11.6Sriastrad/* $NetBSD: makecontext.c,v 1.6 2025/04/24 23:56:25 riastradh Exp $ */ 21.2Sthorpej 31.2Sthorpej/*- 41.2Sthorpej * Copyright (c) 2001 The NetBSD Foundation, Inc. 51.2Sthorpej * All rights reserved. 61.2Sthorpej * 71.2Sthorpej * This code is derived from software contributed to The NetBSD Foundation 81.2Sthorpej * by Klaus Klein. 91.2Sthorpej * 101.2Sthorpej * Redistribution and use in source and binary forms, with or without 111.2Sthorpej * modification, are permitted provided that the following conditions 121.2Sthorpej * are met: 131.2Sthorpej * 1. Redistributions of source code must retain the above copyright 141.2Sthorpej * notice, this list of conditions and the following disclaimer. 151.2Sthorpej * 2. Redistributions in binary form must reproduce the above copyright 161.2Sthorpej * notice, this list of conditions and the following disclaimer in the 171.2Sthorpej * documentation and/or other materials provided with the distribution. 181.2Sthorpej * 191.2Sthorpej * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 201.2Sthorpej * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 211.2Sthorpej * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 221.2Sthorpej * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 231.2Sthorpej * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 241.2Sthorpej * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 251.2Sthorpej * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 261.2Sthorpej * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 271.2Sthorpej * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 281.2Sthorpej * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 291.2Sthorpej * POSSIBILITY OF SUCH DAMAGE. 301.2Sthorpej */ 311.2Sthorpej 321.2Sthorpej#include <sys/cdefs.h> 331.2Sthorpej#if defined(LIBC_SCCS) && !defined(lint) 341.6Sriastrad__RCSID("$NetBSD: makecontext.c,v 1.6 2025/04/24 23:56:25 riastradh Exp $"); 351.2Sthorpej#endif 361.2Sthorpej 371.5Smartin#include <sys/param.h> 381.6Sriastrad 391.2Sthorpej#include <inttypes.h> 401.6Sriastrad#include <stdarg.h> 411.2Sthorpej#include <stddef.h> 421.2Sthorpej#include <ucontext.h> 431.6Sriastrad 441.2Sthorpej#include "extern.h" 451.2Sthorpej 461.2Sthorpejvoid 471.2Sthorpejmakecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 481.2Sthorpej{ 491.2Sthorpej __greg_t *gr = ucp->uc_mcontext.__gregs; 501.2Sthorpej int i; 511.2Sthorpej unsigned long *sp; 521.2Sthorpej va_list ap; 531.2Sthorpej 541.2Sthorpej sp = (unsigned long *) 551.2Sthorpej ((unsigned long)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); 561.2Sthorpej /* Make room for: rwindow, struct return pointer, argd, argx */ 571.2Sthorpej sp -= 8 + 8 + 1 + 6 + 1; /* CCFSZ, only in words */ 581.2Sthorpej /* CCFSZ provides space for up to 7 arguments, add more if necessary */ 591.2Sthorpej if (argc > 7) 601.2Sthorpej sp -= argc - 7; 611.2Sthorpej /* Align on double-word boundary. */ 621.4Sriastrad sp = (unsigned long *)((unsigned long)sp & ~STACK_ALIGNBYTES); 631.2Sthorpej 641.2Sthorpej gr[_REG_O6] = (__greg_t)sp; 651.2Sthorpej gr[_REG_PC] = (__greg_t)func; 661.2Sthorpej gr[_REG_nPC] = (__greg_t)func + 4; 671.2Sthorpej gr[_REG_O7] = (__greg_t)_resumecontext - 8; 681.2Sthorpej 691.2Sthorpej va_start(ap, argc); 701.2Sthorpej /* Pass up to 6 arguments in %o0..%o5. */ 711.2Sthorpej for (i = 0; i < argc && i < 6; i++) 721.2Sthorpej gr[_REG_O0 + i] = va_arg(ap, unsigned long); 731.2Sthorpej /* Pass any additional arguments on the stack. */ 741.2Sthorpej for (/* i = 6 */; i < argc; i++) 751.2Sthorpej sp[8 + 8 + 1 + 6 + (i - 6)] = va_arg(ap, unsigned long); 761.2Sthorpej va_end(ap); 771.2Sthorpej} 78