BRBTS_EL1, Branch Record Buffer Timestamp Register

The BRBTS_EL1 characteristics are:

Purpose

Captures the Timestamp value on a BRBE freeze event.

Configuration

This register is present only when FEAT_BRBE is implemented. Otherwise, direct accesses to BRBTS_EL1 are UNDEFINED.

Attributes

BRBTS_EL1 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
TS
TS

TS, bits [63:0]

Timestamp value at the time of a BRBE freeze event.

The reset behavior of this field is:

When FEAT_BRBEv1p1 is implemented, Arm recommends that this field is preserved on a Warm reset, but it is IMPLEMENTATION DEFINED whether this field resets to 0 or is preserved.

When FEAT_BRBEv1p1 is implemented, on a Cold reset it is IMPLEMENTATION DEFINED whether this field resets to an architecturally UNKNOWN value.

Accessing BRBTS_EL1

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

MRS <Xt>, BRBTS_EL1

op0op1CRnCRmop2
0b100b0010b10010b00000b010

if !IsFeatureImplemented(FEAT_BRBE) then UNDEFINED; elsif PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE IN {'x0'} && SCR_EL3.NS == '1' then UNDEFINED; elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGRTR_EL2.nBRBDATA == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif HaveEL(EL3) && MDCR_EL3.SBRBE IN {'x0'} && SCR_EL3.NS == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = BRBTS_EL1; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE IN {'x0'} && SCR_EL3.NS == '1' then UNDEFINED; elsif HaveEL(EL3) && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif HaveEL(EL3) && MDCR_EL3.SBRBE IN {'x0'} && SCR_EL3.NS == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = BRBTS_EL1; elsif PSTATE.EL == EL3 then X[t, 64] = BRBTS_EL1;

MSR BRBTS_EL1, <Xt>

op0op1CRnCRmop2
0b100b0010b10010b00000b010

if !IsFeatureImplemented(FEAT_BRBE) then UNDEFINED; elsif PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE IN {'x0'} && SCR_EL3.NS == '1' then UNDEFINED; elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGWTR_EL2.nBRBDATA == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif HaveEL(EL3) && MDCR_EL3.SBRBE IN {'x0'} && SCR_EL3.NS == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else BRBTS_EL1 = X[t, 64]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3.SBRBE IN {'x0'} && SCR_EL3.NS == '1' then UNDEFINED; elsif HaveEL(EL3) && MDCR_EL3.SBRBE != '11' && SCR_EL3.NS == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); elsif HaveEL(EL3) && MDCR_EL3.SBRBE IN {'x0'} && SCR_EL3.NS == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else BRBTS_EL1 = X[t, 64]; elsif PSTATE.EL == EL3 then BRBTS_EL1 = X[t, 64];


15/12/2024 22:27; 5e0a212688c6bd7aee92394b6f5e491b4d0fee1d

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