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

# ICC_SGI0R_EL1, Interrupt Controller Software Generated Interrupt Group 0 Register

The ICC_SGI0R_EL1 characteristics are:

## Purpose

Generates Secure Group 0 SGIs.

## Configuration

AArch64 System register ICC_SGI0R_EL1 performs the same function as AArch32 System register ICC_SGI0R.

## Attributes

ICC_SGI0R_EL1 is a 64-bit register.

## Field descriptions

The ICC_SGI0R_EL1 bit assignments are:

63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32
RES0 | Aff3 | RS | RES0 | IRM | Aff2
RES0 | INTID | Aff1 | TargetList
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

#### Bits [63:56]

Reserved, RES0.

#### Aff3, bits [55:48]

The affinity 3 value of the affinity path of the cluster for which SGI interrupts will be generated.

If the IRM bit is 1, this field is RES0.

#### RS, bits [47:44]

RangeSelector

Controls which group of 16 values is represented by the TargetList field.

TargetList[n] represents aff0 value ((RS * 16) + n).

When ICC_CTLR_EL1.RSS==0, RS is RES0.

When ICC_CTLR_EL1.RSS==1 and GICD_TYPER.RSS==0, writing this register with RS != 0 is a CONSTRAINED UNPREDICTABLE choice of :

- The write is ignored.
- The RS field is treated as 0.

#### Bits [43:41]

Reserved, RES0.

#### IRM, bit [40]

Interrupt Routing Mode. Determines how the generated interrupts are distributed to PEs. Possible values are:

IRM | Meaning
--- | ---
0b0 | Interrupts routed to the PEs specified by Aff3.Aff2.Aff1.<target list>.
0b1 | Interrupts routed to all PEs in the system, excluding "self".

#### Aff2, bits [39:32]

The affinity 2 value of the affinity path of the cluster for which SGI interrupts will be generated.

If the IRM bit is 1, this field is RES0.

#### Bits [31:28]

Reserved, RES0.

#### INTID, bits [27:24]

The INTID of the SGI.

#### Aff1, bits [23:16]

The affinity 1 value of the affinity path of the cluster for which SGI interrupts will be generated.

If the IRM bit is 1, this field is RES0.

#### TargetList, bits [15:0]

Target List. The set of PEs for which SGI interrupts will be generated. Each bit corresponds to the PE within a cluster with an Affinity 0 value equal to the bit number.

If a bit is 1 and the bit does not correspond to a valid target PE, the bit must be ignored by the Distributor. It is IMPLEMENTATION DEFINED whether, in such cases, a Distributor can signal a system error.

Note

This restricts a system to sending targeted SGIs to PEs with an affinity 0 number that is less than 16.

If SRE is set only for Secure EL3, software executing at EL3 might use the System register interface to generate SGIs. Therefore, the Distributor must always be able to receive and acknowledge Generate SGI packets received from CPU interface regardless of the ARE settings for a Security state. However, the Distributor might discard such packets.

If the IRM bit is 1, this field is RES0.

## Accessing the ICC_SGI0R_EL1

This register allows software executing in a Secure state to generate Group 0 SGIs. It will also allow software executing in a Non-secure state to generate Group 0 SGIs, if permitted by the settings of GICR_NSACR in the Redistributor corresponding to the target PE.

When GICD_CTLR.DS==0, Non-secure writes do not generate an interrupt for a target PE if not permitted by the GICR_NSACR register associated with the target PE. For more information see Use of control registers for SGI forwarding.

Note

Accesses at EL3 are treated as Secure regardless of the value of SCR_EL3.NS.

Accesses to this register use the following encodings:

#### MSR ICC_SGI0R_EL1, <Xt>

op0 | op1 | CRn | CRm | op2
--- | --- | --- | --- | ---
0b11 | 0b000 | 0b1100 | 0b1011 | 0b111

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if ICC_SRE_EL1.SRE == '0' then AArch64.SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && ICH_HCR_EL2.TC == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.FMO == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.IMO == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then AArch64.SystemAccessTrap(EL3, 0x18); else ICC_SGI0R_EL1 = X[t]; elsif PSTATE.EL == EL2 then if ICC_SRE_EL2.SRE == '0' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then AArch64.SystemAccessTrap(EL3, 0x18); else ICC_SGI0R_EL1 = X[t]; elsif PSTATE.EL == EL3 then if ICC_SRE_EL3.SRE == '0' then AArch64.SystemAccessTrap(EL3, 0x18); else ICC_SGI0R_EL1 = X[t];

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

27/03/2019 21:59; e5e4db499bf9867a4b93324c4dbac985d3da9376

Copyright © 2010-2019 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.