1/* $OpenBSD: tfork_thread.S,v 1.10 2020/10/18 14:28:17 deraadt Exp $ */ 2/*- 3 * Copyright (c) 2000 Peter Wemm <peter@FreeBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28#include <machine/asm.h> 29 30/* 31 * With thanks to John Dyson for the original version of this. 32 */ 33 34#include "SYS.h" 35 36/* 37 * 8 12 16 20 38 * __tfork_thread(param, psize, start_fnc, start_arg); 39 * 40 * param: Arguments to actual system call. 41 * psize: Other argument to pass to the actual kernel call. 42 * start_fnc: Address of thread function to call in child. 43 * start_arg: Argument to pass to the thread function in child. 44 */ 45 46ENTRY(__tfork_thread) 47 pushl %ebp 48 movl %esp, %ebp 49 pushl %esi 50 pushl %edi 51 52 /* 53 * Save the thread info in esi and ebx 54 */ 55 movl 16(%ebp), %esi # get start thread address 56 movl 20(%ebp), %edi # get start argument 57 58 /* 59 * Prepare and execute the thread creation syscall 60 */ 61 pushl 12(%ebp) # push psize 62 pushl 8(%ebp) # push param 63 pushl $0 # slot for return address, ignored by kernel 64 movl $SYS___tfork, %eax 65 int $0x80 66 jb 2f 67 68 /* 69 * Check to see if we are in the parent or child 70 */ 71 cmpl $0, %eax 72 jz 1f 73 addl $12, %esp 74 popl %edi 75 popl %esi 76 movl %ebp, %esp 77 popl %ebp 78 ret 79 .p2align 2 80 81 /* 82 * If we are in the child (new thread), then 83 * set-up the call to the internal subroutine. If it 84 * returns, then call __threxit. 85 */ 861: 87 xorl %ebp, %ebp # mark outermost frame 88 subl $4, %esp # align stack 89 andl $~15, %esp 90 addl $4, %esp 91 pushl %edi # push start argument 92 call *%esi 93 addl $4, %esp 94 95 /* 96 * Exit system call 97 */ 98 pushl $0 # NULL pointer argument to __threxit 99 pushl $0 # slot for return address, ignored by kernel 100 movl $SYS___threxit, %eax 101 int $0x80 102 int3 103 104 /* 105 * Branch here if the thread creation fails: 106 */ 1072: 108 addl $12, %esp 109 popl %edi 110 popl %esi 111 movl %ebp, %esp 112 popl %ebp 113 HANDLE_ERRNO() 114 ret 115END(__tfork_thread) 116