[MTE] Add interface to communicate MTE status to bootloader.

We can use this interface to instruct the bootloader to either
permanently or only for the next reboot enable MTE for userspace
or kernel.

Bug: 206895651
Change-Id: I7330e43b7c4f94fc5913a7bc0f667b6eab06e111
diff --git a/bootloader_message/bootloader_message.cpp b/bootloader_message/bootloader_message.cpp
index b70d54e..1ea56cd 100644
--- a/bootloader_message/bootloader_message.cpp
+++ b/bootloader_message/bootloader_message.cpp
@@ -304,6 +304,16 @@
                                        offsetof(misc_system_space_layout, virtual_ab_message), err);
 }
 
+bool ReadMiscMemtagMessage(misc_memtag_message* message, std::string* err) {
+  return ReadMiscPartitionSystemSpace(message, sizeof(*message),
+                                      offsetof(misc_system_space_layout, memtag_message), err);
+}
+
+bool WriteMiscMemtagMessage(const misc_memtag_message& message, std::string* err) {
+  return WriteMiscPartitionSystemSpace(&message, sizeof(message),
+                                       offsetof(misc_system_space_layout, memtag_message), err);
+}
+
 extern "C" bool write_reboot_bootloader(void) {
   std::string err;
   return write_reboot_bootloader(&err);