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# GITS_STATUSR, ITS Error Reporting Status Register

The GITS_STATUSR characteristics are:

## Purpose

Provides software with a mechanism to detect:

- Accesses to reserved locations.
- Writes to read-only locations.
- Reads of write-only locations.
- Unmapped MSIs.

## Configuration

There are no configuration notes.

## Attributes

GITS_STATUSR is a 32-bit register.

## Field descriptions

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 | Syndrome | Overflow | UMSI | WROD | RWOD | WRD | RRD

#### Bits [31:10]

Reserved, RES0.

#### Syndrome, bits [9:6]

Syndrome for the MSI that set GITS_STATUSR.UMSI to 1.

Syndrome | Meaning
--- | ---
0b0000 | Unknown reason.
0b0010 | DeviceID out of range.
0b0011 | DeviceID unmapped.
0b0100 | EventID out of range.
0b0101 | EventID unmapped.
0b0111 | Collection unmapped.
0b1001 | vPEID unmapped.

An implementation might not support reporting all syndromes, and might report 0b0000 for any cause.

This field is UNKNOWN when GITS_STATUSR.UMSI is 0.

#### Overflow, bit [5]

Reports whether an unmapped MSI has been received while GITS_STATUSR.UMSI is 1.

Overflow | Meaning
--- | ---
0b0 | No unmapped MSIs have been received since GITS_STATUSR.UMSI set to 1.
0b1 | At least one unmapped MSIs have been received since GITS_STATUSR.UMSI set to 1.

A software write of 1 to the bit clears it. A write of any other value is ignored.

If GITS_TYPER.UMSI is 0, this field is RES0.

#### UMSI, bit [4]

Reports whether an unmapped MSI has been received

An unmapped MSI is defined as an MSI arriving at GITS_TRANSLATER for which there is insufficient mapping information for it to be forwarded to a Redistributor.

It is IMPLEMENTATION DEFINED whether an INT command can be reported as an unmapped MSI.

UMSI | Meaning
--- | ---
0b0 | No unmapped MSIs have been received.
0b1 | Unmapped MSI received.

A software write of 1 to the bit clears it. A write of any other value is ignored.

If GITS_TYPER.UMSI is 0, this field is RES0.

#### WROD, bit [3]

Write to an RO location.

WROD | Meaning
--- | ---
0b0 | Normal operation.
0b1 | A write to an RO location has been detected.

When a violation is detected, software must write 1 to this register to reset it.

#### RWOD, bit [2]

Read of a WO location.

RWOD | Meaning
--- | ---
0b0 | Normal operation.
0b1 | A read of a WO location has been detected.

When a violation is detected, software must write 1 to this register to reset it.

#### WRD, bit [1]

Write to a reserved location.

WRD | Meaning
--- | ---
0b0 | Normal operation.
0b1 | A write to a reserved location has been detected.

When a violation is detected, software must write 1 to this register to reset it.

#### RRD, bit [0]

Read of a reserved location.

RRD | Meaning
--- | ---
0b0 | Normal operation.
0b1 | A read of a reserved location has been detected.

When a violation is detected, software must write 1 to this register to reset it.

## Accessing GITS_STATUSR

This is an optional register. If the register is not implemented, the location is RAZ/WI.

#### GITS_STATUSR can be accessed through the memory-mapped interfaces:

Component | Offset | Instance
--- | --- | ---
GIC ITS control | 0x0040 | GITS_STATUSR

Accesses on this interface are RW.

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

26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6

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