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/regnum.h> 42 43 #include <stdarg.h> 44 #include <stdlib.h> 45 #include <unistd.h> 46 #include <stdio.h> 47 #include <ucontext.h> 48 49 __weak_reference(__makecontext, makecontext); 50 51 void _ctx_done(ucontext_t *); 52 void _ctx_start(void); 53 54 void 55 __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 56 { 57 mcontext_t *mc; 58 register_t *sp; 59 int i; 60 va_list ap; 61 62 /* 63 * XXX/juli 64 * We need an mc_len or mc_flags like other architectures 65 * so that we can mark a context as invalid. Store it in 66 * mc->mc_regs[ZERO] perhaps? 67 */ 68 if (argc < 0 || argc > 6 || ucp == NULL || 69 ucp->uc_stack.ss_sp == NULL || 70 ucp->uc_stack.ss_size < MINSIGSTKSZ) 71 return; 72 mc = &ucp->uc_mcontext; 73 74 sp = (register_t *) 75 ((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); 76 #if defined(__mips_o32) || defined(__mips_o64) 77 sp -= (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */ 78 sp = (register_t *) 79 ((uintptr_t)sp & ~0x7); /* Align on double-word boundary. */ 80 #elif defined(__mips_n32) || defined(__mips_n64) 81 sp -= (argc > 8 ? argc - 8 : 0); /* Make room for > 8 arguments. */ 82 sp = (register_t *) 83 ((uintptr_t)sp & ~0xf); /* Align on quad-word boundary. */ 84 #endif 85 86 mc->mc_regs[SP] = (intptr_t)sp; 87 mc->mc_regs[S0] = (intptr_t)ucp; 88 mc->mc_regs[T9] = (intptr_t)func; 89 mc->mc_pc = (intptr_t)_ctx_start; 90 91 /* Construct argument list. */ 92 va_start(ap, argc); 93 #if defined(__mips_o32) || defined(__mips_o64) 94 /* Up to the first four arguments are passed in $a0-3. */ 95 for (i = 0; i < argc && i < 4; i++) 96 /* LINTED register_t is safe */ 97 mc->mc_regs[A0 + i] = va_arg(ap, register_t); 98 /* Pass remaining arguments on the stack above the $a0-3 gap. */ 99 sp += i; 100 #endif 101 #if defined(__mips_n32) || defined(__mips_n64) 102 /* Up to the first 8 arguments are passed in $a0-7. */ 103 for (i = 0; i < argc && i < 8; i++) 104 /* LINTED register_t is safe */ 105 mc->mc_regs[A0 + i] = va_arg(ap, register_t); 106 /* Pass remaining arguments on the stack above the $a0-3 gap. */ 107 #endif 108 /* Pass remaining arguments on the stack above the $a0-3 gap. */ 109 for (; i < argc; i++) 110 /* LINTED uintptr_t is safe */ 111 *sp++ = va_arg(ap, register_t); 112 va_end(ap); 113 } 114 115 void 116 _ctx_done(ucontext_t *ucp) 117 { 118 119 if (ucp->uc_link == NULL) 120 exit(0); 121 else { 122 setcontext((const ucontext_t *)ucp->uc_link); 123 abort(); 124 } 125 } 126