xref: /illumos-gate/usr/src/cmd/mdb/intel/amd64/kmdb/kmdb_makecontext.c (revision 20a7641f9918de8574b8b3b47dbe35c4bfc78df1)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * Context-saving routine used for pipelines.  Designed for use only
29  * with kmdb_setcontext.
30  */
31 
32 #include <strings.h>
33 #include <ucontext.h>
34 #include <sys/types.h>
35 #include <sys/stack.h>
36 
37 #include <kmdb/kmdb_context_impl.h>
38 #include <mdb/mdb_kreg.h>
39 
40 void
41 kmdb_makecontext(ucontext_t *ucp, void (*func)(void *), void *arg, caddr_t stk,
42     size_t stksize)
43 {
44 	uintptr_t *stack = (uintptr_t *)(((uintptr_t)stk + stksize - 1) &
45 	    ~(STACK_ALIGN - 1));
46 
47 	*stack-- = 0;
48 
49 	ucp->uc_mcontext.gregs[REG_PC] = (greg_t)func;
50 	ucp->uc_mcontext.gregs[REG_SP] = (greg_t)stack;
51 	ucp->uc_mcontext.gregs[REG_RDI] = (greg_t)arg;
52 }
53