1 /* $NetBSD: makecontext.c,v 1.3 2008/04/28 20:22:56 martin 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 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$NetBSD: makecontext.c,v 1.3 2008/04/28 20:22:56 martin Exp $"); 35 #endif 36 37 #include <inttypes.h> 38 #include <stddef.h> 39 #include <ucontext.h> 40 #include "extern.h" 41 42 #include <stdarg.h> 43 44 #include <sys/types.h> 45 #include <machine/frame.h> 46 47 void 48 makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 49 { 50 __greg_t *gr = ucp->uc_mcontext.__gregs; 51 __greg_t *gp, rp, fp; 52 register __greg_t dp __asm("r27"); 53 uintptr_t *sp; 54 int i; 55 va_list ap; 56 57 void __resumecontext(void); 58 59 /* LINTED uintptr_t is safe */ 60 sp = (uintptr_t *)ucp->uc_stack.ss_sp; 61 /* LINTED uintptr_t is safe */ 62 sp += 16; /* standard frame */ 63 sp += (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */ 64 sp = (uintptr_t *) 65 ((uintptr_t)(sp + 16) & ~0x3f); /* Align on 64-byte boundary. */ 66 67 /* Save away the registers that we'll need. */ 68 gr[_REG_SP] = (__greg_t)sp; 69 rp = (__greg_t)__resumecontext; 70 if (rp & 2) { 71 gp = (__greg_t *)(rp & ~3); 72 rp = gp[0]; 73 sp[-8] = gp[1]; 74 } 75 gr[_REG_RP] = rp; 76 fp = (__greg_t)func; 77 if (fp & 2) { 78 gp = (__greg_t *)(fp & ~3); 79 fp = gp[0]; 80 gr[_REG_R19] = gp[1]; 81 } 82 gr[_REG_PCOQH] = fp | HPPA_PC_PRIV_USER; 83 gr[_REG_PCOQT] = (fp + 4) | HPPA_PC_PRIV_USER; 84 gr[_REG_DP] = dp; 85 86 /* Construct argument list. */ 87 va_start(ap, argc); 88 /* Up to the first four arguments are passed in %arg0-3. */ 89 for (i = 0; i < argc && i < 4; i++) { 90 /* LINTED uintptr_t is safe */ 91 gr[_REG_ARG0 - i] = va_arg(ap, uintptr_t); 92 } 93 /* Pass remaining arguments on the stack below the %arg0-3 gap. */ 94 for (; i < argc; i++) { 95 /* LINTED uintptr_t is safe */ 96 sp[-9 - i] = va_arg(ap, uintptr_t); 97 } 98 va_end(ap); 99 } 100