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PMCEID0_EL0, Performance Monitors Common Event Identification register 0

The PMCEID0_EL0 characteristics are:

Purpose

Defines which common architectural events and common microarchitectural events are implemented, or counted, using PMU events in the ranges 0x0000 to 0x001F and 0x4000 to 0x401F.

When the value of a bit in the register is 1 the corresponding common event is implemented and counted.

Note

Arm recommends that, if a common event is never counted, the value of the corresponding register bit is 0.

For more information about the common events and the use of the PMCEID<n>_EL0 registers see The section describing 'Event numbers and common events' in chapter D5 'The Performance Monitors Extension' of the Arm Architecture Reference Manual, for Armv8-A architecture profile.

Configuration

AArch64 System register PMCEID0_EL0 bits [31:0] are architecturally mapped to AArch32 System register PMCEID0[31:0] .

AArch64 System register PMCEID0_EL0 bits [63:32] are architecturally mapped to AArch32 System register PMCEID2[31:0] .

AArch64 System register PMCEID0_EL0 bits [31:0] are architecturally mapped to External register PMCEID0[31:0] .

AArch64 System register PMCEID0_EL0 bits [63:32] are architecturally mapped to External register PMCEID2[31:0] .

Attributes

PMCEID0_EL0 is a 64-bit register.

Field descriptions

The PMCEID0_EL0 bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
IDhi<n>, bit [n+32]
ID<n>, bit [n]
313029282726252423222120191817161514131211109876543210

IDhi<n>, bit [n+32], for n = 0 to 31

When ARMv8.1-PMU is implemented:

IDhi[n] corresponds to common event (0x4000 + n).

For each bit:

IDhi<n>Meaning
0b0

The common event is not implemented, or not counted.

0b1

The common event is implemented.

A bit that corresponds to a reserved event number is reserved. The value might be used in a future revision of the architecture to identify an additional common event.

Note

Such an event might be added retrospectively to an earlier version of the PMU architecture, provided the event does not require any additional PMU features and has an event number that can be represented in the PMCEID<n>_EL0 registers of that earlier version of the PMU architecture.


Otherwise:

Reserved, RES0.

ID<n>, bit [n], for n = 0 to 31

ID[n] corresponds to common event n.

For each bit:

ID<n>Meaning
0b0

The common event is not implemented, or not counted.

0b1

The common event is implemented.

A bit that corresponds to a reserved event number is reserved. The value might be used in a future revision of the architecture to identify an additional common event.

Note

Such an event might be added retrospectively to an earlier version of the PMU architecture, provided the event does not require any additional PMU features and has an event number that can be represented in the PMCEID<n>_EL0 registers of that earlier version of the PMU architecture.

Accessing the PMCEID0_EL0

Accesses to this register use the following encodings:

MRS <Xt>, PMCEID0_EL0

op0op1CRnCRmop2
0b110b0110b10010b11000b110
if PSTATE.EL == EL0 then
    if !ELUsingAArch32(EL1) && PMUSERENR_EL0.EN == '0' then
        if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
            AArch64.SystemAccessTrap(EL2, 0x18);
        else
            AArch64.SystemAccessTrap(EL1, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
        AArch64.SystemAccessTrap(EL3, 0x18);
    else
        return PMCEID0_EL0;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TPM == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
        AArch64.SystemAccessTrap(EL3, 0x18);
    else
        return PMCEID0_EL0;
elsif PSTATE.EL == EL2 then
    if HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then
        AArch64.SystemAccessTrap(EL3, 0x18);
    else
        return PMCEID0_EL0;
elsif PSTATE.EL == EL3 then
    return PMCEID0_EL0;


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