1 /* 2 * Copyright (C) 2018 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 #include <private/bionic_asm.h> 30 31 // For arm32 and -mtp=soft, the compiler uses this function to read the thread 32 // pointer for ELF TLS accesses. With -mtp=cp15, the compiler inlines the call 33 // instead. GCC defaults to -mtp=auto, which inlines this function with 34 // -march=armv7-a. Clang does not yet implement -mtp=auto, and instead defaults 35 // to -mtp=soft. 36 // - https://bugs.llvm.org/show_bug.cgi?id=38394. 37 // - https://reviews.llvm.org/D34878?id=114573. 38 // 39 // This function must preserve every register except r0, ip, lr, and cpsr. 40 // 41 // See "Run-time ABI for the ARM Architecture" 42 // http://infocenter.arm.com/help/topic/com.arm.doc.ihi0043d/IHI0043D_rtabi.pdf 43 // 44 ENTRY(__aeabi_read_tp) 45 // __get_tls() 46 mrc p15, 0, r0, c13, c0, 3 47 bx lr 48 END(__aeabi_read_tp) 49
