1 /* $NetBSD: makecontext.c,v 1.1 2004/07/18 22:37:32 chs 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(LIBC_SCCS) && !defined(lint) 41 __RCSID("$NetBSD: makecontext.c,v 1.1 2004/07/18 22:37:32 chs Exp $"); 42 #endif 43 44 #include <inttypes.h> 45 #include <stddef.h> 46 #include <ucontext.h> 47 #include "extern.h" 48 49 #include <stdarg.h> 50 51 #include <sys/types.h> 52 #include <machine/frame.h> 53 54 void 55 makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 56 { 57 __greg_t *gr = ucp->uc_mcontext.__gregs; 58 __greg_t *gp, rp, fp; 59 register __greg_t dp __asm__("r27"); 60 uintptr_t *sp; 61 int i; 62 va_list ap; 63 64 void __resumecontext(void); 65 66 /* LINTED uintptr_t is safe */ 67 sp = (uintptr_t *)ucp->uc_stack.ss_sp; 68 /* LINTED uintptr_t is safe */ 69 sp += 16; /* standard frame */ 70 sp += (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */ 71 sp = (uintptr_t *) 72 ((uintptr_t)(sp + 16) & ~0x3f); /* Align on 64-byte boundary. */ 73 74 /* Save away the registers that we'll need. */ 75 gr[_REG_SP] = (__greg_t)sp; 76 rp = (__greg_t)__resumecontext; 77 if (rp & 2) { 78 gp = (__greg_t *)(rp & ~3); 79 rp = gp[0]; 80 sp[-8] = gp[1]; 81 } 82 gr[_REG_RP] = rp; 83 fp = (__greg_t)func; 84 if (fp & 2) { 85 gp = (__greg_t *)(fp & ~3); 86 fp = gp[0]; 87 gr[_REG_R19] = gp[1]; 88 } 89 gr[_REG_PCOQH] = fp | HPPA_PC_PRIV_USER; 90 gr[_REG_PCOQT] = (fp + 4) | HPPA_PC_PRIV_USER; 91 gr[_REG_DP] = dp; 92 93 /* Construct argument list. */ 94 va_start(ap, argc); 95 /* Up to the first four arguments are passed in %arg0-3. */ 96 for (i = 0; i < argc && i < 4; i++) { 97 /* LINTED uintptr_t is safe */ 98 gr[_REG_ARG0 - i] = va_arg(ap, uintptr_t); 99 } 100 /* Pass remaining arguments on the stack below the %arg0-3 gap. */ 101 for (; i < argc; i++) { 102 /* LINTED uintptr_t is safe */ 103 sp[-9 - i] = va_arg(ap, uintptr_t); 104 } 105 va_end(ap); 106 } 107