tools/bootconfig: Store size and checksum in footer as le32

Store the size and the checksum fields in the footer as le32
instead of u32. This will allow us to apply bootconfig to the
cross build initrd without caring the endianness.

Link: https://lkml.kernel.org/r/160583935332.547349.5897811300636587426.stgit@devnote2

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Author: mhiramat

tools/bootconfig/main.c

@@ -10,6 +10,7 @@
 #include <unistd.h>
 #include <string.h>
 #include <errno.h>
+#include <endian.h>
 
 #include <linux/kernel.h>
 #include <linux/bootconfig.h>
@@ -183,9 +184,11 @@ static int load_xbc_from_initrd(int fd, char **buf)
 
 	if (read(fd, &size, sizeof(u32)) < 0)
 		return pr_errno("Failed to read size", -errno);
+	size = le32toh(size);
 
 	if (read(fd, &csum, sizeof(u32)) < 0)
 		return pr_errno("Failed to read checksum", -errno);
+	csum = le32toh(csum);
 
 	/* Wrong size error  */
 	if (stat.st_size < size + 8 + BOOTCONFIG_MAGIC_LEN) {
@@ -407,10 +410,10 @@ static int apply_xbc(const char *path, const char *xbc_path)
 
 	/* Add a footer */
 	p = data + size;
-	*(u32 *)p = size;
+	*(u32 *)p = htole32(size);
 	p += sizeof(u32);
 
-	*(u32 *)p = csum;
+	*(u32 *)p = htole32(csum);
 	p += sizeof(u32);
 
 	memcpy(p, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN);