PMCR_EL0

Provides details of the Performance Monitors implementation, including the number of counters implemented, and configures and controls the counters.

Configuration

AArch64 System register PMCR_EL0 bits [31:0] are architecturally mapped to AArch32 System register PMCR[31:0].

AArch64 System register PMCR_EL0 bits [31:0] are architecturally mapped to External register PMU.PMCR_EL0[31:0].

AArch64 System register PMCR_EL0 bits [63:32] are architecturally mapped to External register PMU.PMCR_EL0[63:32] when FEAT_PMUv3_EXT64 is implemented.

This register is present only when FEAT_PMUv3 is implemented. Otherwise, direct accesses to PMCR_EL0 are UNDEFINED.

Attributes

Field descriptions

Bits [63:33]

FZS, bit [32]
When FEAT_SPEv1p2 is implemented and FEAT_SPE_DPFZS is implemented:

Freeze-on-SPE event.

Stop counters when PMBLIMITR_EL1.{PMFZ,E} == {1,1} and PMBSR_EL1.S == 1.

In the description of this field:

If EL2 is implemented, then PMN is MDCR_EL2.HPMN.
If EL2 is not implemented, then PMN is PMCR_EL0.N.

FZS	Meaning
0b0	Do not freeze on a Statistical Profiling Buffer Management event.
0b1	Affected counters do not count following a Statistical Profiling Buffer Management event.

The counters affected by this field are:

If EL2 is implemented, event counters PMEVCNTR<n>_EL0 for values of n less than PMN. This applies even when EL2 is disabled in the current Security state.
If EL2 is not implemented, all event counters PMEVCNTR<n>_EL0.
If FEAT_PMUv3_ICNTR is implemented, the instruction counter PMICNTR_EL0.
If PMCR_EL0.DP is 1, the cycle counter PMCCNTR_EL0.

Other event counters are not affected by this field.

When PMCR_EL0.DP is 0, PMCCNTR_EL0 is not affected by this field.

The reset behavior of this field is:

On a Warm reset:
- When AArch32 is supported, this field resets to 0.
- Otherwise, this field resets to an architecturally UNKNOWN value.

When FEAT_SPEv1p2 is implemented:

Freeze-on-SPE event.

Stop counters when PMBLIMITR_EL1.{PMFZ,E} == {1,1} and PMBSR_EL1.S == 1.

In the description of this field:

If EL2 is implemented, then PMN is MDCR_EL2.HPMN.
If EL2 is not implemented, then PMN is PMCR_EL0.N.

FZS	Meaning
0b0	Do not freeze on a Statistical Profiling Buffer Management event.
0b1	Affected counters do not count following a Statistical Profiling Buffer Management event.

The counters affected by this field are:

If EL2 is implemented, event counters PMEVCNTR<n>_EL0 for values of n less than PMN. This applies even when EL2 is disabled in the current Security state.
If EL2 is not implemented, all event counters PMEVCNTR<n>_EL0.
If FEAT_PMUv3_ICNTR is implemented, the instruction counter PMICNTR_EL0.

Other event counters and PMCCNTR_EL0 are not affected by this field.

The reset behavior of this field is:

On a Warm reset:
- When AArch32 is supported, this field resets to 0.
- Otherwise, this field resets to an architecturally UNKNOWN value.

Otherwise:

IMP, bits [31:24]
When FEAT_PMUv3p7 is not implemented:

Implementer code.

If this field is zero, then PMCR_EL0.IDCODE is RES0 and software must use MIDR_EL1 to identify the PE.

Otherwise, this field and PMCR_EL0.IDCODE identify the PMU implementation to software. The implementer codes are allocated by Arm. A nonzero value has the same interpretation as MIDR_EL1.Implementer.

Use of this field is deprecated.

This field has an IMPLEMENTATION DEFINED value.

Access to this field is RO.

Otherwise:

IDCODE, bits [23:16]
When PMCR_EL0.IMP != 0b00000000:

Otherwise:

N, bits [15:11]

Bit [10]

FZO, bit [9]
When FEAT_PMUv3p7 is implemented:

Freeze-on-overflow.

Stop event counters on overflow.

In the description of this field:

If EL2 is implemented, then PMN is MDCR_EL2.HPMN.
If EL2 is not implemented, then PMN is PMCR_EL0.N.

FZO	Meaning
0b0	Do not freeze on overflow.
0b1	Affected counters do not count when any of the following applies: For any value of m less than PMN, PMOVSCLR_EL0[m] is 1, and either FEAT_SEBEP is not implemented or PMEVTYPER<m>_EL0.SYNC is 0. FEAT_PMUv3_ICNTR is implemented, PMOVSCLR_EL0.F0 is 1, and either FEAT_SEBEP is not implemented or PMICFILTR_EL0.SYNC is 0.

FZO

Meaning

0b0

Do not freeze on overflow.

0b1

Affected counters do not count when any of the following applies:

For any value of m less than PMN, PMOVSCLR_EL0[m] is 1, and either FEAT_SEBEP is not implemented or PMEVTYPER<m>_EL0.SYNC is 0.
FEAT_PMUv3_ICNTR is implemented, PMOVSCLR_EL0.F0 is 1, and either FEAT_SEBEP is not implemented or PMICFILTR_EL0.SYNC is 0.

The counters affected by this field are:

If EL2 is implemented, event counters PMEVCNTR<n>_EL0 for values of n less than PMN. This applies even when EL2 is disabled in the current Security state.
If EL2 is not implemented, all event counters PMEVCNTR<n>_EL0.
If FEAT_PMUv3_ICNTR is implemented, the instruction counter PMICNTR_EL0.
If PMCR_EL0.DP is 1, the cycle counter PMCCNTR_EL0.

Other event counters are not affected by this field.

When PMCR_EL0.DP is 0, PMCCNTR_EL0 is not affected by this field.

The reset behavior of this field is:

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

Otherwise:

Bit [8]

LP, bit [7]
When FEAT_PMUv3p5 is implemented:

Long event counter enable.

Determines which event counter bit generates an overflow recorded by PMOVSR[n].

In the description of this field:

If EL2 is implemented, then PMN is MDCR_EL2.HPMN.
If EL2 is not implemented, then PMN is PMCR_EL0.N.

LP	Meaning
0b0	Affected counters overflow on unsigned overflow of PMEVCNTR<n>_EL0[31:0].
0b1	Affected counters overflow on unsigned overflow of PMEVCNTR<n>_EL0[63:0].

When FEAT_EBEP is implemented and the PMU exception is enabled, the Effective value of this field is 1.

The counters affected by this field are:

If EL2 is implemented, event counters PMEVCNTR<n>_EL0 for values of n less than PMN. This applies even when EL2 is disabled in the current Security state.
If EL2 is not implemented, all event counters PMEVCNTR<n>_EL0.

Other event counters, PMCCNTR_EL0, and, if FEAT_PMUv3_ICNTR is implemented, PMICNTR_EL0 are not affected by this field.

The reset behavior of this field is:

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

Otherwise:

LC, bit [6]
When AArch32 is supported:

Long cycle counter enable. Determines when unsigned overflow is recorded by the cycle counter overflow bit.

LC	Meaning
0b0	Cycle counter overflow on increment that causes unsigned overflow of PMCCNTR_EL0[31:0].
0b1	Cycle counter overflow on increment that causes unsigned overflow of PMCCNTR_EL0[63:0].

When FEAT_EBEP is implemented and the PMU exception is enabled, the Effective value of this field is 1.

Arm deprecates use of PMCR_EL0.LC = 0.

The reset behavior of this field is:

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

Otherwise:

DP, bit [5]
When (FEAT_PMUv3p1 is implemented and EL2 is implemented) or EL3 is implemented:

Disable cycle counter when event counting is prohibited.

DP	Meaning
0b0	Cycle counting by PMCCNTR_EL0 is not affected by this mechanism.
0b1	Cycle counting by PMCCNTR_EL0 is disabled in prohibited regions and when event counting is frozen: If FEAT_PMUv3p1 is implemented, EL2 is implemented, and MDCR_EL2.HPMD is 1, then cycle counting by PMCCNTR_EL0 is disabled at EL2. If FEAT_PMUv3p7 is implemented, EL3 is implemented and using AArch64, and MDCR_EL3.MPMX is 1, then cycle counting by PMCCNTR_EL0 is disabled at EL3. If FEAT_PMUv3p7 is implemented and event counting is frozen by PMCR_EL0.FZO, then cycle counting by PMCCNTR_EL0 is disabled. If FEAT_SPE_DPFZS is implemented and event counting is frozen by PMCR_EL0.FZS, then cycle counting by PMCCNTR_EL0 is disabled. If EL3 is implemented, MDCR_EL3.SPME is 0, and either FEAT_PMUv3p7 is not implemented or MDCR_EL3.MPMX is 0, then cycle counting by PMCCNTR_EL0 is disabled at EL3 and in Secure state.

Meaning

0b0

Cycle counting by PMCCNTR_EL0 is not affected by this mechanism.

0b1

Cycle counting by PMCCNTR_EL0 is disabled in prohibited regions and when event counting is frozen:

If FEAT_PMUv3p1 is implemented, EL2 is implemented, and MDCR_EL2.HPMD is 1, then cycle counting by PMCCNTR_EL0 is disabled at EL2.
If FEAT_PMUv3p7 is implemented, EL3 is implemented and using AArch64, and MDCR_EL3.MPMX is 1, then cycle counting by PMCCNTR_EL0 is disabled at EL3.
If FEAT_PMUv3p7 is implemented and event counting is frozen by PMCR_EL0.FZO, then cycle counting by PMCCNTR_EL0 is disabled.
If FEAT_SPE_DPFZS is implemented and event counting is frozen by PMCR_EL0.FZS, then cycle counting by PMCCNTR_EL0 is disabled.
If EL3 is implemented, MDCR_EL3.SPME is 0, and either FEAT_PMUv3p7 is not implemented or MDCR_EL3.MPMX is 0, then cycle counting by PMCCNTR_EL0 is disabled at EL3 and in Secure state.

The conditions when this field disables the cycle counter are the same as when event counting by an event counter PMEVCNTR<n>_EL0 is prohibited or frozen, when either EL2 is not implemented or n is less than MDCR_EL2.HPMN.

If FEAT_PMUv3p7 and FEAT_SPEv1p2 are implemented, meaning PMCR_EL0.FZS is implemented, and FEAT_SPE_DPFZS is not implemented, then cycle counting by PMCCNTR_EL0 is not affected by PMCR_EL0.FZS.

For more information, see 'Prohibiting event and cycle counting'.

The reset behavior of this field is:

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

Otherwise:

X, bit [4]
When the implementation includes a PMU event export bus:

Enable export of events in an IMPLEMENTATION DEFINED PMU event export bus.

X	Meaning
0b0	Do not export events.
0b1	Export events where not prohibited.

This field enables the exporting of events over an IMPLEMENTATION DEFINED PMU event export bus to another device, for example to an OPTIONAL trace unit.

No events are exported when counting is prohibited.

This field does not affect the generation of Performance Monitors overflow interrupt requests or signaling to a cross-trigger interface (CTI) that can be implemented as signals exported from the PE.

The reset behavior of this field is:

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

Otherwise:

D, bit [3]
When AArch32 is supported:

D	Meaning
0b0	When enabled, PMCCNTR_EL0 counts every clock cycle.
0b1	When enabled, PMCCNTR_EL0 counts once every 64 clock cycles.

Otherwise:

C, bit [2]

P, bit [1]

Event counter reset.

In the description of this field:

If EL2 is implemented and is using AArch32, then PMN is HDCR.HPMN.
If EL2 is implemented and is using AArch64, then PMN is MDCR_EL2.HPMN.
If EL2 is not implemented, then PMN is PMCR_EL0.N.

P	Meaning
0b0	No action.
0b1	If n is in the range of affected event counters, resets each event counter PMEVCNTR<n>_EL0 to zero.

The effects of writing to this bit are:

If EL2 is implemented and enabled in the current Security state, in EL0 and EL1, and PMN is not 0, then a write of 1 to this bit resets event counters in the range [0 .. (PMN-1)].
If EL2 is disabled in the current Security state, then a write of 1 to this bit resets all the event counters.
In EL2 and EL3, a write of 1 to this bit resets all the event counters.
This field does not affect the operation of other event counters and PMCCNTR_EL0.

Note

Resetting the event counters does not change the event counter overflow bits. If FEAT_PMUv3p5 is implemented, the values of MDCR_EL2.HLP and PMCR_EL0.LP are ignored, and bits [63:0] of all affected event counters are reset.

Access to this field is WO/RAZ.

E, bit [0]

Enable.

In the description of this field:

If EL2 is implemented, then PMN is MDCR_EL2.HPMN.
If EL2 is not implemented, then PMN is PMCR_EL0.N.

E	Meaning
0b0	Affected counters are disabled and do not count.
0b1	Affected counters are enabled by PMCNTENSET_EL0.

The counters affected by this field are:

If EL2 is implemented, event counters PMEVCNTR<n>_EL0 for values of n less than PMN. This applies even when EL2 is disabled in the current Security state.
If EL2 is not implemented, all event counters PMEVCNTR<n>_EL0.
If FEAT_PMUv3_ICNTR is implemented, the instruction counter PMICNTR_EL0.
The cycle counter PMCCNTR_EL0.

Other event counters are not affected by this field.

The reset behavior of this field is:

On a Warm reset, this field resets to 0.

Accessing PMCR_EL0

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

MRS <Xt>, PMCR_EL0

op0	op1	CRn	CRm	op2
0b11	0b011	0b1001	0b1100	0b000

if PSTATE.EL == EL0 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TPM == '1' then UNDEFINED; elsif PMUSERENR_EL0.EN == '0' || (IsFeatureImplemented(FEAT_PMUv3p9) && PMUSERENR_EL0.UEN == '1') then if EL2Enabled() && HCR_EL2.TGE == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && MDCR_EL2.TPM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.TPMCR == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3.TPM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = PMCR_EL0; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TPM == '1' then UNDEFINED; elsif EL2Enabled() && MDCR_EL2.TPM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.TPMCR == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3.TPM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = PMCR_EL0; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TPM == '1' then UNDEFINED; elsif HaveEL(EL3) && MDCR_EL3.TPM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = PMCR_EL0; elsif PSTATE.EL == EL3 then X[t, 64] = PMCR_EL0;

MSR PMCR_EL0, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b011	0b1001	0b1100	0b000

if PSTATE.EL == EL0 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TPM == '1' then UNDEFINED; elsif PMUSERENR_EL0.EN == '0' || (IsFeatureImplemented(FEAT_PMUv3p9) && PMUSERENR_EL0.UEN == '1') then if EL2Enabled() && HCR_EL2.TGE == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELIsInHost(EL0) && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGWTR_EL2.PMCR_EL0 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.TPM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.TPMCR == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3.TPM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else PMCR_EL0 = X[t, 64]; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TPM == '1' then UNDEFINED; elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGWTR_EL2.PMCR_EL0 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.TPM == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.TPMCR == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3.TPM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else PMCR_EL0 = X[t, 64]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.TPM == '1' then UNDEFINED; elsif HaveEL(EL3) && MDCR_EL3.TPM == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else PMCR_EL0 = X[t, 64]; elsif PSTATE.EL == EL3 then PMCR_EL0 = X[t, 64];

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
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																															FZS
IMP								IDCODE								N					RES0	FZO	RES0	LP	LC	DP	X	D	C	P	E

PMCR_EL0, Performance Monitors Control Register

Purpose

Configuration

Attributes

Field descriptions

Bits [63:33]

FZS, bit [32]
When FEAT_SPEv1p2 is implemented and FEAT_SPE_DPFZS is implemented:

When FEAT_SPEv1p2 is implemented:

Otherwise:

IMP, bits [31:24]
When FEAT_PMUv3p7 is not implemented:

Otherwise:

IDCODE, bits [23:16]
When PMCR_EL0.IMP != 0b00000000:

Otherwise:

N, bits [15:11]

Bit [10]

FZO, bit [9]
When FEAT_PMUv3p7 is implemented:

Otherwise:

Bit [8]

LP, bit [7]
When FEAT_PMUv3p5 is implemented:

Otherwise:

LC, bit [6]
When AArch32 is supported:

Otherwise:

DP, bit [5]
When (FEAT_PMUv3p1 is implemented and EL2 is implemented) or EL3 is implemented:

Otherwise:

X, bit [4]
When the implementation includes a PMU event export bus:

Otherwise:

D, bit [3]
When AArch32 is supported:

Otherwise:

C, bit [2]

P, bit [1]

E, bit [0]

Accessing PMCR_EL0

MRS <Xt>, PMCR_EL0

MSR PMCR_EL0, <Xt>

PMCR_EL0, Performance Monitors Control Register

Purpose

Configuration

Attributes

Field descriptions

Bits [63:33]

FZS, bit [32]When FEAT_SPEv1p2 is implemented and FEAT_SPE_DPFZS is implemented:

When FEAT_SPEv1p2 is implemented:

Otherwise:

IMP, bits [31:24]When FEAT_PMUv3p7 is not implemented:

Otherwise:

IDCODE, bits [23:16]When PMCR_EL0.IMP != 0b00000000:

Otherwise:

N, bits [15:11]

Bit [10]

FZO, bit [9]When FEAT_PMUv3p7 is implemented:

Otherwise:

Bit [8]

LP, bit [7]When FEAT_PMUv3p5 is implemented:

Otherwise:

LC, bit [6]When AArch32 is supported:

Otherwise:

DP, bit [5]When (FEAT_PMUv3p1 is implemented and EL2 is implemented) or EL3 is implemented:

Otherwise:

X, bit [4]When the implementation includes a PMU event export bus:

Otherwise:

D, bit [3]When AArch32 is supported:

Otherwise:

C, bit [2]

P, bit [1]

E, bit [0]

Accessing PMCR_EL0

MRS <Xt>, PMCR_EL0

MSR PMCR_EL0, <Xt>

FZS, bit [32]
When FEAT_SPEv1p2 is implemented and FEAT_SPE_DPFZS is implemented:

IMP, bits [31:24]
When FEAT_PMUv3p7 is not implemented:

IDCODE, bits [23:16]
When PMCR_EL0.IMP != 0b00000000:

FZO, bit [9]
When FEAT_PMUv3p7 is implemented:

LP, bit [7]
When FEAT_PMUv3p5 is implemented:

LC, bit [6]
When AArch32 is supported:

DP, bit [5]
When (FEAT_PMUv3p1 is implemented and EL2 is implemented) or EL3 is implemented:

X, bit [4]
When the implementation includes a PMU event export bus:

D, bit [3]
When AArch32 is supported: