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 UnallocatedEncoding(); boolean pac = (A == '1'); boolean use_key_a = (M == '0'); if !pac && op4 != '00000' then UnallocatedEncoding(); elsif pac && (!HavePACExt() || op4 != '11111') then UnallocatedEncoding(); if Rn != '11111' then UnallocatedEncoding();
AArch64.CheckForERetTrap(pac, use_key_a); bits(64) target = ELR[]; if pac then if use_key_a then target = AuthIA(ELR[], SP[]); else target = AuthIB(ELR[], SP[]); AArch64.ExceptionReturn(target, SPSR[]);
Internal version only: isa v29.05, AdvSIMD v26.0, pseudocode v35.3 ; Build timestamp: 2018-06-16T09:45
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