auto import from //depot/cupcake/@135843
diff --git a/libc/arch-x86/bionic/__set_tls.c b/libc/arch-x86/bionic/__set_tls.c
new file mode 100755
index 0000000..48b55f0
--- /dev/null
+++ b/libc/arch-x86/bionic/__set_tls.c
@@ -0,0 +1,95 @@
+/*
+ * 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.
+ */
+#include <pthread.h>
+
+
+struct user_desc {
+ unsigned int entry_number;
+ unsigned long base_addr;
+ unsigned int limit;
+ unsigned int seg_32bit:1;
+ unsigned int contents:2;
+ unsigned int read_exec_only:1;
+ unsigned int limit_in_pages:1;
+ unsigned int seg_not_present:1;
+ unsigned int useable:1;
+ unsigned int empty:25;
+};
+
+extern int __set_thread_area(struct user_desc *u_info);
+
+/* the following can't be const, since the first call will
+ * update the 'entry_number' field
+ */
+static struct user_desc _tls_desc =
+{
+ -1,
+ 0,
+ 0x1000,
+ 1,
+ 0,
+ 0,
+ 1,
+ 0,
+ 1,
+ 0
+};
+
+struct _thread_area_head {
+ void *self;
+};
+
+/* we implement thread local storage through the gs: segment descriptor
+ * we create a segment descriptor for the tls
+ */
+int __set_tls(void *ptr)
+{
+ int rc, segment;
+
+ _tls_desc.base_addr = (unsigned long)ptr;
+
+ /* We also need to write the location of the tls to ptr[0] */
+ ((struct _thread_area_head *)ptr)->self = ptr;
+
+ rc = __set_thread_area( &_tls_desc );
+ if (rc != 0)
+ {
+ /* could not set thread local area */
+ return -1;
+ }
+
+ /* this weird computation comes from GLibc */
+ segment = _tls_desc.entry_number*8 + 3;
+ asm __volatile__ (
+ " movw %w0, %%gs" :: "q"(segment)
+ );
+ return 0;
+}
+
+
+