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# TRFCR, Trace Filter Control Register

The TRFCR characteristics are:

## Purpose

Provides EL1 controls for Trace.

## Configuration

AArch32 System register TRFCR bits [31:0] are architecturally mapped to AArch64 System register TRFCR_EL1[31:0] .

This register is present only when ARMv8.4-Trace is implemented. Otherwise, direct accesses to TRFCR are UNDEFINED.

This register is in the Warm reset domain. Some or all RW fields of this register have defined reset values. On a Warm or Cold reset these apply only if the PE resets into an Exception level that is using AArch32. Otherwise, on a Warm or Cold reset RW fields in this register reset to architecturally UNKNOWN values.

## Attributes

TRFCR is a 32-bit register.

## Field descriptions

The TRFCR bit assignments are:

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
RES0 | TS | RES0 | E1TRE | E0TRE

#### Bits [31:7]

Reserved, RES0.

#### TS, bits [6:5]

Timestamp Control. Controls which timebase is used for trace timestamps.

TS | Meaning
--- | ---
0b01 | Virtual timestamp. The traced timestamp is the physical counter value minus the value of CNTVOFF.
0b11 | Physical timestamp. The traced timestamp is the physical counter value.

All other values are reserved.

This field is ignored if any of the following are true:

- SelfHostedTraceEnabled() == FALSE.
- HTRFCR.TS is not 0b00.

On a Warm reset, this field resets to an architecturally UNKNOWN value.

#### Bits [4:2]

Reserved, RES0.

#### E1TRE, bit [1]

EL1 Trace Enable.

E1TRE | Meaning
--- | ---
0b0 | Tracing is prohibited in PL1 modes.
0b1 | Tracing is allowed in PL1 modes.

When SelfHostedTraceEnabled() == FALSE, this field is ignored.

On a Warm reset, this field resets to 0.

#### E0TRE, bit [0]

EL0 Trace Enable.

E0TRE | Meaning
--- | ---
0b0 | Tracing is prohibited at EL0.
0b1 | Tracing is allowed at EL0.

This field is ignored if any of the following are true:

- SelfHostedTraceEnabled() == FALSE.
- EL2 is implemented and enabled in the current security state and HCR.TGE == 1.

On a Warm reset, this field resets to 0.

## Accessing the TRFCR

Accesses to this register use the following encodings:

#### MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coproc | opc1 | CRn | CRm | opc2
--- | --- | --- | --- | ---
0b1111 | 0b000 | 0b0001 | 0b0010 | 0b001

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T1 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T1 == '1' then AArch32.TakeHypTrapException(0x03); elsif SCR.NS == '0' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TTRF == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TTRF == '1' then AArch32.TakeHypTrapException(0x03); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TTRF == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SDCR.TTRF == '1' then AArch32.TakeMonitorTrapException(); else return TRFCR; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TTRF == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && SDCR.TTRF == '1' then AArch32.TakeMonitorTrapException(); else return TRFCR; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then UNDEFINED; else return TRFCR;

#### MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coproc | opc1 | CRn | CRm | opc2
--- | --- | --- | --- | ---
0b1111 | 0b000 | 0b0001 | 0b0010 | 0b001

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T1 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T1 == '1' then AArch32.TakeHypTrapException(0x03); elsif SCR.NS == '0' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && MDCR_EL2.TTRF == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HDCR.TTRF == '1' then AArch32.TakeHypTrapException(0x03); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TTRF == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SDCR.TTRF == '1' then AArch32.TakeMonitorTrapException(); else TRFCR = R[t]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && !ELUsingAArch32(EL3) && MDCR_EL3.TTRF == '1' then AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && SDCR.TTRF == '1' then AArch32.TakeMonitorTrapException(); else TRFCR = R[t]; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then UNDEFINED; else TRFCR = R[t];

AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

15/04/2019 16:47; 8c23526ba8a13a72aada4137daf3e3977b49036e

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