sh: BUG() handling through trapa vector.
Previously we haven't been doing anything with verbose BUG() reporting,
and we've been relying on the oops path for handling BUG()'s, which is
rather sub-optimal.
This switches BUG handling to use a fixed trapa vector (#0x3e) where we
construct a small bug frame post trapa instruction to get the context
right. This also makes it trivial to wire up a DIE_BUG for the atomic
die chain, which we couldn't really do before.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/asm-sh/bug.h b/include/asm-sh/bug.h
index 1b4fc52..2f89dd0 100644
--- a/include/asm-sh/bug.h
+++ b/include/asm-sh/bug.h
@@ -1,19 +1,54 @@
#ifndef __ASM_SH_BUG_H
#define __ASM_SH_BUG_H
-
#ifdef CONFIG_BUG
-/*
- * Tell the user there is some problem.
- */
-#define BUG() do { \
- printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); \
- *(volatile int *)0 = 0; \
+
+struct bug_frame {
+ unsigned short opcode;
+ unsigned short line;
+ const char *file;
+ const char *func;
+};
+
+struct pt_regs;
+
+extern void handle_BUG(struct pt_regs *);
+
+#define TRAPA_BUG_OPCODE 0xc33e /* trapa #0x3e */
+
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+
+#define BUG() \
+do { \
+ __asm__ __volatile__ ( \
+ ".align 2\n\t" \
+ ".short %O0\n\t" \
+ ".short %O1\n\t" \
+ ".long %O2\n\t" \
+ ".long %O3\n\t" \
+ : \
+ : "n" (TRAPA_BUG_OPCODE), \
+ "i" (__LINE__), "X" (__FILE__), \
+ "X" (__FUNCTION__)); \
} while (0)
+#else
+
+#define BUG() \
+do { \
+ __asm__ __volatile__ ( \
+ ".align 2\n\t" \
+ ".short %O0\n\t" \
+ : \
+ : "n" (TRAPA_BUG_OPCODE)); \
+} while (0)
+
+#endif /* CONFIG_DEBUG_BUGVERBOSE */
+
#define HAVE_ARCH_BUG
-#endif
+
+#endif /* CONFIG_BUG */
#include <asm-generic/bug.h>
-#endif
+#endif /* __ASM_SH_BUG_H */