OSLAR_EL1 OS Lock Access Register when FEAT_AA64 is implemented OSLAR_EL1 Architectural External 31 0 31 0 31 0 31 0 Used to lock or unlock the OS Lock. Debug The OS Lock can also be locked or unlocked using DBGOSLAR. OSLAR_EL1 is a 64-bit register. 63 1 63:1 Reserved, RES0. OSLK 0 0 0 On writes to OSLAR_EL1, bit[0] is copied to the OS Lock. Use OSLSR_EL1.OSLK to check the current status of the lock. MSR OSLAR_EL1, <Xt> if !IsFeatureImplemented(FEAT_AA64) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().TDOSA == '1' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HDFGWTR_EL2().OSLAR_EL1 == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().[TDE,TDOSA] != '00' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().TDOSA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else OSLAR_EL1() = X{64}(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().TDOSA == '1' then Undefined(); elsif HaveEL(EL3) && MDCR_EL3().TDOSA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else OSLAR_EL1() = X{64}(t); end; elsif PSTATE.EL == EL3 then OSLAR_EL1() = X{64}(t); end; 2026-03-26 20:27:25 2026-03_rel