1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#ifndef __BIONIC_PRIVATE_BIONIC_TLS_H_
30#define __BIONIC_PRIVATE_BIONIC_TLS_H_
31
32#include <sys/cdefs.h>
33
34#include "bionic_macros.h"
35#include "__get_tls.h"
36
37__BEGIN_DECLS
38
39/** WARNING WARNING WARNING
40 **
41 ** This header file is *NOT* part of the public Bionic ABI/API
42 ** and should not be used/included by user-serviceable parts of
43 ** the system (e.g. applications).
44 **
45 ** It is only provided here for the benefit of the system dynamic
46 ** linker and the OpenGL sub-system (which needs to access the
47 ** pre-allocated slot directly for performance reason).
48 **/
49
50// Well-known TLS slots. What data goes in which slot is arbitrary unless otherwise noted.
51enum {
52  TLS_SLOT_SELF = 0, // The kernel requires this specific slot for x86.
53  TLS_SLOT_THREAD_ID,
54  TLS_SLOT_ERRNO,
55
56  // These two aren't used by bionic itself, but allow the graphics code to
57  // access TLS directly rather than using the pthread API.
58  TLS_SLOT_OPENGL_API = 3,
59  TLS_SLOT_OPENGL = 4,
60
61  // This slot is only used to pass information from the dynamic linker to
62  // libc.so when the C library is loaded in to memory. The C runtime init
63  // function will then clear it. Since its use is extremely temporary,
64  // we reuse an existing location that isn't needed during libc startup.
65  TLS_SLOT_BIONIC_PREINIT = TLS_SLOT_OPENGL_API,
66
67  TLS_SLOT_STACK_GUARD = 5, // GCC requires this specific slot for x86.
68  TLS_SLOT_DLERROR,
69
70  // Fast storage for Thread::Current() in ART.
71  TLS_SLOT_ART_THREAD_SELF,
72
73  // Lets TSAN avoid using pthread_getspecific for finding the current thread
74  // state.
75  TLS_SLOT_TSAN,
76
77  BIONIC_TLS_SLOTS // Must come last!
78};
79
80/*
81 * Bionic uses some pthread keys internally. All pthread keys used internally
82 * should be created in constructors, except for keys that may be used in or
83 * before constructors.
84 *
85 * We need to manually maintain the count of pthread keys used internally, but
86 * pthread_test should fail if we forget.
87 *
88 * These are the pthread keys currently used internally by libc:
89 *
90 *  basename               libc (ThreadLocalBuffer)
91 *  dirname                libc (ThreadLocalBuffer)
92 *  uselocale              libc (can be used in constructors)
93 *  getmntent_mntent       libc (ThreadLocalBuffer)
94 *  getmntent_strings      libc (ThreadLocalBuffer)
95 *  ptsname                libc (ThreadLocalBuffer)
96 *  ttyname                libc (ThreadLocalBuffer)
97 *  strerror               libc (ThreadLocalBuffer)
98 *  strsignal              libc (ThreadLocalBuffer)
99 *  passwd                 libc (ThreadLocalBuffer)
100 *  group                  libc (ThreadLocalBuffer)
101 *  _res_key               libc (constructor in BSD code)
102 */
103
104#define LIBC_PTHREAD_KEY_RESERVED_COUNT 12
105
106/* Internally, jemalloc uses a single key for per thread data. */
107#define JEMALLOC_PTHREAD_KEY_RESERVED_COUNT 1
108#define BIONIC_PTHREAD_KEY_RESERVED_COUNT (LIBC_PTHREAD_KEY_RESERVED_COUNT + JEMALLOC_PTHREAD_KEY_RESERVED_COUNT)
109
110/*
111 * Maximum number of pthread keys allocated.
112 * This includes pthread keys used internally and externally.
113 */
114#define BIONIC_PTHREAD_KEY_COUNT (BIONIC_PTHREAD_KEY_RESERVED_COUNT + PTHREAD_KEYS_MAX)
115
116__END_DECLS
117
118#if defined(__cplusplus)
119class KernelArgumentBlock;
120extern void __libc_init_main_thread(KernelArgumentBlock&);
121#endif
122
123#endif /* __BIONIC_PRIVATE_BIONIC_TLS_H_ */
124