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# PMXEVCNTR, Performance Monitors Selected Event Count Register

The PMXEVCNTR characteristics are:

## Purpose

Reads or writes the value of the selected event counter, PMEVCNTR<n>. PMSELR.SEL determines which event counter is selected.

## Configuration

AArch32 System register PMXEVCNTR bits [31:0] are architecturally mapped to AArch64 System register PMXEVCNTR_EL0[31:0] .

This register is in the Warm reset domain. On a Warm or Cold reset RW fields in this register reset to architecturally UNKNOWN values.

## Attributes

PMXEVCNTR is a 32-bit register.

## Field descriptions

The PMXEVCNTR bit assignments are:

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
PMEVCNTR<n>

#### PMEVCNTR<n>, bits [31:0]

Value of the selected event counter, PMEVCNTR<n>, where n is the value stored in PMSELR.SEL.

If ARMv8.5-PMU is implemented, the event counter is 64 bits and only the least-significant part of the event counter is accessible in AArch32 state:

- Reads from PMXEVCNTR return bits [31:0] of the counter.

- Writes to PMXEVCNTR update bits [31:0] and leave bits [63:32] unchanged.

- There is no means to access bits [63:32] directly from AArch32 state.

- If the implementation does not support AArch64 at any Exception level, bits [63:32] are not required to be implemented.

If ARMv8.5-PMU is not implemented, the event counter is 32 bits.

On a Warm reset, this field resets to an architecturally UNKNOWN value.

## Accessing the PMXEVCNTR

If PMSELR.SEL is greater than or equal to the number of accessible counters then reads and writes of PMXEVCNTR are CONSTRAINED UNPREDICTABLE, and the following behaviors are permitted:

- Accesses to the register are UNDEFINED.
- Accesses to the register behave as RAZ/WI.
- Accesses to the register execute as a NOP
- Accesses to the register behave as if PMSELR.SEL has an UNKNOWN value less than the number of counters accessible at the current Exception level and Security state.
- If EL2 is implemented and enabled in the current Security state, and PMSELR.SEL is less than the number of implemented counters, accesses from EL1 or permitted accesses from EL0 are trapped to EL2.

Note

In EL0, an access is permitted if it is enabled by PMUSERENR.{ER,EN} or PMUSERENR_EL0.{ER,EN}.

If EL2 is implemented and enabled in the current Security state, at EL0 and EL1:

- If EL2 is using AArch32, HDCR.HPMN identifies the number of accessible counters.
- If EL2 is using AArch64, MDCR_EL2.HPMN identifies the number of accessible counters.

Otherwise, the number of accessible counters is the number of implemented counters. See HDCR.HPMN and MDCR_EL2.HPMN for more details.

Accesses to this register use the following encodings:

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

coproc | opc1 | CRn | CRm | opc2
--- | --- | --- | --- | ---
0b1111 | 0b000 | 0b1001 | 0b1101 | 0b010

if PSTATE.EL == EL0 then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && HSTR_EL2.T9 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then AArch32.TakeHypTrapException(0x03); elsif !ELUsingAArch32(EL1) && PMUSERENR_EL0.<ER,EN> == '00' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); else AArch64.AArch32SystemAccessTrap(EL1, 0x03); elsif ELUsingAArch32(EL1) && PMUSERENR.<ER,EN> == '00' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then AArch32.TakeHypTrapException(0x00); else UNDEFINED; 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 AArch64.AArch32SystemAccessTrap(EL3, 0x03); else return PMXEVCNTR; elsif PSTATE.EL == EL1 then if 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 AArch64.AArch32SystemAccessTrap(EL3, 0x03); else return PMXEVCNTR; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x03); else return PMXEVCNTR; elsif PSTATE.EL == EL3 then return PMXEVCNTR;

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

coproc | opc1 | CRn | CRm | opc2
--- | --- | --- | --- | ---
0b1111 | 0b000 | 0b1001 | 0b1101 | 0b010

if PSTATE.EL == EL0 then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && HSTR_EL2.T9 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T9 == '1' then AArch32.TakeHypTrapException(0x03); elsif !ELUsingAArch32(EL1) && PMUSERENR_EL0.EN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); else AArch64.AArch32SystemAccessTrap(EL1, 0x03); elsif ELUsingAArch32(EL1) && PMUSERENR.EN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then AArch32.TakeHypTrapException(0x00); else UNDEFINED; 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 AArch64.AArch32SystemAccessTrap(EL3, 0x03); else PMXEVCNTR = R[t]; elsif PSTATE.EL == EL1 then if 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 AArch64.AArch32SystemAccessTrap(EL3, 0x03); else PMXEVCNTR = R[t]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TPM == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x03); else PMXEVCNTR = R[t]; elsif PSTATE.EL == EL3 then PMXEVCNTR = R[t];

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

15/04/2019 16:47; 8c23526ba8a13a72aada4137daf3e3977b49036e

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