1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1988 AT&T */ 28 /* All Rights Reserved */ 29 30 #pragma ident "%Z%%M% %I% %E% SMI" 31 32 #pragma weak _makecontext = makecontext 33 34 #include "lint.h" 35 #include <stdarg.h> 36 #include <ucontext.h> 37 #include <sys/stack.h> 38 39 /* 40 * The ucontext_t that the user passes in must have been primed with a 41 * call to getcontext(2), have the uc_stack member set to reflect the 42 * stack which this context will use, and have the uc_link member set 43 * to the context which should be resumed when this context returns. 44 * When makecontext() returns, the ucontext_t will be set to run the 45 * given function with the given parameters on the stack specified by 46 * uc_stack, and which will return to the ucontext_t specified by uc_link. 47 */ 48 49 static void resumecontext(void); 50 51 void 52 makecontext(ucontext_t *ucp, void (*func)(), int argc, ...) 53 { 54 long *sp; 55 long *tsp; 56 va_list ap; 57 size_t size; 58 59 ucp->uc_mcontext.gregs[EIP] = (greg_t)func; 60 61 size = sizeof (long) * (argc + 1); 62 63 sp = (long *)(((uintptr_t)ucp->uc_stack.ss_sp + 64 ucp->uc_stack.ss_size - size) & ~(STACK_ALIGN - 1)); 65 66 tsp = sp + 1; 67 68 va_start(ap, argc); 69 70 while (argc-- > 0) { 71 *tsp++ = va_arg(ap, long); 72 } 73 74 va_end(ap); 75 76 *sp = (long)resumecontext; /* return address */ 77 78 ucp->uc_mcontext.gregs[UESP] = (greg_t)sp; 79 } 80 81 82 static void 83 resumecontext(void) 84 { 85 ucontext_t uc; 86 87 (void) getcontext(&uc); 88 (void) setcontext(uc.uc_link); 89 } 90