ERET

Exception return

This instruction restores PSTATE from the SPSR, and branches to the address held in the ELR.

The SPSR is checked for the current Exception level for an illegal return event. See Illegal exception returns from AArch64 state.

ERET is UNDEFINED at EL0.

Encoding: System

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
							opc				op2									A	M	Rn					op4

ERET

Decoding algorithm

constant boolean pac = FALSE;
constant boolean use_key_a = TRUE;

Operation

if PSTATE.EL == EL0 then UNDEFINED;
AArch64.CheckForERetTrap(pac, use_key_a);
constant bits(64) target = ELR_ELx[];

AArch64.ExceptionReturn(target, SPSR_ELx[]);

Explanations