1/* 2 * Copyright (c) 1999-2007 Apple Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28/* Copyright (c) 1998 Apple Computer, Inc. All rights reserved. 29 * 30 * File: libc/ppc/sys/vfork.s 31 * 32 * HISTORY 33 * 23-Jun-1998 Umesh Vaishampayan (umeshv@apple.com) 34 * Created from fork.s 35 * 36 */ 37 38#include "SYS.h" 39 40#if defined(__ppc__) || defined(__ppc64__) 41 42/* We use mode-independent "g" opcodes such as "srgi", and/or 43 * mode-independent macros such as MI_GET_ADDRESS. These expand 44 * into word operations when targeting __ppc__, and into doubleword 45 * operations when targeting __ppc64__. 46 */ 47#include <architecture/ppc/mode_independent_asm.h> 48 49/* In vfork(), the child runs in parent's address space. */ 50 51 52MI_ENTRY_POINT(___vfork) 53 MI_GET_ADDRESS(r5,__current_pid) // get address of __current_pid in r5 542: 55 lwarx r6,0,r5 // don't cache pid across vfork 56 cmpwi r6,0 57 ble-- 3f // is another vfork in progress 58 li r6,0 // if not, erase the stored pid 593: 60 addi r6,r6,-1 // count the parallel vforks in 61 stwcx. r6,0,r5 // negative cached pid values 62 bne-- 2b 63 64 li r0,SYS_vfork 65 sc 66 b Lbotch // error return 67 68 cmpwi r4,0 69 beq Lparent // parent, since a1 == 0 in parent, 70 71 li r3,0 // child 72 blr 73 74Lparent: // r3 == child's pid 75 lwarx r6,0,r5 // we're back, decrement vfork count 76 addi r6,r6,1 77 stwcx. r6,0,r5 78 bne-- Lparent 79 blr // return pid 80 81Lbotch: 82 lwarx r6,0,r5 // never went, decrement vfork count 83 addi r6,r6,1 84 stwcx. r6,0,r5 85 bne-- Lbotch 86 87 MI_BRANCH_EXTERNAL(cerror) 88 89#elif defined(__i386__) 90 91#if defined(__DYNAMIC__) 92#define GET_CURRENT_PID PICIFY(__current_pid) 93 94 NON_LAZY_STUB(__current_pid) 95#define __current_pid (%edx) 96#else 97#define GET_CURRENT_PID 98#endif 99 100/* 101 * If __current_pid >= 0, we want to put a -1 in there 102 * otherwise we just decrement it 103 */ 104 105LEAF(___vfork, 0) 106 GET_CURRENT_PID 107 movl __current_pid, %eax 1080: 109 xorl %ecx, %ecx 110 testl %eax, %eax 111 cmovs %eax, %ecx 112 decl %ecx 113 lock 114 cmpxchgl %ecx, __current_pid 115 jne 0b 116 popl %ecx 117 movl $(SYS_vfork), %eax // code for vfork -> eax 118 UNIX_SYSCALL_TRAP // do the system call 119 jnb L1 // jump if CF==0 120 GET_CURRENT_PID 121 lock 122 incl __current_pid 123 pushl %ecx 124 BRANCH_EXTERN(cerror) 125 126L1: 127 testl %edx, %edx // CF=OF=0, ZF set if zero result 128 jz L2 // parent, since r1 == 0 in parent, 1 in child 129 xorl %eax, %eax // zero eax 130 jmp *%ecx 131 132L2: 133 GET_CURRENT_PID 134 lock 135 incl __current_pid 136 jmp *%ecx 137 138#elif defined(__x86_64__) 139 140/* 141 * If __current_pid >= 0, we want to put a -1 in there 142 * otherwise we just decrement it 143 */ 144 145LEAF(___vfork, 0) 146 movq __current_pid@GOTPCREL(%rip), %rax 147 movl (%rax), %eax 1480: 149 xorl %ecx, %ecx 150 testl %eax, %eax 151 cmovs %eax, %ecx 152 subl $1, %ecx 153 movq __current_pid@GOTPCREL(%rip), %rdx 154 lock 155 cmpxchgl %ecx, (%rdx) 156 jne 0b 157 popq %rdi // return address in %rdi 158 movq $ SYSCALL_CONSTRUCT_UNIX(SYS_vfork), %rax // code for vfork -> rax 159 UNIX_SYSCALL_TRAP // do the system call 160 jnb L1 // jump if CF==0 161 movq __current_pid@GOTPCREL(%rip), %rcx 162 lock 163 addq $1, (%rcx) 164 movq (%rcx), %rdi 165 BRANCH_EXTERN(cerror) 166 167L1: 168 testl %edx, %edx // CF=OF=0, ZF set if zero result 169 jz L2 // parent, since r1 == 0 in parent, 1 in child 170 xorq %rax, %rax // zero rax 171 jmp *%rdi 172 173L2: 174 movq __current_pid@GOTPCREL(%rip), %rdx 175 lock 176 addq $1, (%rdx) 177 jmp *%rdi 178 179#else 180#error Unsupported architecture 181#endif 182