GICC_RPR, CPU Interface Running Priority Register

The GICC_RPR characteristics are:

Purpose

This register indicates the running priority of the CPU interface.

Configuration

This register is present only when FEAT_GICv3_LEGACY is implemented. Otherwise, direct accesses to GICC_RPR are RES0.

This register is available in all configurations of the GIC. If the GIC implementation supports two Security states this register is Common.

Attributes

GICC_RPR 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																								Priority

Bits [31:8]

Reserved, RES0.

Priority, bits [7:0]

The current running priority on the CPU interface. This is the group priority of the current active interrupt.

If there are no active interrupts on the CPU interface, or all active interrupts have undergone a priority drop, the value returned is the Idle priority.

The priority returned is the group priority as if the BPR was set to the minimum value.

Accessing GICC_RPR

If there is no active interrupt on the CPU interface, the idle priority value is returned.

If the GIC implementation supports two Security states, a Non-secure read of the Priority field returns:

0x00 if the field value is less than 0x80.
The Non-secure view of the Priority value if the field value is 0x80 or more.

For more information, see 'Interrupt prioritization' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).

Note

Software cannot determine the number of implemented priority bits from this register.

GICC_RPR can be accessed through the memory-mapped interfaces:

Component	Offset	Instance
GIC CPU interface	0x0014	GICC_RPR

This interface is accessible as follows:

When GICD_CTLR.DS == 0, accesses to this register are RO.
When an access is Secure, accesses to this register are RO.
When an access is Non-secure, accesses to this register are RO.

04/07/2023 11:22; 1b994cb0b8c6d1ae5a9a15edbc8bd6ce3b5c7d68