minix/lib/nbsd_libc/arch/x86_64/gen/makecontext.c
Gianluca Guida b6cbf7203b Import unmodified NetBSD libc in trunk
This patch imports the unmodified current version of NetBSD libc.
The NetBSD includes are in /nbsd_include, while the libc code itself is 
split between lib/nbsd_libc and common/lib/libc.
2011-02-14 19:36:03 +00:00

97 lines
3 KiB
C

/* $NetBSD: makecontext.c,v 1.4 2009/07/30 20:57:17 dsl Exp $ */
/*-
* Copyright (c) 1999 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.
*
* Modified from the i386 version for x86_64 by fvdl@wasabisystems.com.
*
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: makecontext.c,v 1.4 2009/07/30 20:57:17 dsl Exp $");
#endif
#include <inttypes.h>
#include <stddef.h>
#include <ucontext.h>
#include "extern.h"
#include <stdarg.h>
void
makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
{
__greg_t *gr = ucp->uc_mcontext.__gregs;
uintptr_t *sp;
va_list ap;
int stackargs, i;
stackargs = argc - 6;
/* LINTED __greg_t is safe */
gr[_REG_RIP] = (__greg_t)func;
/* LINTED uintptr_t is safe */
sp = (uintptr_t *)
((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
/* LINTED uintptr_t is safe */
sp = (uintptr_t *)(((uintptr_t)sp & ~15));
sp--;
if (stackargs > 0)
sp -= stackargs;
/* LINTED __greg_t is safe */
gr[_REG_RSP] = (__greg_t)sp;
gr[_REG_RBP] = (__greg_t)0; /* Wipe out frame pointer. */
/* Put return address on top of stack. */
/* LINTED uintptr_t is safe */
*sp++ = (uintptr_t)_resumecontext;
/*
* Construct argument list.
* The registers used to pass the first 6 arguments
* (rdi, rsi, rdx, rcx, r8, r9) are the first 6 in gregs,
* in that order, so those arguments can just be copied to
* the gregs array.
*/
va_start(ap, argc);
for (i = 0; i < 6 && argc > 0; i++) {
argc--;
/* LINTED __greg_t is safe */
gr[i] = va_arg(ap, __greg_t);
}
while (stackargs-- > 0) {
/* LINTED uintptr_t is safe */
*sp++ = va_arg(ap, uintptr_t);
}
va_end(ap);
}