svn commit: r336919 - head/sys/dev/efidev

[Kyle Evans]

Author: kevans
Date: Mon Jul 30 17:40:27 2018
New Revision: 336919
URL: https://svnweb.freebsd.org/changeset/base/336919

Log:
  efirt: Add tunable to allow disabling EFI Runtime Services
  
  Leading up to enabling EFIRT in GENERIC, allow runtime services to be
  disabled with a new tunable: efi.rt_disabled. This makes it so that EFIRT
  can be disabled easily in case we run into some buggy UEFI implementation
  and fail to boot.
  
  Discussed with:	imp, kib
  MFC after:	1 week

Modified:
  head/sys/dev/efidev/efirt.c

Modified: head/sys/dev/efidev/efirt.c
==============================================================================
--- head/sys/dev/efidev/efirt.c	Mon Jul 30 17:03:15 2018	(r336918)
+++ head/sys/dev/efidev/efirt.c	Mon Jul 30 17:40:27 2018	(r336919)
@@ -133,7 +133,12 @@ efi_init(void)
 	struct efi_md *map;
 	caddr_t kmdp;
 	size_t efisz;
+	int rt_disabled;
 
+	rt_disabled = 0;
+	TUNABLE_INT_FETCH("efi.rt_disabled", &rt_disabled);
+	if (rt_disabled == 1)
+		return (0);
 	mtx_init(&efi_lock, "efi", NULL, MTX_DEF);
 
 	if (efi_systbl_phys == 0) {
@@ -222,6 +227,9 @@ static void
 efi_uninit(void)
 {
 
+	/* Most likely disabled by tunable */
+	if (efi_runtime == NULL)
+		return;
 	efi_destroy_1t1_map();
 
 	efi_systbl = NULL;