minix/lib/libc/arch/vax/gen/_lwp.c

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/* $NetBSD: _lwp.c,v 1.3 2012/03/22 17:32:22 christos Exp $ */
/*-
* Copyright (c) 2009 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas
*
* 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: _lwp.c,v 1.3 2012/03/22 17:32:22 christos Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <inttypes.h>
#include <ucontext.h>
#include <lwp.h>
#include <stdlib.h>
void
_lwp_makecontext(ucontext_t *u, void (*start)(void *),
void *arg, void *private, caddr_t stack_base, size_t stack_size)
{
__greg_t *gr = u->uc_mcontext.__gregs;
int *sp;
getcontext(u);
u->uc_link = NULL;
u->uc_stack.ss_sp = stack_base;
u->uc_stack.ss_size = stack_size;
/* Align to a word */
/* LINTED uintptr_t is safe */
sp = (int *)((uintptr_t)(stack_base + stack_size) & ~0x3);
/*
* Allocate necessary stack space for arguments including arg count
* and call frame
*/
sp -= 1 + 1 + 5;
sp[0] = 0; /* condition handler is null */
sp[1] = 0x20000000; /* make this a CALLS frame */
sp[2] = 0; /* saved argument pointer */
sp[3] = 0; /* saved frame pointer */
sp[4] = (int)(uintptr_t)_lwp_exit + 2;/* return via _lwp_exit */
sp[5] = 1; /* argc */
sp[6] = (int)(uintptr_t)arg; /* argv */
gr[_REG_AP] = (__greg_t)(uintptr_t)(sp + 5);
gr[_REG_SP] = (__greg_t)(uintptr_t)sp;
gr[_REG_FP] = (__greg_t)(uintptr_t)sp;
gr[_REG_PC] = (__greg_t)(uintptr_t)start + 2;
/*
* Push the TLS pointer onto the new stack also.
* The _UC_TLSBASE flag tells the kernel to pop it and use it.
*/
*--sp = (int)(intptr_t)private;
gr[_REG_SP] = (__greg_t)(uintptr_t)sp;
u->uc_flags |= _UC_TLSBASE;
}