1 /* $NetBSD: makecontext.c,v 1.2 2003/01/18 11:06:24 thorpej 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include <stdlib.h> 43 #include <stddef.h> 44 #include <inttypes.h> 45 #include <ucontext.h> 46 47 #include <stdarg.h> 48 49 extern void _ctx_start(void); 50 51 void 52 ctx_done(ucontext_t *ucp) 53 { 54 55 if (ucp->uc_link == NULL) 56 exit(0); 57 else { 58 setcontext((const ucontext_t *)ucp->uc_link); 59 abort(); 60 } 61 } 62 63 __weak_reference(__makecontext, makecontext); 64 65 void 66 __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 67 { 68 __greg_t *gr = ucp->uc_mcontext.__gregs; 69 int i; 70 unsigned int *sp; 71 va_list ap; 72 73 /* Compute and align stack pointer. */ 74 sp = (unsigned int *) 75 (((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size - 76 sizeof(double)) & ~7); 77 /* Allocate necessary stack space for arguments exceeding r0-3. */ 78 if (argc > 4) 79 sp -= argc - 4; 80 gr[_REG_SP] = (__greg_t)sp; 81 /* Wipe out frame pointer. */ 82 gr[_REG_FP] = 0; 83 /* Arrange for return via the trampoline code. */ 84 gr[_REG_PC] = (__greg_t)_ctx_start; 85 gr[_REG_R4] = (__greg_t)func; 86 gr[_REG_R5] = (__greg_t)ucp; 87 88 va_start(ap, argc); 89 /* Pass up to four arguments in r0-3. */ 90 for (i = 0; i < argc && i < 4; i++) 91 gr[_REG_R0 + i] = va_arg(ap, int); 92 /* Pass any additional arguments on the stack. */ 93 for (argc -= i; argc > 0; argc--) 94 *sp++ = va_arg(ap, int); 95 va_end(ap); 96 } 97