da4a3e6515
We cleaned up the auto-generated ones a while back to not touch the stack unnecessarily if they have <= 4 arguments. This patch cleans up some hand-crafted ones. Also improve comments in clone.S. Change-Id: I8850bf98f2b26829385315304472a760e6880ed8
112 lines
3.4 KiB
ArmAsm
112 lines
3.4 KiB
ArmAsm
/*
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* Copyright (C) 2008-2010 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 <linux/err.h>
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#include <machine/asm.h>
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#include <asm/unistd.h>
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// int __pthread_clone(void* (*fn)(void*), void* child_stack, int flags, void* arg);
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ENTRY(__pthread_clone)
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# Push 'fn' and 'arg' onto 'child_stack'.
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stmdb r1!, {r0, r3}
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# The sys_clone system call only takes two arguments: 'flags' and 'child_stack'.
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# 'child_stack' is already in r1, but we need to move 'flags' into position.
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mov r0, r2
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# System call.
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mov ip, r7
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ldr r7, =__NR_clone
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swi #0
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# Child?
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movs r0, r0
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beq 1f
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# Parent.
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mov r7, ip
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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
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1: # Child.
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# Pop 'fn' and 'arg' back off the stack and call __thread_entry.
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pop {r0, r1}
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# __thread_entry also needs our stack pointer.
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mov r2, sp
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b __thread_entry
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END(__pthread_clone)
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#
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# This function is defined as:
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#
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# pid_t __bionic_clone( int flags, void *child_stack,
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# pid_t *pid, void *tls, pid_t *ctid,
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# int (*fn)(void *), void* arg );
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#
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# NOTE: This is not the same signature as the glibc
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# __clone function. Placing 'fn' and 'arg'
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# at the end of the parameter list makes the
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# implementation much simpler.
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#
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ENTRY(__bionic_clone)
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mov ip, sp
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.save {r4, r5, r6, r7}
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# save registers to parent stack
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stmfd sp!, {r4, r5, r6, r7}
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# load extra parameters
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ldmfd ip, {r4, r5, r6}
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# store 'fn' and 'arg' to the child stack
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str r5, [r1, #-4]
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str r6, [r1, #-8]
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# System call
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ldr r7, =__NR_clone
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swi #0
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movs r0, r0
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beq 1f
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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
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1: # The child.
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ldr r0, [sp, #-4]
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ldr r1, [sp, #-8]
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b __bionic_clone_entry
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END(__bionic_clone)
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