uclibc-ng/libc/sysdeps/linux/nds32/vfork.S

/*
 * Copyright (C) 2016-2017 Andes Technology, Inc.
 * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
 */

/* Copyright (C) 1999, 2002, 2003 Free Software Foundation, Inc.
   Contributed by Philip Blundell <philb@gnu.org>.

   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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <sysdep.h>
#define _ERRNO_H    1
#include <bits/errno.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.  */

ENTRY (__vfork)
#ifdef PIC
.pic
#endif

#ifdef __NR_vfork
    syscall __NR_vfork
    bltz $r0, 2f
1:
    ret
2:
    sltsi $r1, $r0, -4096
    bnez $r1, 1b;

# ifdef __ASSUME_VFORK_SYSCALL
#  ifdef PIC
	pushm	$gp,	$lp
	cfi_adjust_cfa_offset(8)
	cfi_rel_offset(gp, 0)
	cfi_rel_offset(lp, 4)
	mfusr 	$r15, 	$PC
	sethi	$gp,	hi20(_GLOBAL_OFFSET_TABLE_+4)
	ori	$gp,	$gp,	lo12(_GLOBAL_OFFSET_TABLE_+8)
	add	$gp,	$gp,	$r15

	! r15=C_SYMBOL_NAME(__syscall_error)@PLT
	sethi	$r15, 	hi20(C_SYMBOL_NAME(__syscall_error)@PLT)
	ori	$r15,	$r15, lo12(C_SYMBOL_NAME(__syscall_error)@PLT)
	add	$r15, 	$r15, 	$gp

	! jump to SYSCALL_ERROR
	jral		$r15
	popm	$gp,	$lp
	cfi_adjust_cfa_offset(-8)
	cfi_restore(lp)
	cfi_restore(gp)
	ret
#  else
	j C_SYMBOL_NAME(__syscall_error)
#  endif
# else
    /* Check if vfork syscall is known at all. */
	li $r1, -ENOSYS
	beq	$r0, $r1, 1f

# ifdef PIC
3:
	pushm	$gp,	$lp
	cfi_adjust_cfa_offset(8)
	cfi_rel_offset(gp, 0)
	cfi_rel_offset(lp, 4)
	mfusr	$r15,   $PC
	sethi   $gp,    hi20(_GLOBAL_OFFSET_TABLE_+4)
	ori     $gp,    $gp,    lo12(_GLOBAL_OFFSET_TABLE_+8)
	add     $gp,    $gp,    $r15

	! r15=C_SYMBOL_NAME(__syscall_error)@PLT
	sethi	$r15,	hi20(C_SYMBOL_NAME(__syscall_error)@PLT)
	ori     $r15,	$r15, lo12(C_SYMBOL_NAME(__syscall_error)@PLT)
	add     $r15,	$r15, 	$gp

	! jump to SYSCALL_ERROR
	jral		$r15
	popm	$gp,	$lp
	cfi_adjust_cfa_offset(-8)
	cfi_restore(lp)
	cfi_restore(gp)
	ret
# else
        j C_SYMBOL_NAME(__syscall_error)
# endif
1:
# endif
#endif

#ifndef __ASSUME_VFORK_SYSCALL
    /* If we don't have vfork, fork is close enough. */
	syscall __NR_fork
	bgez $r0, 1f
	sltsi $r1, $r0, -4096
	bnez	$r1, 1f

# ifdef PIC
        b       3b
# else
        j C_SYMBOL_NAME(__syscall_error)
# endif
1:
    ret

#elif !defined __NR_vfork
# error "__NR_vfork not available and __ASSUME_VFORK_SYSCALL defined"
#endif

PSEUDO_END (__vfork)
weak_alias (__vfork, vfork)
libc_hidden_def (vfork)