Counter-timer Secure Virtual Timer TimerValue Register (EL2)
Provides AArch32 access to the timer value for the Secure EL2 virtual timer.
AArch32 System register CNTHVS_TVAL bits [31:0] are architecturally mapped to AArch64 System register CNTHVS_TVAL_EL2[31:0].
This register is present only when FEAT_AA32 is implemented and FEAT_SEL2 is implemented. Otherwise, direct accesses to CNTHVS_TVAL are UNDEFINED.
CNTHVS_TVAL is a 32-bit register.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| TimerValue | |||||||||||||||||||||||||||||||
The TimerValue view of the EL2 virtual timer.
On a read of this register:
On a write of this register, CNTHVS_CVAL is set to (CNTVCT + TimerValue), where TimerValue is treated as a signed 32-bit integer.
When CNTHVS_CTL.ENABLE is 1, the timer condition is met when (CNTVCT - CNTHVS_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 CNTHVS_CTL.ENABLE is 0, the TimerValue cannot be read but continues to decrement. When the timer is enabled, the TimerValue represents the elapsed time whether that time was spent enabled or disabled.
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>}
(coproc = 0b1111, opc1 = 0b000, CRn = 0b1110, CRm = 0b0011, opc2 = 0b000)
if !IsFeatureImplemented(FEAT_AA32) then Undefined(); elsif PSTATE.EL == EL0 then if IsFeatureImplemented(FEAT_AA64EL1) && !ELUsingAArch32(EL1) && EffectivelyAtEL0NotInHost() && CNTKCTL_EL1().EL0VTEN == '0' then AArch64_AArch32SystemAccessTraptoEL1orEL2(0x03); elsif IsFeatureImplemented(FEAT_AA32EL1) && ELUsingAArch32(EL1) && CNTKCTL().PL0VTEN == '0' then if EL2Enabled() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && HCR_EL2().TGE == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2)) && HCR().TGE == '1' then AArch32_TakeHypTrapException(0x00); else Undefined(); end; elsif EffectivelyAtEL0InHost() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && CNTHCTL_EL2().EL0VTEN == '0' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && EffectivelyAtEL0NotInHost() && IsFeatureImplemented(FEAT_ECV) && CNTHCTL_EL2().EL1TVT == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EffectivelyAtEL0InHost() && IsCurrentSecurityState(SS_Secure) && IsFeatureImplemented(FEAT_SEL2) then if CNTHVS_CTL_EL2().ENABLE == '0' then R(t) = ARBITRARY:bits(32); else R(t) = (CNTHVS_CVAL_EL2() - PhysicalCountInt())[31:0]; end; elsif EffectivelyAtEL0InHost() && !IsCurrentSecurityState(SS_Secure) then if CNTHV_CTL_EL2().ENABLE == '0' then R(t) = ARBITRARY:bits(32); else R(t) = (CNTHV_CVAL_EL2() - PhysicalCountInt())[31:0]; end; else if CNTV_CTL().ENABLE == '0' then R(t) = ARBITRARY:bits(32); elsif HaveEL(EL2) && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) then R(t) = (CNTV_CVAL() - (PhysicalCountInt() - CNTVOFF_EL2()))[31:0]; elsif HaveEL(EL2) && IsFeatureImplemented(FEAT_AA32EL2) then R(t) = (CNTV_CVAL() - (PhysicalCountInt() - CNTVOFF()))[31:0]; else R(t) = (CNTV_CVAL() - PhysicalCountInt())[31:0]; end; end; elsif PSTATE.EL == EL1 then if EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && IsFeatureImplemented(FEAT_ECV) && CNTHCTL_EL2().EL1TVT == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); else if CNTV_CTL().ENABLE == '0' then R(t) = ARBITRARY:bits(32); elsif HaveEL(EL2) && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) then R(t) = (CNTV_CVAL() - (PhysicalCountInt() - CNTVOFF_EL2()))[31:0]; elsif HaveEL(EL2) && IsFeatureImplemented(FEAT_AA32EL2) then R(t) = (CNTV_CVAL() - (PhysicalCountInt() - CNTVOFF()))[31:0]; else R(t) = (CNTV_CVAL() - PhysicalCountInt())[31:0]; end; end; elsif PSTATE.EL == EL2 then if CNTV_CTL().ENABLE == '0' then R(t) = ARBITRARY:bits(32); else R(t) = (CNTV_CVAL() - (PhysicalCountInt() - CNTVOFF()))[31:0]; end; elsif PSTATE.EL == EL3 then if CNTV_CTL().ENABLE == '0' then R(t) = ARBITRARY:bits(32); elsif HaveEL(EL2) then R(t) = (CNTV_CVAL() - (PhysicalCountInt() - CNTVOFF()))[31:0]; else R(t) = (CNTV_CVAL() - PhysicalCountInt())[31:0]; end; end;
MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}
(coproc = 0b1111, opc1 = 0b000, CRn = 0b1110, CRm = 0b0011, opc2 = 0b000)
if !IsFeatureImplemented(FEAT_AA32) then Undefined(); elsif PSTATE.EL == EL0 then if IsFeatureImplemented(FEAT_AA64EL1) && !ELUsingAArch32(EL1) && EffectivelyAtEL0NotInHost() && CNTKCTL_EL1().EL0VTEN == '0' then AArch64_AArch32SystemAccessTraptoEL1orEL2(0x03); elsif IsFeatureImplemented(FEAT_AA32EL1) && ELUsingAArch32(EL1) && CNTKCTL().PL0VTEN == '0' then if EL2Enabled() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && HCR_EL2().TGE == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2)) && HCR().TGE == '1' then AArch32_TakeHypTrapException(0x00); else Undefined(); end; elsif EffectivelyAtEL0InHost() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && CNTHCTL_EL2().EL0VTEN == '0' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && (IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2)) && EffectivelyAtEL0NotInHost() && IsFeatureImplemented(FEAT_ECV) && CNTHCTL_EL2().EL1TVT == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); elsif EffectivelyAtEL0InHost() && IsCurrentSecurityState(SS_Secure) && IsFeatureImplemented(FEAT_SEL2) then CNTHVS_CVAL_EL2() = SignExtend{64}(R(t)) + PhysicalCountInt(); elsif EffectivelyAtEL0InHost() && !IsCurrentSecurityState(SS_Secure) then CNTHV_CVAL_EL2() = SignExtend{64}(R(t)) + PhysicalCountInt(); else if HaveEL(EL2) && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) then CNTV_CVAL() = (SignExtend{64}(R(t)) + PhysicalCountInt()) - CNTVOFF_EL2(); elsif HaveEL(EL2) && IsFeatureImplemented(FEAT_AA32EL2) then CNTV_CVAL() = (SignExtend{64}(R(t)) + PhysicalCountInt()) - CNTVOFF(); else CNTV_CVAL() = SignExtend{64}(R(t)) + PhysicalCountInt(); end; end; elsif PSTATE.EL == EL1 then if EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && IsFeatureImplemented(FEAT_ECV) && CNTHCTL_EL2().EL1TVT == '1' then AArch64_AArch32SystemAccessTrap(EL2, 0x03); else if HaveEL(EL2) && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) then CNTV_CVAL() = (SignExtend{64}(R(t)) + PhysicalCountInt()) - CNTVOFF_EL2(); elsif HaveEL(EL2) && IsFeatureImplemented(FEAT_AA32EL2) then CNTV_CVAL() = (SignExtend{64}(R(t)) + PhysicalCountInt()) - CNTVOFF(); else CNTV_CVAL() = SignExtend{64}(R(t)) + PhysicalCountInt(); end; end; elsif PSTATE.EL == EL2 then CNTV_CVAL() = (SignExtend{64}(R(t)) + PhysicalCountInt()) - CNTVOFF(); elsif PSTATE.EL == EL3 then if HaveEL(EL2) then CNTV_CVAL() = (SignExtend{64}(R(t)) + PhysicalCountInt()) - CNTVOFF(); else CNTV_CVAL() = SignExtend{64}(R(t)) + PhysicalCountInt(); end; end;
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