[MIPS] Add some debugfs files to debug unaligned accesses

Currently a number of unaligned instructions is counted but not used.
Add /debug/mips/unaligned_instructions file to show the value.

And add /debug/mips/unaligned_action to control behavior upon an
unaligned access.  Possible actions are:

0: silently fixup the unaligned access.
1: send SIGBUS.
2: dump registers, process name, etc. and fixup.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 4975da0..316685f 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -20,6 +20,7 @@
 #include <linux/highmem.h>
 #include <linux/console.h>
 #include <linux/pfn.h>
+#include <linux/debugfs.h>
 
 #include <asm/addrspace.h>
 #include <asm/bootinfo.h>
@@ -574,3 +575,18 @@
 
 unsigned long kernelsp[NR_CPUS];
 unsigned long fw_arg0, fw_arg1, fw_arg2, fw_arg3;
+
+#ifdef CONFIG_DEBUG_FS
+struct dentry *mips_debugfs_dir;
+static int __init debugfs_mips(void)
+{
+	struct dentry *d;
+
+	d = debugfs_create_dir("mips", NULL);
+	if (IS_ERR(d))
+		return PTR_ERR(d);
+	mips_debugfs_dir = d;
+	return 0;
+}
+arch_initcall(debugfs_mips);
+#endif