CNTHVS_TVAL_EL2, Counter-timer Secure Virtual Timer TimerValue register (EL2)

The CNTHVS_TVAL_EL2 characteristics are:

Purpose

Holds the timer value for the Secure EL2 virtual timer.

Configuration

AArch64 System register CNTHVS_TVAL_EL2 bits [31:0] are architecturally mapped to AArch32 System register CNTHVS_TVAL[31:0] .

This register is present only when ARMv8.4-SecEL2 is implemented. Otherwise, direct accesses to CNTHVS_TVAL_EL2 are UNDEFINED.

RW fields in this register reset to architecturally UNKNOWN values.

Attributes

CNTHVS_TVAL_EL2 is a 64-bit register.

Field descriptions

The CNTHVS_TVAL_EL2 bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
RES0
TimerValue
313029282726252423222120191817161514131211109876543210

Bits [63:32]

Reserved, RES0.

TimerValue, bits [31:0]

From Armv8.1:

The TimerValue view of the EL2 virtual timer.

On a read of this register:

On a write of this register, CNTHVS_CVAL_EL2 is set to (CNTVCT_EL0 + TimerValue), where TimerValue is treated as a signed 32-bit integer.

When CNTHVS_CTL_EL2.ENABLE is 1, the timer condition is met when ((CNTVCT_EL0 - CNTHVS_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 CNTHVS_CTL_EL2.ENABLE is 0, the timer condition is not met, but CNTVCT_EL0 continues to count, so the TimerValue view appears to continue to count down.

This field resets to an architecturally UNKNOWN value.


Otherwise:

Reserved, RES0.

Accessing the CNTHVS_TVAL_EL2

Accesses to this register use the following encodings:

MRS <Xt>, CNTHVS_TVAL_EL2

op0op1CRnCRmop2
0b110b1000b11100b01000b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.NV == '1' then if SCR_EL3.NS == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if SCR_EL3.NS == '1' then UNDEFINED; else return CNTHVS_TVAL_EL2; elsif PSTATE.EL == EL3 then return CNTHVS_TVAL_EL2;

MSR CNTHVS_TVAL_EL2, <Xt>

op0op1CRnCRmop2
0b110b1000b11100b01000b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.NV == '1' then if SCR_EL3.NS == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if SCR_EL3.NS == '1' then UNDEFINED; else CNTHVS_TVAL_EL2 = X[t]; elsif PSTATE.EL == EL3 then CNTHVS_TVAL_EL2 = X[t];

MRS <Xt>, CNTV_TVAL_EL0

op0op1CRnCRmop2
0b110b0110b11100b00110b000

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.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0VTEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' 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_EL0; elsif PSTATE.EL == EL1 then return CNTV_TVAL_EL0; elsif PSTATE.EL == EL2 then if HCR_EL2.E2H == '1' && SCR_EL3.NS == '0' then return CNTHVS_TVAL_EL2; elsif HCR_EL2.E2H == '1' && SCR_EL3.NS == '1' then return CNTHV_TVAL_EL2; else return CNTV_TVAL_EL0; elsif PSTATE.EL == EL3 then return CNTV_TVAL_EL0;

MSR CNTV_TVAL_EL0, <Xt>

op0op1CRnCRmop2
0b110b0110b11100b00110b000

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.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0VTEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' then CNTHVS_TVAL_EL2 = X[t]; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then CNTHV_TVAL_EL2 = X[t]; else CNTV_TVAL_EL0 = X[t]; elsif PSTATE.EL == EL1 then CNTV_TVAL_EL0 = X[t]; elsif PSTATE.EL == EL2 then if HCR_EL2.E2H == '1' && SCR_EL3.NS == '0' then CNTHVS_TVAL_EL2 = X[t]; elsif HCR_EL2.E2H == '1' && SCR_EL3.NS == '1' then CNTHV_TVAL_EL2 = X[t]; else CNTV_TVAL_EL0 = X[t]; elsif PSTATE.EL == EL3 then CNTV_TVAL_EL0 = X[t];




27/03/2019 21:59; e5e4db499bf9867a4b93324c4dbac985d3da9376

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