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CNTPS_CVAL_EL1: Counter-timer Physical Secure Timer CompareValue Register

Purpose

Holds the compare value for the secure physical timer, usually accessible at EL3 but configurably accessible at EL1 in Secure state.

Configuration

This register is present only when EL3 is implemented. Otherwise, direct accesses to CNTPS_CVAL_EL1 are UNDEFINED.

Attributes

CNTPS_CVAL_EL1 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
CompareValue
CompareValue

CompareValue, bits [63:0]

Holds the secure physical timer CompareValue.

When CNTPS_CTL_EL1.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:

When CNTPS_CTL_EL1.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.

The reset behavior of this field is:

Accessing CNTPS_CVAL_EL1

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

MRS <Xt>, CNTPS_CVAL_EL1

op0op1CRnCRmop2
0b110b1110b11100b00100b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && SCR_EL3.NS == '0' then if SCR_EL3.EEL2 == '1' then UNDEFINED; elsif SCR_EL3.ST == '0' then AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = CNTPS_CVAL_EL1; else UNDEFINED; elsif PSTATE.EL == EL2 then UNDEFINED; elsif PSTATE.EL == EL3 then X[t, 64] = CNTPS_CVAL_EL1;

MSR CNTPS_CVAL_EL1, <Xt>

op0op1CRnCRmop2
0b110b1110b11100b00100b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && SCR_EL3.NS == '0' then if SCR_EL3.EEL2 == '1' then UNDEFINED; elsif SCR_EL3.ST == '0' then AArch64.SystemAccessTrap(EL3, 0x18); else CNTPS_CVAL_EL1 = X[t, 64]; else UNDEFINED; elsif PSTATE.EL == EL2 then UNDEFINED; elsif PSTATE.EL == EL3 then CNTPS_CVAL_EL1 = X[t, 64];