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AMUSERENR, Activity Monitors User Enable Register

The AMUSERENR characteristics are:

Purpose

Global user enable register for the activity monitors. Enables or disables EL0 access to the activity monitors. AMUSERENR is applicable to both the architected and the auxiliary counter groups.

Configuration

AArch32 System register AMUSERENR bits [31:0] are architecturally mapped to AArch64 System register AMUSERENR_EL0[31:0] .

This register is present only when AMUv1 is implemented. Otherwise, direct accesses to AMUSERENR are UNDEFINED.

Attributes

AMUSERENR is a 32-bit register.

Field descriptions

The AMUSERENR bit assignments are:

313029282726252423222120191817161514131211109876543210
RES0EN

Bits [31:1]

Reserved, RES0.

EN, bit [0]

Traps EL0 accesses to the activity monitors registers to EL1.

ENMeaning
0b0

EL0 accesses to the activity monitors registers are trapped to EL1.

0b1

This control does not cause any instructions to be trapped. Software can access all activity monitor registers at EL0.

Note
  • AMUSERENR can always be read at EL0 and is not governed by this bit.

Accessing the AMUSERENR

Accesses to this register use the following encodings:

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

coprocopc1CRnCRmopc2
0b11110b0000b11010b00100b011
if PSTATE.EL == EL0 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && HSTR_EL2.T13 == '1' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T13 == '1' then
        AArch32.TakeHypTrapException(0x03);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && CPTR_EL2.TAM == '1' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && HCPTR.TAM == '1' then
        AArch32.TakeHypTrapException(0x03);
    elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then
        AArch64.AArch32SystemAccessTrap(EL3, 0x03);
    else
        return AMUSERENR;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T13 == '1' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T13 == '1' then
        AArch32.TakeHypTrapException(0x03);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && CPTR_EL2.TAM == '1' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && HCPTR.TAM == '1' then
        AArch32.TakeHypTrapException(0x03);
    elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then
        AArch64.AArch32SystemAccessTrap(EL3, 0x03);
    else
        return AMUSERENR;
elsif PSTATE.EL == EL2 then
    if HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then
        AArch64.AArch32SystemAccessTrap(EL3, 0x03);
    else
        return AMUSERENR;
elsif PSTATE.EL == EL3 then
    return AMUSERENR;

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

coprocopc1CRnCRmopc2
0b11110b0000b11010b00100b011
if PSTATE.EL == EL0 then
    UNDEFINED;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T13 == '1' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T13 == '1' then
        AArch32.TakeHypTrapException(0x03);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && CPTR_EL2.TAM == '1' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x03);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && HCPTR.TAM == '1' then
        AArch32.TakeHypTrapException(0x03);
    elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then
        AArch64.AArch32SystemAccessTrap(EL3, 0x03);
    else
        AMUSERENR = R[t];
elsif PSTATE.EL == EL2 then
    if HaveEL(EL3) && !ELUsingAArch32(EL3) && CPTR_EL3.TAM == '1' then
        AArch64.AArch32SystemAccessTrap(EL3, 0x03);
    else
        AMUSERENR = R[t];
elsif PSTATE.EL == EL3 then
    AMUSERENR = R[t];


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