HRMR, Hyp Reset Management Register

The HRMR characteristics are:

Purpose

If EL2 is the highest implemented Exception level and this register is implemented:

Configuration

AArch32 System register HRMR bits [31:0] are architecturally mapped to AArch64 System register RMR_EL2[31:0].

This register is present only when AArch32 is supported at any Exception level. Otherwise, direct accesses to HRMR are UNDEFINED.

Only implemented if EL2 is the highest implemented Exception level. In this case:

Attributes

HRMR is a 32-bit register.

Field descriptions

The HRMR bit assignments are:

313029282726252423222120191817161514131211109876543210
RES0RRAA64

Bits [31:2]

Reserved, RES0.

RR, bit [1]

Reset Request. Setting this bit to 1 requests a Warm reset.

On a Warm reset, this field resets to 0.

AA64, bit [0]

When EL2 can use AArch64, determines which Execution state the PE boots into after a Warm reset:

AA64Meaning
0b0

AArch32.

0b1

AArch64.

On coming out of the Warm reset, execution starts at the IMPLEMENTATION DEFINED reset vector address of the specified Execution state.

If EL2 cannot use AArch64 this bit is RAZ/WI.

When implemented as a RW field, this field resets to 0 on a Cold reset.

Accessing the HRMR

Accesses to this register use the following encodings:

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

coprocopc1CRnCRmopc2
0b11110b1000b11000b00000b010

if PSTATE.EL == EL1 && EL2Enabled() && IsHighestEL(EL2) && !ELUsingAArch32(EL2) && HSTR_EL2.T12 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif PSTATE.EL == EL1 && EL2Enabled() && IsHighestEL(EL2) && ELUsingAArch32(EL2) && HSTR.T12 == '1' then AArch32.TakeHypTrapException(0x03); elsif PSTATE.EL == EL2 && IsHighestEL(EL2) then return HRMR; else UNDEFINED;

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

coprocopc1CRnCRmopc2
0b11110b1000b11000b00000b010

if PSTATE.EL == EL1 && EL2Enabled() && IsHighestEL(EL2) && !ELUsingAArch32(EL2) && HSTR_EL2.T12 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif PSTATE.EL == EL1 && EL2Enabled() && IsHighestEL(EL2) && ELUsingAArch32(EL2) && HSTR.T12 == '1' then AArch32.TakeHypTrapException(0x03); elsif PSTATE.EL == EL2 && IsHighestEL(EL2) then HRMR = R[t]; else UNDEFINED;


30/03/2021 20:51; e3551d56dc294a4d55296a6c10544191ada08a8e

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