GICR_NSACR

Enables Secure software to permit Non-secure software to create SGIs targeting the PE connected to this Redistributor by writing to ICC_SGI1R_EL1, ICC_ASGI1R_EL1 or ICC_SGI0R_EL1.

For more information, see 'Forwarding an SGI to a target PE' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).

Configuration

For a description on when a write to ICC_SGI0R_EL1, ICC_SGI1R_EL1 or ICC_ASGI1R_EL1 is permitted to generate an interrupt, see 'Use of control registers for SGI forwarding' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).

Attributes

Field descriptions

NS_access<x>, bits [2x+1:2x], for x = 15 to 0

Configures the level of Non-secure access permitted when the SGI is in Secure Group 0 or Secure Group 1, as defined from GICR_IGROUPR0 and GICR_IGRPMODR0. A field is provided for each SGI. The possible values of each 2-bit field are:

NS_access<x>	Meaning
0b00	Non-secure writes are not permitted to generate Secure Group 0 SGIs or Secure Group 1 SGIs.
0b01	Non-secure writes are permitted to generate a Secure Group 0 SGI.
0b10	As 0b01, but additionally Non-secure writes to are permitted to generate a Secure Group 1 SGI.
0b11	Reserved. If the field is programmed to the reserved value, then the hardware will treat the field as if it has been programmed to an IMPLEMENTATION DEFINED choice of the valid values. However, to maintain the principle that as the value increases additional accesses are permitted Arm strongly recommends that implementations treat this value as 0b10. It is IMPLEMENTATION DEFINED whether the value read back is the value programmed or the valid value chosen.

The reset behavior of this field is:

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

Accessing GICR_NSACR

This register is used when affinity routing is enabled. When affinity routing is not enabled for the Security state of the interrupt, GICD_NSACR<n> with n=0 provides equivalent functionality.

GICR_NSACR can be accessed through the memory-mapped interfaces:

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
NS_access15		NS_access14		NS_access13		NS_access12		NS_access11		NS_access10		NS_access9		NS_access8		NS_access7		NS_access6		NS_access5		NS_access4		NS_access3		NS_access2		NS_access1		NS_access0