559f27828c
This CL adds an instruction to the _start label that clears the frame pointer. This allows stack walking code to determine when it has reached the end of the stack. The __bionic_clone function is similarly modified, for architectures that weren't already doing both. Test: bionic-unit-tests Test: CtsBionicTestCases Change-Id: Iea3949f52c44f7931f9fff2d60d4d9e5c742c120
71 lines
2.6 KiB
ArmAsm
71 lines
2.6 KiB
ArmAsm
/*
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* Copyright (C) 2008 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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// pid_t __bionic_clone(int flags, void* child_stack, pid_t* parent_tid, void* tls, pid_t* child_tid, int (*fn)(void*), void* arg);
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ENTRY_PRIVATE(__bionic_clone)
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mov ip, sp
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# save registers to parent stack
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stmfd sp!, {r4, r5, r6, r7}
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.cfi_def_cfa_offset 16
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.cfi_rel_offset r4, 0
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.cfi_rel_offset r5, 4
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.cfi_rel_offset r6, 8
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.cfi_rel_offset r7, 12
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# load extra parameters
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ldmfd ip, {r4, r5, r6}
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# Push 'fn' and 'arg' onto the child stack.
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stmdb r1!, {r5, r6}
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# Make the system call.
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ldr r7, =__NR_clone
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swi #0
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# Are we the child?
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movs r0, r0
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beq .L_bc_child
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# In the parent, reload saved registers then either return or set errno.
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ldmfd sp!, {r4, r5, r6, r7}
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cmn r0, #(MAX_ERRNO + 1)
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bxls lr
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neg r0, r0
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b __set_errno_internal
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.L_bc_child:
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# We're in the child now. Set the end of the frame record chain.
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mov fp, #0
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# Setting lr to 0 will make the unwinder stop at __start_thread.
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mov lr, #0
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# Call __start_thread with the 'fn' and 'arg' we stored on the child stack.
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pop {r0, r1}
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b __start_thread
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END(__bionic_clone)
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