From e793a55a74eb34ae3225d620a9619554667efb30 Mon Sep 17 00:00:00 2001
From: Andrew Turner <andrew@FreeBSD.org>
Date: Tue, 8 Mar 2022 11:02:02 +0000
Subject: [PATCH] Print the instruction for the unknown exception

The arm64 unknown exception will be raised when we execute an
instruction that id invalid or disabled. To help debug these print
the instruction that failed.

Sponsored by:	The FreeBSD Foundation
---
 sys/arm64/arm64/trap.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/arm64/arm64/trap.c b/sys/arm64/arm64/trap.c
index 93167f4d234..fa921e39b84 100644
--- a/sys/arm64/arm64/trap.c
+++ b/sys/arm64/arm64/trap.c
@@ -492,6 +492,8 @@ do_el1h_sync(struct thread *td, struct trapframe *frame)
 	case EXCP_UNKNOWN:
 		if (undef_insn(1, frame))
 			break;
+		printf("Undefined instruction: %08x\n",
+		    *(uint32_t *)frame->tf_elr);
 		/* FALLTHROUGH */
 	default:
 		print_registers(frame);