AArch64 Multiprocessor Affinity Register (MPIDR_EL1, read-only). More...

#include <utils.h>

Data Fields
uint64_t	raw
	Raw 64-bit register value.

struct {

uint32_t aff0: 8
	[7:0] Aff0: Thread/core ID within a cluster. On most simple systems this is the linear core number. When MT==1, this identifies the thread within a core instead.

uint32_t aff1: 8
	[15:8] Aff1: Cluster ID. Groups of cores sharing L2 cache or a cluster block typically share the same Aff1.

uint32_t aff2: 8
	[23:16] Aff2: Higher-level cluster or socket ID.

bool mt: 1
	[24] MT: Multithreading. When 1, Aff0 identifies a thread within a core rather than a core within a cluster.

uint32_t res0_29_25: 5
	[29:25] Reserved.

bool uniprocessor: 1
	[30] U: Uniprocessor flag. Set to 1 if the implementation is a single PE with no affinity structure.

uint32_t res1: 1
	[31] RES1: Always reads as 1 at EL1.

uint32_t aff3: 8
	[39:32] Aff3: Highest-level affinity (multi-socket or NUMA node). Zero on most embedded/server implementations.

uint32_t res0_63_40: 24
	[63:40] RES1 / implementation defined. Mask before use.

};

Detailed Description

AArch64 Multiprocessor Affinity Register (MPIDR_EL1, read-only).

Identifies the PE within a multiprocessor system. In a simple single-cluster system (e.g. QEMU virt), Aff1/Aff2/Aff3 are 0 and Aff0 is the core number.

Compare AffinityValue (Aff3.Aff2.Aff1.Aff0) against GICR_TYPER.AffinityValue to find the Redistributor frame belonging to this PE.

Note:

This is a system register, not a memory-mapped register.
Read via mrs <Xn>, mpidr_el1.
Bits [63:40] are RES1 or implementation-defined; mask them before use.

The documentation for this union was generated from the following file:

src/include/utils/utils.h

Data Fields

Detailed Description