[efi] Ensure that all drivers are shut down before the OS boots

Reported-by: Itay Gazit <itayg@mellanox.co.il>
Suggested-by: Michael R Turner <mikeyt@us.ibm.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/src/interface/efi/efi_init.c b/src/interface/efi/efi_init.c
index 029bc06f..6c7b4955 100644
--- a/src/interface/efi/efi_init.c
+++ b/src/interface/efi/efi_init.c
@@ -22,6 +22,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/Protocol/LoadedImage.h>
 #include <ipxe/uuid.h>
+#include <ipxe/init.h>
 
 /** Image handle passed to entry point */
 EFI_HANDLE efi_image_handle;
@@ -36,6 +37,21 @@ EFI_SYSTEM_TABLE *efi_systab;
 static EFI_GUID efi_loaded_image_protocol_guid
 	= EFI_LOADED_IMAGE_PROTOCOL_GUID;
 
+/** Event used to signal shutdown */
+static EFI_EVENT efi_shutdown_event;
+
+/**
+ * Shut down in preparation for booting an OS.
+ *
+ * This hook gets called at ExitBootServices time in order to make
+ * sure that everything is properly shut down before the OS takes
+ * over.
+ */
+static EFIAPI void efi_shutdown_hook ( EFI_EVENT event __unused,
+				       void *context __unused ) {
+	shutdown_boot();
+}
+
 /**
  * Look up EFI configuration table
  *
@@ -129,5 +145,18 @@ EFI_STATUS efi_init ( EFI_HANDLE image_handle,
 		}
 	}
 
+	/* EFI is perfectly capable of gracefully shutting down any
+	 * loaded devices if it decides to fall back to a legacy boot.
+	 * For no particularly comprehensible reason, it doesn't
+	 * bother doing so when ExitBootServices() is called.
+	 */
+	if ( ( efirc = bs->CreateEvent ( EVT_SIGNAL_EXIT_BOOT_SERVICES,
+					 TPL_CALLBACK, efi_shutdown_hook,
+					 NULL, &efi_shutdown_event ) ) != 0 ) {
+		DBGC ( systab, "EFI could not create ExitBootServices event: "
+		       "%s\n", efi_strerror ( efirc ) );
+		return efirc;
+	}
+
 	return 0;
 }