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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 | #ifndef _SYS_TLS_H | |
29 | #define _SYS_TLS_H | |
30 | ||
31 | #include <sys/cdefs.h> | |
32 | ||
33 | __BEGIN_DECLS | |
34 | ||
35 | /** WARNING WARNING WARNING | |
36 | ** | |
37 | ** This header file is *NOT* part of the public Bionic ABI/API | |
38 | ** and should not be used/included by user-serviceable parts of | |
39 | ** the system (e.g. applications). | |
40 | ** | |
41 | ** It is only provided here for the benefit of the system dynamic | |
42 | ** linker and the OpenGL sub-system (which needs to access the | |
43 | ** pre-allocated slot directly for performance reason). | |
44 | **/ | |
45 | ||
46 | /* maximum number of elements in the TLS array */ | |
47 | #define BIONIC_TLS_SLOTS 64 | |
48 | ||
49 | /* note that slot 0, called TLS_SLOT_SELF must point to itself. | |
50 | * this is required to implement thread-local storage with the x86 | |
51 | * Linux kernel, that reads the TLS from fs:[0], where 'fs' is a | |
52 | * thread-specific segment descriptor... | |
53 | */ | |
54 | ||
55 | /* Well known TLS slots */ | |
56 | #define TLS_SLOT_SELF 0 | |
57 | #define TLS_SLOT_THREAD_ID 1 | |
58 | #define TLS_SLOT_ERRNO 2 | |
59 | ||
60 | #define TLS_SLOT_OPENGL_API 3 | |
61 | #define TLS_SLOT_OPENGL 4 | |
62 | ||
63 | /* this slot is only used to pass information from the dynamic linker to | |
64 | * libc.so when the C library is loaded in to memory. The C runtime init | |
65 | * function will then clear it. Since its use is extremely temporary, | |
66 | * we reuse an existing location. | |
67 | */ | |
68 | #define TLS_SLOT_BIONIC_PREINIT (TLS_SLOT_ERRNO+1) | |
69 | ||
70 | /* small technical note: it is not possible to call pthread_setspecific | |
71 | * on keys that are <= TLS_SLOT_MAX_WELL_KNOWN, which is why it is set to | |
72 | * TLS_SLOT_ERRNO. | |
73 | * | |
74 | * later slots like TLS_SLOT_OPENGL are pre-allocated through the use of | |
75 | * TLS_DEFAULT_ALLOC_MAP. this means that there is no need to use | |
76 | * pthread_key_create() to initialize them. on the other hand, there is | |
77 | * no destructor associated to them (we might need to implement this later) | |
78 | */ | |
79 | #define TLS_SLOT_MAX_WELL_KNOWN TLS_SLOT_ERRNO | |
80 | ||
81 | #define TLS_DEFAULT_ALLOC_MAP 0x0000001F | |
82 | ||
83 | /* set the Thread Local Storage, must contain at least BIONIC_TLS_SLOTS pointers */ | |
84 | extern void __init_tls(void** tls, void* thread_info); | |
85 | ||
86 | /* syscall only, do not call directly */ | |
87 | extern int __set_tls(void *ptr); | |
88 | ||
89 | /* get the TLS */ | |
90 | #ifdef __arm__ | |
91 | /* The standard way to get the TLS is to call a kernel helper | |
92 | * function (i.e. a function provided at a fixed address in a | |
93 | * "magic page" mapped in all user-space address spaces ), which | |
94 | * contains the most appropriate code path for the target device. | |
95 | * | |
96 | * However, for performance reasons, we're going to use our own | |
97 | * machine code for the system's C shared library. | |
98 | * | |
99 | * We cannot use this optimization in the static version of the | |
100 | * C library, because we don't know where the corresponding code | |
101 | * is going to run. | |
102 | */ | |
103 | # ifdef LIBC_STATIC | |
104 | ||
105 | /* Use the kernel helper in static C library. */ | |
106 | typedef volatile void* (__kernel_get_tls_t)(void); | |
107 | # define __get_tls() (*(__kernel_get_tls_t *)0xffff0fe0)() | |
108 | ||
109 | # else /* !LIBC_STATIC */ | |
110 | /* Use optimized code path. | |
111 | * Note that HAVE_ARM_TLS_REGISTER is build-specific | |
112 | * (it must match your kernel configuration) | |
113 | */ | |
114 | # ifdef HAVE_ARM_TLS_REGISTER | |
115 | /* We can read the address directly from a coprocessor | |
116 | * register, which avoids touching the data cache | |
117 | * completely. | |
118 | */ | |
119 | # define __get_tls() \ | |
120 | ({ register unsigned int __val asm("r0"); \ | |
121 | asm ("mrc p15, 0, r0, c13, c0, 3" : "=r"(__val) ); \ | |
122 | (volatile void*)__val; }) | |
123 | # else /* !HAVE_ARM_TLS_REGISTER */ | |
124 | /* The kernel provides the address of the TLS at a fixed | |
125 | * address of the magic page too. | |
126 | */ | |
127 | # define __get_tls() ( *((volatile void **) 0xffff0ff0) ) | |
128 | # endif | |
129 | # endif /* !LIBC_STATIC */ | |
130 | #else /* !ARM */ | |
131 | extern void* __get_tls( void ); | |
132 | #endif /* !ARM */ | |
133 | ||
134 | /* return the stack base and size, used by our malloc debugger */ | |
135 | extern void* __get_stack_base(int *p_stack_size); | |
136 | ||
137 | __END_DECLS | |
138 | ||
139 | #endif /* _SYS_TLS_H */ |