From: kettenis <kettenis@openbsd.org>
Date: Mon, 24 Apr 2023 10:22:48 +0000 (+0000)
Subject: Enable branch target control flow enforcement on arm64.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=88d0d93d60e314d78e0c9ecdbab1a3b845a8baf7;p=openbsd

Enable branch target control flow enforcement on arm64.

ok robert@, deraadt@
---

diff --git a/sys/arch/arm64/arm64/machdep.c b/sys/arch/arm64/arm64/machdep.c
index ff7886b9db7..20ad76d57c6 100644
--- a/sys/arch/arm64/arm64/machdep.c
+++ b/sys/arch/arm64/arm64/machdep.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: machdep.c,v 1.80 2023/03/30 15:09:01 kn Exp $ */
+/* $OpenBSD: machdep.c,v 1.81 2023/04/24 10:22:48 kettenis Exp $ */
 /*
  * Copyright (c) 2014 Patrick Wildt <patrick@blueri.se>
  * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
@@ -454,6 +454,11 @@ setregs(struct proc *p, struct exec_package *pack, u_long stack,
 	struct pcb *pcb = &p->p_addr->u_pcb;
 	struct trapframe *tf = pcb->pcb_tf;
 
+	if (pack->ep_flags & EXEC_NOBTCFI)
+		p->p_vmspace->vm_map.pmap->pm_guarded = 0;
+	else
+		p->p_vmspace->vm_map.pmap->pm_guarded = ATTR_GP;
+
 	/* If we were using the FPU, forget about it. */
 	memset(&pcb->pcb_fpstate, 0, sizeof(pcb->pcb_fpstate));
 	pcb->pcb_flags &= ~PCB_FPU;