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HACTLR2: Hyp Auxiliary Control Register 2

Purpose

Provides additional space to the HACTLR register to hold IMPLEMENTATION DEFINED trap functionality.

Configuration

AArch32 System register HACTLR2 bits [31:0] are architecturally mapped to AArch64 System register ACTLR_EL2[63:32].

This register is present only when EL2 is capable of using AArch32. Otherwise, direct accesses to HACTLR2 are UNDEFINED.

In Armv8.0 and Armv8.1, it is IMPLEMENTATION DEFINED whether this register is implemented, or whether it causes UNDEFINED exceptions when accessed. The implementation of this register can be detected by examining ID_MMFR4.AC2.

From Armv8.2 this register must be implemented.

Attributes

HACTLR2 is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
IMPLEMENTATION DEFINED

IMPLEMENTATION DEFINED, bits [31:0]

IMPLEMENTATION DEFINED.

The reset behavior of this field is:

Accessing HACTLR2

Accesses to this register use the following encodings in the System register encoding space:

MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11110b1000b00010b00000b011

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T1 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T1 == '1' then AArch32.TakeHypTrapException(0x03); else UNDEFINED; elsif PSTATE.EL == EL2 then R[t] = HACTLR2; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then UNDEFINED; else R[t] = HACTLR2;

MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11110b1000b00010b00000b011

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T1 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T1 == '1' then AArch32.TakeHypTrapException(0x03); else UNDEFINED; elsif PSTATE.EL == EL2 then HACTLR2 = R[t]; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then UNDEFINED; else HACTLR2 = R[t];