1 /* $NetBSD: makecontext.c,v 1.4 2008/04/28 20:22:57 martin 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 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$NetBSD: makecontext.c,v 1.4 2008/04/28 20:22:57 martin Exp $"); 35 #endif 36 37 #include <inttypes.h> 38 #include <stddef.h> 39 #include <sys/types.h> 40 #include <ucontext.h> 41 #include "extern.h" 42 43 #include <stdarg.h> 44 45 void 46 makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 47 { 48 __greg_t *gr = ucp->uc_mcontext.__gregs; 49 int i; 50 ulong *sp; 51 va_list ap; 52 53 sp = (ulong *)((caddr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); 54 /* Align on quad-word boundary. */ 55 sp = (ulong *)((ulong)sp & ~0xf); 56 57 /* Make room for: argx, argd, struct return pointer(?), rwindow. */ 58 sp -= (argc > 6 ? argc - 6 : 0) + 6 + 8 + 8; 59 60 va_start(ap, argc); 61 62 /* Pass up to 6 arguments in %o0-5. */ 63 for (i = 0; i < argc && i < 6; i++) 64 gr[_REG_O0 + i] = sp[i + 16] = va_arg(ap, unsigned long); 65 66 /* Pass any additional arguments on the stack. */ 67 for (; i < argc; i++) 68 sp[i + 16] = va_arg(ap, unsigned long); 69 va_end(ap); 70 71 sp[14] = (ulong)sp - 2047; 72 sp[15] = (ulong)_resumecontext - 8; 73 74 sp = (ulong *)((caddr_t)sp - 2047); 75 76 gr[_REG_O6] = (__greg_t)sp; 77 gr[_REG_PC] = (__greg_t)func; 78 gr[_REG_nPC] = (__greg_t)func + 4; 79 gr[_REG_O7] = (__greg_t)_resumecontext - 8; 80 81 } 82