CNTPOFF

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.

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

Attributes

Field descriptions

Bits [63:0]

Accessing CNTPOFF_EL2

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

MRS <Xt>, CNTPOFF_EL2

op0	op1	CRn	CRm	op2
0b11	0b100	0b1110	0b0000	0b110

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.<NV2,NV> == '11' then X[t, 64] = 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 X[t, 64] = CNTPOFF_EL2; elsif PSTATE.EL == EL3 then X[t, 64] = CNTPOFF_EL2;

MSR CNTPOFF_EL2, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b100	0b1110	0b0000	0b110

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.<NV2,NV> == '11' then NVMem[0x1A8] = X[t, 64]; 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, 64]; elsif PSTATE.EL == EL3 then CNTPOFF_EL2 = X[t, 64];

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
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
Physical offset
Physical offset

CNTPOFF_EL2, Counter-timer Physical Offset Register