CNTVCT_EL0, Counter-timer Virtual Count register

The CNTVCT_EL0 characteristics are:

Purpose

Holds the 64-bit virtual count value. The virtual count value is equal to the physical count value minus the virtual offset visible in CNTVOFF_EL2.

Configuration

AArch64 System register CNTVCT_EL0 bits [63:0] are architecturally mapped to AArch32 System register CNTVCT[63:0] .

The value of this register is the same as the value of CNTPCT_EL0 in the following conditions:

Attributes

CNTVCT_EL0 is a 64-bit register.

Field descriptions

The CNTVCT_EL0 bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
Virtual count value
Virtual count value
313029282726252423222120191817161514131211109876543210

Bits [63:0]

Virtual count value.

Accessing the CNTVCT_EL0

Accesses to this register use the following encodings:

MRS <Xt>, CNTVCT_EL0

op0op1CRnCRmop2
0b110b0110b11100b00000b010

if PSTATE.EL == EL0 then if IsFeatureImplemented("Morello") && CCTLR_EL0.PERMVCT == '0' && !CapIsSystemAccessEnabled() && !Halted() then if TargetELForCapabilityExceptions() == EL1 then AArch64.SystemAccessTrap(EL1, 0x18); elsif TargetELForCapabilityExceptions() == EL2 then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL3, 0x18); elsif !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0VCTEN == '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.EL0VCTEN == '0' then AArch64.SystemAccessTrap(EL2, 0x18); else return CNTVCT_EL0; elsif PSTATE.EL == EL1 then if IsFeatureImplemented("Morello") && CCTLR_EL1.PERMVCT == '0' && !CapIsSystemAccessEnabled() && !Halted() then if TargetELForCapabilityExceptions() == EL1 then AArch64.SystemAccessTrap(EL1, 0x18); elsif TargetELForCapabilityExceptions() == EL2 then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL3, 0x18); else return CNTVCT_EL0; elsif PSTATE.EL == EL2 then if IsFeatureImplemented("Morello") && CCTLR_EL2.PERMVCT == '0' && !CapIsSystemAccessEnabled() && !Halted() then if TargetELForCapabilityExceptions() == EL2 then AArch64.SystemAccessTrap(EL2, 0x18); else AArch64.SystemAccessTrap(EL3, 0x18); else return CNTVCT_EL0; elsif PSTATE.EL == EL3 then if IsFeatureImplemented("Morello") && CCTLR_EL3.PERMVCT == '0' && !CapIsSystemAccessEnabled() && !Halted() then AArch64.SystemAccessTrap(EL3, 0x18); else return CNTVCT_EL0;




12/01/2022 09:56; 05a4944b4b04e7ab50def8c126b479d22136f35b

Copyright © 2010-2022 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.