LORC_EL1

This register is present only when FEAT_LOR is implemented. Otherwise, direct accesses to LORC_EL1 are UNDEFINED.

Attributes

Field descriptions

Bits [63:10]

DS, bits [9:2]

Descriptor Select. Selects the current LORegion descriptor accessed by LORSA_EL1, LOREA_EL1, and LORN_EL1.

If this field points to an LORegion descriptor that is not supported by an implementation, then the registers LORN_EL1, LOREA_EL1, and LORSA_EL1 are RES0.

The number of LORegion descriptors in IMPLEMENTATION DEFINED. The maximum number of LORegion descriptors supported is 256. If the number is less than 256, then bits[63:M+2] are RES0, where M is Log₂(Number of LORegion descriptors supported by the implementation).

The reset behavior of this field is:

On a Warm reset, this field resets to an architecturally UNKNOWN value.

Bit [1]

EN, bit [0]

Enable. Indicates whether LORegions are enabled.

EN	Meaning
0b0	Disabled. Memory accesses do not match any LORegions.
0b1	Enabled. Memory accesses may match a LORegion.

This bit is permitted to be cached in a TLB.

The reset behavior of this field is:

On a Warm reset, this field resets to 0.

Accessing LORC_EL1

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

MRS <Xt>, LORC_EL1

op0	op1	CRn	CRm	op2
0b11	0b000	0b1010	0b0100	0b011

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.TLOR == '1' then UNDEFINED; elsif HaveEL(EL3) && SCR_EL3.NS == '0' then UNDEFINED; elsif EL2Enabled() && HCR_EL2.TLOR == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGRTR_EL2.LORC_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3.TLOR == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = LORC_EL1; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && SCR_EL3.NS == '0' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.TLOR == '1' then UNDEFINED; elsif HaveEL(EL3) && SCR_EL3.TLOR == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = LORC_EL1; elsif PSTATE.EL == EL3 then if SCR_EL3.NS == '0' then UNDEFINED; else X[t, 64] = LORC_EL1;

MSR LORC_EL1, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b000	0b1010	0b0100	0b011

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.TLOR == '1' then UNDEFINED; elsif HaveEL(EL3) && SCR_EL3.NS == '0' then UNDEFINED; elsif EL2Enabled() && HCR_EL2.TLOR == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGWTR_EL2.LORC_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3.TLOR == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else LORC_EL1 = X[t, 64]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && SCR_EL3.NS == '0' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.TLOR == '1' then UNDEFINED; elsif HaveEL(EL3) && SCR_EL3.TLOR == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else LORC_EL1 = X[t, 64]; elsif PSTATE.EL == EL3 then if SCR_EL3.NS == '0' then UNDEFINED; else LORC_EL1 = X[t, 64];

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
RES0
RES0																						DS								RES0	EN

LORC_EL1, LORegion Control (EL1)

Purpose

Configuration