HACTLR2, Hyp Auxiliary Control Register 2

The HACTLR2 characteristics are:

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 AArch32 is supported at any Exception level. 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

The HACTLR2 bit assignments are:

313029282726252423222120191817161514131211109876543210
IMPLEMENTATION DEFINED

IMPLEMENTATION DEFINED, bits [31:0]

IMPLEMENTATION DEFINED.

On a Warm reset, this field resets to an architecturally UNKNOWN value.

Accessing the HACTLR2

Accesses to this register use the following encodings:

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 return HACTLR2; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then UNDEFINED; else return 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];




30/09/2020 15:07; ccead0cb9f089f9ceec50268e82aec9e71047211

Copyright © 2010-2020 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.