isb after the reg_tcr_el1_write in pmap_md_xtab_activate when enabling

non-kernel translation table walk.

Fixes GENERIC64_PMAPMI boot on Apple silicon.

Author: skrll

sys/arch/aarch64/aarch64/pmap_machdep.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: pmap_machdep.c,v 1.6 2023/04/20 08:28:02 skrll Exp $	*/
+/*	$NetBSD: pmap_machdep.c,v 1.7 2026/01/22 06:56:40 skrll Exp $	*/
 
 /*-
  * Copyright (c) 2022 The NetBSD Foundation, Inc.
@@ -37,7 +37,7 @@
 #define __PMAP_PRIVATE
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap_machdep.c,v 1.6 2023/04/20 08:28:02 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap_machdep.c,v 1.7 2026/01/22 06:56:40 skrll Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -549,6 +549,7 @@ pmap_md_xtab_activate(pmap_t pm, struct lwp *l)
 
 	if (pm != pmap_kernel()) {
 		reg_tcr_el1_write(old_tcrel1 & ~TCR_EPD0);
+		isb();
 	}
 
 	UVMHIST_LOG(maphist, " pm %#jx pm->pm_l0 %016jx pm->pm_l0_pa %016jx asid %ju... done",