SPMSCR_EL1 System Performance Monitors Secure Control Register when Secure EL1 is implemented, FEAT_SPMU is implemented, and FEAT_AA64 is implemented Controls observability of Secure events by System PMU <s>, and optionally controls Secure attributes for message signaled interrupts and Non-secure access to the performance monitor registers. Unknown SPMSCR_EL1 is a 64-bit register. IMPLEMENTATION DEFINED 63 32 63:32 IMPLEMENTATION DEFINED observation controls. Additional IMPLEMENTATION DEFINED bits to control certain types of filter or events by System PMU <s>. ID 31 31 31 Reserved, RAO. Indicates SPMSCR_EL1 is implemented by System PMU <s>. This field reads-as-one. 30 5 30:5 Reserved, RES0. NAO 4 4 0 Non-attributable Observation. Controls whether events or monitorable characteristics not attributable with any source can be monitored by System PMU <s>. 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. SPMSCR_EL1.NAO has the opposite reset polarity to SPMROOTCR_EL3.NAO. This field is optional if Root and Realm states are not implemented. When this field is not implemented, System PMU <s> behaves as if SPMSCR_EL1.NAO is 0, and whether events or monitorable characteristics not attributable with any source can be monitored is controlled by SPMSCR_EL1.SO. 0b0 Events not attributable with any event source are not counted by System PMU <s>, unless overridden by SPMSCR_EL1.SO. 0b1 Counting non-attributable events by System PMU <s> is not prevented by this mechanism. '0' When System PMU <s> can count or monitor non-attributable events 4 4 4 Reserved, RES0. Otherwise 3 1 3:1 Reserved, RES0. SO 0 0 0 Secure Observation. Controls whether events or monitorable characteristics attributable to a Secure event source can be monitored by System PMU <s>. Also controls whether events or monitorable characteristics not attributable with any source can be monitored by System PMU <s>. See SPMSCR_EL1.NAO. 0b0 Events attributable to a Secure event source are not counted by System PMU <s>. 0b1 Counting events by System PMU <s> that are attributable to a Secure event source is not prevented by this mechanism. '0' To access SPMSCR_EL1 for System PMU <s>, set SPMSELR_EL0.SYSPMUSEL to s. SPMSCR_EL1 reads-as-zero and ignores writes if any of the following are true: System PMU <s> is not implemented. System PMU <s> does not implement SPMSCR_EL1. SPMSCR_EL1 is UNDEFINED if accessed in Non-secure or Realm state. MRS <Xt>, SPMSCR_EL1 if !(HaveELUsingSecurityState(EL1, TRUE) && IsFeatureImplemented(FEAT_SPMU) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif IsCurrentSecurityState(SS_NonSecure) || (IsFeatureImplemented(FEAT_RME) && IsCurrentSecurityState(SS_Realm)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); 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().nSPMSCR_EL1 == '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) = SPMSCR_EL1(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) = SPMSCR_EL1(UInt(SPMSELR_EL0().SYSPMUSEL)); end; elsif PSTATE.EL == EL3 then X{64}(t) = SPMSCR_EL1(UInt(SPMSELR_EL0().SYSPMUSEL)); end; MSR SPMSCR_EL1, <Xt> if !(HaveELUsingSecurityState(EL1, TRUE) && IsFeatureImplemented(FEAT_SPMU) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif IsCurrentSecurityState(SS_NonSecure) || (IsFeatureImplemented(FEAT_RME) && IsCurrentSecurityState(SS_Realm)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); 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().nSPMSCR_EL1 == '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 SPMSCR_EL1(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 SPMSCR_EL1(UInt(SPMSELR_EL0().SYSPMUSEL)) = X{64}(t); end; elsif PSTATE.EL == EL3 then SPMSCR_EL1(UInt(SPMSELR_EL0().SYSPMUSEL)) = X{64}(t); end; 2026-03-26 20:27:25 2026-03_rel