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AMAIR_EL1, Auxiliary Memory Attribute Indirection Register (EL1)

The AMAIR_EL1 characteristics are:

Purpose

Provides IMPLEMENTATION DEFINED memory attributes for the memory regions specified by MAIR_EL1.

Configuration

AArch64 System register AMAIR_EL1 bits [31:0] are architecturally mapped to AArch32 System register AMAIR0[31:0] .

AArch64 System register AMAIR_EL1 bits [63:32] are architecturally mapped to AArch32 System register AMAIR1[31:0] .

RW fields in this register reset to architecturally UNKNOWN values.

Attributes

AMAIR_EL1 is a 64-bit register.

Field descriptions

The AMAIR_EL1 bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
IMPLEMENTATION DEFINED
IMPLEMENTATION DEFINED
313029282726252423222120191817161514131211109876543210

AMAIR_EL1 is permitted to be cached in a TLB.

IMPLEMENTATION DEFINED, bits [63:0]

IMPLEMENTATION DEFINED.

This field resets to an architecturally UNKNOWN value.

Accessing the AMAIR_EL1

When HCR_EL2.E2H is 1, without explicit synchronization, access from EL3 using the mnemonic AMAIR_EL1 or AMAIR_EL12 are not guaranteed to be ordered with respect to accesses using the other mnemonic.

Accesses to this register use the following encodings:

MRS <Xt>, AMAIR_EL1

op0op1CRnCRmop2
0b110b0000b10100b00110b000
if PSTATE.EL == EL0 then
    UNDEFINED;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TRVM == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGRTR_EL2.AMAIR_EL1 == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<NV2,NV1,NV> == '111' then
        return NVMem[0x148];
    else
        return AMAIR_EL1;
elsif PSTATE.EL == EL2 then
    if HCR_EL2.E2H == '1' then
        return AMAIR_EL2;
    else
        return AMAIR_EL1;
elsif PSTATE.EL == EL3 then
    return AMAIR_EL1;
              

MSR AMAIR_EL1, <Xt>

op0op1CRnCRmop2
0b110b0000b10100b00110b000
if PSTATE.EL == EL0 then
    UNDEFINED;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TVM == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGWTR_EL2.AMAIR_EL1 == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<NV2,NV1,NV> == '111' then
        NVMem[0x148] = X[t];
    else
        AMAIR_EL1 = X[t];
elsif PSTATE.EL == EL2 then
    if HCR_EL2.E2H == '1' then
        AMAIR_EL2 = X[t];
    else
        AMAIR_EL1 = X[t];
elsif PSTATE.EL == EL3 then
    AMAIR_EL1 = X[t];
              

MRS <Xt>, AMAIR_EL12

op0op1CRnCRmop2
0b110b1010b10100b00110b000
if PSTATE.EL == EL0 then
    UNDEFINED;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && HCR_EL2.<NV2,NV1,NV> == '101' then
        return NVMem[0x148];
    elsif EL2Enabled() && HCR_EL2.NV == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    else
        UNDEFINED;
elsif PSTATE.EL == EL2 then
    if EL2Enabled() && HCR_EL2.E2H == '1' then
        return AMAIR_EL1;
    else
        UNDEFINED;
elsif PSTATE.EL == EL3 then
    if EL2Enabled() && HCR_EL2.E2H == '1' then
        return AMAIR_EL1;
    else
        UNDEFINED;
              

MSR AMAIR_EL12, <Xt>

op0op1CRnCRmop2
0b110b1010b10100b00110b000
if PSTATE.EL == EL0 then
    UNDEFINED;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && HCR_EL2.<NV2,NV1,NV> == '101' then
        NVMem[0x148] = X[t];
    elsif EL2Enabled() && HCR_EL2.NV == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    else
        UNDEFINED;
elsif PSTATE.EL == EL2 then
    if EL2Enabled() && HCR_EL2.E2H == '1' then
        AMAIR_EL1 = X[t];
    else
        UNDEFINED;
elsif PSTATE.EL == EL3 then
    if EL2Enabled() && HCR_EL2.E2H == '1' then
        AMAIR_EL1 = X[t];
    else
        UNDEFINED;
              


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