DACR32

This is a collection of Intel®’ IA32® Software Developer's Manuals (URL of the day) and AMD' AMD64 Architecture Programmer's Manual together with the related specifications, application notes, white papers, and change logs. The collection aims to keep all available revisions. It was originally created by Michal Necasek, see OS/2 Museum.

If you have a public document, related to the IA32® specifications and missing from the collection, please mail it to me. The content of this URL and all sub-ULRs is available for convenient bulk download by rsync x86docs password "" (empty).

DACR32_EL2, Domain Access Control Register

Purpose

Allows access to the AArch32 DACR register from AArch64 state only. Its value has no effect on execution in AArch64 state.

Configuration

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

This register is present only when FEAT_AA32EL1 is implemented and FEAT_AA64 is implemented. Otherwise, direct accesses to DACR32_EL2 are UNDEFINED.

If EL2 is not implemented but EL3 is implemented, and EL1 is capable of using AArch32, then this register is not RES0.

Attributes

Field descriptions

Bits [63:32]

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 behavior of this field is:

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

Accessing DACR32_EL2

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

MRS <Xt>, DACR32_EL2

op0	op1	CRn	CRm	op2
0b11	0b100	0b0011	0b0000	0b000

if !(IsFeatureImplemented(FEAT_AA32EL1) && 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 X{64}(t) = DACR32_EL2(); elsif PSTATE.EL == EL3 then X{64}(t) = DACR32_EL2(); end;

MSR DACR32_EL2, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b100	0b0011	0b0000	0b000

if !(IsFeatureImplemented(FEAT_AA32EL1) && 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 DACR32_EL2() = X{64}(t); elsif PSTATE.EL == EL3 then DACR32_EL2() = X{64}(t); 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
D15		D14		D13		D12		D11		D10		D9		D8		D7		D6		D5		D4		D3		D2		D1		D0