif
+
+EXPORT_SYMBOL_GPL(return_address);