1/* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22/* Copyright (c) 1988 AT&T */ 23/* All Rights Reserved */ 24 25/* 26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 27 * Use is subject to license terms. 28 */ 29 30#pragma ident "%Z%%M% %I% %E% SMI" 31 32 .file "%M%" 33 34#include <sys/asm_linkage.h> 35 36 ANSI_PRAGMA_WEAK(vforkx,function) 37 ANSI_PRAGMA_WEAK(vfork,function) 38 39#include "SYS.h" 40#include <assym.h> 41 42/* 43 * pid = vforkx(flags); 44 * syscall trap: forksys(2, flags) 45 * 46 * pid = vfork(); 47 * syscall trap: forksys(2, 0) 48 * 49 * From the syscall: 50 * %o1 == 0 in parent process, %o1 == 1 in child process. 51 * %o0 == pid of child in parent, %o0 == pid of parent in child. 52 * 53 * The child gets a zero return value. 54 * The parent gets the pid of the child. 55 */ 56 57/* 58 * Note that since the SPARC architecture maintains stack maintence 59 * information (return pc, sp, fp) in the register windows, both parent 60 * and child can execute in a common address space without conflict. 61 * 62 * We block all blockable signals while performing the vfork() system call 63 * trap. This enables us to set curthread->ul_vfork safely, so that we 64 * don't end up in a signal handler with curthread->ul_vfork set wrong. 65 */ 66 67 ENTRY_NP(vforkx) 68 ba 0f 69 mov %o0, %o3 /* flags */ 70 ENTRY_NP(vfork) 71 clr %o3 /* flags = 0 */ 720: 73 mov SIG_SETMASK, %o0 /* block all signals */ 74 set MASKSET0, %o1 75 set MASKSET1, %o2 76 SYSTRAP_2RVALS(lwp_sigmask) 77 78 mov %o3, %o1 /* flags */ 79 mov 2, %o0 80 SYSTRAP_2RVALS(forksys) /* vforkx(flags) */ 81 bcc,a,pt %icc, 1f 82 tst %o1 83 84 mov %o0, %o3 /* save the vfork() error number */ 85 86 mov SIG_SETMASK, %o0 /* reinstate signals */ 87 ld [%g7 + UL_SIGMASK], %o1 88 ld [%g7 + UL_SIGMASK + 4], %o2 89 SYSTRAP_2RVALS(lwp_sigmask) 90 91 ba __cerror 92 mov %o3, %o0 /* restore the vfork() error number */ 93 941: 95 /* 96 * To determine if we are (still) a child of vfork(), the child 97 * increments curthread->ul_vfork by one and the parent decrements 98 * it by one. If the result is zero, then we are not a child of 99 * vfork(), else we are. We do this to deal with the case of 100 * a vfork() child calling vfork(). 101 */ 102 bnz,pt %icc, 2f 103 ld [%g7 + UL_VFORK], %g1 104 brnz,a,pt %g1, 3f /* don't let it go negative */ 105 sub %g1, 1, %g1 /* curthread->ul_vfork--; */ 106 ba,a 3f 1072: 108 clr %o0 /* zero the return value in the child */ 109 add %g1, 1, %g1 /* curthread->ul_vfork++; */ 1103: 111 st %g1, [%g7 + UL_VFORK] 112 /* 113 * Clear the schedctl interface in both parent and child. 114 * (The child might have modified the parent.) 115 */ 116 stn %g0, [%g7 + UL_SCHEDCTL] 117 stn %g0, [%g7 + UL_SCHEDCTL_CALLED] 118 mov %o0, %o3 /* save the vfork() return value */ 119 120 mov SIG_SETMASK, %o0 /* reinstate signals */ 121 ld [%g7 + UL_SIGMASK], %o1 122 ld [%g7 + UL_SIGMASK + 4], %o2 123 SYSTRAP_2RVALS(lwp_sigmask) 124 125 retl 126 mov %o3, %o0 /* restore the vfork() return value */ 127 SET_SIZE(vfork) 128 SET_SIZE(vforkx) 129