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, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2004 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 31 #pragma ident "%Z%%M% %I% %E% SMI" 32 33 #pragma weak makecontext = _makecontext 34 35 #include "synonyms.h" 36 #include <stdarg.h> 37 #include <ucontext.h> 38 #include <sys/stack.h> 39 40 /* 41 * The ucontext_t that the user passes in must have been primed with a 42 * call to getcontext(2), have the uc_stack member set to reflect the 43 * stack which this context will use, and have the uc_link member set 44 * to the context which should be resumed when this context returns. 45 * When makecontext() returns, the ucontext_t will be set to run the 46 * given function with the given parameters on the stack specified by 47 * uc_stack, and which will return to the ucontext_t specified by uc_link. 48 */ 49 50 static void resumecontext(void); 51 52 void 53 makecontext(ucontext_t *ucp, void (*func)(), int argc, ...) 54 { 55 long *sp; 56 long *tsp; 57 va_list ap; 58 size_t size; 59 int pusharg = (argc > 6 ? argc - 6 : 0); 60 greg_t tmp; 61 int i; 62 63 ucp->uc_mcontext.gregs[REG_PC] = (greg_t)func; 64 65 size = sizeof (long) * (pusharg + 1); 66 67 /* 68 * Calculate new value for %rsp. On entry to a function, 69 * %rsp must be STACK_ENTRY_ALIGNed but not STACK_ALIGNed. 70 * This is because the pushq %rbp will correct the alignment. 71 */ 72 73 sp = (long *)(((uintptr_t)ucp->uc_stack.ss_sp + 74 ucp->uc_stack.ss_size - size) & ~(STACK_ENTRY_ALIGN - 1)); 75 76 if (((uintptr_t)sp & (STACK_ALIGN - 1ul)) == 0) 77 sp -= STACK_ENTRY_ALIGN / sizeof (*sp); 78 79 tsp = sp + 1; 80 81 va_start(ap, argc); 82 83 for (i = 0; i < argc; i++) { 84 tmp = va_arg(ap, long); 85 switch (i) { 86 case 0: 87 ucp->uc_mcontext.gregs[REG_RDI] = tmp; 88 break; 89 case 1: 90 ucp->uc_mcontext.gregs[REG_RSI] = tmp; 91 break; 92 case 2: 93 ucp->uc_mcontext.gregs[REG_RDX] = tmp; 94 break; 95 case 3: 96 ucp->uc_mcontext.gregs[REG_RCX] = tmp; 97 break; 98 case 4: 99 ucp->uc_mcontext.gregs[REG_R8] = tmp; 100 break; 101 case 5: 102 ucp->uc_mcontext.gregs[REG_R9] = tmp; 103 break; 104 default: 105 *tsp++ = tmp; 106 break; 107 } 108 } 109 110 va_end(ap); 111 112 *sp = (long)resumecontext; /* return address */ 113 114 ucp->uc_mcontext.gregs[REG_SP] = (greg_t)sp; 115 } 116 117 118 static void 119 resumecontext(void) 120 { 121 ucontext_t uc; 122 123 getcontext(&uc); 124 setcontext(uc.uc_link); 125 } 126