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CNTPOFF_EL2, Counter-timer Physical Offset register

The CNTPOFF_EL2 characteristics are:

Purpose

Holds the 64-bit physical offset. This is the offset for the AArch64 physical timers and counters when Enhanced Counter Virtualization is enabled.

Configuration

This register is present only when FEAT_ECV is implemented. Otherwise, direct accesses to CNTPOFF_EL2 are UNDEFINED.

The offsetting of the timers and counters based on EL2 using AArch64 apply at:

When EL2 is implemented and enabled in the current Security state, the physical counter uses a fixed physical offset of zero if either of the following are true:

Attributes

CNTPOFF_EL2 is a 64-bit register.

Field descriptions

The CNTPOFF_EL2 bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
Physical offset
Physical offset
313029282726252423222120191817161514131211109876543210

Bits [63:0]

Physical offset.

On a Warm reset, thisThis field resets to an architecturally UNKNOWN value.

Accessing the CNTPOFF_EL2

Accesses to this register use the following encodings:

MRS <Xt>, CNTPOFF_EL2

op0op1CRnCRmop2
0b110b1000b11100b00000b110

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.<NV2,NV> == '11' then return NVMem[0x1A8]; elsif EL2Enabled() && HCR_EL2.NV == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && SCR_EL3.ECVEn == '0' then UNDEFINED; elsif HaveEL(EL3) && SCR_EL3.ECVEn == '0' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else return CNTPOFF_EL2; elsif PSTATE.EL == EL3 then return CNTPOFF_EL2;

MSR CNTPOFF_EL2, <Xt>

op0op1CRnCRmop2
0b110b1000b11100b00000b110

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.<NV2,NV> == '11' then NVMem[0x1A8] = X[t]; elsif EL2Enabled() && HCR_EL2.NV == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && SCR_EL3.ECVEn == '0' then UNDEFINED; elsif HaveEL(EL3) && SCR_EL3.ECVEn == '0' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else CNTPOFF_EL2 = X[t]; elsif PSTATE.EL == EL3 then CNTPOFF_EL2 = X[t];




3001/0907/2020 15:0757; ccead0cb9f089f9ceec50268e82aec9e7104721180324f0b9997bede489cc15ad1565345720bcd2a

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