[RFC PATCH v1 1/5] unwind_user: Enable arch-specific signal frame unwinders

@@ -67,7 +67,8 @@ static inline int unwind_user_get_reg(unsigned long *val, unsigned int regnum)
 		.offset		= -2*(ws),		\
 			},				\
 	.sp_off		= 0,				\
-	.outermost	= false,
+	.outermost	= false,			\
+	.signal		= false,
 
 #define ARCH_INIT_USER_FP_ENTRY_FRAME(ws)		\
 	.cfa		= {				\

@@ -82,7 +83,8 @@ static inline int unwind_user_get_reg(unsigned long *val, unsigned int regnum)
 		.rule		= UNWIND_USER_RULE_RETAIN,\
 			},				\
 	.sp_off		= 0,				\
-	.outermost	= false,
+	.outermost	= false,			\
+	.signal		= false,
 
 static inline int unwind_user_fp_get_frame(struct unwind_user_state *state,
 					   struct unwind_user_frame *frame)

@@ -34,6 +34,15 @@ static inline int unwind_user_get_reg(unsigned long *val, unsigned int regnum)
 #define unwind_user_get_reg unwind_user_get_reg
 #endif
 
+#ifndef unwind_user_signal_next
+static inline int unwind_user_signal_next(struct unwind_user_state *state)
+{
+	WARN_ON_ONCE(1);
+	return -EINVAL;
+}
+#define unwind_user_signal_next unwind_user_signal_next
+#endif
+
 int unwind_user(struct unwind_stacktrace *trace, unsigned int max_entries);
 
 #endif /* _LINUX_UNWIND_USER_H */

@@ -68,6 +68,7 @@ struct unwind_user_frame {
 	struct unwind_user_rule_data fp;
 	s32 sp_off;
 	bool outermost;
+	bool signal;
 };
 
 struct unwind_user_state {

@@ -32,6 +32,10 @@ static int unwind_user_next_common(struct unwind_user_state *state,
 {
 	unsigned long cfa, sp, fp, ra;
 
+	/* Use signal frame unwinder for signal frames. */
+	if (frame->signal)
+		return unwind_user_signal_next(state);
+
 	/* Stop unwinding when reaching an outermost frame. */
 	if (frame->outermost) {
 		state->done = true;