From bc394ad824f5f09b9ab659c445ed83ef36e7c313 Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Mon, 11 Dec 2023 09:08:08 -0500
Subject: [PATCH] arm: Fix handling of undefined instructions in kernel mode

Only panic if no undefined instruction handler matched the exception.
This can arise in practice if the VFP is enabled lazily.

While here, fix the panic string to not include a newline.

Reviewed by:	andrew
Obtained from:	Stormshield
Sponsored by:	Klara, Inc.
Sponsored by:	Stormshield
Differential Revision:	https://reviews.freebsd.org/D42970

(cherry picked from commit ecc2e6deae71b69a30bf3b7e3354aba002a37d69)
---
 sys/arm/arm/undefined.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sys/arm/arm/undefined.c b/sys/arm/arm/undefined.c
index 2ebe8797c50..7f93cc231fe 100644
--- a/sys/arm/arm/undefined.c
+++ b/sys/arm/arm/undefined.c
@@ -343,11 +343,11 @@ undefinedinstruction(struct trapframe *frame)
 #else
 			printf("No debugger in kernel.\n");
 #endif
-			return;
-		}
-		else
-			panic("Undefined instruction in kernel (0x%08x).\n",
+		} else if (uh == NULL) {
+			panic("Undefined instruction in kernel (0x%08x)",
 			    fault_instruction);
+		}
+		return;
 	}
 
 	userret(td, frame);