1/* $NetBSD: __clone.S,v 1.7 2008/04/28 20:22:56 martin 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#ifdef WEAK_ALIAS 37WEAK_ALIAS(clone, __clone) 38#endif 39 40/* 41 * int __clone(int (*fn)(void *), void *stack, int flags, void *arg); 42 */ 43LEAF(__clone) 44 PIC_PROLOGUE(__clone, t9) 45 46 /* 47 * Sanity checks: func and stack may not be NULL. 48 */ 49 li v0, EINVAL 50 beq a0, zero, 8f 51 beq a1, zero, 8f 52 53 /* 54 * We need to be able to get at the func and arg arguments 55 * in the child. Luckily, we have a convenient place to 56 * do this: the child's stack. 57 */ 58 subu a1, a1, (2 * SZREG) 59 REG_S a0, 0(a1) 60 REG_S a3, SZREG(a1) 61 62 /* 63 * The system call expects (flags, stack). 64 */ 65 move a0, a2 66 SYSTRAP(__clone) 67 bne a3, zero, 8f 68 69 bne v1, zero, 9f # v1 (rv[1]) == 0, parent, child pid in v0 70 71 j ra # parent return 72 738: PIC_CALL(__cerror, t9) 74 /* NOTREACHED */ 75 769: /* 77 * Child: Fetch the function and argument from the new stack, 78 * and create a frame so that the child can be safely called. 79 * 80 * There are already register slots on the stack from above. 81 * We take 4 register slots more. The lower 4 accommodate o32 82 * argument save area. The next higher is used to save GP (if 83 * ABICALLS). The highest is unused. 84 */ 85 REG_L t9, 0(sp) 86 REG_L a0, SZREG(sp) 87 subu sp, sp, (4 * SZREG) 88 89#ifdef __ABICALLS__ 90 .cprestore (4 * SZREG) 91#endif 92 93 /* Call the clone's entry point. */ 94 jal t9 95 96 /* Pass the return value to _exit(). */ 97 move a0, v0 98 PIC_CALL(_exit, t9) 99 100 /* NOTREACHED */ 101END(__clone) 102