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CNTHP_CVAL_EL2, Counter-timer Physical Timer CompareValue register (EL2)

The CNTHP_CVAL_EL2 characteristics are:

Purpose

Holds the compare value for the EL2 physical timer.

Configuration

AArch64 System register CNTHP_CVAL_EL2 bits [63:0] are architecturally mapped to AArch32 System register CNTHP_CVAL[63:0] .

If EL2 is not implemented, this register is RES0 from EL3.

RW fields in this register reset to architecturally UNKNOWN values.

Attributes

CNTHP_CVAL_EL2 is a 64-bit register.

Field descriptions

The CNTHP_CVAL_EL2 bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
CompareValue
CompareValue
313029282726252423222120191817161514131211109876543210

CompareValue, bits [63:0]

Holds the EL2 physical timer CompareValue.

When CNTHP_CTL_EL2.ENABLE is 1, the timer condition is met when (CNTPCT_EL0 - CompareValue) is greater than or equal to zero. This means that CompareValue acts like a 64-bit upcounter timer. When the timer condition is met:

When CNTHP_CTL_EL2.ENABLE is 0, the timer condition is not met, but CNTPCT_EL0 continues to count.

If the Generic counter is implemented at a size less than 64 bits, then this field is permitted to be implemented at the same width as the counter, and the upper bits are RES0.

The value of this field is treated as zero-extended in all counter calculations.

This field resets to an architecturally UNKNOWN value.

Accessing the CNTHP_CVAL_EL2

When HCR_EL2.E2H is 1, without explicit synchronization, access from EL2 using the mnemonic CNTHP_CVAL_EL2 or CNTP_CVAL_EL0 are not guaranteed to be ordered with respect to accesses using the other mnemonic.

Accesses to this register use the following encodings:

MRS <Xt>, CNTHP_CVAL_EL2

op0op1CRnCRmop2
0b110b1000b11100b00100b010
if PSTATE.EL == EL0 then
    UNDEFINED;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && HCR_EL2.NV == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    else
        UNDEFINED;
elsif PSTATE.EL == EL2 then
    return CNTHP_CVAL_EL2;
elsif PSTATE.EL == EL3 then
    return CNTHP_CVAL_EL2;
              

MSR CNTHP_CVAL_EL2, <Xt>

op0op1CRnCRmop2
0b110b1000b11100b00100b010
if PSTATE.EL == EL0 then
    UNDEFINED;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && HCR_EL2.NV == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    else
        UNDEFINED;
elsif PSTATE.EL == EL2 then
    CNTHP_CVAL_EL2 = X[t];
elsif PSTATE.EL == EL3 then
    CNTHP_CVAL_EL2 = X[t];
              

MRS <Xt>, CNTP_CVAL_EL0

op0op1CRnCRmop2
0b110b0110b11100b00100b010
if PSTATE.EL == EL0 then
    if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0PTEN == '0' then
        if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
            AArch64.SystemAccessTrap(EL2, 0x18);
        else
            AArch64.SystemAccessTrap(EL1, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '10' && CNTHCTL_EL2.EL1PTEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0PTEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' then
        return CNTHPS_CVAL_EL2;
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then
        return CNTHP_CVAL_EL2;
    else
        return CNTP_CVAL_EL0;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '1' && CNTHCTL_EL2.EL1PTEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<NV2,NV1,NV> == '111' then
        return NVMem[0x178];
    else
        return CNTP_CVAL_EL0;
elsif PSTATE.EL == EL2 then
    if HCR_EL2.E2H == '1' && SCR_EL3.NS == '0' then
        return CNTHPS_CVAL_EL2;
    elsif HCR_EL2.E2H == '1' && SCR_EL3.NS == '1' then
        return CNTHP_CVAL_EL2;
    else
        return CNTP_CVAL_EL0;
elsif PSTATE.EL == EL3 then
    return CNTP_CVAL_EL0;
              

MSR CNTP_CVAL_EL0, <Xt>

op0op1CRnCRmop2
0b110b0110b11100b00100b010
if PSTATE.EL == EL0 then
    if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0PTEN == '0' then
        if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
            AArch64.SystemAccessTrap(EL2, 0x18);
        else
            AArch64.SystemAccessTrap(EL1, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '10' && CNTHCTL_EL2.EL1PTEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0PTEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' then
        CNTHPS_CVAL_EL2 = X[t];
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then
        CNTHP_CVAL_EL2 = X[t];
    else
        CNTP_CVAL_EL0 = X[t];
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '1' && CNTHCTL_EL2.EL1PTEN == '0' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<NV2,NV1,NV> == '111' then
        NVMem[0x178] = X[t];
    else
        CNTP_CVAL_EL0 = X[t];
elsif PSTATE.EL == EL2 then
    if HCR_EL2.E2H == '1' && SCR_EL3.NS == '0' then
        CNTHPS_CVAL_EL2 = X[t];
    elsif HCR_EL2.E2H == '1' && SCR_EL3.NS == '1' then
        CNTHP_CVAL_EL2 = X[t];
    else
        CNTP_CVAL_EL0 = X[t];
elsif PSTATE.EL == EL3 then
    CNTP_CVAL_EL0 = X[t];
              


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