sh: dwarf unwinder support.

This is a first cut at a generic DWARF unwinder for the kernel. It's
still lacking DWARF64 support and the DWARF expression support hasn't
been tested very well but it is generating proper stacktraces on SH for
WARN_ON() and NULL dereferences.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/vmlinux.lds.h

@@ -0,0 +1,17 @@
+#ifndef __ASM_SH_VMLINUX_LDS_H
+#define __ASM_SH_VMLINUX_LDS_H
+
+#include <asm-generic/vmlinux.lds.h>
+
+#ifdef CONFIG_DWARF_UNWINDER
+#define DWARF_EH_FRAME							\
+	.eh_frame : AT(ADDR(.eh_frame) - LOAD_OFFSET) {			\
+		  VMLINUX_SYMBOL(__start_eh_frame) = .;			\
+		  *(.eh_frame)						\
+		  VMLINUX_SYMBOL(__stop_eh_frame) = .;			\
+	}
+#else
+#define DWARF_EH_FRAME
+#endif
+
+#endif /* __ASM_SH_VMLINUX_LDS_H */