1 /* $NetBSD: makecontext.c,v 1.5 2009/12/14 01:07:42 matt Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-2-Clause-NetBSD 5 * 6 * Copyright (c) 2001 The NetBSD Foundation, Inc. 7 * All rights reserved. 8 * 9 * This code is derived from software contributed to The NetBSD Foundation 10 * by Klaus Klein. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 #if defined(LIBC_SCCS) && !defined(lint) 37 __RCSID("$NetBSD: makecontext.c,v 1.5 2009/12/14 01:07:42 matt Exp $"); 38 #endif 39 40 #include <sys/param.h> 41 #include <machine/abi.h> 42 #include <machine/regnum.h> 43 44 #include <stdarg.h> 45 #include <stdlib.h> 46 #include <unistd.h> 47 #include <stdio.h> 48 #include <ucontext.h> 49 50 __weak_reference(__makecontext, makecontext); 51 52 void _ctx_done(ucontext_t *); 53 void _ctx_start(void); 54 55 void 56 __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 57 { 58 mcontext_t *mc; 59 register_t *sp; 60 int i; 61 va_list ap; 62 63 /* 64 * XXX/juli 65 * We need an mc_len or mc_flags like other architectures 66 * so that we can mark a context as invalid. Store it in 67 * mc->mc_regs[ZERO] perhaps? 68 */ 69 if (argc < 0 || ucp == NULL || 70 ucp->uc_stack.ss_sp == NULL || 71 ucp->uc_stack.ss_size < MINSIGSTKSZ) 72 return; 73 mc = &ucp->uc_mcontext; 74 75 sp = (register_t *) 76 ((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); 77 #if defined(__mips_o32) || defined(__mips_o64) 78 sp -= (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */ 79 #elif defined(__mips_n32) || defined(__mips_n64) 80 sp -= (argc > 8 ? argc - 8 : 0); /* Make room for > 8 arguments. */ 81 #endif 82 sp = (register_t *)((uintptr_t)sp & ~(STACK_ALIGN - 1)); 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 /* Skip over the $a0-3 gap. */ 97 sp += 4; 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 #endif 105 /* Pass remaining arguments on the stack. */ 106 for (; i < argc; i++) 107 /* LINTED register_t is safe */ 108 *sp++ = va_arg(ap, register_t); 109 va_end(ap); 110 } 111 112 void 113 _ctx_done(ucontext_t *ucp) 114 { 115 116 if (ucp->uc_link == NULL) 117 exit(0); 118 else { 119 setcontext((const ucontext_t *)ucp->uc_link); 120 abort(); 121 } 122 } 123