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 /* Well-known TLS slots. What data goes in which slot is arbitrary unless otherwise noted. */ 47 enum { 48 TLS_SLOT_SELF = 0, /* The kernel requires this specific slot for x86. */ 49 TLS_SLOT_THREAD_ID, 50 TLS_SLOT_ERRNO, 51 52 /* These two aren't used by bionic itself, but allow the graphics code to 53 * access TLS directly rather than using the pthread API. */ 54 TLS_SLOT_OPENGL_API = 3, 55 TLS_SLOT_OPENGL = 4, 56 57 /* This slot is only used to pass information from the dynamic linker to 58 * libc.so when the C library is loaded in to memory. The C runtime init 59 * function will then clear it. Since its use is extremely temporary, 60 * we reuse an existing location that isn't needed during libc startup. */ 61 TLS_SLOT_BIONIC_PREINIT = TLS_SLOT_OPENGL_API, 62 63 TLS_SLOT_STACK_GUARD = 5, /* GCC requires this specific slot for x86. */ 64 TLS_SLOT_DLERROR, 65 66 TLS_SLOT_FIRST_USER_SLOT /* Must come last! */ 67 }; 68 69 /* 70 * Maximum number of elements in the TLS array. 71 * POSIX says this must be at least 128, but Android has traditionally had only 64, minus those 72 * ones used internally by bionic itself. 73 * There are two kinds of slot used internally by bionic --- there are the well-known slots 74 * enumerated above, and then there are those that are allocated during startup by calls to 75 * pthread_key_create; grep for GLOBAL_INIT_THREAD_LOCAL_BUFFER to find those. We need to manually 76 * maintain that second number, but pthread_test will fail if we forget. 77 */ 78 #define GLOBAL_INIT_THREAD_LOCAL_BUFFER_COUNT 4 79 /* 80 * This is PTHREAD_KEYS_MAX + TLS_SLOT_FIRST_USER_SLOT + GLOBAL_INIT_THREAD_LOCAL_BUFFER_COUNT 81 * rounded up to maintain stack alignment. 82 */ 83 #define BIONIC_ALIGN(x, a) (((x) + (a - 1)) & ~(a - 1)) 84 #define BIONIC_TLS_SLOTS BIONIC_ALIGN(128 + TLS_SLOT_FIRST_USER_SLOT + GLOBAL_INIT_THREAD_LOCAL_BUFFER_COUNT, 4) 85 86 /* syscall only, do not call directly */ 87 extern int __set_tls(void* ptr); 88 89 /* get the TLS */ 90 #if defined(__arm__) 91 # define __get_tls() \ 92 ({ register unsigned int __val; \ 93 asm ("mrc p15, 0, %0, c13, c0, 3" : "=r"(__val)); \ 94 (volatile void*) __val; }) 95 #elif defined(__mips__) 96 # define __get_tls() \ 97 /* On mips32r1, this goes via a kernel illegal instruction trap that's optimized for v1. */ \ 98 ({ register unsigned int __val asm("v1"); \ 99 asm (" .set push\n" \ 100 " .set mips32r2\n" \ 101 " rdhwr %0,$29\n" \ 102 " .set pop\n" : "=r"(__val)); \ 103 (volatile void*) __val; }) 104 #elif defined(__i386__) 105 # define __get_tls() \ 106 ({ register void* __val; \ 107 asm ("movl %%gs:0, %0" : "=r"(__val)); \ 108 (volatile void*) __val; }) 109 #else 110 #error unsupported architecture 111 #endif 112 113 __END_DECLS 114 115 #if defined(__cplusplus) 116 struct KernelArgumentBlock; 117 extern __LIBC_HIDDEN__ void __libc_init_tls(KernelArgumentBlock& args); 118 #endif 119 120 #endif /* _SYS_TLS_H */ 121