efi_loader: Add runtime services

After booting has finished, EFI allows firmware to still interact with the OS
using the "runtime services". These callbacks live in a separate address space,
since they are available long after U-Boot has been overwritten by the OS.

This patch adds enough framework for arbitrary code inside of U-Boot to become
a runtime service with the right section attributes set. For now, we don't make
use of it yet though.

We could maybe in the future map U-boot environment variables to EFI variables
here.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index e60fae9..87400de 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -39,7 +39,7 @@
  * In most cases we want to pass an FDT to the payload, so reserve one slot of
  * config table space for it. The pointer gets populated by do_bootefi_exec().
  */
-static struct efi_configuration_table efi_conf_table[1];
+static struct efi_configuration_table EFI_RUNTIME_DATA efi_conf_table[1];
 
 /*
  * The "gd" pointer lives in a register on ARM and AArch64 that we declare
@@ -761,10 +761,10 @@
 };
 
 
-static uint16_t firmware_vendor[] =
+static uint16_t EFI_RUNTIME_DATA firmware_vendor[] =
 	{ 'D','a','s',' ','U','-','b','o','o','t',0 };
 
-struct efi_system_table systab = {
+struct efi_system_table EFI_RUNTIME_DATA systab = {
 	.hdr = {
 		.signature = EFI_SYSTEM_TABLE_SIGNATURE,
 		.revision = 0x20005, /* 2.5 */