1 /* $NetBSD: makecontext.c,v 1.2 2003/01/18 11:06:24 thorpej Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-2-Clause 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 <stdlib.h> 35 #include <stddef.h> 36 #include <inttypes.h> 37 #include <ucontext.h> 38 39 #include <stdarg.h> 40 41 extern void _ctx_start(void); 42 43 void 44 ctx_done(ucontext_t *ucp) 45 { 46 47 if (ucp->uc_link == NULL) 48 exit(0); 49 else { 50 setcontext((const ucontext_t *)ucp->uc_link); 51 abort(); 52 } 53 } 54 55 __weak_reference(__makecontext, makecontext); 56 57 void 58 __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 59 { 60 __greg_t *gr = ucp->uc_mcontext.__gregs; 61 int i; 62 unsigned int *sp; 63 va_list ap; 64 65 /* Compute and align stack pointer. */ 66 sp = (unsigned int *) 67 (((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size - 68 sizeof(double)) & ~7); 69 /* Allocate necessary stack space for arguments exceeding r0-3. */ 70 if (argc > 4) 71 sp -= argc - 4; 72 gr[_REG_SP] = (__greg_t)sp; 73 /* Wipe out frame pointer. */ 74 gr[_REG_FP] = 0; 75 /* Arrange for return via the trampoline code. */ 76 gr[_REG_PC] = (__greg_t)_ctx_start; 77 gr[_REG_R4] = (__greg_t)func; 78 gr[_REG_R5] = (__greg_t)ucp; 79 80 va_start(ap, argc); 81 /* Pass up to four arguments in r0-3. */ 82 for (i = 0; i < argc && i < 4; i++) 83 gr[_REG_R0 + i] = va_arg(ap, int); 84 /* Pass any additional arguments on the stack. */ 85 for (argc -= i; argc > 0; argc--) 86 *sp++ = va_arg(ap, int); 87 va_end(ap); 88 } 89