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CNTHV_TVAL, Counter-timer Virtual Timer TimerValue register (EL2)

The CNTHV_TVAL characteristics are:

Purpose

Provides AArch32 access to the timer value for the EL2 virtual timer.

Configuration

AArch32 System register CNTHV_TVAL bits [31:0] are architecturally mapped to AArch64 System register CNTHV_TVAL_EL2[31:0].

This register is present only when AArch32 is supported at EL0any Exception level and FEAT_VHE is implemented. Otherwise, direct accesses to CNTHV_TVAL are UNDEFINED.

Attributes

CNTHV_TVAL is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
TimerValue

TimerValue, bits [31:0]

The TimerValue view of the EL2 virtual timer.

On a read of this register:

On a write of this register, CNTHV_CVAL is set to (CNTVCT + TimerValue), where TimerValue is treated as a signed 32-bit integer.

When CNTHV_CTL.ENABLE is 1, the timer condition is met when (CNTVCT - CNTHV_CVAL) is greater than or equal to zero. This means that TimerValue acts like a 32-bit downcounter timer. When the timer condition is met:

When CNTHV_CTL.ENABLE is 0, the timer condition is not met, but CNTVCT continues to count, so the TimerValue view appears to continue to count down.

Accessing CNTHV_TVAL

This register is accessed using the encoding for CNTV_TVAL.

Accesses to this register use the following encodings in the System register encoding space:

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

coprocopc1CRnCRmopc2
0b11110b0000b11100b00110b000

if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0VTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); else AArch64.AArch32SystemAccessTrap(EL1, 0x03); elsif ELUsingAArch32(EL1) && CNTKCTL.PL0VTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then AArch32.TakeHypTrapException(0x00); else UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0VTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' && IsFeatureImplemented(FEAT_SEL2) then return CNTHVS_TVAL_EL2; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then return CNTHV_TVAL_EL2; else return CNTV_TVAL; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); else return CNTV_TVAL; elsif PSTATE.EL == EL2 then return CNTV_TVAL; elsif PSTATE.EL == EL3 then return CNTV_TVAL;

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

coprocopc1CRnCRmopc2
0b11110b0000b11100b00110b000

if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0VTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); else AArch64.AArch32SystemAccessTrap(EL1, 0x03); elsif ELUsingAArch32(EL1) && CNTKCTL.PL0VTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then AArch32.TakeHypTrapException(0x00); else UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0VTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' && IsFeatureImplemented(FEAT_SEL2) then CNTHVS_TVAL_EL2 = R[t]; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then CNTHV_TVAL_EL2 = R[t]; else CNTV_TVAL = R[t]; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); else CNTV_TVAL = R[t]; elsif PSTATE.EL == EL2 then CNTV_TVAL = R[t]; elsif PSTATE.EL == EL3 then CNTV_TVAL = R[t];


30/06/2021 1509:2139; 2a17f7750cfd1ab239f20f6cf29877ba8041794f4f5dd962f4e34e1ac282f76da4d6e7fc4cab087e

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