Use DYNAMIC entries for MTE enablement
Adds support for the dynamic entries to specify MTE enablement. This is
now the preferred way for dynamically linked executables to specify to
the loader what mode MTE should be in, and whether stack MTE should be
enabled. In future, this is also needed for MTE globals support.
Leave the existing ELF note parsing as a backup option because dynamic
entries are not supported for fully static executables, and there's
still a bunch of glue sitting around in the build system and tests that
explicitly include the note. When -fsanitize=memtag* is specified, lld
will create the note implicitly (along with the new dynamic entries),
but at some point once we've cleaned up all the old references to the
note, we can remove the notegen from lld.
Bug: N/A
Test: atest bionic-unit-tests CtsBionicTestCases --test-filter=*Memtag*
Test: Build/boot the device under _fullmte.
Change-Id: I954b7e78afa5ff4274a3948b968cfad8eba94d88
diff --git a/libc/private/bionic_globals.h b/libc/private/bionic_globals.h
index 510d556..d9c4234 100644
--- a/libc/private/bionic_globals.h
+++ b/libc/private/bionic_globals.h
@@ -66,6 +66,15 @@
MallocDispatch malloc_dispatch_table;
};
+struct memtag_dynamic_entries_t {
+ void* memtag_globals;
+ size_t memtag_globalssz;
+ bool has_memtag_mode;
+ unsigned memtag_mode;
+ bool memtag_heap;
+ bool memtag_stack;
+};
+
#ifdef __aarch64__
static_assert(OFFSETOF_libc_globals_memtag_stack == offsetof(libc_globals, memtag_stack));
#endif