/* * 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);