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/* Copyright (C) 2005-2013 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include "sysdep.h"
#include <sys/syscall.h>
#define _SIGNAL_H
#include <bits/signum.h>
#define __ASSEMBLY__
#include <linux/sched.h>
/*
Clone the calling process, but without copying the whole address space.
The calling process is suspended until the new process exits or is
replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
and the process ID of the new process to the old process.
Note that it is important that we don't create a new stack frame for the
caller.
*/
#ifndef SAVE_PID
#define SAVE_PID(a,b,c,d)
#endif
#ifndef RESTORE_PID
#define RESTORE_PID(a,b,c)
#endif
#ifndef RESTORE_PID12
#define RESTORE_PID12(a,b,c)
#endif
/*
pid_t vfork(void);
Implemented as __clone_syscall(CLONE_VFORK | CLONE_VM | SIGCHLD, 0)
*/
HIDDEN_ENTRY (__vfork)
#if defined(__XTENSA_WINDOWED_ABI__)
.literal .Ljumptable, 0, .L4, .L8, .L12
mov a3, a0 # move return address out of the way
movi a0, .Ljumptable
extui a2, a3, 30, 2 # call-size: call4/8/12 = 1/2/3
addx4 a0, a2, a0 # find return address in jumptable
slli a2, a2, 30
l32i a0, a0, 0
xor a3, a3, a2 # remove call-size from return address
or a0, a0, a2 # create temporary return address
retw
/* a7: return address */
.L4: mov a12, a2
mov a13, a3
SAVE_PID(a5,a15,a2,a3)
/* use syscall 'clone' and set new stack pointer to the same address */
movi a2, SYS_ify(clone)
movi a3, 0
movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD
syscall
RESTORE_PID(a5,a15,a2)
movi a5, -4096
mov a6, a2
mov a2, a12
mov a3, a13
bgeu a6, a5, 1f
jx a7
1: call4 .Lerr
/* a11: return address */
.L8: mov a12, a2
mov a13, a3
mov a14, a6
SAVE_PID(a9,a15,a2,a3)
movi a2, SYS_ify(clone)
movi a3, 0
movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD
syscall
RESTORE_PID(a9,a15,a2)
movi a9, -4096
mov a10, a2
mov a2, a12
mov a3, a13
mov a6, a14
bgeu a10, a9, 1f
jx a11
1: call8 .Lerr
/* a15: return address */
.L12: mov a12, a2
mov a13, a3
mov a14, a6
SAVE_PID (a2,a3,a2,a6)
movi a2, SYS_ify(clone)
movi a3, 0
movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD
syscall
RESTORE_PID12(a3,a6,a15)
mov a3, a13
movi a13, -4096
mov a6, a14
mov a14, a2
mov a2, a12
bgeu a14, a13, 1f
jx a15
1: call12 .Lerr
.align 4
.Lerr: entry a1, 16
/* Restore return address */
extui a4, a0, 30, 2
slli a4, a4, 30
or a0, a3, a4
PSEUDO_END (__vfork)
.Lpseudo_end:
retw
#elif defined(__XTENSA_CALL0_ABI__)
SAVE_PID(a5, a8, a3, a4)
/* Use syscall 'clone'. Set new stack pointer to the same address. */
movi a2, SYS_ify (clone)
movi a3, 0
movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD
syscall
RESTORE_PID(a5, a8, a2)
movi a3, -4096
bgeu a2, a3, 1f
ret
1:
PSEUDO_END (__vfork)
.Lpseudo_end:
ret
#else
#error Unsupported Xtensa ABI
#endif
weak_alias (__vfork, vfork)
libc_hidden_def(vfork)
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