Move memtag_stack out of libc_globals
We cannot use a WriteProtected because we are accessing it in a
multithreaded context.
Test: atest memtag_stack_dlopen_test w/ MTE
Test: atest bionic-unit-tests w/ MTE
Test: atest bionic-unit-tests on _fullmte
Bug: 328256432
Change-Id: I39faa75f97fd5b3fb755a46e88346c17c0e9a8e2
diff --git a/libc/private/bionic_asm_offsets.h b/libc/private/bionic_asm_offsets.h
deleted file mode 100644
index e72adda..0000000
--- a/libc/private/bionic_asm_offsets.h
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * Copyright (C) 2023 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * * Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#pragma once
-
-#if defined(__aarch64__)
-#define OFFSETOF_libc_globals_memtag_stack 64
-#endif
diff --git a/libc/private/bionic_globals.h b/libc/private/bionic_globals.h
index 6f1e389..0949056 100644
--- a/libc/private/bionic_globals.h
+++ b/libc/private/bionic_globals.h
@@ -38,7 +38,6 @@
#include "private/WriteProtected.h"
#include "private/bionic_allocator.h"
-#include "private/bionic_asm_offsets.h"
#include "private/bionic_elf_tls.h"
#include "private/bionic_fdsan.h"
#include "private/bionic_malloc_dispatch.h"
@@ -48,7 +47,6 @@
vdso_entry vdso[VDSO_END];
long setjmp_cookie;
uintptr_t heap_pointer_tag;
- _Atomic(bool) memtag_stack;
_Atomic(bool) decay_time_enabled;
_Atomic(bool) memtag;
@@ -77,11 +75,11 @@
bool memtag_stack;
};
-#ifdef __aarch64__
-static_assert(OFFSETOF_libc_globals_memtag_stack == offsetof(libc_globals, memtag_stack));
-#endif
-
__LIBC_HIDDEN__ extern WriteProtected<libc_globals> __libc_globals;
+// This cannot be in __libc_globals, because we cannot access the
+// WriteProtected in a thread-safe way.
+// See b/328256432.
+__LIBC_HIDDEN__ extern _Atomic(bool) __libc_memtag_stack;
struct abort_msg_t;
struct crash_detail_page_t;