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This provides the architecture-specific functions needed to access PMU hardware on the 64-bit PowerPC processors. It has been designed for the IBM POWER family (POWER 4/4+/5/5+/6 and PPC970) but will hopefully also suit other 64-bit PowerPC machines (although probably not Cell given how different it is in this area). This doesn't include back-ends for any specific processors. This implements a system which allows back-ends to express the constraints that their hardware has on what events can be counted simultaneously. The constraints are expressed as a 64-bit mask + 64-bit value for each event, and the encoding is capable of expressing the constraints arising from having a set of multiplexers feeding an event bus, with some events being available through multiple multiplexer settings, such as we get on POWER4 and PPC970. Furthermore, the back-end can supply alternative event codes for each event, and the constraint checking code will try all possible combinations of alternative event codes to try to find a combination that will fit. Signed-off-by: Paul Mackerras <paulus@samba.org>
73 lines
2.9 KiB
C
73 lines
2.9 KiB
C
/*
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* Performance counter support - PowerPC-specific definitions.
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*
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* Copyright 2008-2009 Paul Mackerras, IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/types.h>
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#define MAX_HWCOUNTERS 8
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#define MAX_EVENT_ALTERNATIVES 8
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/*
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* This struct provides the constants and functions needed to
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* describe the PMU on a particular POWER-family CPU.
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*/
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struct power_pmu {
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int n_counter;
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int max_alternatives;
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u64 add_fields;
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u64 test_adder;
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int (*compute_mmcr)(unsigned int events[], int n_ev,
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unsigned int hwc[], u64 mmcr[]);
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int (*get_constraint)(unsigned int event, u64 *mskp, u64 *valp);
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int (*get_alternatives)(unsigned int event, unsigned int alt[]);
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void (*disable_pmc)(unsigned int pmc, u64 mmcr[]);
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int n_generic;
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int *generic_events;
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};
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extern struct power_pmu *ppmu;
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/*
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* The power_pmu.get_constraint function returns a 64-bit value and
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* a 64-bit mask that express the constraints between this event and
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* other events.
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*
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* The value and mask are divided up into (non-overlapping) bitfields
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* of three different types:
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*
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* Select field: this expresses the constraint that some set of bits
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* in MMCR* needs to be set to a specific value for this event. For a
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* select field, the mask contains 1s in every bit of the field, and
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* the value contains a unique value for each possible setting of the
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* MMCR* bits. The constraint checking code will ensure that two events
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* that set the same field in their masks have the same value in their
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* value dwords.
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*
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* Add field: this expresses the constraint that there can be at most
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* N events in a particular class. A field of k bits can be used for
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* N <= 2^(k-1) - 1. The mask has the most significant bit of the field
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* set (and the other bits 0), and the value has only the least significant
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* bit of the field set. In addition, the 'add_fields' and 'test_adder'
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* in the struct power_pmu for this processor come into play. The
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* add_fields value contains 1 in the LSB of the field, and the
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* test_adder contains 2^(k-1) - 1 - N in the field.
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*
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* NAND field: this expresses the constraint that you may not have events
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* in all of a set of classes. (For example, on PPC970, you can't select
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* events from the FPU, ISU and IDU simultaneously, although any two are
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* possible.) For N classes, the field is N+1 bits wide, and each class
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* is assigned one bit from the least-significant N bits. The mask has
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* only the most-significant bit set, and the value has only the bit
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* for the event's class set. The test_adder has the least significant
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* bit set in the field.
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*
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* If an event is not subject to the constraint expressed by a particular
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* field, then it will have 0 in both the mask and value for that field.
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*/
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