Provides IMPLEMENTATION DEFINED configuration and control options for EL2.
Arm recommends the contents of this register are updated to apply to EL0 when the Effective value of HCR_EL2.{E2H, TGE} is {1, 1}, gaining configuration and control fields from the ACTLR_EL1. This avoids the need for software to manage the contents of these register when switching between a Guest OS and a Host OS.
AArch64 System register ACTLR_EL2 bits [31:0] are architecturally mapped to AArch32 System register HACTLR[31:0].
AArch64 System register ACTLR_EL2 bits [63:32] are architecturally mapped to AArch32 System register HACTLR2[31:0].
This register is present only when FEAT_AA64 is implemented. Otherwise, direct accesses to ACTLR_EL2 are UNDEFINED.
If EL2 is not implemented, this register is RES0 from EL3.
This register has no effect if EL2 is not enabled in the current Security state.
ACTLR_EL2 is a 64-bit register.
| 63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32 |
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| IMPLEMENTATION DEFINED | |||||||||||||||||||||||||||||||
| IMPLEMENTATION DEFINED | |||||||||||||||||||||||||||||||
IMPLEMENTATION DEFINED.
The reset behavior of this field is:
Accesses to this register use the following encodings in the System register encoding space:
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b100 | 0b0001 | 0b0000 | 0b001 |
if !IsFeatureImplemented(FEAT_AA64) then UNDEFINED; elsif PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then X[t, 64] = ACTLR_EL2; elsif PSTATE.EL == EL3 then X[t, 64] = ACTLR_EL2;
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b100 | 0b0001 | 0b0000 | 0b001 |
if !IsFeatureImplemented(FEAT_AA64) then UNDEFINED; elsif PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if IsFeatureImplemented(FEAT_SRMASK) then ACTLR_EL2 = (X[t, 64] AND NOT EffectiveACTLRMASK_EL2()) OR (ACTLR_EL2 AND EffectiveACTLRMASK_EL2()); else ACTLR_EL2 = X[t, 64]; elsif PSTATE.EL == EL3 then ACTLR_EL2 = X[t, 64];
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b000 | 0b0001 | 0b0000 | 0b001 |
if !IsFeatureImplemented(FEAT_AA64) then UNDEFINED; elsif PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.TACR == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EffectiveHCR_EL2_NVx() IN {'1x1'} && (!boolean IMPLEMENTATION_DEFINED "IMPLEMENTED_ACTLR_ELx accessor behavior" || EffectiveHCR_EL2_NVx() == '111') then X[t, 64] = NVMem[0x118]; else X[t, 64] = ACTLR_EL1; elsif PSTATE.EL == EL2 then if boolean IMPLEMENTATION_DEFINED "IMPLEMENTED_ACTLR_ELx accessor behavior" && ELIsInHost(EL2) then X[t, 64] = ACTLR_EL2; else X[t, 64] = ACTLR_EL1; elsif PSTATE.EL == EL3 then X[t, 64] = ACTLR_EL1;
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b000 | 0b0001 | 0b0000 | 0b001 |
if !IsFeatureImplemented(FEAT_AA64) then UNDEFINED; elsif PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.TACR == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EffectiveHCR_EL2_NVx() IN {'1x1'} && (!boolean IMPLEMENTATION_DEFINED "IMPLEMENTED_ACTLR_ELx accessor behavior" || EffectiveHCR_EL2_NVx() == '111') then NVMem[0x118] = X[t, 64]; else if IsFeatureImplemented(FEAT_SRMASK) then ACTLR_EL1 = (X[t, 64] AND NOT EffectiveACTLRMASK_EL1()) OR (ACTLR_EL1 AND EffectiveACTLRMASK_EL1()); else ACTLR_EL1 = X[t, 64]; elsif PSTATE.EL == EL2 then if boolean IMPLEMENTATION_DEFINED "IMPLEMENTED_ACTLR_ELx accessor behavior" && ELIsInHost(EL2) then if IsFeatureImplemented(FEAT_SRMASK) then ACTLR_EL2 = (X[t, 64] AND NOT EffectiveACTLRMASK_EL2()) OR (ACTLR_EL2 AND EffectiveACTLRMASK_EL2()); else ACTLR_EL2 = X[t, 64]; else ACTLR_EL1 = X[t, 64]; elsif PSTATE.EL == EL3 then ACTLR_EL1 = X[t, 64];