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SPMCR_EL0
AArch32 Registers
AArch64 Registers
AArch32 Instructions
AArch64 Instructions
Index by Encoding
External Registers
External Registers by Offset
Registers by Functional Group
Proprietary Notice

SPMCR_EL0, System Performance Monitor Control Register

The SPMCR_EL0 characteristics are:

Purpose

Main control register for System PMU <s>.

Configuration

This register is present only when FEAT_SPMU is implemented and FEAT_AA64 is implemented. Otherwise, direct accesses to SPMCR_EL0 are UNDEFINED.

Attributes

SPMCR_EL0 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
RES0
RES0TROHDBGFZONARES0EXRES0PE

Bits [63:12]

Reserved, RES0.

TRO, bit [11]
When SPMCFGR_EL1.TRO == 1:

Trace enable. For more information on this field, see 'CoreSight PMU Architecture'.

The reset behavior of this field is:

Accessing this field has the following behavior:


Otherwise:

Reserved, RES0.

HDBG, bit [10]
When SPMCFGR_EL1.HDBG == 1:

Halt-on-debug. For more information on this field, see 'CoreSight PMU Architecture'.

The reset behavior of this field is:

Accessing this field has the following behavior:


Otherwise:

Reserved, RES0.

FZO, bit [9]
When SPMCFGR_EL1.FZO == 1:

Freeze-on-overflow. For more information on this field, see 'CoreSight PMU Architecture'.

Note

If implemented by a System PMU, then freeze-on-overflow affects only the counters of System PMU <s>, not other System PMUs nor the PE PMU.

The reset behavior of this field is:


Otherwise:

Reserved, RES0.

NA, bit [8]
When SPMCFGR_EL1.NA == 1:

Not accessible. For more information on this field, see 'CoreSight PMU Architecture'.

Access to this field is RO.


Otherwise:

Reserved, RES0.

Bits [7:5]

Reserved, RES0.

EX, bit [4]
When SPMCFGR_EL1.EX == 1:

Export enable. For more information on this field, see 'CoreSight PMU Architecture'.

The reset behavior of this field is:


Otherwise:

Reserved, RES0.

Bits [3:2]

Reserved, RES0.

P, bit [1]

Event counter reset.

PMeaning
0b0

Write is ignored.

0b1

Reset all event counters in System PMU <s> to zero.

Note

Resetting the event counters does not affect any overflow flags.

Access to this field is WO/RAZ.

E, bit [0]

Count enable. This field controls System PMU <s>.

EMeaning
0b0

Monitor is disabled.

0b1

Monitor is enabled.

Performance monitor overflow IRQs are only signaled by System PMU <s> when this field is 1.

The reset behavior of this field is:

Accessing SPMCR_EL0

To access SPMCR_EL0 for System PMU <s>, set SPMSELR_EL0.SYSPMUSEL to s.

SPMCR_EL0 reads-as-zero and ignores writes if System PMU <s> is not implemented.

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

MRS <Xt>, SPMCR_EL0

op0op1CRnCRmop2
0b100b0110b10010b11000b000

if !(IsFeatureImplemented(FEAT_SPMU) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnPM2 == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then Undefined(); elsif MDSCR_EL1().EnSPM == '0' then if EL2Enabled() && HCR_EL2().TGE == '1' then AArch64_SystemAccessTrap(EL2, 0x18); else AArch64_SystemAccessTrap(EL1, 0x18); end; elsif !ELIsInHost(EL0) && SPMACCESSR_EL1()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then if EL2Enabled() && HCR_EL2().TGE == '1' then AArch64_SystemAccessTrap(EL2, 0x18); else AArch64_SystemAccessTrap(EL1, 0x18); end; elsif EL2Enabled() && !ELIsInHost(EL0) && IsFeatureImplemented(FEAT_FGT2) && ((HaveEL(EL3) && SCR_EL3().FGTEn2 == '0') || HDFGRTR2_EL2().nSPMCR_EL0 == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().EnSPM == '0' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && SPMACCESSR_EL2()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().EnPM2 == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = SPMCR_EL0(UInt(SPMSELR_EL0().SYSPMUSEL)); end; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnPM2 == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT2) && ((HaveEL(EL3) && SCR_EL3().FGTEn2 == '0') || HDFGRTR2_EL2().nSPMCR_EL0 == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().EnSPM == '0' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && SPMACCESSR_EL2()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().EnPM2 == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = SPMCR_EL0(UInt(SPMSELR_EL0().SYSPMUSEL)); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnPM2 == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then Undefined(); elsif HaveEL(EL3) && MDCR_EL3().EnPM2 == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = SPMCR_EL0(UInt(SPMSELR_EL0().SYSPMUSEL)); end; elsif PSTATE.EL == EL3 then X{64}(t) = SPMCR_EL0(UInt(SPMSELR_EL0().SYSPMUSEL)); end;

MSR SPMCR_EL0, <Xt>

op0op1CRnCRmop2
0b100b0110b10010b11000b000

if !(IsFeatureImplemented(FEAT_SPMU) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnPM2 == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] != '11' then Undefined(); elsif MDSCR_EL1().EnSPM == '0' then if EL2Enabled() && HCR_EL2().TGE == '1' then AArch64_SystemAccessTrap(EL2, 0x18); else AArch64_SystemAccessTrap(EL1, 0x18); end; elsif !ELIsInHost(EL0) && SPMACCESSR_EL1()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] != '11' then if EL2Enabled() && HCR_EL2().TGE == '1' then AArch64_SystemAccessTrap(EL2, 0x18); else AArch64_SystemAccessTrap(EL1, 0x18); end; elsif EL2Enabled() && !ELIsInHost(EL0) && IsFeatureImplemented(FEAT_FGT2) && ((HaveEL(EL3) && SCR_EL3().FGTEn2 == '0') || HDFGWTR2_EL2().nSPMCR_EL0 == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().EnSPM == '0' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && SPMACCESSR_EL2()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] != '11' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().EnPM2 == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] != '11' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else SPMCR_EL0(UInt(SPMSELR_EL0().SYSPMUSEL)) = X{64}(t); end; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnPM2 == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] != '11' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT2) && ((HaveEL(EL3) && SCR_EL3().FGTEn2 == '0') || HDFGWTR2_EL2().nSPMCR_EL0 == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().EnSPM == '0' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && SPMACCESSR_EL2()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] != '11' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().EnPM2 == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] != '11' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else SPMCR_EL0(UInt(SPMSELR_EL0().SYSPMUSEL)) = X{64}(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnPM2 == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] != '11' then Undefined(); elsif HaveEL(EL3) && MDCR_EL3().EnPM2 == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] != '11' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else SPMCR_EL0(UInt(SPMSELR_EL0().SYSPMUSEL)) = X{64}(t); end; elsif PSTATE.EL == EL3 then SPMCR_EL0(UInt(SPMSELR_EL0().SYSPMUSEL)) = X{64}(t); end;

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

2026-03-12 12:23:09, 2025-09_rel_asl1

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