OSDLR_EL1 OS Double Lock Register when FEAT_AA64 is implemented DBGOSDLR Architectural AArch32 31 0 31 0 31 0 31 0 Used to control the OS Double Lock. Debug OSDLR_EL1 is a 64-bit register. 63 1 63:1 Reserved, RES0. DLK 0 0 0 OS Double Lock control bit. 0b0 OS Double Lock unlocked. 0b1 OS Double Lock locked, if DBGPRCR_EL1.CORENPDRQ (Core no powerdown request) bit is set to 0 and the PE is in Non-debug state. '0' When FEAT_DoubleLock is implemented 0 0 0 Reserved, RAZ/WI. Otherwise MRS <Xt>, OSDLR_EL1 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' && (IsFeatureImplemented(FEAT_DoubleLock) || ImpDefBool("Trapped by MDCR_EL3.TDOSA")) then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && IsFeatureImplemented(FEAT_DoubleLock) && HDFGRTR_EL2().OSDLR_EL1 == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().[TDE,TDOSA] != '00' && (IsFeatureImplemented(FEAT_DoubleLock) || ImpDefBool("Trapped by MDCR_EL2.TDOSA")) then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().TDOSA == '1' && (IsFeatureImplemented(FEAT_DoubleLock) || ImpDefBool("Trapped by MDCR_EL3.TDOSA")) then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = OSDLR_EL1(); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().TDOSA == '1' && (IsFeatureImplemented(FEAT_DoubleLock) || ImpDefBool("Trapped by MDCR_EL3.TDOSA")) then Undefined(); elsif HaveEL(EL3) && MDCR_EL3().TDOSA == '1' && (IsFeatureImplemented(FEAT_DoubleLock) || ImpDefBool("Trapped by MDCR_EL3.TDOSA")) then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = OSDLR_EL1(); end; elsif PSTATE.EL == EL3 then X{64}(t) = OSDLR_EL1(); end; MSR OSDLR_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' && (IsFeatureImplemented(FEAT_DoubleLock) || ImpDefBool("Trapped by MDCR_EL3.TDOSA")) then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && IsFeatureImplemented(FEAT_DoubleLock) && HDFGWTR_EL2().OSDLR_EL1 == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().[TDE,TDOSA] != '00' && (IsFeatureImplemented(FEAT_DoubleLock) || ImpDefBool("Trapped by MDCR_EL2.TDOSA")) then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().TDOSA == '1' && (IsFeatureImplemented(FEAT_DoubleLock) || ImpDefBool("Trapped by MDCR_EL3.TDOSA")) then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else OSDLR_EL1() = X{64}(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().TDOSA == '1' && (IsFeatureImplemented(FEAT_DoubleLock) || ImpDefBool("Trapped by MDCR_EL3.TDOSA")) then Undefined(); elsif HaveEL(EL3) && MDCR_EL3().TDOSA == '1' && (IsFeatureImplemented(FEAT_DoubleLock) || ImpDefBool("Trapped by MDCR_EL3.TDOSA")) then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else OSDLR_EL1() = X{64}(t); end; elsif PSTATE.EL == EL3 then OSDLR_EL1() = X{64}(t); end; 2026-03-26 20:27:25 2026-03_rel