diff --git a/libc/platform/bionic/tls.h b/libc/platform/bionic/tls.h
new file mode 100644
index 0000000..ca39020
--- /dev/null
+++ b/libc/platform/bionic/tls.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2008 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 __get_tls() ({ void** __val; __asm__("mrs %0, tpidr_el0" : "=r"(__val)); __val; })
+#elif defined(__arm__)
+# define __get_tls() ({ void** __val; __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__val)); __val; })
+#elif defined(__mips__)
+# define __get_tls() \
+    /* On mips32r1, this goes via a kernel illegal instruction trap that's optimized for v1. */ \
+    ({ register void** __val asm("v1"); \
+       __asm__(".set    push\n" \
+               ".set    mips32r2\n" \
+               "rdhwr   %0,$29\n" \
+               ".set    pop\n" : "=r"(__val)); \
+       __val; })
+#elif defined(__i386__)
+# define __get_tls() ({ void** __val; __asm__("movl %%gs:0, %0" : "=r"(__val)); __val; })
+#elif defined(__x86_64__)
+# define __get_tls() ({ void** __val; __asm__("mov %%fs:0, %0" : "=r"(__val)); __val; })
+#else
+#error unsupported architecture
+#endif
+
+#include "tls_defines.h"