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 49 void _ctx_done(ucontext_t *); 50 void _ctx_start(void); 51 52 void 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 } 112 113 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