efi_loader: ARM: don't attempt to enter non-secure mode twice

Multiple EFI binaries may be executed in sequence.  So if we already
are in non-secure mode after running the first one we should skip
the switching code since it no longer works once we're non-secure.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

cmd/bootefi.c

@@ -200,6 +200,8 @@ static efi_status_t efi_run_in_el2(EFIAPI efi_status_t (*entry)(
 #endif
 
 #ifdef CONFIG_ARMV7_NONSEC
+static bool is_nonsec;
+
 static efi_status_t efi_run_in_hyp(EFIAPI efi_status_t (*entry)(
 			efi_handle_t image_handle, struct efi_system_table *st),
 			efi_handle_t image_handle, struct efi_system_table *st)
@@ -207,6 +209,8 @@ static efi_status_t efi_run_in_hyp(EFIAPI efi_status_t (*entry)(
 	/* Enable caches again */
 	dcache_enable();
 
+	is_nonsec = true;
+
 	return efi_do_enter(image_handle, st, entry);
 }
 #endif
@@ -368,7 +372,7 @@ static efi_status_t do_bootefi_exec(void *efi,
 #endif
 
 #ifdef CONFIG_ARMV7_NONSEC
-	if (armv7_boot_nonsec()) {
+	if (armv7_boot_nonsec() && !is_nonsec) {
 		dcache_disable();	/* flush cache before switch to HYP */
 
 		armv7_init_nonsec();