AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

# PMMIR, Performance Monitors Machine Identification Register

The PMMIR characteristics are:

## Purpose

Describes Performance Monitors parameters specific to the implementation to software.

## Configuration

This register is present only when EL1 is capable of using AArch32 and FEAT_PMUv3p4 is implemented. Otherwise, direct accesses to PMMIR are UNDEFINED.

## Attributes

PMMIR is a 32-bit register.

## Field descriptions

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
RES0 | EDGE | THWIDTH | BUS_WIDTH | BUS_SLOTS | SLOTS

#### Bits [31:28]

Reserved, RES0.

#### EDGE, bits [27:24]

PMU event edge detection. With PMMIR.THWIDTH, indicates implementation of event counter thresholding features.

The value of this field is an IMPLEMENTATION DEFINED choice of:

EDGE | Meaning
--- | ---
0b0000 | FEAT_PMUv3_EDGE is not implemented.
0b0001 | FEAT_PMUv3_EDGE is implemented.

All other values are reserved.

If FEAT_PMUv3_TH is not implemented, the only permitted value is 0b0000.

FEAT_PMUv3_EDGE implements the functionality identified by the value 0b0001.

Note

PMEVTYPER<n>_EL0.TE cannot be accessed through PMEVTYPER<n>.

Access to this field is RO.

#### THWIDTH, bits [23:20]

PMEVTYPER<n>_EL0.TH width. Indicates implementation of the FEAT_PMUv3_TH feature, and, if implemented, the size of the PMEVTYPER<n>_EL0.TH field.

The value of this field is an IMPLEMENTATION DEFINED choice of:

THWIDTH | Meaning
--- | ---
0b0000 | FEAT_PMUv3_TH is not implemented.
0b0001 | 1 bit. PMEVTYPER<n>_EL0.TH[11:1] are RES0.
0b0010 | 2 bits. PMEVTYPER<n>_EL0.TH[11:2] are RES0.
0b0011 | 3 bits. PMEVTYPER<n>_EL0.TH[11:3] are RES0.
0b0100 | 4 bits. PMEVTYPER<n>_EL0.TH[11:4] are RES0.
0b0101 | 5 bits. PMEVTYPER<n>_EL0.TH[11:5] are RES0.
0b0110 | 6 bits. PMEVTYPER<n>_EL0.TH[11:6] are RES0.
0b0111 | 7 bits. PMEVTYPER<n>_EL0.TH[11:7] are RES0.
0b1000 | 8 bits. PMEVTYPER<n>_EL0.TH[11:8] are RES0.
0b1001 | 9 bits. PMEVTYPER<n>_EL0.TH[11:9] are RES0.
0b1010 | 10 bits. PMEVTYPER<n>_EL0.TH[11:10] are RES0.
0b1011 | 11 bits. PMEVTYPER<n>_EL0.TH[11] is RES0.
0b1100 | 12 bits.

All other values are reserved.

If FEAT_PMUv3_TH is not implemented, this field is zero.

Otherwise, the largest value that can be written to PMEVTYPER<n>_EL0.TH is 2(PMMIR.THWIDTH) minus one.

Note

PMEVTYPER<n>_EL0.TH cannot be accessed through PMEVTYPER<n>.

Access to this field is RO.

#### BUS_WIDTH, bits [19:16]

Bus width. Indicates the number of bytes each BUS_ACCESS event relates to. Encoded as Log2(number of bytes), plus one.

The value of this field is an IMPLEMENTATION DEFINED choice of:

BUS_WIDTH | Meaning
--- | ---
0b0000 | The information is not available.
0b0011 | Four bytes.
0b0100 | 8 bytes.
0b0101 | 16 bytes.
0b0110 | 32 bytes.
0b0111 | 64 bytes.
0b1000 | 128 bytes.
0b1001 | 256 bytes.
0b1010 | 512 bytes.
0b1011 | 1024 bytes.
0b1100 | 2048 bytes.

All other values are reserved.

Each transfer is up to this number of bytes. An access might be smaller than the bus width.

When this field is nonzero, each access counted by BUS_ACCESS is at most BUS_WIDTH bytes. An implementation might treat a wide bus as multiple narrower buses, such that a wide access on the bus increments the BUS_ACCESS counter by more than one.

Access to this field is RO.

#### BUS_SLOTS, bits [15:8]

Bus count. The largest value by which the BUS_ACCESS event might increment in a single BUS_CYCLES cycle.

When this field is nonzero, the largest value by which the BUS_ACCESS event might increment in a single BUS_CYCLES cycle is BUS_SLOTS.

If the bus count information is not available, this field will read as zero.

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

#### SLOTS, bits [7:0]

Operation width. The largest value by which the STALL_SLOT event might increment by in a single cycle. If the STALL_SLOT event is not implemented, this field might read as zero.

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

## Accessing PMMIR

Accesses to this register use the following encodings in the System register encoding space:

#### MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coproc | opc1 | CRn | CRm | opc2
--- | --- | --- | --- | ---
0b1111 | 0b000 | 0b1001 | 0b1110 | 0b110

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T9 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TPM == '1' then AArch32.TakeHypTrapException(0x03); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); else R[t] = PMMIR; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); else R[t] = PMMIR; elsif PSTATE.EL == EL3 then R[t] = PMMIR;

AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6

Copyright © 2010-2024 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.