auto import from //depot/cupcake/@135843
diff --git a/libc/private/bionic_tls.h b/libc/private/bionic_tls.h
new file mode 100644
index 0000000..da34344
--- /dev/null
+++ b/libc/private/bionic_tls.h
@@ -0,0 +1,94 @@
+/*
+ * 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.
+ */
+#ifndef _SYS_TLS_H
+#define _SYS_TLS_H
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
+/** WARNING WARNING WARNING
+ **
+ ** This header file is *NOT* part of the public Bionic ABI/API
+ ** and should not be used/included by user-serviceable parts of
+ ** the system (e.g. applications).
+ **
+ ** It is only provided here for the benefit of the system dynamic
+ ** linker and the OpenGL sub-system (which needs to access the
+ ** pre-allocated slot directly for performance reason).
+ **/
+
+/* maximum number of elements in the TLS array */
+#define BIONIC_TLS_SLOTS 64
+
+/* note that slot 0, called TLS_SLOT_SELF must point to itself.
+ * this is required to implement thread-local storage with the x86
+ * Linux kernel, that reads the TLS from fs:[0], where 'fs' is a
+ * thread-specific segment descriptor...
+ */
+
+/* Well known TLS slots */
+#define TLS_SLOT_SELF 0
+#define TLS_SLOT_THREAD_ID 1
+#define TLS_SLOT_ERRNO 2
+
+#define TLS_SLOT_OPENGL_API 3
+#define TLS_SLOT_OPENGL 4
+
+/* small technical note: it is not possible to call pthread_setspecific
+ * on keys that are <= TLS_SLOT_MAX_WELL_KNOWN, which is why it is set to
+ * TLS_SLOT_ERRNO.
+ *
+ * later slots like TLS_SLOT_OPENGL are pre-allocated through the use of
+ * TLS_DEFAULT_ALLOC_MAP. this means that there is no need to use
+ * pthread_key_create() to initialize them. on the other hand, there is
+ * no destructor associated to them (we might need to implement this later)
+ */
+#define TLS_SLOT_MAX_WELL_KNOWN TLS_SLOT_ERRNO
+
+#define TLS_DEFAULT_ALLOC_MAP 0x0000001F
+
+/* set the Thread Local Storage, must contain at least BIONIC_TLS_SLOTS pointers */
+extern void __init_tls(void** tls, void* thread_info);
+
+/* syscall only, do not call directly */
+extern int __set_tls(void *ptr);
+
+/* get the TLS */
+#ifdef __arm__
+# define __get_tls() ( *((volatile void **) 0xffff0ff0) )
+#else
+extern void* __get_tls( void );
+#endif
+
+/* return the stack base and size, used by our malloc debugger */
+extern void* __get_stack_base(int *p_stack_size);
+
+__END_DECLS
+
+#endif /* _SYS_TLS_H */