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CNTHPS_CVAL, Counter-timer Secure Physical Timer CompareValue Register (EL2)

The CNTHPS_CVAL characteristics are:

Purpose

Provides AArch32 access to the compare value for the Secure EL2 physical timer.

Note

The Secure EL2 timer is implemented by ARMv8.4-SecEL2. It is only accessible from AArch32 state when EL2 is using AArch64 and the value of SCR_EL3.{EEL2, NS} is {1, 0}.

Configuration

AArch32 System register CNTHPS_CVAL bits [63:0] are architecturally mapped to AArch64 System register CNTHPS_CVAL_EL2[63:0] .

This register is present only when ARMv8.4-SecEL2 is implemented. Otherwise, direct accesses to CNTHPS_CVAL are UNDEFINED.

RW fields in this register reset to architecturally UNKNOWN values.

Attributes

CNTHPS_CVAL is a 64-bit register.

Field descriptions

The CNTHPS_CVAL bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
CompareValue
CompareValue
313029282726252423222120191817161514131211109876543210

CompareValue, bits [63:0]

Holds the EL2 physical timer CompareValue.

When CNTHPS_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 CNTHPS_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 CNTHPS_CVAL

This register is accessed using the encoding for CNTP_CVAL.

Accesses to this register use the following encodings:

MRRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <Rt2>, <CRm>

coprocCRmopc1
0b11110b11100b0010
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.AArch32SystemAccessTrap(EL2, 0x04);
        else
            AArch64.AArch32SystemAccessTrap(EL1, 0x04);
    elsif ELUsingAArch32(EL1) && CNTKCTL.PL0PTEN == '0' then
        if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
            AArch64.AArch32SystemAccessTrap(EL2, 0x04);
        elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then
            AArch32.TakeHypTrapException(0x00);
        else
            UNDEFINED;
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x04);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '10' && CNTHCTL_EL2.EL1PTEN == '0' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x04);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0PTEN == '0' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x04);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && CNTHCTL.PL1PCEN == '0' then
        AArch32.TakeHypTrapException(0x04);
    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;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x04);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '1' && CNTHCTL_EL2.EL1PTEN == '0' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x04);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && CNTHCTL.PL1PCEN == '0' then
        AArch32.TakeHypTrapException(0x04);
    elsif HaveEL(EL3) && ELUsingAArch32(EL3) then
        if SCR.NS == '0' then
            return CNTP_CVAL_S;
        else
            return CNTP_CVAL_NS;
    else
        return CNTP_CVAL;
elsif PSTATE.EL == EL2 then
    if HaveEL(EL3) && ELUsingAArch32(EL3) then
        return CNTP_CVAL_NS;
    else
        return CNTP_CVAL;
elsif PSTATE.EL == EL3 then
    if SCR.NS == '0' then
        return CNTP_CVAL_S;
    else
        return CNTP_CVAL_NS;
              

MCRR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <Rt2>, <CRm>

coprocCRmopc1
0b11110b11100b0010
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.AArch32SystemAccessTrap(EL2, 0x04);
        else
            AArch64.AArch32SystemAccessTrap(EL1, 0x04);
    elsif ELUsingAArch32(EL1) && CNTKCTL.PL0PTEN == '0' then
        if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
            AArch64.AArch32SystemAccessTrap(EL2, 0x04);
        elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then
            AArch32.TakeHypTrapException(0x00);
        else
            UNDEFINED;
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x04);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '10' && CNTHCTL_EL2.EL1PTEN == '0' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x04);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0PTEN == '0' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x04);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && CNTHCTL.PL1PCEN == '0' then
        AArch32.TakeHypTrapException(0x04);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' then
        CNTHPS_CVAL_EL2 = R[t2]:R[t];
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then
        CNTHP_CVAL_EL2 = R[t2]:R[t];
    else
        CNTP_CVAL = R[t2]:R[t];
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x04);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '1' && CNTHCTL_EL2.EL1PTEN == '0' then
        AArch64.AArch32SystemAccessTrap(EL2, 0x04);
    elsif EL2Enabled() && ELUsingAArch32(EL2) && CNTHCTL.PL1PCEN == '0' then
        AArch32.TakeHypTrapException(0x04);
    elsif HaveEL(EL3) && ELUsingAArch32(EL3) then
        if SCR.NS == '0' then
            CNTP_CVAL_S = R[t2]:R[t];
        else
            CNTP_CVAL_NS = R[t2]:R[t];
    else
        CNTP_CVAL = R[t2]:R[t];
elsif PSTATE.EL == EL2 then
    if HaveEL(EL3) && ELUsingAArch32(EL3) then
        CNTP_CVAL_NS = R[t2]:R[t];
    else
        CNTP_CVAL = R[t2]:R[t];
elsif PSTATE.EL == EL3 then
    if SCR.NS == '0' then
        CNTP_CVAL_S = R[t2]:R[t];
    else
        CNTP_CVAL_NS = R[t2]:R[t];
              


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