[efi] Defer autoboot link-layer address and autoexec script probing

The code to detect the autoboot link-layer address and to load the
autoexec script currently runs before the call to initialise() and so
has to function without a working heap.

This requirement can be relaxed by deferring this code to run via an
initialisation function.  This gives the code a normal runtime
environment, but still invokes it early enough to guarantee that the
original loaded image device handle has not yet been invalidated.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 20 insertions, 6 deletions

diff --git a/src/interface/efi/efiprefix.c b/src/interface/efi/efiprefix.c
index 928f41c7..47fbe79a 100644
--- a/src/interface/efi/efiprefix.c
+++ b/src/interface/efi/efiprefix.c
@@ -22,6 +22,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <stdlib.h>
 #include <errno.h>
 #include <ipxe/device.h>
+#include <ipxe/init.h>
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/efi_driver.h>
 #include <ipxe/efi/efi_snp.h>
@@ -49,12 +50,6 @@ EFI_STATUS EFIAPI _efi_start ( EFI_HANDLE image_handle,
 	if ( ( efirc = efi_init ( image_handle, systab ) ) != 0 )
 		goto err_init;
 
-	/* Identify autoboot device, if any */
-	efi_set_autoboot_ll_addr ( efi_loaded_image->DeviceHandle );
-
-	/* Load autoexec script, if any */
-	efi_autoexec_load ( efi_loaded_image->DeviceHandle );
-
 	/* Claim SNP devices for use by iPXE */
 	efi_snp_claim();
 
@@ -77,6 +72,25 @@ EFI_STATUS EFIAPI _efi_start ( EFI_HANDLE image_handle,
 }
 
 /**
+ * Initialise EFI application
+ *
+ */
+static void efi_init_application ( void ) {
+	EFI_HANDLE device = efi_loaded_image->DeviceHandle;
+
+	/* Identify autoboot device, if any */
+	efi_set_autoboot_ll_addr ( device );
+
+	/* Load autoexec script, if any */
+	efi_autoexec_load ( device );
+}
+
+/** EFI application initialisation function */
+struct init_fn efi_init_application_fn __init_fn ( INIT_NORMAL ) = {
+	.initialise = efi_init_application,
+};
+
+/**
  * Probe EFI root bus
  *
  * @v rootdev		EFI root device