1/*	$NetBSD: subr_spldebug.c,v 1.2 2009/11/24 17:28:32 dyoung Exp $	*/
2
3/*-
4 * Copyright (c) 2009, 2010 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by David Young.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * Interrupt priority level debugging code.
34 */
35
36#include <sys/cdefs.h>
37__KERNEL_RCSID(0, "$NetBSD: subr_spldebug.c,v 1.2 2009/11/24 17:28:32 dyoung Exp $");
38
39#include <sys/param.h>
40#include <sys/spldebug.h>
41#include <sys/systm.h>
42#include <sys/kernel.h>
43#include <sys/cpu.h>
44#include <machine/return.h>
45
46#define SPLRAISE_STACKLEN 32
47
48void *splraise_retaddrs[MAXCPUS][SPLRAISE_STACKLEN][4];
49int splraise_depth[MAXCPUS] = {0};
50int spllowered_to[MAXCPUS] = {0};
51void *spllowered_from[MAXCPUS][2] = {{0}};
52bool spldebug = false;
53
54void	spldebug_start(void);
55void	spldebug_stop(void);
56
57void
58spldebug_start(void)
59{
60	spldebug = true;
61}
62
63void
64spldebug_stop(void)
65{
66	spldebug = false;
67}
68
69void
70spldebug_lower(int ipl)
71{
72	u_int cidx;
73
74	if (!spldebug)
75		return;
76
77	if (ipl == IPL_HIGH)
78		return;
79
80	cidx = cpu_index(curcpu());
81
82	KASSERT(cidx < maxcpus);
83
84	splraise_depth[cidx] = 0;
85	spllowered_to[cidx] = ipl;
86#if 0
87	spllowered_from[cidx][0] = return_address(0);
88	spllowered_from[cidx][1] = return_address(1);
89#endif
90}
91
92void
93spldebug_raise(int ipl)
94{
95	int i;
96	u_int cidx;
97	void **retaddrs;
98
99	if (!spldebug)
100		return;
101
102	if (ipl != IPL_HIGH)
103		return;
104
105	cidx = cpu_index(curcpu());
106
107	KASSERT(cidx < maxcpus);
108
109	if (splraise_depth[cidx] >= SPLRAISE_STACKLEN)
110		return;
111
112	retaddrs = &splraise_retaddrs[cidx][splraise_depth[cidx]++][0];
113
114	retaddrs[0] = retaddrs[1] = retaddrs[2] = retaddrs[3] = NULL;
115
116	for (i = 0; i < 4; i++) {
117		retaddrs[i] = return_address(i);
118
119		if (retaddrs[i] == NULL)
120			break;
121	}
122}
123