kmdb_makecontext.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (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 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Context-saving routine used for pipelines. Designed for use only
* with kmdb_setcontext, and with the assumption that func() will never
* return.
*/
#include <strings.h>
#include <ucontext.h>
#include <sys/types.h>
#include <sys/stack.h>
#include <kmdb/kmdb_context_impl.h>
#include <mdb/mdb_kreg.h>
void
kmdb_makecontext(ucontext_t *ucp, void (*func)(void *), void *arg, caddr_t stk,
size_t stksize)
{
/*
* Top-of-stack must be rounded down to STACK_ALIGN and
* there must be a minimum frame for the register window.
*/
uintptr_t stack = (((uintptr_t)stk + stksize - 1) &
~(STACK_ALIGN - 1)) - SA(MINFRAME);
/* clear the top stack frame */
bzero((void *)stack, SA(MINFRAME));
/* fill in registers of interest */
ucp->uc_mcontext.gregs[REG_PC] = (greg_t)func;
ucp->uc_mcontext.gregs[REG_nPC] = (greg_t)func + 4;
ucp->uc_mcontext.gregs[REG_O0] = (greg_t)arg;
ucp->uc_mcontext.gregs[REG_SP] = (greg_t)(stack - STACK_BIAS);
ucp->uc_mcontext.gregs[REG_O7] = NULL;
ucp->uc_mcontext.gregs[REG_G7] = NULL;
}