Initial import

1 files changed, 61 insertions, 0 deletions

diff --git a/arch/arm/kernel/return_address.c b/arch/arm/kernel/return_address.c
new file mode 100644
index 000000000..36ed35073
--- /dev/null
+++ b/arch/arm/kernel/return_address.c
@@ -0,0 +1,61 @@
+/*
+ * arch/arm/kernel/return_address.c
+ *
+ * Copyright (C) 2009 Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
+ * for Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+#include <linux/export.h>
+#include <linux/ftrace.h>
+
+#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
+#include <linux/sched.h>
+
+#include <asm/stacktrace.h>
+
+struct return_address_data {
+	unsigned int level;
+	void *addr;
+};
+
+static int save_return_addr(struct stackframe *frame, void *d)
+{
+	struct return_address_data *data = d;
+
+	if (!data->level) {
+		data->addr = (void *)frame->pc;
+
+		return 1;
+	} else {
+		--data->level;
+		return 0;
+	}
+}
+
+void *return_address(unsigned int level)
+{
+	struct return_address_data data;
+	struct stackframe frame;
+
+	data.level = level + 2;
+	data.addr = NULL;
+
+	frame.fp = (unsigned long)__builtin_frame_address(0);
+	frame.sp = current_stack_pointer;
+	frame.lr = (unsigned long)__builtin_return_address(0);
+	frame.pc = (unsigned long)return_address;
+
+	walk_stackframe(&frame, save_return_addr, &data);
+
+	if (!data.level)
+		return data.addr;
+	else
+		return NULL;
+}
+
+#endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */
+
+EXPORT_SYMBOL_GPL(return_address);