sh: Use a jump call table for debug trap handlers.

This rips out most of the needlessly complicated sh_bios and kgdb
trap handling, and forces it all through a common fast dispatch path.
As more debug traps are inserted, it's important to keep them in sync
for all of the parts, not just SH-3/4.

As the SH-2 parts are unable to do traps in the >= 0x40 range, we
restrict the debug traps to the 0x30-0x3f range on all parts, and
also bump the kgdb breakpoint trap down in to this range (from 0xff
to 0x3c) so it's possible to use for nommu.

Optionally, this table can be padded out to catch spurious traps for
SH-3/4, but we don't do that yet..

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/arch/sh/kernel/debugtraps.S b/arch/sh/kernel/debugtraps.S
new file mode 100644
index 000000000000..13b66746410a
--- /dev/null
+++ b/arch/sh/kernel/debugtraps.S
@@ -0,0 +1,41 @@
+/*
+ * arch/sh/kernel/debugtraps.S
+ *
+ * Debug trap jump tables for SuperH
+ *
+ *  Copyright (C) 2006  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/sys.h>
+#include <linux/linkage.h>
+
+#if !defined(CONFIG_SH_KGDB)
+#define kgdb_handle_exception   debug_trap_handler
+#endif
+
+#if !defined(CONFIG_SH_STANDARD_BIOS)
+#define sh_bios_handler         debug_trap_handler
+#endif
+
+        .data
+
+ENTRY(debug_trap_table)
+        .long debug_trap_handler        /* 0x30 */
+        .long debug_trap_handler        /* 0x31 */
+        .long debug_trap_handler        /* 0x32 */
+        .long debug_trap_handler        /* 0x33 */
+        .long debug_trap_handler        /* 0x34 */
+        .long debug_trap_handler        /* 0x35 */
+        .long debug_trap_handler        /* 0x36 */
+        .long debug_trap_handler        /* 0x37 */
+        .long debug_trap_handler        /* 0x38 */
+        .long debug_trap_handler        /* 0x39 */
+        .long debug_trap_handler        /* 0x3a */
+        .long debug_trap_handler        /* 0x3b */
+        .long kgdb_handle_exception     /* 0x3c */
+        .long debug_trap_handler        /* 0x3d */
+        .long bug_trap_handler          /* 0x3e */
+        .long sh_bios_handler           /* 0x3f */