CPACRMASK

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CPACRMASK_EL1, Architectural Feature Access Control Masking Register

Purpose

Mask register to prevent updates of fields in CPACR_EL1 on writes to CPACR_EL1 or CPACRALIAS_EL1.

Configuration

This register is present only when FEAT_SRMASK is implemented and FEAT_AA64 is implemented. Otherwise, direct accesses to CPACRMASK_EL1 are UNDEFINED.

Attributes

Field descriptions

Bits [63:32]

TCPAC, bit [31]
When FEAT_NV2p1 is implemented:

TCPAC	Meaning
0b0	CPACR_EL1.TCPAC is writable.
0b1	CPACR_EL1.TCPAC is not writable.

Otherwise:

TAM, bit [30]
When FEAT_AMUv1 is implemented and FEAT_NV2p1 is implemented:

TAM	Meaning
0b0	CPACR_EL1.TAM is writable.
0b1	CPACR_EL1.TAM is not writable.

Otherwise:

E0POE, bit [29]
When FEAT_S1POE is implemented:

E0POE	Meaning
0b0	CPACR_EL1.E0POE is writable.
0b1	CPACR_EL1.E0POE is not writable.

Otherwise:

TTA, bit [28]
When System register access to the trace unit registers is implemented:

TTA	Meaning
0b0	CPACR_EL1.TTA is writable.
0b1	CPACR_EL1.TTA is not writable.

Otherwise:

Bits [27:25]

SMEN, bit [24]
When FEAT_SME is implemented:

SMEN	Meaning
0b0	CPACR_EL1.SMEN is writable.
0b1	CPACR_EL1.SMEN is not writable.

Otherwise:

Bits [23:21]

FPEN, bit [20]

Bits [19:17]

FPEN	Meaning
0b0	CPACR_EL1.FPEN is writable.
0b1	CPACR_EL1.FPEN is not writable.

ZEN, bit [16]
When FEAT_SVE is implemented:

ZEN	Meaning
0b0	CPACR_EL1.ZEN is writable.
0b1	CPACR_EL1.ZEN is not writable.

Otherwise:

Bits [15:0]

Accessing CPACRMASK_EL1

When the Effective value of HCR_EL2.E2H is 1, without explicit synchronization, accesses from EL3 using the accessor name CPACRMASK_EL1 or CPACRMASK_EL12 are not guaranteed to be ordered with respect to accesses using the other accessor name.

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

MRS <Xt>, CPACRMASK_EL1

op0	op1	CRn	CRm	op2
0b11	0b000	0b0001	0b0100	0b010

if !(IsFeatureImplemented(FEAT_SRMASK) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3().SRMASKEn == '0' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT2) && ((HaveEL(EL3) && SCR_EL3().FGTEn2 == '0') || HFGRTR2_EL2().nCPACRMASK_EL1 == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && (!IsHCRXEL2Enabled() || HCRX_EL2().SRMASKEn == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3().SRMASKEn == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif EffectiveHCR_EL2_NVx() IN {'111'} then X{64}(t) = NVMem(0x320); else X{64}(t) = CPACRMASK_EL1(); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3().SRMASKEn == '0' then Undefined(); elsif HaveEL(EL3) && SCR_EL3().SRMASKEn == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif ELIsInHost(EL2) then X{64}(t) = CPTRMASK_EL2(); else X{64}(t) = CPACRMASK_EL1(); end; elsif PSTATE.EL == EL3 then X{64}(t) = CPACRMASK_EL1(); end;

MSR CPACRMASK_EL1, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b000	0b0001	0b0100	0b010

if !(IsFeatureImplemented(FEAT_SRMASK) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3().SRMASKEn == '0' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT2) && ((HaveEL(EL3) && SCR_EL3().FGTEn2 == '0') || HFGWTR2_EL2().nCPACRMASK_EL1 == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && (!IsHCRXEL2Enabled() || HCRX_EL2().SRMASKEn == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3().SRMASKEn == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif EffectiveHCR_EL2_NVx() IN {'111'} then NVMem(0x320) = X{64}(t); elsif !IsZero(CPACRMASK_EL1()) then Undefined(); else CPACRMASK_EL1() = X{64}(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3().SRMASKEn == '0' then Undefined(); elsif HaveEL(EL3) && SCR_EL3().SRMASKEn == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif ELIsInHost(EL2) then if !IsZero(CPTRMASK_EL2()) then Undefined(); else CPTRMASK_EL2() = X{64}(t); end; else CPACRMASK_EL1() = X{64}(t); end; elsif PSTATE.EL == EL3 then CPACRMASK_EL1() = X{64}(t); end;

When FEAT_VHE is implemented

MRS <Xt>, CPACRMASK_EL12

op0	op1	CRn	CRm	op2
0b11	0b101	0b0001	0b0100	0b010

if !(IsFeatureImplemented(FEAT_SRMASK) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() == '101' then X{64}(t) = NVMem(0x320); elsif EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64_SystemAccessTrap(EL2, 0x18); else Undefined(); end; elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3().SRMASKEn == '0' then Undefined(); elsif HaveEL(EL3) && SCR_EL3().SRMASKEn == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = CPACRMASK_EL1(); end; else Undefined(); end; elsif PSTATE.EL == EL3 then if ELIsInHost(EL2) then X{64}(t) = CPACRMASK_EL1(); else Undefined(); end; end;

When FEAT_VHE is implemented

MSR CPACRMASK_EL12, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b101	0b0001	0b0100	0b010

if !(IsFeatureImplemented(FEAT_SRMASK) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() == '101' then NVMem(0x320) = X{64}(t); elsif EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64_SystemAccessTrap(EL2, 0x18); else Undefined(); end; elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3().SRMASKEn == '0' then Undefined(); elsif HaveEL(EL3) && SCR_EL3().SRMASKEn == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else CPACRMASK_EL1() = X{64}(t); end; else Undefined(); end; elsif PSTATE.EL == EL3 then if ELIsInHost(EL2) then CPACRMASK_EL1() = X{64}(t); else Undefined(); 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
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
TCPAC	TAM	E0POE	TTA	RES0			SMEN	RES0			FPEN	RES0			ZEN	RES0

CPACRMASK_EL1, Architectural Feature Access Control Masking Register

Purpose

Configuration

Attributes

Field descriptions

Bits [63:32]

TCPAC, bit [31]When FEAT_NV2p1 is implemented:

Otherwise:

TAM, bit [30]When FEAT_AMUv1 is implemented and FEAT_NV2p1 is implemented:

Otherwise:

E0POE, bit [29]When FEAT_S1POE is implemented:

Otherwise:

TTA, bit [28]When System register access to the trace unit registers is implemented:

Otherwise:

Bits [27:25]

SMEN, bit [24]When FEAT_SME is implemented:

Otherwise:

Bits [23:21]

FPEN, bit [20]

Bits [19:17]

ZEN, bit [16]When FEAT_SVE is implemented:

Otherwise:

Bits [15:0]

Accessing CPACRMASK_EL1

MRS <Xt>, CPACRMASK_EL1

MSR CPACRMASK_EL1, <Xt>

When FEAT_VHE is implemented

MRS <Xt>, CPACRMASK_EL12

When FEAT_VHE is implemented

MSR CPACRMASK_EL12, <Xt>

TCPAC, bit [31]
When FEAT_NV2p1 is implemented:

TAM, bit [30]
When FEAT_AMUv1 is implemented and FEAT_NV2p1 is implemented:

E0POE, bit [29]
When FEAT_S1POE is implemented:

TTA, bit [28]
When System register access to the trace unit registers is implemented:

SMEN, bit [24]
When FEAT_SME is implemented:

ZEN, bit [16]
When FEAT_SVE is implemented: