3 files changed, 36 insertions, 0 deletions
diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h
index c0171804016..b7d9822fd6c 100644
--- a/arch/sh/include/asm/bug.h
+++ b/arch/sh/include/asm/bug.h
@@ -1,6 +1,7 @@
 #ifndef __ASM_SH_BUG_H
 #define __ASM_SH_BUG_H
 
+#define TRAPA_UNWINDER_BUG_OPCODE 0xc33b /* trapa #0x3b */
 #define TRAPA_BUG_OPCODE	0xc33e	/* trapa #0x3e */
 
 #ifdef CONFIG_GENERIC_BUG
@@ -72,6 +73,30 @@ do {							\
 	unlikely(__ret_warn_on);				\
 })
 
+#define UNWINDER_BUG()						\
+do {							\
+	__asm__ __volatile__ (				\
+		"1:\t.short %O0\n"			\
+		_EMIT_BUG_ENTRY		\
+		 :					\
+		 : "n" (TRAPA_UNWINDER_BUG_OPCODE),	\
+		   "i" (__FILE__),			\
+		   "i" (__LINE__), "i" (0),		\
+		   "i" (sizeof(struct bug_entry)));	\
+} while (0)
+
+#define UNWINDER_BUG_ON(x) ({					\
+	int __ret_unwinder_on = !!(x);				\
+	if (__builtin_constant_p(__ret_unwinder_on)) {		\
+		if (__ret_unwinder_on)				\
+			UNWINDER_BUG();				\
+	} else {						\
+		if (unlikely(__ret_unwinder_on))		\
+			UNWINDER_BUG();				\
+	}							\
+	unlikely(__ret_unwinder_on);				\
+})
+
 #endif /* CONFIG_GENERIC_BUG */
 
 #include <asm-generic/bug.h>
diff --git a/arch/sh/include/asm/system.h b/arch/sh/include/asm/system.h
index ab79e1f4fbe..f9e2ceb94d9 100644
--- a/arch/sh/include/asm/system.h
+++ b/arch/sh/include/asm/system.h
@@ -181,6 +181,11 @@ BUILD_TRAP_HANDLER(breakpoint);
 BUILD_TRAP_HANDLER(singlestep);
 BUILD_TRAP_HANDLER(fpu_error);
 BUILD_TRAP_HANDLER(fpu_state_restore);
+BUILD_TRAP_HANDLER(unwinder);
+
+#ifdef CONFIG_BUG
+extern void handle_BUG(struct pt_regs *);
+#endif
 
 #define arch_align_stack(x) (x)
 
diff --git a/arch/sh/include/asm/unwinder.h b/arch/sh/include/asm/unwinder.h
index 3dc551453e2..1e65c07b3e1 100644
--- a/arch/sh/include/asm/unwinder.h
+++ b/arch/sh/include/asm/unwinder.h
@@ -22,4 +22,10 @@ extern void stack_reader_dump(struct task_struct *, struct pt_regs *,
 			      unsigned long *, const struct stacktrace_ops *,
 			      void *);
 
+/*
+ * Used by fault handling code to signal to the unwinder code that it
+ * should switch to a different unwinder.
+ */
+extern int unwinder_faulted;
+
 #endif /* _LINUX_UNWINDER_H */