1209233Sjchandra/* $NetBSD: makecontext.c,v 1.5 2009/12/14 01:07:42 matt Exp $ */ 2178580Simp 3178580Simp/*- 4178580Simp * Copyright (c) 2001 The NetBSD Foundation, Inc. 5178580Simp * All rights reserved. 6178580Simp * 7178580Simp * This code is derived from software contributed to The NetBSD Foundation 8178580Simp * by Klaus Klein. 9178580Simp * 10178580Simp * Redistribution and use in source and binary forms, with or without 11178580Simp * modification, are permitted provided that the following conditions 12178580Simp * are met: 13178580Simp * 1. Redistributions of source code must retain the above copyright 14178580Simp * notice, this list of conditions and the following disclaimer. 15178580Simp * 2. Redistributions in binary form must reproduce the above copyright 16178580Simp * notice, this list of conditions and the following disclaimer in the 17178580Simp * documentation and/or other materials provided with the distribution. 18178580Simp * 19178580Simp * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20178580Simp * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21178580Simp * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22178580Simp * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23178580Simp * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24178580Simp * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25178580Simp * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26178580Simp * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27178580Simp * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28178580Simp * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29178580Simp * POSSIBILITY OF SUCH DAMAGE. 30178580Simp */ 31178580Simp 32178580Simp#include <sys/cdefs.h> 33178580Simp__FBSDID("$FreeBSD$"); 34178580Simp#if defined(LIBC_SCCS) && !defined(lint) 35209233Sjchandra__RCSID("$NetBSD: makecontext.c,v 1.5 2009/12/14 01:07:42 matt Exp $"); 36178580Simp#endif 37178580Simp 38209233Sjchandra#include <sys/param.h> 39209233Sjchandra#include <machine/regnum.h> 40209233Sjchandra 41209233Sjchandra#include <stdarg.h> 42209233Sjchandra#include <stdlib.h> 43209233Sjchandra#include <unistd.h> 44209233Sjchandra#include <stdio.h> 45178580Simp#include <ucontext.h> 46178580Simp 47209233Sjchandra__weak_reference(__makecontext, makecontext); 48209233Sjchandra 49209233Sjchandravoid _ctx_done(ucontext_t *); 50209233Sjchandravoid _ctx_start(void); 51209233Sjchandra 52178580Simpvoid 53209233Sjchandra__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 54178580Simp{ 55209233Sjchandra mcontext_t *mc; 56209233Sjchandra register_t *sp; 57178580Simp int i; 58178580Simp va_list ap; 59178580Simp 60209233Sjchandra /* 61209233Sjchandra * XXX/juli 62209233Sjchandra * We need an mc_len or mc_flags like other architectures 63209233Sjchandra * so that we can mark a context as invalid. Store it in 64209233Sjchandra * mc->mc_regs[ZERO] perhaps? 65209233Sjchandra */ 66209233Sjchandra if (argc < 0 || argc > 6 || ucp == NULL || 67209233Sjchandra ucp->uc_stack.ss_sp == NULL || 68209233Sjchandra ucp->uc_stack.ss_size < MINSIGSTKSZ) 69209233Sjchandra return; 70209233Sjchandra mc = &ucp->uc_mcontext; 71178580Simp 72209233Sjchandra sp = (register_t *) 73178580Simp ((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); 74209233Sjchandra#if defined(__mips_o32) || defined(__mips_o64) 75178580Simp sp -= (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */ 76209233Sjchandra sp = (register_t *) 77209233Sjchandra ((uintptr_t)sp & ~0x7); /* Align on double-word boundary. */ 78209233Sjchandra#elif defined(__mips_n32) || defined(__mips_n64) 79209233Sjchandra sp -= (argc > 8 ? argc - 8 : 0); /* Make room for > 8 arguments. */ 80209233Sjchandra sp = (register_t *) 81209233Sjchandra ((uintptr_t)sp & ~0xf); /* Align on quad-word boundary. */ 82209233Sjchandra#endif 83178580Simp 84209233Sjchandra mc->mc_regs[SP] = (intptr_t)sp; 85209233Sjchandra mc->mc_regs[S0] = (intptr_t)ucp; 86209233Sjchandra mc->mc_regs[T9] = (intptr_t)func; 87209233Sjchandra mc->mc_pc = (intptr_t)_ctx_start; 88178580Simp 89178580Simp /* Construct argument list. */ 90178580Simp va_start(ap, argc); 91209233Sjchandra#if defined(__mips_o32) || defined(__mips_o64) 92178580Simp /* Up to the first four arguments are passed in $a0-3. */ 93178580Simp for (i = 0; i < argc && i < 4; i++) 94209233Sjchandra /* LINTED register_t is safe */ 95209233Sjchandra mc->mc_regs[A0 + i] = va_arg(ap, register_t); 96178580Simp /* Pass remaining arguments on the stack above the $a0-3 gap. */ 97209233Sjchandra sp += i; 98209233Sjchandra#endif 99209233Sjchandra#if defined(__mips_n32) || defined(__mips_n64) 100209233Sjchandra /* Up to the first 8 arguments are passed in $a0-7. */ 101209233Sjchandra for (i = 0; i < argc && i < 8; i++) 102209233Sjchandra /* LINTED register_t is safe */ 103209233Sjchandra mc->mc_regs[A0 + i] = va_arg(ap, register_t); 104209233Sjchandra /* Pass remaining arguments on the stack above the $a0-3 gap. */ 105209233Sjchandra#endif 106209233Sjchandra /* Pass remaining arguments on the stack above the $a0-3 gap. */ 107209233Sjchandra for (; i < argc; i++) 108178580Simp /* LINTED uintptr_t is safe */ 109209233Sjchandra *sp++ = va_arg(ap, register_t); 110178580Simp va_end(ap); 111178580Simp} 112209233Sjchandra 113209233Sjchandravoid 114209233Sjchandra_ctx_done(ucontext_t *ucp) 115209233Sjchandra{ 116209233Sjchandra 117209233Sjchandra if (ucp->uc_link == NULL) 118209233Sjchandra exit(0); 119209233Sjchandra else { 120209233Sjchandra setcontext((const ucontext_t *)ucp->uc_link); 121209233Sjchandra abort(); 122209233Sjchandra } 123209233Sjchandra} 124