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

   1 /*      $NetBSD: _lwp.c,v 1.7 2012/03/21 00:34:04 christos Exp $        */
   2
   3 /*-
   4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  26  * POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 __RCSID("$NetBSD: _lwp.c,v 1.7 2012/03/21 00:34:04 christos Exp $");
  32 #endif /* LIBC_SCCS and not lint */
  33
  34 #include "namespace.h"
  35 #include <sys/types.h>
  36 #include <ucontext.h>
  37 #include <lwp.h>
  38 #include <stdlib.h>
  39
  40 void
  41 _lwp_makecontext(ucontext_t *u, void (*start)(void *), void *arg,
  42                  void *private, caddr_t stack_base, size_t stack_size)
  43 {
  44         __greg_t *gr;
  45         unsigned long *sp;
  46
  47         getcontext(u);
  48         gr = u->uc_mcontext.__gregs;
  49
  50         u->uc_link = NULL;
  51
  52         u->uc_stack.ss_sp = stack_base;
  53         u->uc_stack.ss_size = stack_size;
  54
  55
  56         sp = (void *)(stack_base + stack_size);
  57         sp = (ulong *)((ulong)sp & ~0x07);
  58
  59         /* Make room for the fake caller stack frame (CCFSZ, only in words) */
  60         sp -= 8 + 8 + 1 + 6 + 1;
  61
  62         /* Entering (*start)(arg), return is to _lwp_exit */
  63         gr[_REG_PC] = (ulong) start;
  64         gr[_REG_nPC] = (ulong) start + 4;
  65         gr[_REG_O0] = (ulong)arg;
  66         gr[_REG_O6] = (ulong)sp;
  67         gr[_REG_O7] = (ulong)_lwp_exit - 8;
  68         gr[_REG_G7] = (ulong)private;
  69
  70         /* XXX: uwe: why do we need this? */
  71         /* create loopback in the window save area on the stack? */
  72         sp[8+6] = (ulong)sp;            /* %i6 */
  73         sp[8+7] = (ulong)_lwp_exit - 8; /* %i7 */
  74 }