diff --git a/libc/arch-arm/arm.mk b/libc/arch-arm/arm.mk index fbde87cef..b1edfccf3 100644 --- a/libc/arch-arm/arm.mk +++ b/libc/arch-arm/arm.mk @@ -55,7 +55,6 @@ libc_bionic_src_files_arm += \ arch-arm/bionic/_exit_with_stack_teardown.S \ arch-arm/bionic/libgcc_compat.c \ arch-arm/bionic/memcmp.S \ - arch-arm/bionic/__restore_rt.S \ arch-arm/bionic/__restore.S \ arch-arm/bionic/_setjmp.S \ arch-arm/bionic/setjmp.S \ diff --git a/libc/arch-arm/bionic/__restore.S b/libc/arch-arm/bionic/__restore.S index e76628e16..98981256b 100644 --- a/libc/arch-arm/bionic/__restore.S +++ b/libc/arch-arm/bionic/__restore.S @@ -28,8 +28,34 @@ #include -// This function must have exactly this instruction sequence for gdb and libunwind. +// gdb is smart enough to unwind through signal frames with just the regular +// CFI information but libgcc and libunwind both need extra help. We do this +// by using .fnstart/.fnend and inserting a nop before both __restore and +// __restore_rt (but covered by the .fnstart/.fnend) so that although they're +// not inside the functions from objdump's point of view, an unwinder that +// blindly looks at the previous instruction (but is then smart enough to check +// the DWARF information to find out where it landed) gets the right answer. + +// We need to place .fnstart ourselves (but we may as well keep the free .fnend). +#undef __bionic_asm_custom_entry +#define __bionic_asm_custom_entry(f) + + .fnstart + .save {r0-r15} + .pad #32 + nop ENTRY_PRIVATE(__restore) + // This function must have exactly this instruction sequence. mov r7, #__NR_sigreturn swi #0 END(__restore) + + .fnstart + .save {r0-r15} + .pad #160 + nop +ENTRY_PRIVATE(__restore_rt) + // This function must have exactly this instruction sequence. + mov r7, #__NR_rt_sigreturn + swi #0 +END(__restore_rt) diff --git a/libc/arch-arm/bionic/__restore_rt.S b/libc/arch-arm/bionic/__restore_rt.S deleted file mode 100644 index 5a1fca182..000000000 --- a/libc/arch-arm/bionic/__restore_rt.S +++ /dev/null @@ -1,35 +0,0 @@ -/* - * Copyright (C) 2014 The Android Open Source Project - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * * Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * * Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in - * the documentation and/or other materials provided with the - * distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS - * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE - * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, - * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, - * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS - * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED - * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, - * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT - * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - */ - -#include - -// This function must have exactly this instruction sequence for gdb and libunwind. -ENTRY_PRIVATE(__restore_rt) - mov r7, #__NR_rt_sigreturn - swi #0 -END(__restore_rt)