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#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29/*
30 * Debugger co-routine context support.  kmdb co-routines are essentially the
31 * same as the ones used by mdb, with the exception that we allocate the stack
32 * for the co-routine from our heap.
33 */
34
35#include <kmdb/kmdb_context_impl.h>
36#include <mdb/mdb_modapi.h>
37#include <mdb/mdb_debug.h>
38#include <mdb/mdb_err.h>
39#include <mdb/mdb_umem.h>
40#include <mdb/mdb.h>
41
42#include <sys/types.h>
43
44#include <ucontext.h>
45#include <setjmp.h>
46
47static void
48context_init(mdb_context_t *volatile c)
49{
50	c->ctx_status = c->ctx_func();
51	ASSERT(c->ctx_resumes > 0);
52	longjmp(c->ctx_pcb, 1);
53}
54
55mdb_context_t *
56mdb_context_create(int (*func)(void))
57{
58	mdb_context_t *c = mdb_zalloc(sizeof (mdb_context_t), UM_NOSLEEP);
59	size_t pagesize = mdb.m_pagesize;
60
61	if (c == NULL)
62		return (NULL);
63
64	c->ctx_func = func;
65	c->ctx_stacksize = pagesize * 4;
66	c->ctx_stack = mdb_alloc_align(c->ctx_stacksize, pagesize, UM_NOSLEEP);
67
68	if (c->ctx_stack == NULL) {
69		mdb_free(c, sizeof (mdb_context_t));
70		return (NULL);
71	}
72
73	kmdb_makecontext(&c->ctx_uc, (void (*)(void *))context_init, c,
74	    c->ctx_stack, c->ctx_stacksize);
75
76	return (c);
77}
78
79void
80mdb_context_destroy(mdb_context_t *c)
81{
82	mdb_free_align(c->ctx_stack, c->ctx_stacksize);
83	mdb_free(c, sizeof (mdb_context_t));
84}
85
86void
87mdb_context_switch(mdb_context_t *c)
88{
89	if (setjmp(c->ctx_pcb) == 0 && kmdb_setcontext(&c->ctx_uc) == -1)
90		fail("failed to change context to %p", (void *)c);
91	else
92		fail("unexpectedly returned from context %p", (void *)c);
93}
94
95jmp_buf *
96mdb_context_getpcb(mdb_context_t *c)
97{
98	c->ctx_resumes++;
99	return (&c->ctx_pcb);
100}
101