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SPMROOTCR_EL3: System Performance Monitors Root and Realm Control Register

Purpose

Controls observability of Root and Realm events by System PMU <s>.

Configuration

This register is present only when FEAT_RME is implemented and FEAT_SPMU is implemented. Otherwise, direct accesses to SPMROOTCR_EL3 are UNDEFINED.

Attributes

SPMROOTCR_EL3 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
IMPLEMENTATION DEFINED
RAORES0NAORES0RLORTO

IMPLEMENTATION DEFINED, bits [63:32]

IMPLEMENTATION DEFINED observation controls. Additional IMPLEMENTATION DEFINED bits to control certain types of filter or events by System PMU <s>.

The reset behavior of this field is:

Bit [31]

Reserved, RAO.

Indicates SPMROOTCR_EL3 is implemented by System PMU <s>.

Bits [30:4]

Reserved, RES0.

NAO, bit [3]

When System PMU <s> can count or monitor non-attributable events:

Non-attributable Observation. Controls whether events or monitorable characteristics not attributable with any source can be monitored by System PMU <s>.

NAOMeaning
0b0

Events not attributable with any event source are not counted by System PMU <s>.

0b1

Counting non-attributable events by System PMU <s> is not prevented by this mechanism.

When both SPMROOTCR_EL3 and SPMSCR_EL1 are implemented, non-attributable events are counted only if both SPMROOTCR_EL3.NAO is 1 and SPMSCR_EL1.{NAO, SO} is nonzero.

SPMROOTCR_EL3.NAO has the opposite reset polarity to SPMSCR_EL1.NAO.

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

Bit [2]

Reserved, RES0.

RLO, bit [1]

Realm Observation. Controls whether events or monitorable characteristics attributable to a Realm event source can be monitored by System PMU <s>.

RLOMeaning
0b0

Events attributable to a Realm event source are not counted by System PMU <s>.

0b1

Counting events by System PMU <s> that are attributable to a Realm event source is not prevented by this mechanism.

The reset behavior of this field is:

RTO, bit [0]

Root Observation. Controls whether events or monitorable characteristics attributable to a Root event source can be monitored by System PMU <s>.

RTOMeaning
0b0

Events attributable to a Root event source are not counted by System PMU <s>.

0b1

Counting events by System PMU <s> that are attributable to a Root event source is not prevented by this mechanism.

The reset behavior of this field is:

Accessing SPMROOTCR_EL3

To access SPMROOTCR_EL3 for System PMU <s>, set SPMSELR_EL0.SYSPMUSEL to s.

SPMROOTCR_EL3 reads-as-zero and ignores writes if any of the following are true:

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

MRS <Xt>, SPMROOTCR_EL3

op0op1CRnCRmop2
0b100b1100b10010b11100b111

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then UNDEFINED; elsif PSTATE.EL == EL2 then UNDEFINED; elsif PSTATE.EL == EL3 then X[t, 64] = SPMROOTCR_EL3[UInt(SPMSELR_EL0.SYSPMUSEL)];

MSR SPMROOTCR_EL3, <Xt>

op0op1CRnCRmop2
0b100b1100b10010b11100b111

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then UNDEFINED; elsif PSTATE.EL == EL2 then UNDEFINED; elsif PSTATE.EL == EL3 then if IsFeatureImplemented(FEAT_FGWTE3) && FGWTE3_EL3.SPMROOTCR_EL3 == '1' then AArch64.SystemAccessTrap(EL3, 0x18); else SPMROOTCR_EL3[UInt(SPMSELR_EL0.SYSPMUSEL)] = X[t, 64];