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 #define _WANT_MIPS_REGNUM 43 #include <machine/regnum.h> 44 45 #include <stdarg.h> 46 #include <stdlib.h> 47 #include <unistd.h> 48 #include <stdio.h> 49 #include <ucontext.h> 50 51 __weak_reference(__makecontext, makecontext); 52 53 void _ctx_done(ucontext_t *); 54 void _ctx_start(void); 55 56 void 57 __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 58 { 59 mcontext_t *mc; 60 register_t *sp; 61 int i; 62 va_list ap; 63 64 /* 65 * XXX/juli 66 * We need an mc_len or mc_flags like other architectures 67 * so that we can mark a context as invalid. Store it in 68 * mc->mc_regs[ZERO] perhaps? 69 */ 70 if (argc < 0 || ucp == NULL || 71 ucp->uc_stack.ss_sp == NULL || 72 ucp->uc_stack.ss_size < MINSIGSTKSZ) 73 return; 74 mc = &ucp->uc_mcontext; 75 76 sp = (register_t *) 77 ((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); 78 #if defined(__mips_o32) || defined(__mips_o64) 79 sp -= (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */ 80 #elif defined(__mips_n32) || defined(__mips_n64) 81 sp -= (argc > 8 ? argc - 8 : 0); /* Make room for > 8 arguments. */ 82 #endif 83 sp = (register_t *)((uintptr_t)sp & ~(STACK_ALIGN - 1)); 84 85 mc->mc_regs[SP] = (intptr_t)sp; 86 mc->mc_regs[S0] = (intptr_t)ucp; 87 mc->mc_regs[T9] = (intptr_t)func; 88 mc->mc_pc = (intptr_t)_ctx_start; 89 90 /* Construct argument list. */ 91 va_start(ap, argc); 92 #if defined(__mips_o32) || defined(__mips_o64) 93 /* Up to the first four arguments are passed in $a0-3. */ 94 for (i = 0; i < argc && i < 4; i++) 95 /* LINTED register_t is safe */ 96 mc->mc_regs[A0 + i] = va_arg(ap, register_t); 97 /* Skip over the $a0-3 gap. */ 98 sp += 4; 99 #endif 100 #if defined(__mips_n32) || defined(__mips_n64) 101 /* Up to the first 8 arguments are passed in $a0-7. */ 102 for (i = 0; i < argc && i < 8; i++) 103 /* LINTED register_t is safe */ 104 mc->mc_regs[A0 + i] = va_arg(ap, register_t); 105 #endif 106 /* Pass remaining arguments on the stack. */ 107 for (; i < argc; i++) 108 /* LINTED register_t is safe */ 109 *sp++ = va_arg(ap, register_t); 110 va_end(ap); 111 } 112 113 void 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