148dff3ec6
gdb was already okay; libgcc and libunwind need a little extra help. Bug: 17436734 Change-Id: I1f5108f9877373be078554a1ea4938aa4436204e
61 lines
2.4 KiB
ArmAsm
61 lines
2.4 KiB
ArmAsm
/*
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* Copyright (C) 2014 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <private/bionic_asm.h>
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// gdb is smart enough to unwind through signal frames with just the regular
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// CFI information but libgcc and libunwind both need extra help. We do this
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// by using .fnstart/.fnend and inserting a nop before both __restore and
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// __restore_rt (but covered by the .fnstart/.fnend) so that although they're
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// not inside the functions from objdump's point of view, an unwinder that
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// blindly looks at the previous instruction (but is then smart enough to check
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// the DWARF information to find out where it landed) gets the right answer.
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// We need to place .fnstart ourselves (but we may as well keep the free .fnend).
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#undef __bionic_asm_custom_entry
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#define __bionic_asm_custom_entry(f)
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.fnstart
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.save {r0-r15}
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.pad #32
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nop
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ENTRY_PRIVATE(__restore)
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// This function must have exactly this instruction sequence.
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mov r7, #__NR_sigreturn
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swi #0
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END(__restore)
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.fnstart
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.save {r0-r15}
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.pad #160
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nop
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ENTRY_PRIVATE(__restore_rt)
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// This function must have exactly this instruction sequence.
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mov r7, #__NR_rt_sigreturn
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swi #0
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END(__restore_rt)
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