83 lines
2.8 KiB
C
83 lines
2.8 KiB
C
|
/* $NetBSD: makecontext.c,v 1.3 2008/04/28 20:22:57 martin 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 1.3 2008/04/28 20:22:57 martin Exp $");
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#include <inttypes.h>
|
||
|
|
#include <stddef.h>
|
||
|
|
#include <ucontext.h>
|
||
|
|
#include "extern.h"
|
||
|
|
|
||
|
|
#if __STDC__
|
||
|
|
#include <stdarg.h>
|
||
|
|
#else
|
||
|
|
#include <varargs.h>
|
||
|
|
#endif
|
||
|
|
|
||
|
|
void
|
||
|
|
makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
|
||
|
|
{
|
||
|
|
__greg_t *gr = ucp->uc_mcontext.__gregs;
|
||
|
|
__greg_t sp, *spp;
|
||
|
|
int i;
|
||
|
|
va_list ap;
|
||
|
|
|
||
|
|
sp = (__greg_t) ((uintptr_t)ucp->uc_stack.ss_sp
|
||
|
|
+ ucp->uc_stack.ss_size);
|
||
|
|
sp -= 2 + (argc > 8 ? argc - 8: 0); /* Make room for call frame. */
|
||
|
|
sp = (__greg_t) ((uintptr_t)sp & ~0xf);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Start executing at <func> -- when <func> completes, return to
|
||
|
|
* <_resumecontext>.
|
||
|
|
*/
|
||
|
|
gr[_REG_R1] = sp;
|
||
|
|
gr[_REG_LR] = (__greg_t)_resumecontext;
|
||
|
|
gr[_REG_PC] = (__greg_t)func; // XXX -- this is the descriptor address!
|
||
|
|
|
||
|
|
/* Wipe out stack frame backchain pointer. */
|
||
|
|
spp = (__greg_t *)sp;
|
||
|
|
*spp = 0;
|
||
|
|
|
||
|
|
/* Construct argument list. */
|
||
|
|
va_start(ap, argc);
|
||
|
|
/* Up to the first eight arguments are passed in r3-10. */
|
||
|
|
for (i = 0; i < argc && i < 8; i++)
|
||
|
|
gr[_REG_R3 + i] = va_arg(ap, long);
|
||
|
|
/* Pass remaining arguments on the stack above the backchain/lr gap. */
|
||
|
|
for (spp += 2; i < argc; i++)
|
||
|
|
*spp++ = va_arg(ap, long);
|
||
|
|
va_end(ap);
|
||
|
|
}
|