1 /* $NetBSD: makecontext.c,v 1.2 2003/01/18 11:06:24 thorpej 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 __FBSDID("$FreeBSD$"); 34 35 #include <stdlib.h> 36 #include <stddef.h> 37 #include <inttypes.h> 38 #include <ucontext.h> 39 40 #include <stdarg.h> 41 42 extern void _ctx_start(void); 43 44 void 45 ctx_done(ucontext_t *ucp) 46 { 47 48 if (ucp->uc_link == NULL) 49 exit(0); 50 else { 51 setcontext((const ucontext_t *)ucp->uc_link); 52 abort(); 53 } 54 } 55 56 __weak_reference(__makecontext, makecontext); 57 58 void 59 __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 60 { 61 __greg_t *gr = ucp->uc_mcontext.__gregs; 62 int i; 63 unsigned int *sp; 64 va_list ap; 65 66 /* Compute and align stack pointer. */ 67 sp = (unsigned int *) 68 (((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size - 69 sizeof(double)) & ~7); 70 /* Allocate necessary stack space for arguments exceeding r0-3. */ 71 if (argc > 4) 72 sp -= argc - 4; 73 gr[_REG_SP] = (__greg_t)sp; 74 /* Wipe out frame pointer. */ 75 gr[_REG_FP] = 0; 76 /* Arrange for return via the trampoline code. */ 77 gr[_REG_PC] = (__greg_t)_ctx_start; 78 gr[_REG_R4] = (__greg_t)func; 79 gr[_REG_R5] = (__greg_t)ucp; 80 81 va_start(ap, argc); 82 /* Pass up to four arguments in r0-3. */ 83 for (i = 0; i < argc && i < 4; i++) 84 gr[_REG_R0 + i] = va_arg(ap, int); 85 /* Pass any additional arguments on the stack. */ 86 for (argc -= i; argc > 0; argc--) 87 *sp++ = va_arg(ap, int); 88 va_end(ap); 89 } 90