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 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
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 * IOReporting group names.
123 */
124static const char * const kInterruptAccountingGroupName = "Interrupt Statistics (by index)";
125
126/*
127 * TODO: Generate the subgroup name strings?
128 */
129#define IA_MAX_SUBGROUP_NAME (32)
130
131static const char * const kInterruptAccountingSubgroupNames[IA_MAX_SUBGROUP_NAME] = {
132    "0", "1", "2" , "3", "4", "5", "6", "7",
133    "8", "9", "10", "11", "12", "13", "14", "15",
134    "16", "17", "18", "19", "20", "21", "22", "23",
135    "24", "25", "26", "27", "28", "29", "30", "31"};
136
137/*
138 * As long as we use a lookup table, we may be out of bounds for a valid index.  In this case, fall
139 * back on a generic subgroup name that indicates we have screwed up.
140 */
141static const char * const kInterruptAccountingGenericSubgroupName = "(Index > 31)";
142
143/*
144 * For updating the statistics in the data structure.  We cannot guarantee all of our platforms will be
145 * able to do a 64-bit store in a single transaction.  So, for new platforms, call out to the hardware
146 * atomic add routine; it will either be unsupported, or do the right thing.  For architectures or
147 * platforms that do support it; just do regular assignment.
148 *
149 * We use this routine instead of a lock because at the moment, there is no way (in the interrupt context)
150 * to reconcile a lock (even a spinlock) with the IOReporting synchonization (as we have no guarantee that
151 * IOReporting will not block on a mutex, which would result in a panic if it held a spinlock).  This
152 * means that reported values may have a disparity if we update the reporter values while an interrupt is
153 * being handled.
154 *
155 * Atomic modification should not be strictly required, as a given interrupt should not be dispatched to
156 * two processors at once (and the interrupt should serve to force out stores), and the second level
157 * handler should be synchonized by the work loop it runs on.
158 */
159#if __x86_64__ || __arm64
160#define IA_ADD_VALUE(target, value) \
161    (*(target) += (value))
162#else
163#define IA_ADD_VALUE(target, value) \
164    (OSAddAtomic64((value), (target)))
165#endif
166
167/*
168 * TODO: Should this be an OSObject?  Or properly pull in its methods as member functions?
169 */
170struct IOInterruptAccountingData {
171    OSObject * owner; /* The owner of the statistics; currently always an IOIES or a subclass of it */
172    queue_chain_t chain;
173    /*
174     * We have no guarantee that the owner will not temporarily mutate its index value (i.e, in setWorkLoop
175     * for IOIES).  To ensure we can properly recalculate our own identity (and our channel IDs for the
176     * reporter), stash the index we set up the reporter with here.
177     *
178     * Note that we should never remap the interrupt (point it to a different specifier).  The mutation of
179     * the index value is usually to negate it; I am uncertain of the reason for this at the moment.  The
180     * practical impact being that we should never need to update the stashed index value; it should stay
181     * valid for the lifetime of the owner.
182     */
183    int interruptIndex;
184
185    /*
186     * As long as we are based on the simple reporter, all our channels will be 64 bits.  Align the data
187     * to allow for safe atomic updates (we don't want to cross a cache line on any platform, but for some
188     * it would cause a panic).
189     */
190    volatile uint64_t interruptStatistics[IA_NUM_INTERRUPT_ACCOUNTING_STATISTICS] __attribute__((aligned(8)));
191};
192
193/*
194 * Initializes global values/structures related to interrupt accounting.
195 */
196void interruptAccountingInit(void);
197
198/*
199 * Routines for adding and removing objects from the global queue of IOInterruptAccountingData objects;
200 * the queue exists as a debugging aid (no entities other than these routines should care about the
201 * queue at runtime).
202 */
203void interruptAccountingDataAddToList(IOInterruptAccountingData * data);
204void interruptAccountingDataRemoveFromList(IOInterruptAccountingData * data);
205
206/*
207 * Updates reporter with the statistics contained within data.  Invoked when IOReporting has been asked
208 * for updated statistics; requiring explicit synchronization of data between the statistic fields and
209 * the reporter helps keep interrupt accounting overhead down.
210 */
211void interruptAccountingDataUpdateChannels(IOInterruptAccountingData * data, IOSimpleReporter * reporter);
212
213/*
214 * Initializes the statistics in data using the statistics currently held by reporter.  Typically invoked
215 * when data is first associated with reporter.  The nub that an interrupt is associated with will be
216 * longer lived than the interrupt; as a result, our owner may not be the first to register for a
217 * particular interrupt index with that nub, so we need to inherit the existing statistics (as we describe
218 * statistics in terms of {nub id, index}, not in terms of our owner).
219 */
220void interruptAccountingDataInheritChannels(IOInterruptAccountingData * data, IOSimpleReporter * reporter);
221
222#endif /* __IOKIT_IOINTERRUPTACCOUNTING_PRIVATE_H */
223
224