PMCCFILTR_EL0, Performance Monitors Cycle Counter Filter Register

The PMCCFILTR_EL0 characteristics are:

Purpose

Determines the modes in which the Cycle Counter, PMCCNTR_EL0, increments.

Configuration

External register PMCCFILTR_EL0 bits [31:0] are architecturally mapped to AArch64 System register PMCCFILTR_EL0[31:0].

External register PMCCFILTR_EL0 bits [31:0] are architecturally mapped to AArch32 System register PMCCFILTR[31:0].

PMCCFILTR_EL0 is in the Core power domain.

On a Warm or Cold reset, RW fields in this register reset to:

The register is not affected by an External debug reset.

Attributes

PMCCFILTR_EL0 is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
PUNSKNSUNSHMRES0SHRES0RLKRLURLHRES0

P, bit [31]

Privileged filtering bit. Controls counting in EL1.

If EL3 is implemented, then counting in Non-secure EL1 is further controlled by the PMCCFILTR_EL0.NSK bit.

If FEAT_RME is implemented, then counting in Realm EL1 is further controlled by the PMCCFILTR_EL0.RLK bit.

PMeaning
0b0

Count cycles in EL1.

0b1

Do not count cycles in EL1.

U, bit [30]

User filtering bit. Controls counting in EL0.

If EL3 is implemented, then counting in Non-secure EL0 is further controlled by the PMCCFILTR_EL0.NSU bit.

If FEAT_RME is implemented, then counting in Realm EL0 is further controlled by the PMCCFILTR_EL0.RLU bit.

UMeaning
0b0

Count cycles in EL0.

0b1

Do not count cycles in EL0.

NSK, bit [29]
When EL3 is implemented:

Non-secure EL1 (kernel) modes filtering bit. Controls counting in Non-secure EL1.

If the value of this bit is equal to the value of the PMCCFILTR_EL0.P bit, cycles in Non-secure EL1 are counted.

Otherwise, cycles in Non-secure EL1 are not counted.


Otherwise:

Reserved, RES0.

NSU, bit [28]
When EL3 is implemented:

Non-secure EL0 (Unprivileged) filtering bit. Controls counting in Non-secure EL0.

If the value of this bit is equal to the value of the PMCCFILTR_EL0.U bit, cycles in Non-secure EL0 are counted.

Otherwise, cycles in Non-secure EL0 are not counted.


Otherwise:

Reserved, RES0.

NSH, bit [27]
When EL2 is implemented:

EL2 (Hypervisor) filtering bit. Controls counting in EL2.

If FEAT_SEL2 and EL3 are implemented, counting in Secure EL2 is further controlled by the PMCCFILTR_EL0.SH bit.

If FEAT_RME is implemented, then counting in Realm EL2 is further controlled by the PMCCFILTR_EL0.RLH bit.

NSHMeaning
0b0

Do not count cycles in EL2.

0b1

Count cycles in EL2.


Otherwise:

Reserved, RES0.

M, bit [26]
When EL3 is implemented:

Secure EL3 filtering bit.

If the value of this bit is equal to the value of the PMCCFILTR_EL0.P bit, cycles in Secure EL3 are counted.

Otherwise, cycles in Secure EL3 are not counted.

Most applications can ignore this field and set its value to 0.

Note

This field is not visible in the AArch32 PMCCFILTR System register.


Otherwise:

Reserved, RES0.

Bit [25]

Reserved, RES0.

SH, bit [24]
When FEAT_SEL2 is implemented and EL3 is implemented:

Secure EL2 filtering.

If the value of this bit is not equal to the value of the PMCCFILTR_EL0.NSH bit, cycles in Secure EL2 are counted.

Otherwise, cycles in Secure EL2 are not counted.

Note

This field is not visible in the AArch32 PMCCFILTR System register.


Otherwise:

Reserved, RES0.

Bit [23]

Reserved, RES0.

RLK, bit [22]
When FEAT_RME is implemented:

Realm EL1 (kernel) filtering bit. Controls counting in Realm EL1.

If the value of this bit is equal to the value of the PMCCFILTR_EL0.P bit, cycles in Realm EL1 are counted.

Otherwise, cycles in Realm EL1 are not counted.

The reset behavior of this field is:


Otherwise:

Reserved, RES0.

RLU, bit [21]
When FEAT_RME is implemented:

Realm EL0 (unprivileged) filtering bit. Controls counting in Realm EL0.

If the value of this bit is equal to the value of the PMCCFILTR_EL0.U bit, cycles in Realm EL0 are counted.

Otherwise, cycles in Realm EL0 are not counted.

The reset behavior of this field is:


Otherwise:

Reserved, RES0.

RLH, bit [20]
When FEAT_RME is implemented:

Realm EL2 filtering bit. Controls counting in Realm EL2.

If the value of this bit is not equal to the value of the PMCCFILTR_EL0.NSH bit, cycles in Realm EL2 are counted.

Otherwise, cycles in Realm EL2 are not counted.

The reset behavior of this field is:


Otherwise:

Reserved, RES0.

Bits [19:0]

Reserved, RES0.

Accessing PMCCFILTR_EL0

Note

SoftwareLockStatus() depends on the type of access attempted and AllowExternalPMUAccess() has a new definition from Armv8.4. Refer to the Pseudocode definitions for more information.

PMCCFILTR_EL0 can be accessed through the external debug interface:

ComponentOffsetInstance
PMU0x47CPMCCFILTR_EL0

This interface is accessible as follows:


05/07/2022 17:07; b0421fa9a8865165f9b91af9b4a566111f866305

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