2016-01-04 16:05:18 +00:00
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/* Copyright (C) 1999-2016 Free Software Foundation, Inc.
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2012-11-09 17:53:51 +00:00
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#define _ERRNO_H 1
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#include <bits/errno.h>
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/* Clone the calling process, but without copying the whole address space.
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The calling process is suspended until the new process exits or is
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replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
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and the process ID of the new process to the old process. */
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ENTRY (__vfork)
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2014-05-23 20:23:32 +00:00
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/* Save the TCB-cached PID away in w3, and then negate the TCB
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field. But if it's zero, set it to 0x80000000 instead. See
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raise.c for the logic that relies on this value. */
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mrs x2, tpidr_el0
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sub x2, x2, #PTHREAD_SIZEOF
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ldr w3, [x2, #PTHREAD_PID_OFFSET]
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mov w1, #0x80000000
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negs w0, w3
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csel w0, w1, w0, eq
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str w0, [x2, #PTHREAD_PID_OFFSET]
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2012-11-09 17:53:51 +00:00
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mov x0, #0x4111 /* CLONE_VM | CLONE_VFORK | SIGCHLD */
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mov x1, sp
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DO_CALL (clone, 2)
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2014-05-23 20:23:32 +00:00
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/* Restore the original value of the TCB cache of the PID, if we're
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the parent. But in the child (syscall return value equals zero),
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leave things as they are. */
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cbz x0, 1f
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str w3, [x2, #PTHREAD_PID_OFFSET]
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1:
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2012-11-09 17:53:51 +00:00
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cmn x0, #4095
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2014-05-23 20:23:32 +00:00
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b.cs .Lsyscall_error
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2012-11-09 17:53:51 +00:00
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RET
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PSEUDO_END (__vfork)
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libc_hidden_def (__vfork)
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weak_alias (__vfork, vfork)
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2014-05-23 20:23:32 +00:00
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strong_alias (__vfork, __libc_vfork)
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