1/* $NetBSD: makecontext.c,v 1.5 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 Klaus Klein. 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/cdefs.h> 33__FBSDID("$FreeBSD$"); 34#if defined(LIBC_SCCS) && !defined(lint) 35__RCSID("$NetBSD: makecontext.c,v 1.5 2009/12/14 01:07:42 matt Exp $"); 36#endif 37 38#include <sys/param.h> 39#include <machine/regnum.h> 40 41#include <stdarg.h> 42#include <stdlib.h> 43#include <unistd.h> 44#include <stdio.h> 45#include <ucontext.h> 46 47__weak_reference(__makecontext, makecontext); 48 49void _ctx_done(ucontext_t *); 50void _ctx_start(void); 51 52void 53__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 54{ 55 mcontext_t *mc; 56 register_t *sp; 57 int i; 58 va_list ap; 59 60 /* 61 * XXX/juli 62 * We need an mc_len or mc_flags like other architectures 63 * so that we can mark a context as invalid. Store it in 64 * mc->mc_regs[ZERO] perhaps? 65 */ 66 if (argc < 0 || argc > 6 || ucp == NULL || 67 ucp->uc_stack.ss_sp == NULL || 68 ucp->uc_stack.ss_size < MINSIGSTKSZ) 69 return; 70 mc = &ucp->uc_mcontext; 71 72 sp = (register_t *) 73 ((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); 74#if defined(__mips_o32) || defined(__mips_o64) 75 sp -= (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */ 76 sp = (register_t *) 77 ((uintptr_t)sp & ~0x7); /* Align on double-word boundary. */ 78#elif defined(__mips_n32) || defined(__mips_n64) 79 sp -= (argc > 8 ? argc - 8 : 0); /* Make room for > 8 arguments. */ 80 sp = (register_t *) 81 ((uintptr_t)sp & ~0xf); /* Align on quad-word boundary. */ 82#endif 83 84 mc->mc_regs[SP] = (intptr_t)sp; 85 mc->mc_regs[S0] = (intptr_t)ucp; 86 mc->mc_regs[T9] = (intptr_t)func; 87 mc->mc_pc = (intptr_t)_ctx_start; 88 89 /* Construct argument list. */ 90 va_start(ap, argc); 91#if defined(__mips_o32) || defined(__mips_o64) 92 /* Up to the first four arguments are passed in $a0-3. */ 93 for (i = 0; i < argc && i < 4; i++) 94 /* LINTED register_t is safe */ 95 mc->mc_regs[A0 + i] = va_arg(ap, register_t); 96 /* Pass remaining arguments on the stack above the $a0-3 gap. */ 97 sp += i; 98#endif 99#if defined(__mips_n32) || defined(__mips_n64) 100 /* Up to the first 8 arguments are passed in $a0-7. */ 101 for (i = 0; i < argc && i < 8; i++) 102 /* LINTED register_t is safe */ 103 mc->mc_regs[A0 + i] = va_arg(ap, register_t); 104 /* Pass remaining arguments on the stack above the $a0-3 gap. */ 105#endif 106 /* Pass remaining arguments on the stack above the $a0-3 gap. */ 107 for (; i < argc; i++) 108 /* LINTED uintptr_t is safe */ 109 *sp++ = va_arg(ap, register_t); 110 va_end(ap); 111} 112 113void 114_ctx_done(ucontext_t *ucp) 115{ 116 117 if (ucp->uc_link == NULL) 118 exit(0); 119 else { 120 setcontext((const ucontext_t *)ucp->uc_link); 121 abort(); 122 } 123} 124