LORSA_EL1 LORegion Start Address (EL1) when FEAT_LOR is implemented and FEAT_AA64 is implemented Indicates whether the current LORegion descriptor selected by LORC_EL1.DS is enabled, and holds the physical address of the start of the LORegion. Memory This register is RES0 if any of the following apply: No LORegion descriptors are supported by the PE. LORC_EL1.DS points to a LORegion that is not supported by the PE. LORSA_EL1 is a 64-bit register. Any of the fields in this register are permitted to be cached in a TLB. 63 56 63:56 Reserved, RES0. SA 55 16 55:16 When FEAT_D128 is implemented SA 39 0 39:0 Bits [55:16] of the start physical address of the LORegion described in the current LORegion descriptor selected by LORC_EL1.DS. Bits[15:0] of this address are 0x0000. For implementations with fewer than 56 physical address bits, the corresponding upper bits of this field are RES0. AU When FEAT_D128 is implemented When FEAT_LPA is implemented and FEAT_D128 is not implemented 39 36 39:36 Reserved, RES0. SA 35 0 35:0 Bits [51:16] of the start physical address of the LORegion described in the current LORegion descriptor selected by LORC_EL1.DS. Bits[15:0] of this address are 0x0000. For implementations with fewer than 52 physical address bits, the corresponding upper bits of this field are RES0. AU When FEAT_LPA is implemented and FEAT_D128 is not implemented When FEAT_LPA is not implemented 39 32 39:32 Reserved, RES0. SA 31 0 31:0 Bits [47:16] of the start physical address of the LORegion described in the current LORegion descriptor selected by LORC_EL1.DS. Bits[15:0] of this address are 0x0000. For implementations with fewer than 48 physical address bits, the corresponding upper bits of this field are RES0. AU When FEAT_LPA is not implemented 15 1 15:1 Reserved, RES0. Valid 0 0 0 Indicates whether the current LORegion descriptor is enabled. 0b0 LORegion descriptor is disabled. 0b1 LORegion descriptor is enabled. '0' MRS <Xt>, LORSA_EL1 if !(IsFeatureImplemented(FEAT_LOR) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3().TLOR == '1' then Undefined(); elsif HaveEL(EL3) && SCR_EL3().NS == '0' then Undefined(); elsif EL2Enabled() && HCR_EL2().TLOR == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HFGRTR_EL2().LORSA_EL1 == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3().TLOR == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = LORSA_EL1(); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && SCR_EL3().NS == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3().TLOR == '1' then Undefined(); elsif HaveEL(EL3) && SCR_EL3().TLOR == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = LORSA_EL1(); end; elsif PSTATE.EL == EL3 then if SCR_EL3().NS == '0' then Undefined(); else X{64}(t) = LORSA_EL1(); end; end; MSR LORSA_EL1, <Xt> if !(IsFeatureImplemented(FEAT_LOR) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3().TLOR == '1' then Undefined(); elsif HaveEL(EL3) && SCR_EL3().NS == '0' then Undefined(); elsif EL2Enabled() && HCR_EL2().TLOR == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HFGWTR_EL2().LORSA_EL1 == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3().TLOR == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else LORSA_EL1() = X{64}(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && SCR_EL3().NS == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3().TLOR == '1' then Undefined(); elsif HaveEL(EL3) && SCR_EL3().TLOR == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else LORSA_EL1() = X{64}(t); end; elsif PSTATE.EL == EL3 then if SCR_EL3().NS == '0' then Undefined(); else LORSA_EL1() = X{64}(t); end; end; 2026-03-26 20:27:25 2026-03_rel