xref: /xnu-11215.61.5/iokit/IOKit/IOReportMacros.h (revision 4f1223e81cd707a65cc109d0b8ad6653699da3c4)

/*
 * Copyright (c) 2012-2020 Apple Computer, Inc.  All Rights Reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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 */

#ifndef _IOREPORT_MACROS_H_
#define _IOREPORT_MACROS_H_

#include "IOReportTypes.h"
#include <string.h>
#include <os/overflow.h>

#ifdef __cplusplus
extern "C" {
#endif

#ifndef IOREPORT_ABORT
#define IOREPORT_ABORT panic
#endif

/*
 *   Background
 *
 *   These macros allow non-I/O Kit software to generate IOReporting
 *   reports.  Clients must prevent concurrent access to any given
 *   report buffer from multiple threads.
 *
 *   While these macros allow non-I/O Kit software to participate
 *   in IOReporting, an IOService instance must lend its driver ID,
 *   respond to the appropriate IOService overrides, and shuttle
 *   data back and forth.  In some cases, it may be useful to have
 *   the I/O Kit driver initialize the report buffer with the
 *   appropriate macro.
 */


/* ----- Reporting Single Integers (SimpleReport) ----- */

/*
 * The buffer size required for a SimpleReport.
 */

#define SIMPLEREPORT_BUFSIZE   (sizeof(IOReportElement))


/*
 * Initialize a buffer to hold a SimpleReport.
 *
 *                  void* buffer - ptr to SIMPLEREPORT_BUFSIZE bytes
 *                size_t bufSize - sanity check of buffer's size
 *           uint64_t providerID - registry Entry ID of the reporting service
 *            uint64_t channelID - the report's channel ID
 * IOReportCategories categories - categories of this channel
 *
 * If the buffer is not of sufficient size, the macro calls IOREPORT_ABORT().
 * If that returns, the buffer is left full of '&'.
 */

#define SIMPLEREPORT_INIT(buf, bufSize, providerID, channelID, cats)  \
do {  \
    memset((buf), '&', (bufSize));  \
    IOReportElement     *__elem = (IOReportElement *)(buf);  \
    IOSimpleReportValues *__vals;  \
    if ((bufSize) >= SIMPLEREPORT_BUFSIZE) {  \
	__elem->provider_id = (providerID);  \
	__elem->channel_id = (channelID);  \
	__elem->channel_type.report_format = kIOReportFormatSimple;  \
	__elem->channel_type.reserved = 0;  \
	__elem->channel_type.categories = (cats);  \
	__elem->channel_type.nelements = 1;  \
	__elem->channel_type.element_idx = 0;  \
	__elem->timestamp = 0;  \
	__vals = (IOSimpleReportValues*)&__elem->values;  \
	__vals->simple_value = kIOReportInvalidIntValue;  \
    }  \
    else {  \
	IOREPORT_ABORT("bufSize is smaller than the required size\n");  \
    }  \
} while(0)


/*
 * Set a SimpleReport to a new value.
 *
 *    void* simp_buf - ptr to memory initialized by SIMPLEREPORT_INIT()
 * int64_t new_value - new value for the report
 */

#define SIMPLEREPORT_SETVALUE(simp_buf, new_value)  \
do {  \
    IOReportElement *__elem = (IOReportElement *)(simp_buf);  \
    IOSimpleReportValues *__vals;  \
    __vals = (IOSimpleReportValues*)&__elem->values;  \
    __vals->simple_value = (new_value);  \
} while(0)


/*
 * Increment the value of a SimpleReport.
 *
 *    void* simp_buf - ptr to memory initialized by SIMPLEREPORT_INIT()
 * int64_t increment - amount by which to increment the value
 */
#define SIMPLEREPORT_INCREMENTVALUE(simp_buf, increment_by)  \
do {  \
    IOReportElement *__elem = (IOReportElement *)(simp_buf);  \
    IOSimpleReportValues *__vals;  \
    __vals = (IOSimpleReportValues*)&__elem->values;  \
    int64_t __simple_value = INT64_MAX;  \
    if (os_add_overflow(__vals->simple_value, (increment_by), &__simple_value)) {  \
    __vals->simple_value = INT64_MAX;  \
    } else {  \
    __vals->simple_value = __simple_value;  \
    }  \
} while(0)


/*
 * Prepare a SimpleReport for
 * IOService::updateReport(kIOReportCopyChannelData...)
 *
 * void* simp_buf  - Ptr to memory updated by SIMPLEREPORT_SETVALUE()
 * void* ptr2cpy   - On return, 'ptr2cpy' points to the memory that needs to be
 *                   copied for kIOReportCopyChannelData.
 * size_t size2cpy - On return, 'size2cpy' is set to the size of the report
 *                   data that needs to be copied for kIOReportCopyChannelData.
 */

#define SIMPLEREPORT_UPDATEPREP(simp_buf, ptr2cpy, size2cpy)  \
do {  \
    (ptr2cpy) = (simp_buf);  \
    (size2cpy) = sizeof(IOReportElement);  \
} while(0)


/*
 * Update the result field received as a parameter for
 * kIOReportGetDimensions & kIOReportCopyChannelData actions.
 *
 * IOReportConfigureAction action - configure/updateReport() 'action' param
 *                   void* result - configure/updateReport() 'result' param
 */

#define SIMPLEREPORT_UPDATERES(action, result)  \
do {  \
    if (((action) == kIOReportGetDimensions) || ((action) == kIOReportCopyChannelData)) {  \
	int *__nElements = (int *)(result);  \
	*__nElements += 1;  \
    }  \
} while (0)


/*
 * Get the 64-bit channel ID of a SimpleReport.
 *
 * void* simp_buf - ptr to memory initialized by SIMPLEREPORT_INIT()
 */

#define SIMPLEREPORT_GETCHID(simp_buf)  \
    (((IOReportElement *)(simp_buf))->channel_id)

/*
 * Get the IOReportChannelType of a SimpleReport.
 *
 * void* simp_buf - ptr to memory initialized by SIMPLEREPORT_INIT()
 */

#define SIMPLEREPORT_GETCHTYPE(simp_buf)  \
    (*(uint64_t*)&(((IOReportElement *)(simp_buf))->channel_type))


/*
 * Get the integer value of a SimpleReport.
 *
 * void* simp_buf - memory initialized by SIMPLEREPORT_INIT()
 */

#define SIMPLEREPORT_GETVALUE(simp_buf)  \
    (((IOSimpleReportValues*)&(((IOReportElement*)(simp_buf))->values))  \
	    ->simple_value)


/* ----- State Machine Reporting (StateReport) ----- */

// Internal struct for StateReport
typedef struct {
	uint16_t        curr_state;
	uint64_t        update_ts;
	IOReportElement elem[]; // Array of elements
} IOStateReportInfo;

/*
 * Determine the size required for a StateReport buffer.
 *
 * int nstates - number of states to be reported
 */
#define STATEREPORT_BUFSIZE(nstates)  \
    (sizeof(IOStateReportInfo) + (nstates) * sizeof(IOReportElement))


/*
 * Initialize a StateReport buffer.
 *
 *              uint16_t nstates - number of states to be reported
 *                  void* buffer - ptr to STATEREPORT_BUFSIZE(nstates) bytes
 *                size_t bufSize - sanity check of buffer's size
 *           uint64_t providerID - registry Entry ID of the reporting service
 *            uint64_t channelID - ID of this channel, see IOREPORT_MAKEID()
 * IOReportCategories categories - categories of this channel
 *
 * If the buffer is not of sufficient size, the macro invokes IOREPORT_ABORT.
 * If that returns, the buffer is left full of '&'.
 */
#define STATEREPORT_INIT(nstates, buf, bufSize, providerID, channelID, cats) \
do {  \
    memset((buf), '&', (bufSize));  \
    IOStateReportInfo *__info = (IOStateReportInfo *)(buf);  \
    IOStateReportValues *__rep;  \
    IOReportElement     *__elem;  \
    if ((bufSize) >= STATEREPORT_BUFSIZE(nstates)) {  \
	for (uint16_t __no = 0; __no < (nstates); __no++) {  \
	    __elem =  &(__info->elem[__no]);  \
	    __rep = (IOStateReportValues *) &(__elem->values);  \
	    __elem->provider_id = (providerID);  \
	    __elem->channel_id = (channelID);  \
	    __elem->channel_type.report_format = kIOReportFormatState;  \
	    __elem->channel_type.reserved = 0;  \
	    __elem->channel_type.categories = (cats);  \
	    __elem->channel_type.nelements = (nstates);  \
	    __elem->channel_type.element_idx = __no;  \
	    __elem->timestamp = 0;  \
	    __rep->state_id = __no;  \
	    __rep->intransitions = 0;  \
	    __rep->upticks = 0;  \
	    __rep->last_intransition = 0;  \
	}  \
	__info->curr_state = 0;  \
	__info->update_ts = 0;  \
    }  \
    else {  \
	IOREPORT_ABORT("bufSize is smaller than the required size\n");  \
    }  \
} while(0)

/*
 * Initialize the state id field of a state with the specified value.  By
 * default, STATEREPORT_INIT() initializes the state IDs with the index of
 * that state.  This macro can be used to provide a more descriptive state id.
 *
 *   void* state_buf - ptr to memory initialized by STATEREPORT_INIT()
 * unsigned stateIdx - index of the state, out of bounds -> no-op
 *  uint64_t stateID - new state id, see IOREPORT_MAKEID()
 */
#define STATEREPORT_SETSTATEID(state_buf, stateIdx, stateID)  \
do {  \
    IOStateReportInfo *__info = (IOStateReportInfo *)(state_buf);  \
    IOStateReportValues *__rep;  \
    if ((stateIdx) < __info->elem[0].channel_type.nelements) {  \
	__rep = (IOStateReportValues*) &(__info->elem[(stateIdx)].values);  \
	__rep->state_id = (stateID);  \
    }  \
} while (0)


/*
 * Set the state of a StateReport.
 *
 *      void* state_buf - pointer to memory initialized by STATEREPORT_INIT()
 * unsigned newStateIdx - index of new state, out of bounds -> no-op
 *  uint64_t changeTime - time at which the transition occurred
 */
#define STATEREPORT_SETSTATE(state_buf, newStateIdx, changeTime)  \
do {  \
    IOStateReportInfo *__info = (IOStateReportInfo *)(state_buf);  \
    IOStateReportValues *__rep;  \
    if ((newStateIdx) < __info->elem[0].channel_type.nelements ) {  \
	__rep = (IOStateReportValues*) &(__info->elem[__info->curr_state].values);  \
	if (__info->update_ts)  \
	    __rep->upticks += (changeTime) - __info->update_ts;  \
	__info->elem[(newStateIdx)].timestamp = (changeTime);  \
	__rep = (IOStateReportValues*) &(__info->elem[(newStateIdx)].values);  \
	__rep->intransitions++;  \
	__info->curr_state = (newStateIdx);  \
	__info->update_ts = (changeTime);  \
    }  \
} while(0)

/*
 * Prepare a StateReport for
 * IOService::updateReport(kIOReportCopyChannelData...)
 *
 *      void* state_buf - ptr to memory initialized by STATEREPORT_INIT()
 * uint64_t currentTime - current timestamp
 *        void* ptr2cpy - filled in with pointer to buffer to be copied out
 *      size_t size2cpy - filled in with the size of the buffer to copy out
 */
#define STATEREPORT_UPDATEPREP(state_buf, currentTime, ptr2cpy, size2cpy)  \
do {  \
    IOStateReportInfo *__info = (IOStateReportInfo *)(state_buf);  \
    IOReportElement     *__elem;  \
    IOStateReportValues *__state;  \
    (size2cpy) = __info->elem[0].channel_type.nelements * sizeof(IOReportElement);  \
    (ptr2cpy) =  (void *) &__info->elem[0];  \
    if (__info->update_ts)  {  \
	__elem = &__info->elem[__info->curr_state];  \
	__state = (IOStateReportValues *)&__elem->values;  \
	__elem->timestamp = (currentTime);  \
	__state->upticks  += (currentTime) - __info->update_ts;  \
	__info->update_ts = (currentTime);  \
    }  \
} while(0)

/*
 * Update the result field received as a parameter for kIOReportGetDimensions &
 * kIOReportCopyChannelData actions.
 *
 *                void* state_buf - memory initialized by STATEREPORT_INIT()
 * IOReportConfigureAction action - configure/updateReport() 'action'
 *                   void* result - configure/updateReport() 'result'
 */

#define STATEREPORT_UPDATERES(state_buf, action, result)  \
do {  \
    IOStateReportInfo *__info = (IOStateReportInfo *)(state_buf);  \
    IOReportElement     *__elem;  \
    int *__nElements = (int *)(result);  \
    if (((action) == kIOReportGetDimensions) || ((action) == kIOReportCopyChannelData)) {  \
	__elem =  &(__info->elem[0]);  \
    if (os_add_overflow(*__nElements, __elem->channel_type.nelements, __nElements)) {  \
	*__nElements = INT_MAX;  \
    }  \
    }  \
} while (0)


/*
 * Get the 64-bit channel ID of a StateReport.
 *
 * void* state_buf - ptr to memory initialized by STATEREPORT_INIT()
 */
#define STATEREPORT_GETCHID(state_buf)  \
    (((IOStateReportInfo *)(state_buf))->elem[0].channel_id)

/*
 * Get the IOReportChannelType of a StateReport.
 *
 * void* state_buf - ptr to memory initialized by STATEREPORT_INIT()
 */
#define STATEREPORT_GETCHTYPE(state_buf)  \
    (*(uint64_t*)&(((IOStateReportInfo *)(state_buf))->elem[0].channel_type))

/*
 * Get the number of transitions into a given state.
 *
 *   void* state_buf - ptr to memory initialized by STATEREPORT_INIT()
 * unsigned stateIdx - index of state, out of bounds -> kIOReportInvalidValue
 *
 */
#define STATEREPORT_GETTRANSITIONS(state_buf, stateIdx)  \
    (((stateIdx) < ((IOStateReportInfo *)(state_buf))->elem[0].channel_type.nelements)  \
	? ((IOStateReportValues*)&(((IOStateReportInfo*)(state_buf))->elem[(stateIdx)].values))->intransitions  \
	: kIOReportInvalidValue)

/*
 * Get the total number of ticks spent in a given state.
 *
 *   void* state_buf - ptr to memory initialized by STATEREPORT_INIT()
 * unsigned stateIdx - index of state, out of bounds -> kIOReportInvalidValue
 */
#define STATEREPORT_GETTICKS(state_buf, stateIdx)  \
    (((stateIdx) < ((IOStateReportInfo*)(state_buf))->elem[0].channel_type.nelements)  \
	? ((IOStateReportValues*)&(((IOStateReportInfo*)(state_buf))->elem[(stateIdx)].values))->upticks  \
	: kIOReportInvalidValue)


/* ----- Reporting an Array of Integers (SimpleArrayReport) ----- */

/*
 * Determine the buffer size for a SimpleArrayReport.
 *
 * int nValues - number of values to be reported
 */

#define SIMPLEARRAY_BUFSIZE(nValues) \
    ((((nValues)/IOR_VALUES_PER_ELEMENT) + (((nValues) % IOR_VALUES_PER_ELEMENT) ? 1:0)) \
	* sizeof(IOReportElement))

/*
 * Initialize a buffer for use as a SimpleArrayReport.
 *
 *                   int nValues   - number of elements to be reported
 *                     void* buf   - ptr to SIMPLEARRAY_BUFSIZE(nValues) bytes
 *                size_t bufSize   - sanity check of buffer's size
 *           uint64_t providerID   - registry Entry ID of the reporting service
 *            uint64_t channelID   - ID of this channel, see IOREPORT_MAKEID()
 * IOReportCategories categories   - categories of this channel
 *
 * If the buffer is not of sufficient size, the macro invokes IOREPORT_ABORT().
 * If that returns, the buffer is left full of '&'.
 */

#define SIMPLEARRAY_INIT(nValues, buf, bufSize, providerID, channelID, cats) \
do {  \
    memset((buf), '&', (bufSize));  \
    IOSimpleArrayReportValues *__rep;  \
    IOReportElement     *__elem;  \
    uint32_t            __nElems = (((nValues) / IOR_VALUES_PER_ELEMENT) + \
	                            (((nValues) % IOR_VALUES_PER_ELEMENT) ? 1 : 0)); \
    if ((bufSize) >= SIMPLEARRAY_BUFSIZE(nValues)) {  \
	for (unsigned __no = 0; __no < __nElems; __no++) {  \
	    __elem =  &(((IOReportElement *)(buf))[__no]);  \
	    __rep = (IOSimpleArrayReportValues *) &(__elem->values);  \
	    __elem->provider_id = (providerID);  \
	    __elem->channel_id = (channelID);  \
	    __elem->channel_type.report_format = kIOReportFormatSimpleArray;  \
	    __elem->channel_type.reserved = 0;  \
	    __elem->channel_type.categories = (cats);  \
	    __elem->channel_type.nelements = (__nElems);  \
	    __elem->channel_type.element_idx = __no;  \
	    __elem->timestamp = 0;  \
	    __rep->simple_values[0] = kIOReportInvalidIntValue;  \
	    __rep->simple_values[1] = kIOReportInvalidIntValue;  \
	    __rep->simple_values[2] = kIOReportInvalidIntValue;  \
	    __rep->simple_values[3] = kIOReportInvalidIntValue;  \
	}  \
    }  \
    else {  \
	IOREPORT_ABORT("bufSize is smaller than the required size\n");  \
    }  \
} while(0)


/* SimpleArrayReport helpers */

    #define __SA_FINDREP(array_buf, idx)  \
	IOSimpleArrayReportValues *__rep;  \
	IOReportElement     *__elem;  \
	unsigned __elemIdx = (idx) / IOR_VALUES_PER_ELEMENT;  \
	unsigned __valueIdx = (idx) % IOR_VALUES_PER_ELEMENT;  \
	__elem = &(((IOReportElement *)(array_buf))[0]);  \
	if (__elemIdx < __elem->channel_type.nelements)  { \
	    __elem = &(((IOReportElement *)(array_buf))[__elemIdx]);  \
	    __rep = (IOSimpleArrayReportValues *) &(__elem->values);  \

    #define __SA_MAXINDEX(array_buf)  \
	((((IOReportElement*)(array_buf))->channel_type.nelements)  \
	    * IOR_VALUES_PER_ELEMENT) - 1

/*
 * Set a value at a specified index in a SimpleArrayReport.
 *
 *   void* array_bufbuf - ptr to memory initialized by SIMPLEARRAY_INIT()
 *        unsigned idx  - array index, out of bounds -> no-op
 *    uint64_t newValue - new value to be stored at array[idx]
 */
#define SIMPLEARRAY_SETVALUE(array_buf, idx, newValue) \
do {  \
    __SA_FINDREP((array_buf), (idx)) \
	__rep->simple_values[__valueIdx] = (newValue);  \
    } \
} while(0)

/*
 * Increment an array value within a SimpleArrayReport.
 *
 *     void* array_buf - ptr to memory initialized by SIMPLEARRAY_INIT()
 *       unsigned idx  - array index to increment, out of bounds -> no-op
 *      int64_t value  - amount by which to increment array[idx]
 */
#define SIMPLEARRAY_INCREMENTVALUE(array_buf, idx, value)  \
do {  \
    __SA_FINDREP((array_buf), (idx)) \
    if (os_add_overflow(__rep->simple_values[__valueIdx], (value), &__rep->simple_values[__valueIdx])) {  \
	__rep->simple_values[__valueIdx] = INT64_MAX;  \
    } \
    } \
} while(0)


/*
 * Prepare a SimpleArrayReport for
 * IOService::updateReport(kIOReportCopyChannelData...)
 *
 *      void* array_buf - ptr to memory initialized by SIMPLEARRAY_INIT()
 *        void* ptr2cpy - filled in with pointer to buffer to be copied out
 *      size_t size2cpy - filled in with the size of the buffer to copy out
 */

#define SIMPLEARRAY_UPDATEPREP(array_buf, ptr2cpy, size2cpy) \
do {  \
    IOReportElement     *__elem;  \
    __elem = &(((IOReportElement *)(array_buf))[0]);  \
    (ptr2cpy) =  (void *) (array_buf);  \
    (size2cpy) = __elem->channel_type.nelements * sizeof(IOReportElement);  \
} while(0)


/*
 * Update the result field received as a parameter for kIOReportGetDimensions &
 * kIOReportCopyChannelData actions.
 *
 *                void* array_buf - memory initialized by SIMPLEARRAY_INIT()
 * IOReportConfigureAction action - configure/updateReport() 'action'
 *                   void* result - configure/updateReport() 'result'
 */

#define SIMPLEARRAY_UPDATERES(array_buf, action, result) \
do {  \
    IOReportElement     *__elem;  \
    int *__nElements = (int *)(result);  \
    __elem = &(((IOReportElement *)(array_buf))[0]);  \
    if (((action) == kIOReportGetDimensions) || ((action) == kIOReportCopyChannelData)) {  \
    if (os_add_overflow(*__nElements, __elem->channel_type.nelements, __nElements)) {  \
	*__nElements = INT_MAX;  \
    }  \
    }  \
} while (0)


/*
 * Get the 64-bit channel ID of a SimpleArrayReport.
 *
 * void* array_buf - ptr to memory initialized by SIMPLEARRAY_INIT()
 */
#define SIMPLEARRAY_GETCHID(array_buf)  \
    (((IOReportElement *)(array_buf))->channel_id)


/*
 * Get the IOReportChannelType of a SimpleArrayReport.
 *
 * void* simp_buf - ptr to memory initialized by SIMPLEREPORT_INIT()
 */
#define SIMPLEARRAY_GETCHTYPE(array_buf)  \
    (*(uint64_t*)&(((IOReportElement *)(array_buf))->channel_type))

/*
 * Get a value from a SimpleArrayReport.
 *
 * void* array_buf - ptr to memory initialized by SIMPLEARRAY_INIT()
 *   unsigned idx  - index of the value, out of bounds -> kIOReportInvalidValue
 */
#define SIMPLEARRAY_GETVALUE(array_buf, idx)  \
    (((idx) > __SA_MAXINDEX(array_buf) || (idx) < 0) ? kIOReportInvalidIntValue :  \
    ((IOSimpleArrayReportValues*)&(  \
	((IOReportElement*)(array_buf))[(idx) / IOR_VALUES_PER_ELEMENT].values))  \
	    ->simple_values[(idx) % IOR_VALUES_PER_ELEMENT])


/* ----- Histogram Reporting (HistogramReport) ----- */

// Internal struct for HistogramReport
typedef struct {
	int             bucketWidth;
	IOReportElement elem[]; // Array of elements
} IOHistReportInfo;

/*
 * Determine the size required for a HistogramReport buffer.
 *
 * int nbuckets - number of buckets in the histogram
 */
#define HISTREPORT_BUFSIZE(nbuckets)  \
    (sizeof(IOHistReportInfo) + ((nbuckets) * sizeof(IOReportElement)))

/*
 * Initialize a HistogramReport buffer. Supports only linear scale histogram.
 *
 *             uint16_t nbuckets - number of buckets data is combined into
 *          uint32_t bucketWidth - size of each bucket
 *                  void* buffer - ptr to HISTREPORT_BUFSIZE(nbuckets) bytes
 *                size_t bufSize - sanity check of buffer's size
 *           uint64_t providerID - registry Entry ID of the reporting service
 *            uint64_t channelID - ID of this channel, see IOREPORT_MAKEID()
 * IOReportCategories categories - categories of this channel
 *
 * If the buffer is not of sufficient size, the macro invokes IOREPORT_ABORT.
 * If that returns, the buffer is left full of '&'.
 */
#define HISTREPORT_INIT(nbuckets, bktSize, buf, bufSize, providerID, channelID, cats) \
do {  \
    memset((buf), '&', (bufSize));  \
    IOHistReportInfo   *__info = (IOHistReportInfo *)(buf);  \
    IOReportElement         *__elem;  \
    IOHistogramReportValues *__rep;  \
    if ((bufSize) >= HISTREPORT_BUFSIZE(nbuckets)) {  \
	__info->bucketWidth = (bktSize);  \
	for (uint16_t __no = 0; __no < (nbuckets); __no++) {  \
	    __elem =  &(__info->elem[__no]);  \
	    __rep = (IOHistogramReportValues *) &(__elem->values);  \
	    __elem->provider_id = (providerID);  \
	    __elem->channel_id = (channelID);  \
	    __elem->channel_type.report_format = kIOReportFormatHistogram;  \
	    __elem->channel_type.reserved = 0;  \
	    __elem->channel_type.categories = (cats);  \
	    __elem->channel_type.nelements = (nbuckets);  \
	    __elem->channel_type.element_idx = __no;  \
	    __elem->timestamp = 0;  \
	    memset(__rep, '\0', sizeof(IOHistogramReportValues)); \
	}  \
    }  \
    else {  \
	IOREPORT_ABORT("bufSize is smaller than the required size\n");  \
    }  \
} while (0)

/*
 * Update histogram with a new value.
 *
 *
 *      void* hist_buf - pointer to memory initialized by HISTREPORT_INIT()
 *        int64_t value - new value to add to the histogram
 */
#define HISTREPORT_TALLYVALUE(hist_buf, value) \
do {  \
    IOHistReportInfo   *__info = (IOHistReportInfo *)(hist_buf);  \
    IOReportElement         *__elem;  \
    IOHistogramReportValues *__rep;  \
    for (unsigned __no = 0; __no < __info->elem[0].channel_type.nelements; __no++) {  \
	if ((value) <= __info->bucketWidth * (__no+1)) {  \
	    __elem =  &(__info->elem[__no]);  \
	    __rep = (IOHistogramReportValues *) &(__elem->values);  \
	    if (__rep->bucket_hits == 0) {  \
	        __rep->bucket_min = __rep->bucket_max = (value);  \
	    }  \
	    else if ((value) < __rep->bucket_min) {  \
	        __rep->bucket_min = (value);  \
	    }  \
	    else if ((value) > __rep->bucket_max) {  \
	        __rep->bucket_max = (value);  \
	    }  \
	int64_t __sum = 0;  \
	if (os_add_overflow(__rep->bucket_sum, (value), &__sum)) {  \
	    __rep->bucket_sum = INT64_MAX;  \
	} else {  \
	    __rep->bucket_sum = __sum;  \
	}  \
	    __rep->bucket_hits++;  \
	    break;  \
	}  \
    }  \
} while (0)

/*
 * Prepare a HistogramReport for
 * IOService::updateReport(kIOReportCopyChannelData...)
 *
 *      void* array_buf - ptr to memory initialized by HISTREPORT_INIT()
 *        void* ptr2cpy - filled in with pointer to buffer to be copied out
 *      size_t size2cpy - filled in with the size of the buffer to copy out
 */

#define HISTREPORT_UPDATEPREP(hist_buf, ptr2cpy, size2cpy) \
do {  \
    IOHistReportInfo   *__info = (IOHistReportInfo *)(hist_buf);  \
    (size2cpy) = __info->elem[0].channel_type.nelements * sizeof(IOReportElement);  \
    (ptr2cpy) =  (void *) &__info->elem[0];  \
} while(0)


/*
 * Update the result field received as a parameter for kIOReportGetDimensions &
 * kIOReportCopyChannelData actions.
 *
 *                void* array_buf - memory initialized by HISTREPORT_INIT()
 * IOReportConfigureAction action - configure/updateReport() 'action'
 *                   void* result - configure/updateReport() 'result'
 */

#define HISTREPORT_UPDATERES(hist_buf, action, result) \
do {  \
    IOHistReportInfo   *__info = (IOHistReportInfo *)(hist_buf);  \
    int *__nElements = (int *)(result);  \
    if (((action) == kIOReportGetDimensions) || ((action) == kIOReportCopyChannelData)) {  \
	if (os_add_overflow(*__nElements, __info->elem[0].channel_type.nelements, __nElements)) {  \
	    *__nElements = INT_MAX;  \
	}  \
    }  \
} while (0)

/*
 * Get the 64-bit channel ID of a HistogramReport.
 *
 * void* hist_buf - ptr to memory initialized by HISTREPORT_INIT()
 */
#define HISTREPORT_GETCHID(hist_buf)  \
    (((IOHistReportInfo *)(hist_buf))->elem[0].channel_id)

/*
 * Get the IOReportChannelType of a HistogramReport.
 *
 * void* hist_buf - ptr to memory initialized by HISTREPORT_INIT()
 */
#define HISTREPORT_GETCHTYPE(hist_buf)  \
    (*(uint64_t*)&(((IOHistReportInfo *)(hist_buf))->elem[0].channel_type))

#ifdef __cplusplus
}
#endif

#endif // _IOREPORT_MACROS_H_