ERRDEVAFF Device Affinity Register when the group of error records has affinity with a PE or cluster of PEs and an implementation implements ERRDEVAFF RAS 0xFA8 ERRDEVAFF RO For a group of error records that has affinity with a single PE or a group of PEs, ERRDEVAFF is a copy of MPIDR_EL1 or part of MPIDR_EL1: If the group of error records has affinity with a single PE, the affinity level is 0, then ERRDEVAFF reads the same value as MPIDR_EL1, and ERRDEVAFF.F0V reads-as-one to indicate affinity level 0. If the group of error records has affinity with a group of PEs, the affinity level is 1, 2, or 3, then parts of ERRDEVAFF reads the same value as parts of MPIDR_EL1, and the rest of ERRDEVAFF indicates the level. For example, if the group of PEs is a subset of the PEs at affinity level 1, then all of the following are true: All the PEs in the group have the same values in MPIDR_EL1.{Aff3,Aff2}, and these values are equal to ERRDEVAFF.{Aff3,Aff2}. ERRDEVAFF.Aff1 is nonzero and not 0x80, and ERRDEVAFF.{Aff0,F0V} read-as-zero, to indicate at least affinity level 1. The subset of PEs at level 1 that the group of error records has affinity with is indicated by the least-significant set bit in ERRDEVAFF.Aff1. In this example, if ERRDEVAFF.Aff1[2:0] is 0b100, then the group of error records has affinity with the up-to 8 PEs that have MPIDR_EL1.Aff1[7:3] == ERRDEVAFF.Aff1[7:3]. Depending on the IMPLEMENTATION DEFINED nature of the system, it might be possible that ERRDEVAFF is read before system firmware has configured the group of error records or the PE or group of PEs that the group of error records has affinity with. When this is the case, ERRDEVAFF reads as zero. If RAS System Architecture v1.1 is not implemented, then ERRDEVAFF can only describe a group of error records that is affine with a single PE or all the PEs at an affinity level. RAS ERRDEVAFF is implemented only as part of a memory-mapped group of error records. Arm deprecates use of this register by software ERRDEVAFF is a 64-bit register. 63 40 63:40 Reserved, RES0. Aff3 39 32 39:32 PE affinity level 3. The MPIDR_EL1.Aff3 field, viewed from the highest Exception level of the associated PE or PEs. This field has an IMPLEMENTATION DEFINED value. RO F0V 31 31 31 Indicates that the ERRDEVAFF.Aff0 field is valid. 0b0 ERRDEVAFF.Aff0 is not valid, and the PE affinity is above level 0 or a subset of level 0. 0b1 ERRDEVAFF.Aff0 is valid, and the PE affinity is at level 0. RO U 30 30 0 Uniprocessor. The MPIDR_EL1.U field, viewed from the highest Exception level of the associated PE. When ERRDEVAFF.F0V == '1' 30 30 30 Reserved, UNKNOWN. Otherwise 29 25 29:25 Reserved, RES0. MT 24 24 0 Multithreaded. The MPIDR_EL1.MT field, viewed from the highest Exception level of the associated PE. When ERRDEVAFF.F0V == '1' 24 24 24 Reserved, UNKNOWN. Otherwise Aff2 23 16 7:0 PE affinity level 2. The MPIDR_EL1.Aff2 field, viewed from the highest Exception level of the associated PE or PEs. This field has an IMPLEMENTATION DEFINED value. RO When !IsZero(ERRDEVAFF.[Aff1,Aff0,F0V]) Aff2 23 16 7:0 PE affinity level 2. Defines part of the MPIDR_EL1.Aff2 field, viewed from the highest Exception level of the associated PEs. 0bxxxxxxx1 PE affinity is the subset of level 2 where ERRDEVAFF.Aff2[7:1] is the value of MPIDR_EL1.Aff2[7:1], viewed from the highest Exception level of the associated PEs. 0bxxxxxx10 PE affinity is the subset of level 2 where ERRDEVAFF.Aff2[7:2] is the value of MPIDR_EL1.Aff2[7:2], viewed from the highest Exception level of the associated PEs. 0bxxxxx100 PE affinity is the subset of level 2 where ERRDEVAFF.Aff2[7:3] is the value of MPIDR_EL1.Aff2[7:3], viewed from the highest Exception level of the associated PEs. 0bxxxx1000 PE affinity is the subset of level 2 where ERRDEVAFF.Aff2[7:4] is the value of MPIDR_EL1.Aff2[7:4], viewed from the highest Exception level of the associated PEs. 0bxxx10000 PE affinity is the subset of level 2 where ERRDEVAFF.Aff2[7:5] is the value of MPIDR_EL1.Aff2[7:5], viewed from the highest Exception level of the associated PEs. 0bxx100000 PE affinity is the subset of level 2 where ERRDEVAFF.Aff2[7:6] is the value of MPIDR_EL1.Aff2[7:6], viewed from the highest Exception level of the associated PEs. 0bx1000000 PE affinity is the subset of level 2 where ERRDEVAFF.Aff2[7] is the value of MPIDR_EL1.Aff2[7], viewed from the highest Exception level of the associated PEs. 0x80 PE affinity is at level 3. RO Otherwise Aff1 15 8 7:0 PE affinity level 1. The MPIDR_EL1.Aff1 field, viewed from the highest Exception level of the associated PE or PEs. This field has an IMPLEMENTATION DEFINED value. RO When !IsZero(ERRDEVAFF.[Aff0,F0V]) Aff1 15 8 7:0 PE affinity level 1. Defines part of the MPIDR_EL1.Aff1 field, viewed from the highest Exception level of the associated PEs. 0x00 PE affinity is above level 2 or a subset of level 2. 0bxxxxxxx1 PE affinity is the subset of level 1 where ERRDEVAFF.Aff1[7:1] is the value of MPIDR_EL1.Aff1[7:1], viewed from the highest Exception level of the associated PEs. 0bxxxxxx10 PE affinity is the subset of level 1 where ERRDEVAFF.Aff1[7:2] is the value of MPIDR_EL1.Aff1[7:2], viewed from the highest Exception level of the associated PEs. 0bxxxxx100 PE affinity is the subset of level 1 where ERRDEVAFF.Aff1[7:3] is the value of MPIDR_EL1.Aff1[7:3], viewed from the highest Exception level of the associated PEs. 0bxxxx1000 PE affinity is the subset of level 1 where ERRDEVAFF.Aff1[7:4] is the value of MPIDR_EL1.Aff1[7:4], viewed from the highest Exception level of the associated PEs. 0bxxx10000 PE affinity is the subset of level 1 where ERRDEVAFF.Aff1[7:5] is the value of MPIDR_EL1.Aff1[7:5], viewed from the highest Exception level of the associated PEs. 0bxx100000 PE affinity is the subset of level 1 where ERRDEVAFF.Aff1[7:6] is the value of MPIDR_EL1.Aff1[7:6], viewed from the highest Exception level of the associated PEs. 0bx1000000 PE affinity is the subset of level 1 where ERRDEVAFF.Aff1[7] is the value of MPIDR_EL1.Aff1[7], viewed from the highest Exception level of the associated PEs. 0x80 PE affinity is at level 2. RO Otherwise Aff0 7 0 7:0 PE affinity level 0. The MPIDR_EL1.Aff0 field, viewed from the highest Exception level of the associated PE. This field has an IMPLEMENTATION DEFINED value. RO When ERRDEVAFF.F0V == '1' Aff0 7 0 7:0 PE affinity level 0. Defines part of the MPIDR_EL1.Aff0 field, viewed from the highest Exception level of the associated PEs. 0x00 PE affinity is above level 1 or a subset of level 1. 0bxxxxxxx1 PE affinity is the subset of level 0 where ERRDEVAFF.Aff0[7:1] is the value of MPIDR_EL1.Aff0[7:1], viewed from the highest Exception level of the associated PEs. 0bxxxxxx10 PE affinity is the subset of level 0 where ERRDEVAFF.Aff0[7:2] is the value of MPIDR_EL1.Aff0[7:2], viewed from the highest Exception level of the associated PEs. 0bxxxxx100 PE affinity is the subset of level 0 where ERRDEVAFF.Aff0[7:3] is the value of MPIDR_EL1.Aff0[7:3], viewed from the highest Exception level of the associated PEs. 0bxxxx1000 PE affinity is the subset of level 0 where ERRDEVAFF.Aff0[7:4] is the value of MPIDR_EL1.Aff0[7:4], viewed from the highest Exception level of the associated PEs. 0bxxx10000 PE affinity is the subset of level 0 where ERRDEVAFF.Aff0[7:5] is the value of MPIDR_EL1.Aff0[7:5], viewed from the highest Exception level of the associated PEs. 0bxx100000 PE affinity is the subset of level 0 where ERRDEVAFF.Aff0[7:6] is the value of MPIDR_EL1.Aff0[7:6], viewed from the highest Exception level of the associated PEs. 0bx1000000 PE affinity is the subset of level 0 where ERRDEVAFF.Aff0[7] is the value of MPIDR_EL1.Aff0[7], viewed from the highest Exception level of the associated PEs. 0x80 PE affinity is at level 1. RO Otherwise This section shows the offset of ERRDEVAFF when FEAT_RASSA_4KB_GRP is implemented. If FEAT_RASSA_16KB_GRP or FEAT_RASSA_64KB_GRP is implemented, see 'RAS memory-mapped register views' for the offset of ERRDEVAFF. 2026-03-26 20:27:25 2026-03_rel