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TRCCONFIGR: Trace Configuration Register

Purpose

Controls the tracing options.

Configuration

External register TRCCONFIGR bits [31:0] are architecturally mapped to AArch64 System register TRCCONFIGR[31:0].

This register is present only when FEAT_ETE is implemented and FEAT_TRC_EXT is implemented. Otherwise, direct accesses to TRCCONFIGR are RES0.

Attributes

TRCCONFIGR is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
RES0ITORES0VMIDOPTQERSTSRES0VMIDCIDRES0CCIBBRES0RES1

Bits [31:19]

Reserved, RES0.

ITO, bit [18]

When TRCIDR0.ITE == 1:

Instrumentation Trace Override.

ITOMeaning
0b0

Instrumentation Trace Override disabled.

0b1

Instrumentation Trace Override enabled.

This field is ignored when SelfHostedTraceEnabled() returns TRUE.

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

Bits [17:16]

Reserved, RES0.

VMIDOPT, bit [15]

When TRCIDR2.VMIDOPT == 0b01:

Virtual context identifier selection control.

VMIDOPTMeaning
0b0

VTTBR_EL2.VMID is used as the Virtual context identifier.

0b1

CONTEXTIDR_EL2.PROCID is used as the Virtual context identifier.



When TRCIDR2.VMIDOPT == 0b00:

Reserved, RES0.

Virtual context identifier selection control.

VTTBR_EL2.VMID is used as the Virtual context identifier.



When TRCIDR2.VMIDOPT == 0b10:

Reserved, RES1.

Virtual context identifier selection control.

CONTEXTIDR_EL2.PROCID is used as the Virtual context identifier.



Otherwise:

Reserved, RES0.

QE, bits [14:13]

When TRCIDR0.QSUPP == 0b01:

Q element generation control.

QEMeaning
0b00

Q elements are disabled.

0b01

Q elements with instruction counts are enabled.

Q elements without instruction counts are disabled.

All other values are reserved.



When TRCIDR0.QSUPP == 0b10:

Q element generation control.

QEMeaning
0b00

Q elements are disabled.

0b11

Q elements with instruction counts are enabled.

Q elements without instruction counts are enabled.

All other values are reserved.



When TRCIDR0.QSUPP == 0b11:

Q element generation control.

QEMeaning
0b00

Q elements are disabled.

0b01

Q elements with instruction counts are enabled.

Q elements without instruction counts are disabled.

0b11

Q elements with instruction counts are enabled.

Q elements without instruction counts are enabled.

All other values are reserved.



Otherwise:

Reserved, RES0.

RS, bit [12]

When TRCIDR0.RETSTACK == 1:

Return stack control.

RSMeaning
0b0

Return stack is disabled.

0b1

Return stack is enabled.

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

TS, bit [11]

When TRCIDR0.TSSIZE != 0b00000:

Global timestamp tracing control.

TSMeaning
0b0

Global timestamp tracing is disabled.

0b1

Global timestamp tracing is enabled.

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

Bits [10:8]

Reserved, RES0.

VMID, bit [7]

When TRCIDR2.VMIDSIZE != 0b00000:

Virtual context identifier tracing control.

VMIDMeaning
0b0

Virtual context identifier tracing is disabled.

0b1

Virtual context identifier tracing is enabled.

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

CID, bit [6]

When TRCIDR2.CIDSIZE != 0b00000:

Context identifier tracing control.

CIDMeaning
0b0

Context identifier tracing is disabled.

0b1

Context identifier tracing is enabled.

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

Bit [5]

Reserved, RES0.

CCI, bit [4]

When TRCIDR0.TRCCCI == 1:

Cycle counting instruction tracing control.

CCIMeaning
0b0

Cycle counting instruction tracing is disabled.

0b1

Cycle counting instruction tracing is enabled.

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

BB, bit [3]

When TRCIDR0.TRCBB == 1:

Branch broadcasting control.

BBMeaning
0b0

Branch broadcasting is disabled.

0b1

Branch broadcasting is enabled.

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

Bits [2:1]

Reserved, RES0.

Bit [0]

Reserved, RES1.

Accessing TRCCONFIGR

Must always be programmed.

TRCCONFIGR.QE must be set to 0b00 if TRCCONFIGR.BB is not 0.

Writes are CONSTRAINED UNPREDICTABLE if the trace unit is not in the Idle state.

TRCCONFIGR can be accessed through the external debug interface:

ComponentOffsetInstance
ETE0x010TRCCONFIGR

This interface is accessible as follows: