1/* 2 * Copyright (C) 2014 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// gdb is able to unwind through signal frames with just the regular 32// CFI information but libgcc and libunwind both need extra help. We do this 33// by using .fnstart/.fnend and inserting a nop before both __restore and 34// __restore_rt (but covered by the .fnstart/.fnend) so that although they're 35// not inside the functions from objdump's point of view, an unwinder that 36// just assumes it should look at the previous instruction (but is then smart 37// enough to check the unwind information to find out where it landed) gets 38// the right answer. 39// Make sure not to have both DWARF and ARM unwind information, so only 40// use the ARM unwind information. 41 42// We need to place .fnstart ourselves (but we may as well keep the free .fnend). 43#undef __bionic_asm_custom_entry 44#define __bionic_asm_custom_entry(f) 45 46 .fnstart 47 .save {r0-r15} 48 .pad #32 49 nop 50ENTRY_NO_DWARF_PRIVATE(__restore) 51 // This function must have exactly this instruction sequence. 52 mov r7, #__NR_sigreturn 53 swi #0 54END_NO_DWARF(__restore) 55 56 .fnstart 57 .save {r0-r15} 58 .pad #160 59 nop 60ENTRY_NO_DWARF_PRIVATE(__restore_rt) 61 // This function must have exactly this instruction sequence. 62 mov r7, #__NR_rt_sigreturn 63 swi #0 64END_NO_DWARF(__restore_rt) 65