/* $NetBSD: makecontext.c,v 1.8 2016/08/10 16:40:24 skrll Exp $ */ /*- * Copyright (c) 2001 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Klaus Klein. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include <sys/cdefs.h> #if defined(LIBC_SCCS) && !defined(lint) __RCSID("$NetBSD: makecontext.c,v 1.8 2016/08/10 16:40:24 skrll Exp $"); #endif #include <inttypes.h> #include <stddef.h> #include <ucontext.h> #include "extern.h" #include <stdarg.h> void __resumecontext(void) __dead; void makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) { __greg_t *gr = ucp->uc_mcontext.__gregs; __greg_t *sp; int i; va_list ap; /* LINTED uintptr_t is safe */ sp = (__greg_t *) ((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); /* LINTED uintptr_t is safe */ #if defined(__mips_o32) || defined(__mips_o64) sp -= (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */ sp = (__greg_t *) ((uintptr_t)sp & ~0x7); /* Align on double-word boundary. */ #elif defined(__mips_n32) || defined(__mips_n64) sp -= (argc > 8 ? argc - 8 : 0); /* Make room for > 8 arguments. */ sp = (__greg_t *) ((uintptr_t)sp & ~0xf); /* Align on quad-word boundary. */ #endif gr[_REG_SP] = (intptr_t)sp; gr[_REG_RA] = (intptr_t)__resumecontext; gr[_REG_T9] = (intptr_t)func; /* required for .abicalls */ gr[_REG_EPC] = (intptr_t)func; /* Construct argument list. */ va_start(ap, argc); #if defined(__mips_o32) || defined(__mips_o64) /* Up to the first four arguments are passed in $a0-3. */ for (i = 0; i < argc && i < 4; i++) /* LINTED __greg_t is safe */ gr[_REG_A0 + i] = va_arg(ap, __greg_t); /* Pass remaining arguments on the stack above the $a0-3 gap. */ sp += i; #endif #if defined(__mips_n32) || defined(__mips_n64) /* Up to the first 8 arguments are passed in $a0-7. */ for (i = 0; i < argc && i < 8; i++) /* LINTED __greg_t is safe */ gr[_REG_A0 + i] = va_arg(ap, __greg_t); /* Pass remaining arguments on the stack */ #endif for (; i < argc; i++) /* LINTED uintptr_t is safe */ *sp++ = va_arg(ap, __greg_t); va_end(ap); }