TRBTRG_EL1, Trace Buffer Trigger Counter Register

The TRBTRG_EL1 characteristics are:

Purpose

Specifies the number of bytes of trace to capture following a Detected Trigger before a Trigger Event.

Configuration

This register is present only when FEAT_TRBE is implemented. Otherwise, direct accesses to TRBTRG_EL1 are UNDEFINED.

Attributes

TRBTRG_EL1 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
RES0
TRG

Bits [63:32]

Reserved, RES0.

TRG, bits [31:0]

Trigger count.

Specifies the number of bytes of trace to capture following a Detected Trigger before a Trigger Event.

TRBTRG_EL1 decrements by 1 for every byte of trace written to the trace buffer when all of the following are true:

The architecture places restrictions on the values that software can write to the counter.

Note

As a result of the restrictions an implementation might treat some of TRG[M:0] as RES0, where M is defined by TRBIDR_EL1.Align.

The reset behavior of this field is:

Accessing TRBTRG_EL1

The PE might ignore a direct write to TRBTRG_EL1 if TRBLIMITR_EL1.E == 1.

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

MRS <Xt>, TRBTRG_EL1

op0op1CRnCRmop2
0b110b0000b10010b10110b110

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && (MDCR_EL3.NSTB[0] == '0' || MDCR_EL3.NSTB[1] != SCR_EL3.NS || (IsFeatureImplemented(FEAT_RME) && MDCR_EL3.NSTBE != SCR_EL3.NSE)) then UNDEFINED; elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGRTR_EL2.TRBTRG_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.E2TB == 'x0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && (MDCR_EL3.NSTB[0] == '0' || MDCR_EL3.NSTB[1] != SCR_EL3.NS || (IsFeatureImplemented(FEAT_RME) && MDCR_EL3.NSTBE != SCR_EL3.NSE)) then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = TRBTRG_EL1; elsif PSTATE.EL == EL2 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && (MDCR_EL3.NSTB[0] == '0' || MDCR_EL3.NSTB[1] != SCR_EL3.NS || (IsFeatureImplemented(FEAT_RME) && MDCR_EL3.NSTBE != SCR_EL3.NSE)) then UNDEFINED; elsif HaveEL(EL3) && (MDCR_EL3.NSTB[0] == '0' || MDCR_EL3.NSTB[1] != SCR_EL3.NS || (IsFeatureImplemented(FEAT_RME) && MDCR_EL3.NSTBE != SCR_EL3.NSE)) then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = TRBTRG_EL1; elsif PSTATE.EL == EL3 then X[t, 64] = TRBTRG_EL1;

MSR TRBTRG_EL1, <Xt>

op0op1CRnCRmop2
0b110b0000b10010b10110b110

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && (MDCR_EL3.NSTB[0] == '0' || MDCR_EL3.NSTB[1] != SCR_EL3.NS || (IsFeatureImplemented(FEAT_RME) && MDCR_EL3.NSTBE != SCR_EL3.NSE)) then UNDEFINED; elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HDFGWTR_EL2.TRBTRG_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2.E2TB == 'x0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && (MDCR_EL3.NSTB[0] == '0' || MDCR_EL3.NSTB[1] != SCR_EL3.NS || (IsFeatureImplemented(FEAT_RME) && MDCR_EL3.NSTBE != SCR_EL3.NSE)) then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else TRBTRG_EL1 = X[t, 64]; elsif PSTATE.EL == EL2 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && (MDCR_EL3.NSTB[0] == '0' || MDCR_EL3.NSTB[1] != SCR_EL3.NS || (IsFeatureImplemented(FEAT_RME) && MDCR_EL3.NSTBE != SCR_EL3.NSE)) then UNDEFINED; elsif HaveEL(EL3) && (MDCR_EL3.NSTB[0] == '0' || MDCR_EL3.NSTB[1] != SCR_EL3.NS || (IsFeatureImplemented(FEAT_RME) && MDCR_EL3.NSTBE != SCR_EL3.NSE)) then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else TRBTRG_EL1 = X[t, 64]; elsif PSTATE.EL == EL3 then TRBTRG_EL1 = X[t, 64];


30/09/2022 15:58; 21c5a6dd0fdaf10a712e2f2d6fffbdbd66d4d96f

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