lib/libc/arch/i386/gen/_lwp.c

   1 /*      $NetBSD: _lwp.c,v 1.6 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 Nathan J. Williams.
   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: _lwp.c,v 1.6 2008/04/28 20:22:56 martin Exp $");
  35 #endif /* LIBC_SCCS and not lint */
  36
  37 #include "namespace.h"
  38 #include <sys/types.h>
  39 #include <inttypes.h>
  40 #include <ucontext.h>
  41 #include <lwp.h>
  42 #include <stdlib.h>
  43
  44 void
  45 _lwp_makecontext(ucontext_t *u, void (*start)(void *),
  46     void *arg, void *private, caddr_t stack_base, size_t stack_size)
  47 {
  48         void **sp;
  49
  50         getcontext(u);
  51         u->uc_link = NULL;
  52
  53         u->uc_stack.ss_sp = stack_base;
  54         u->uc_stack.ss_size = stack_size;
  55
  56         /* LINTED uintptr_t is safe */
  57         u->uc_mcontext.__gregs[_REG_EIP] = (uintptr_t)start;
  58
  59         /* Align to a word */
  60         /* LINTED uintptr_t is safe */
  61         sp = (void **) ((uintptr_t)(stack_base + stack_size) & ~0x3);
  62
  63         *--sp = arg;
  64         *--sp = (void *) _lwp_exit;
  65
  66         /* LINTED uintptr_t is safe */
  67         u->uc_mcontext.__gregs[_REG_UESP] = (uintptr_t) sp;
  68
  69         /* LINTED private is currently unused */
  70 }