DACR, Domain Access Control Register

The DACR characteristics are:

Purpose

Defines the access permission for each of the sixteen memory domains.

Configuration

AArch32 System register DACR bits [31:0] are architecturally mapped to AArch64 System register DACR32_EL2[31:0].

This register is present only when AArch32 is supported at any Exception level. Otherwise, direct accesses to DACR are UNDEFINED.

This register has no function when TTBCR.EAE is set to 1, to select the Long-descriptor translation table format.

Attributes

DACR is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
D15D14D13D12D11D10D9D8D7D6D5D4D3D2D1D0

D<n>, bits [2n+1:2n], for n = 15 to 0

Domain n access permission, where n = 0 to 15. Permitted values are:

D<n>Meaning
0b00

No access. Any access to the domain generates a Domain fault.

0b01

Client. Accesses are checked against the permission bits in the translation tables.

0b11

Manager. Accesses are not checked against the permission bits in the translation tables.

The value 0b10 is reserved.

The reset behaviour of this field is:

Accessing DACR

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

MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11110b0000b00110b00000b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T3 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T3 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TRVM == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TRVM == '1' then AArch32.TakeHypTrapException(0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) then return DACR_NS; else return DACR; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && ELUsingAArch32(EL3) then return DACR_NS; else return DACR; elsif PSTATE.EL == EL3 then if SCR.NS == '0' then return DACR_S; else return DACR_NS;

MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11110b0000b00110b00000b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T3 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T3 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TVM == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TVM == '1' then AArch32.TakeHypTrapException(0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) then DACR_NS = R[t]; else DACR = R[t]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && ELUsingAArch32(EL3) then DACR_NS = R[t]; else DACR = R[t]; elsif PSTATE.EL == EL3 then if SCR.NS == '0' && CP15SDISABLE == HIGH then UNDEFINED; elsif SCR.NS == '0' && CP15SDISABLE2 == HIGH then UNDEFINED; else if SCR.NS == '0' then DACR_S = R[t]; else DACR_NS = R[t];


30/06/2021 09:39; 4f5dd962f4e34e1ac282f76da4d6e7fc4cab087e

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