lib/cbfs: deserialize cbfs_stage objects correctly

cbfstool emits cbfs_stage objects in little endian encoding.
However, big endian targets then read the wrong values from
these objects. To maintain backwards compatibility with existing
cbfs objects add in the little endian deserialization.

Change-Id: Ia113f7ddfa93f0ba5a76e0397f06f9b84c833727
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46227
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Marty E. Plummer <hanetzer@startmail.com>
diff --git a/src/lib/cbfs.c b/src/lib/cbfs.c
index cb66f81..35193d0 100644
--- a/src/lib/cbfs.c
+++ b/src/lib/cbfs.c
@@ -4,8 +4,8 @@
 #include <boot_device.h>
 #include <cbfs.h>
 #include <commonlib/bsd/compression.h>
+#include <commonlib/endian.h>
 #include <console/console.h>
-#include <endian.h>
 #include <fmap.h>
 #include <lib.h>
 #include <security/tpm/tspi/crtm.h>
@@ -296,10 +296,16 @@
 	foffset = 0;
 	foffset += sizeof(stage);
 
+	/* cbfs_stage fields are written in little endian despite the other
+	   cbfs data types being encoded in big endian. */
+	stage.compression = read_le32(&stage.compression);
+	stage.entry = read_le64(&stage.entry);
+	stage.load = read_le64(&stage.load);
+	stage.len = read_le32(&stage.len);
+	stage.memlen = read_le32(&stage.memlen);
+
 	assert(fsize == stage.len);
 
-	/* Note: cbfs_stage fields are currently in the endianness of the
-	 * running processor. */
 	load = (void *)(uintptr_t)stage.load;
 	entry = (void *)(uintptr_t)stage.entry;