CNTHP_TVAL_EL2, Counter-timer Physical Timer TimerValue Register (EL2)

The CNTHP_TVAL_EL2 characteristics are:

Purpose

Holds the timer value for the EL2 physical timer.

Configuration

AArch64 System register CNTHP_TVAL_EL2 bits [31:0] are architecturally mapped to AArch32 System register CNTHP_TVAL[31:0].

This register is present only when EL3 is implemented or (EL3 is not implemented, EL2 is implemented and FEAT_SEL2 is not implemented). Otherwise, direct accesses to CNTHP_TVAL_EL2 are UNDEFINED.

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

Attributes

CNTHP_TVAL_EL2 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
RES0
TimerValue

Bits [63:32]

Reserved, RES0.

TimerValue, bits [31:0]

The TimerValue view of the EL2 physical timer.

On a read of this register:

On a write of this register, CNTHP_CVAL_EL2 is set to (CNTPCT_EL0 + TimerValue), where TimerValue is treated as a signed 32-bit integer.

When CNTHP_CTL_EL2.ENABLE is 1, the timer condition is met when (CNTPCT_EL0 - CNTHP_CVAL_EL2) 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 CNTHP_CTL_EL2.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.

The reset behavior of this field is:

Accessing CNTHP_TVAL_EL2

When the Effective value of HCR_EL2.E2H is 1, without explicit synchronization, accesses from EL2 using the accessor name CNTHP_TVAL_EL2 or CNTP_TVAL_EL0 are not guaranteed to be ordered with respect to accesses using the other accessor name.

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

MRS <Xt>, CNTHP_TVAL_EL2

op0op1CRnCRmop2
0b110b1000b11100b00100b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if CNTHP_CTL_EL2.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTHP_CVAL_EL2 - PhysicalCountInt(); elsif PSTATE.EL == EL3 then if CNTHP_CTL_EL2.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTHP_CVAL_EL2 - PhysicalCountInt();

MSR CNTHP_TVAL_EL2, <Xt>

op0op1CRnCRmop2
0b110b1000b11100b00100b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then CNTHP_CVAL_EL2 = SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt(); elsif PSTATE.EL == EL3 then CNTHP_CVAL_EL2 = SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt();

MRS <Xt>, CNTP_TVAL_EL0

op0op1CRnCRmop2
0b110b0110b11100b00100b000

if PSTATE.EL == EL0 then if !ELIsInHost(EL0) && CNTKCTL_EL1.EL0PTEN == '0' then if EL2Enabled() && HCR_EL2.TGE == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELIsInHost(EL2) && CNTHCTL_EL2.EL1PCEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif ELIsInHost(EL2) && HCR_EL2.TGE == '0' && CNTHCTL_EL2.EL1PTEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif ELIsInHost(EL0) && CNTHCTL_EL2.EL0PTEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif ELIsInHost(EL0) && IsCurrentSecurityState(SS_Secure) && IsFeatureImplemented(FEAT_SEL2) then if CNTHPS_CTL_EL2.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTHPS_CVAL_EL2 - PhysicalCountInt(); elsif ELIsInHost(EL0) && !IsCurrentSecurityState(SS_Secure) then if CNTHP_CTL_EL2.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTHP_CVAL_EL2 - PhysicalCountInt(); elsif IsFeatureImplemented(FEAT_ECV) && EL2Enabled() && SCR_EL3.ECVEn == '1' && CNTHCTL_EL2.ECV == '1' && !ELIsInHost(EL0) then if CNTP_CTL_EL0.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTP_CVAL_EL0 - (PhysicalCountInt() - CNTPOFF_EL2); else if CNTP_CTL_EL0.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTP_CVAL_EL0 - PhysicalCountInt(); elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELIsInHost(EL2) && CNTHCTL_EL2.EL1PCEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif ELIsInHost(EL2) && CNTHCTL_EL2.EL1PTEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif IsFeatureImplemented(FEAT_ECV) && EL2Enabled() && SCR_EL3.ECVEn == '1' && CNTHCTL_EL2.ECV == '1' then if CNTP_CTL_EL0.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTP_CVAL_EL0 - (PhysicalCountInt() - CNTPOFF_EL2); else if CNTP_CTL_EL0.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTP_CVAL_EL0 - PhysicalCountInt(); elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) && IsCurrentSecurityState(SS_Secure) && IsFeatureImplemented(FEAT_SEL2) then if CNTHPS_CTL_EL2.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTHPS_CVAL_EL2 - PhysicalCountInt(); elsif ELIsInHost(EL2) && !IsCurrentSecurityState(SS_Secure) then if CNTHP_CTL_EL2.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTHP_CVAL_EL2 - PhysicalCountInt(); else if CNTP_CTL_EL0.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTP_CVAL_EL0 - PhysicalCountInt(); elsif PSTATE.EL == EL3 then if CNTP_CTL_EL0.ENABLE == '0' then X[t, 64] = bits(64) UNKNOWN; else X[t, 64] = CNTP_CVAL_EL0 - PhysicalCountInt();

MSR CNTP_TVAL_EL0, <Xt>

op0op1CRnCRmop2
0b110b0110b11100b00100b000

if PSTATE.EL == EL0 then if !ELIsInHost(EL0) && CNTKCTL_EL1.EL0PTEN == '0' then if EL2Enabled() && HCR_EL2.TGE == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELIsInHost(EL2) && CNTHCTL_EL2.EL1PCEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif ELIsInHost(EL2) && HCR_EL2.TGE == '0' && CNTHCTL_EL2.EL1PTEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif ELIsInHost(EL0) && CNTHCTL_EL2.EL0PTEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif ELIsInHost(EL0) && IsCurrentSecurityState(SS_Secure) && IsFeatureImplemented(FEAT_SEL2) then CNTHPS_CVAL_EL2 = SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt(); elsif ELIsInHost(EL0) && !IsCurrentSecurityState(SS_Secure) then CNTHP_CVAL_EL2 = SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt(); elsif IsFeatureImplemented(FEAT_ECV) && EL2Enabled() && SCR_EL3.ECVEn == '1' && CNTHCTL_EL2.ECV == '1' && !ELIsInHost(EL0) then CNTP_CVAL_EL0 = (SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt()) - CNTPOFF_EL2; else CNTP_CVAL_EL0 = SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt(); elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELIsInHost(EL2) && CNTHCTL_EL2.EL1PCEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif ELIsInHost(EL2) && CNTHCTL_EL2.EL1PTEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif IsFeatureImplemented(FEAT_ECV) && EL2Enabled() && SCR_EL3.ECVEn == '1' && CNTHCTL_EL2.ECV == '1' then CNTP_CVAL_EL0 = (SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt()) - CNTPOFF_EL2; else CNTP_CVAL_EL0 = SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt(); elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) && IsCurrentSecurityState(SS_Secure) && IsFeatureImplemented(FEAT_SEL2) then CNTHPS_CVAL_EL2 = SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt(); elsif ELIsInHost(EL2) && !IsCurrentSecurityState(SS_Secure) then CNTHP_CVAL_EL2 = SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt(); else CNTP_CVAL_EL0 = SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt(); elsif PSTATE.EL == EL3 then CNTP_CVAL_EL0 = SignExtend(X[t, 64]<31:0>, 64) + PhysicalCountInt();


26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6

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