AT S1E2A

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AT S1E2A, Address Translate Stage 1 EL2 Without Permission checks

Purpose

Performs stage 1 address translation as defined for EL2, while ignoring permissions checks from the given virtual address.

When FEAT_RME is implemented, if the Effective value of SCR_EL3.{NSE, NS} is a reserved value, this instruction is UNDEFINED at EL3.

Configuration

This instruction is present only when FEAT_ATS1A is implemented and FEAT_AA64 is implemented. Otherwise, direct accesses to AT S1E2A are UNDEFINED.

Attributes

Field descriptions

IA, bits [63:0]

Executing AT S1E2A

This system instruction is an alias of the SYS instruction.

Accesses to this instruction use the following encodings in the System instruction encoding space:

AT S1E2A, <Xt>

op0	op1	CRn	CRm	op2
0b01	0b100	0b0111	0b1001	0b010

if !(IsFeatureImplemented(FEAT_ATS1A) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64_SystemAccessTrap(EL2, 0x18); else Undefined(); end; elsif PSTATE.EL == EL2 then AArch64_AT(X{64}(t), TranslationStage_1, EL2, ATAccess_Any); elsif PSTATE.EL == EL3 then if !EL2Enabled() then Undefined(); else AArch64_AT(X{64}(t), TranslationStage_1, EL2, ATAccess_Any); end; end;

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
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IA
IA

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
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IA
IA

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
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
IA
IA

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
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IA
IA