efi: Correct address handling with ACPI tables

The current EFI implementation confuses pointers and addresses. Normally
we can get away with this but in the case of sandbox it causes failures.

Despite the fact that efi_allocate_pages() returns a u64, it is actually
a pointer, not an address. Add special handling to avoid a crash when
running 'bootefi hello'.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/efi_loader/efi_acpi.c b/lib/efi_loader/efi_acpi.c
index f2b55b4..2ddc350 100644
--- a/lib/efi_loader/efi_acpi.c
+++ b/lib/efi_loader/efi_acpi.c
@@ -8,6 +8,7 @@
 #include <common.h>
 #include <efi_loader.h>
 #include <log.h>
+#include <mapmem.h>
 #include <acpi/acpi_table.h>
 
 static const efi_guid_t acpi_guid = EFI_ACPI_TABLE_GUID;
@@ -22,6 +23,7 @@
 	/* Map within the low 32 bits, to allow for 32bit ACPI tables */
 	u64 acpi = U32_MAX;
 	efi_status_t ret;
+	ulong addr;
 
 	/* Reserve 64kiB page for ACPI */
 	ret = efi_allocate_pages(EFI_ALLOCATE_MAX_ADDRESS,
@@ -34,7 +36,8 @@
 	 * a 4k-aligned address, so it is safe to assume that
 	 * write_acpi_tables() will write the table at that address.
 	 */
-	write_acpi_tables((ulong)acpi);
+	addr = map_to_sysmem((void *)(ulong)acpi);
+	write_acpi_tables(addr);
 
 	/* And expose them to our EFI payload */
 	return efi_install_configuration_table(&acpi_guid,