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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1988 AT&T */
/* All Rights Reserved */
#pragma ident "%Z%%M% %I% %E% SMI"
#pragma weak _makecontext = makecontext
#include "lint.h"
#include <stdarg.h>
#include <ucontext.h>
#include <sys/stack.h>
/*
* The ucontext_t that the user passes in must have been primed with a
* call to getcontext(2), have the uc_stack member set to reflect the
* stack which this context will use, and have the uc_link member set
* to the context which should be resumed when this context returns.
* When makecontext() returns, the ucontext_t will be set to run the
* given function with the given parameters on the stack specified by
* uc_stack, and which will return to the ucontext_t specified by uc_link.
*/
static void resumecontext(void);
void
makecontext(ucontext_t *ucp, void (*func)(), int argc, ...)
{
long *sp;
long *tsp;
va_list ap;
size_t size;
int pusharg = (argc > 6 ? argc - 6 : 0);
greg_t tmp;
int i;
ucp->uc_mcontext.gregs[REG_PC] = (greg_t)func;
size = sizeof (long) * (pusharg + 1);
/*
* Calculate new value for %rsp. On entry to a function,
* %rsp must be STACK_ENTRY_ALIGNed but not STACK_ALIGNed.
* This is because the pushq %rbp will correct the alignment.
*/
sp = (long *)(((uintptr_t)ucp->uc_stack.ss_sp +
ucp->uc_stack.ss_size - size) & ~(STACK_ENTRY_ALIGN - 1));
if (((uintptr_t)sp & (STACK_ALIGN - 1ul)) == 0)
sp -= STACK_ENTRY_ALIGN / sizeof (*sp);
tsp = sp + 1;
va_start(ap, argc);
for (i = 0; i < argc; i++) {
tmp = va_arg(ap, long);
switch (i) {
case 0:
ucp->uc_mcontext.gregs[REG_RDI] = tmp;
break;
case 1:
ucp->uc_mcontext.gregs[REG_RSI] = tmp;
break;
case 2:
ucp->uc_mcontext.gregs[REG_RDX] = tmp;
break;
case 3:
ucp->uc_mcontext.gregs[REG_RCX] = tmp;
break;
case 4:
ucp->uc_mcontext.gregs[REG_R8] = tmp;
break;
case 5:
ucp->uc_mcontext.gregs[REG_R9] = tmp;
break;
default:
*tsp++ = tmp;
break;
}
}
va_end(ap);
*sp = (long)resumecontext; /* return address */
ucp->uc_mcontext.gregs[REG_SP] = (greg_t)sp;
}
static void
resumecontext(void)
{
ucontext_t uc;
(void) getcontext(&uc);
(void) setcontext(uc.uc_link);
}
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