1/* $NetBSD: __clone.S,v 1.8 2009/12/14 01:07:42 matt Exp $ */ 2 3/*- 4 * Copyright (c) 2001 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include <sys/errno.h> 33 34#include "SYS.h" 35 36#if defined(SYSLIBC_SCCS) && !defined(lint) 37 RCSID("$NetBSD: __clone.S,v 1.8 2009/12/14 01:07:42 matt Exp $"); 38#endif /* SYSLIBC_SCCS and not lint */ 39 40#ifdef WEAK_ALIAS 41WEAK_ALIAS(clone, __clone) 42#endif 43 44/* 45 * int __clone(int (*fn)(void *), void *stack, int flags, void *arg); 46 */ 47LEAF(__clone) 48 PIC_PROLOGUE(__clone) 49 50 /* 51 * Sanity checks: func and stack may not be NULL. 52 */ 53 li v0, EINVAL 54 beq a0, zero, 8f 55 beq a1, zero, 8f 56 57 /* 58 * We need to be able to get at the func and arg arguments 59 * in the child. Luckily, we have a convenient place to 60 * do this: the child's stack. 61 */ 62 PTR_SUBU a1, a1, CALLFRAME_SIZ 63 REG_S a0, 0(a1) 64 REG_S a3, SZREG(a1) 65 66 /* 67 * The system call expects (flags, stack). 68 */ 69 move a0, a2 70 SYSTRAP(__clone) 71 bne a3, zero, 8f 72 73 bne v1, zero, 9f # v1 (rv[1]) == 0, parent, child pid in v0 74 75 PIC_RETURN() # parent return 76 778: PIC_TAILCALL(__cerror) 78 /* NOTREACHED */ 79 809: /* 81 * Child: Fetch the function and argument from the new stack and create 82 a frame so that the child can be safely called. 83 * 84 * There are already register slots on the stack from above. 85 * They already include the o32 argument save area. The 86 * highest is unused. a1 should equal sp now. 87 */ 88 89 REG_L t9, 0(sp) 90 REG_L a0, SZREG(sp) 91 92 REG_S zero, CALLFRAME_RA(sp) /* make sure stack frame ends */ 93 94 /* Call the clone's entry point. */ 95 SAVE_GP(CALLFRAME_GP) 96 jal t9 97 98 /* Pass the return value to _exit. */ 99 move a0, v0 100 PIC_TAILCALL(_exit) 101 102 /* NOTREACHED */ 103END(__clone) 104