1/*
2 * Copyright (c) 2014 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
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25 *
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27 */
28
29#ifndef __IOKIT_IOINTERRUPTACCOUNTING_PRIVATE_H
30#define __IOKIT_IOINTERRUPTACCOUNTING_PRIVATE_H
31
32/*
33 * Header containing interrupt accounting related prototypes/defines that should be kept private to
34 * xnu itself (no userspace, no kexts, no nothing!).
35 */
36
37#include <stdint.h>
38#include <IOKit/IOInterruptAccounting.h>
39#include <kern/queue.h>
40
41class OSObject;
42class IOSimpleReporter;
43
44/*
45 * A brief overview. Interrupt accounting (as implemented in IOKit) pertains to infrastructure for
46 * gathering information (currently, statistics only) on interrupts, and allowing them to be reported
47 * (either to userspace through IOReporting, or through lldb; lldb macros have yet to be implemented).
48 *
49 * Currently, interrupt accounting consists of of a relationship between an IOService (a nub, which
50 * will contain interrupt specifiers), an IOInterruptEventSource (if we add other interrupt target
51 * abstractions, support could be added for them as well), and objects necessary to support them. An
52 * interrupt is "named" by a tuple of {provider, interrupt index}; no nub should ever have more than
53 * one interrupt registered for a given index, so this tuple should be unique.
54 *
55 * The "additional objects" mentioned above consist of an IOReporter object (lazily allocated and
56 * tied to the nub; once allocated it will live until the nub is freed), and a statistics object
57 * (effectively part of the IOIES in terms of lifecycle). The statistics object is used by the
58 * interrupt codepath itself, and by the nub when it needs to update the reporter; the reporter is
59 * used to report values to userspace.
60 *
61 * As a consequence of the above relationship, we do not track statistics for directly registered
62 * interrupt handlers. We have no guarantees what the handler or the target may be; if you don't
63 * follow the generic IOKit interrupt model, you will not be tracked by interrupt accounting. For
64 * now, this means you must use an IOIES to be eligible for interrupt accounting. We also do not
65 * track IOIES' that do not have providers (this is indicative that it is only being used to drive
66 * workloop activity, and is not actually handling interrupts).
67 */
68
69/*
70 * This is meant to let us set up the set of interrupt statistics we are actually interested in, by
71 * setting a boot-arg. If we want to track a statistic, the bit corresponding to the index for that
72 * statistic should be set in the bitmask.
73 *
74 * There is a bit of a mismatch here, in that our IOReporting channel namespace allows for 256 statistics,
75 * but this bitmask actually limits it to 32.
76 */
77extern uint32_t gInterruptAccountingStatisticBitmask;
78
79/*
80 * Check the bitmask by statistic index; useful for setting the initial value and conditionalizing code.
81 */
82#define IA_GET_ENABLE_BIT(statisticIndex) \
83 (((uint32_t) 1) << ((uint32_t) statisticIndex))
84
85#define IA_GET_STATISTIC_ENABLED(statisticIndex) \
86 (IA_GET_ENABLE_BIT(statisticIndex) & gInterruptAccountingStatisticBitmask)
87
88/*
89 * Check if any valid statistics are enabled.
90 */
91#define IA_ANY_STATISTICS_ENABLED \
92 ((IA_GET_ENABLE_BIT(kInterruptAccountingInvalidStatisticIndex) - 1) & gInterruptAccountingStatisticBitmask)
93
94/*
95 * Actual string names for the statistics we gather.
96 */
97#define kInterruptAccountingChannelNameFirstLevelCount (" First Level Interrupt Handler Count")
98#define kInterruptAccountingChannelNameSecondLevelCount (" Second Level Interrupt Handler Count")
99#define kInterruptAccountingChannelNameFirstLevelTime (" First Level Interrupt Handler Time (MATUs)")
100#define kInterruptAccountingChannelNameSecondLevelCPUTime (" Second Level Interrupt Handler CPU Time (MATUs)")
101#define kInterruptAccountingChannelNameSecondLevelSystemTime ("Second Level Interrupt Handler System Time (MATUs)")
102#define kInterruptAccountingChannelNameNoThreadWakeups (" Interrupts that did not try to wake a thread")
103#define kInterruptAccountingChannelNameTotalThreadWakeups (" Sleeping threads woken up by this interrupt")
104#define kInterruptAccountingChannelNamePackageWakeups (" Package wakeups caused by this interrupt")
105#define kInterruptAccountingChannelNameCPUWakeups (" CPU wakeups caused by this interrupt")
106#define kInterruptAccountingChannelNameIdleExits (" Idle exits caused by this interrupt")
107
108static const char * const kInterruptAccountingStatisticNameArray[IA_NUM_INTERRUPT_ACCOUNTING_STATISTICS] = {
109 [kInterruptAccountingFirstLevelCountIndex] = kInterruptAccountingChannelNameFirstLevelCount,
110 [kInterruptAccountingSecondLevelCountIndex] = kInterruptAccountingChannelNameSecondLevelCount,
111 [kInterruptAccountingFirstLevelTimeIndex] = kInterruptAccountingChannelNameFirstLevelTime,
112 [kInterruptAccountingSecondLevelCPUTimeIndex] = kInterruptAccountingChannelNameSecondLevelCPUTime,
113 [kInterruptAccountingSecondLevelSystemTimeIndex] = kInterruptAccountingChannelNameSecondLevelSystemTime,
114 [kInterruptAccountingNoThreadWakeupsIndex] = kInterruptAccountingChannelNameNoThreadWakeups,
115 [kInterruptAccountingTotalThreadWakeupsIndex] = kInterruptAccountingChannelNameTotalThreadWakeups,
116 [kInterruptAccountingPackageWakeupsIndex] = kInterruptAccountingChannelNamePackageWakeups,
117 [kInterruptAccountingCPUWakeupsIndex] = kInterruptAccountingChannelNameCPUWakeups,
118 [kInterruptAccountingIdleExitsIndex] = kInterruptAccountingChannelNameIdleExits,
119};
120
121/*
122 * For updating the statistics in the data structure. We cannot guarantee all of our platforms will be
123 * able to do a 64-bit store in a single transaction. So, for new platforms, call out to the hardware
124 * atomic add routine; it will either be unsupported, or do the right thing. For architectures or
125 * platforms that do support it; just do regular assignment.
126 *
127 * We use this routine instead of a lock because at the moment, there is no way (in the interrupt context)
128 * to reconcile a lock (even a spinlock) with the IOReporting synchonization (as we have no guarantee that
129 * IOReporting will not block on a mutex, which would result in a panic if it held a spinlock). This
130 * means that reported values may have a disparity if we update the reporter values while an interrupt is
131 * being handled.
132 *
133 * Atomic modification should not be strictly required, as a given interrupt should not be dispatched to
134 * two processors at once (and the interrupt should serve to force out stores), and the second level
135 * handler should be synchonized by the work loop it runs on.
136 */
137#if __x86_64__ || __arm64
138#define IA_ADD_VALUE(target, value) \
139 (*(target) += (value))
140#else
141#define IA_ADD_VALUE(target, value) \
142 (OSAddAtomic64((value), (target)))
143#endif
144
145/*
146 * TODO: Should this be an OSObject? Or properly pull in its methods as member functions?
147 */
148struct IOInterruptAccountingData {
149 OSObject * owner; /* The owner of the statistics; currently always an IOIES or a subclass of it */
150 queue_chain_t chain;
151 /*
152 * We have no guarantee that the owner will not temporarily mutate its index value (i.e, in setWorkLoop
153 * for IOIES). To ensure we can properly recalculate our own identity (and our channel IDs for the
154 * reporter), stash the index we set up the reporter with here.
155 *
156 * Note that we should never remap the interrupt (point it to a different specifier). The mutation of
157 * the index value is usually to negate it; I am uncertain of the reason for this at the moment. The
158 * practical impact being that we should never need to update the stashed index value; it should stay
159 * valid for the lifetime of the owner.
160 */
161 int interruptIndex;
162
163 /*
164 * As long as we are based on the simple reporter, all our channels will be 64 bits. Align the data
165 * to allow for safe atomic updates (we don't want to cross a cache line on any platform, but for some
166 * it would cause a panic).
167 */
168 volatile uint64_t interruptStatistics[IA_NUM_INTERRUPT_ACCOUNTING_STATISTICS] __attribute__((aligned(8)));
169};
170
171/*
172 * Initializes global values/structures related to interrupt accounting.
173 */
174void interruptAccountingInit(void);
175
176/*
177 * Routines for adding and removing objects from the global queue of IOInterruptAccountingData objects;
178 * the queue exists as a debugging aid (no entities other than these routines should care about the
179 * queue at runtime).
180 */
181void interruptAccountingDataAddToList(IOInterruptAccountingData * data);
182void interruptAccountingDataRemoveFromList(IOInterruptAccountingData * data);
183
184/*
185 * Updates reporter with the statistics contained within data. Invoked when IOReporting has been asked
186 * for updated statistics; requiring explicit synchronization of data between the statistic fields and
187 * the reporter helps keep interrupt accounting overhead down.
188 */
189void interruptAccountingDataUpdateChannels(IOInterruptAccountingData * data, IOSimpleReporter * reporter);
190
191/*
192 * Initializes the statistics in data using the statistics currently held by reporter. Typically invoked
193 * when data is first associated with reporter. The nub that an interrupt is associated with will be
194 * longer lived than the interrupt; as a result, our owner may not be the first to register for a
195 * particular interrupt index with that nub, so we need to inherit the existing statistics (as we describe
196 * statistics in terms of {nub id, index}, not in terms of our owner).
197 */
198void interruptAccountingDataInheritChannels(IOInterruptAccountingData * data, IOSimpleReporter * reporter);
199
200#endif /* __IOKIT_IOINTERRUPTACCOUNTING_PRIVATE_H */
201
202