vforkx.s revision 7257d1b4d25bfac0c802847390e98a464fd787ac
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1988 AT&T */
/* All Rights Reserved */
#pragma ident "%Z%%M% %I% %E% SMI"
.file "%M%"
#include "SYS.h"
#include <assym.h>
/*
* pid = vforkx(flags);
* syscall trap: forksys(2, flags)
*
* pid = vfork();
* syscall trap: forksys(2, 0)
*
* From the syscall:
* %o1 == 0 in parent process, %o1 == 1 in child process.
* %o0 == pid of child in parent, %o0 == pid of parent in child.
*
* The child gets a zero return value.
* The parent gets the pid of the child.
*/
/*
* Note that since the SPARC architecture maintains stack maintence
* information (return pc, sp, fp) in the register windows, both parent
* and child can execute in a common address space without conflict.
*
* We block all blockable signals while performing the vfork() system call
* trap. This enables us to set curthread->ul_vfork safely, so that we
* don't end up in a signal handler with curthread->ul_vfork set wrong.
*/
ENTRY_NP(vforkx)
ba 0f
mov %o0, %o3 /* flags */
ENTRY_NP(vfork)
clr %o3 /* flags = 0 */
0:
mov SIG_SETMASK, %o0 /* block all signals */
set MASKSET0, %o1
set MASKSET1, %o2
SYSTRAP_2RVALS(lwp_sigmask)
mov %o3, %o1 /* flags */
mov 2, %o0
SYSTRAP_2RVALS(forksys) /* vforkx(flags) */
bcc,a,pt %icc, 1f
tst %o1
mov %o0, %o3 /* save the vfork() error number */
mov SIG_SETMASK, %o0 /* reinstate signals */
ld [%g7 + UL_SIGMASK], %o1
ld [%g7 + UL_SIGMASK + 4], %o2
SYSTRAP_2RVALS(lwp_sigmask)
ba __cerror
mov %o3, %o0 /* restore the vfork() error number */
1:
/*
* To determine if we are (still) a child of vfork(), the child
* increments curthread->ul_vfork by one and the parent decrements
* it by one. If the result is zero, then we are not a child of
* vfork(), else we are. We do this to deal with the case of
* a vfork() child calling vfork().
*/
bnz,pt %icc, 2f
ld [%g7 + UL_VFORK], %g1
brnz,a,pt %g1, 3f /* don't let it go negative */
sub %g1, 1, %g1 /* curthread->ul_vfork--; */
ba,a 3f
2:
clr %o0 /* zero the return value in the child */
add %g1, 1, %g1 /* curthread->ul_vfork++; */
3:
st %g1, [%g7 + UL_VFORK]
/*
* Clear the schedctl interface in both parent and child.
* (The child might have modified the parent.)
*/
stn %g0, [%g7 + UL_SCHEDCTL]
stn %g0, [%g7 + UL_SCHEDCTL_CALLED]
mov %o0, %o3 /* save the vfork() return value */
mov SIG_SETMASK, %o0 /* reinstate signals */
ld [%g7 + UL_SIGMASK], %o1
ld [%g7 + UL_SIGMASK + 4], %o2
SYSTRAP_2RVALS(lwp_sigmask)
retl
mov %o3, %o0 /* restore the vfork() return value */
SET_SIZE(vfork)
SET_SIZE(vforkx)