Exception Return using the ELR and SPSR for the current Exception level. When executed, the PE restores PSTATE from the SPSR, and branches to the address held in the ELR.
The PE checks the SPSR for the current Exception level for an illegal return event. See Illegal return events from AArch64 state.
ERET is undefined at EL0.
| 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 |
| 1 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 |
| A | M | Rn | op4 | ||||||||||||||||||||||||||||
if PSTATE.EL == EL0 then UNDEFINED; boolean pac = (A == '1'); boolean use_key_a = (M == '0'); if !pac && op4 != '00000' then UNDEFINED; elsif pac && (!HavePACExt() || op4 != '11111') then UNDEFINED; if Rn != '11111' then UNDEFINED;
AArch64.CheckForERetTrap(pac, use_key_a); bits(64) target = ELR[]; boolean auth_then_branch = TRUE; if pac then if use_key_a then target = AuthIA(ELR[], SP[], auth_then_branch); else target = AuthIB(ELR[], SP[], auth_then_branch); AArch64.ExceptionReturn(target, SPSR[]);
Internal version only: isa v33.11seprel, AdvSIMD v29.05, pseudocode v2021-09_rel, sve v2021-09_rc3d ; Build timestamp: 2021-10-06T11:41
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