CNTHPS_CVAL, Counter-timer Secure Physical Timer CompareValue Register (EL2)
The CNTHPS_CVAL characteristics are:
Purpose
Provides AArch32 access to the compare value for the Secure EL2 physical timer.
The Secure EL2 timer is implemented by ARMv8.4-SecEL2. It is only accessible from AArch32 state when EL2 is using AArch64 and the value of SCR_EL3.{EEL2, NS} is {1, 0}.
Configuration
AArch32 System register CNTHPS_CVAL bits [63:0] are architecturally mapped to AArch64 System register CNTHPS_CVAL_EL2[63:0] .
This register is present only when ARMv8.4-SecEL2 is implemented. Otherwise, direct accesses to CNTHPS_CVAL are UNDEFINED.
RW fields in this register reset to architecturally UNKNOWN values.
Attributes
CNTHPS_CVAL is a 64-bit register.
Field descriptions
The CNTHPS_CVAL bit assignments are:
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 |
CompareValue | |||||||||||||||||||||||||||||||
CompareValue | |||||||||||||||||||||||||||||||
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 |
CompareValue, bits [63:0]
Holds the EL2 physical timer CompareValue.
When CNTHPS_CTL_EL2.ENABLE is 1, the timer condition is met when (CNTPCT_EL0 - CompareValue) is greater than or equal to zero. This means that CompareValue acts like a 64-bit upcounter timer. When the timer condition is met:
- CNTHPS_CTL_EL2.ISTATUS is set to 1.
- If CNTHPS_CTL_EL2.IMASK is 0, an interrupt is generated.
When CNTHPS_CTL_EL2.ENABLE is 0, the timer condition is not met, but CNTPCT_EL0 continues to count
If the Generic counter is implemented at a size less than 64 bits, then this field is permitted to be implemented at the same width as the counter, and the upper bits are RES0.
The value of this field is treated as zero-extended in all counter calculations.
This field resets to an architecturally UNKNOWN value.
Accessing the CNTHPS_CVAL
This register is accessed using the encoding for CNTP_CVAL.
Accesses to this register use the following encodings:
MRRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <Rt2>, <CRm>
coproc | CRm | opc1 |
---|---|---|
0b1111 | 0b1110 | 0b0010 |
if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0PTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); else AArch64.AArch32SystemAccessTrap(EL1, 0x04); elsif ELUsingAArch32(EL1) && CNTKCTL.PL0PTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then AArch32.TakeHypTrapException(0x00); else UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '10' && CNTHCTL_EL2.EL1PTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0PTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && ELUsingAArch32(EL2) && CNTHCTL.PL1PCEN == '0' then AArch32.TakeHypTrapException(0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' then return CNTHPS_CVAL_EL2; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then return CNTHP_CVAL_EL2; else return CNTP_CVAL; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '1' && CNTHCTL_EL2.EL1PTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && ELUsingAArch32(EL2) && CNTHCTL.PL1PCEN == '0' then AArch32.TakeHypTrapException(0x04); elsif HaveEL(EL3) && ELUsingAArch32(EL3) then if SCR.NS == '0' then return CNTP_CVAL_S; else return CNTP_CVAL_NS; else return CNTP_CVAL; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && ELUsingAArch32(EL3) then return CNTP_CVAL_NS; else return CNTP_CVAL; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then return CNTP_CVAL_S; else return CNTP_CVAL_NS;
MCRR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <Rt2>, <CRm>
coproc | CRm | opc1 |
---|---|---|
0b1111 | 0b1110 | 0b0010 |
if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0PTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); else AArch64.AArch32SystemAccessTrap(EL1, 0x04); elsif ELUsingAArch32(EL1) && CNTKCTL.PL0PTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then AArch32.TakeHypTrapException(0x00); else UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '10' && CNTHCTL_EL2.EL1PTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0PTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && ELUsingAArch32(EL2) && CNTHCTL.PL1PCEN == '0' then AArch32.TakeHypTrapException(0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' then CNTHPS_CVAL_EL2 = R[t2]:R[t]; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then CNTHP_CVAL_EL2 = R[t2]:R[t]; else CNTP_CVAL = R[t2]:R[t]; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '0' && CNTHCTL_EL2.EL1PCEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.E2H == '1' && CNTHCTL_EL2.EL1PTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && ELUsingAArch32(EL2) && CNTHCTL.PL1PCEN == '0' then AArch32.TakeHypTrapException(0x04); elsif HaveEL(EL3) && ELUsingAArch32(EL3) then if SCR.NS == '0' then CNTP_CVAL_S = R[t2]:R[t]; else CNTP_CVAL_NS = R[t2]:R[t]; else CNTP_CVAL = R[t2]:R[t]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && ELUsingAArch32(EL3) then CNTP_CVAL_NS = R[t2]:R[t]; else CNTP_CVAL = R[t2]:R[t]; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then CNTP_CVAL_S = R[t2]:R[t]; else CNTP_CVAL_NS = R[t2]:R[t];