CP15DMB, Data Memory Barrier System instruction

The CP15DMB characteristics are:

Purpose

Performs a Data Memory Barrier.

Arm deprecates any use of this operation, and strongly recommends that software use the DMB instruction instead.

Configuration

Attributes

CP15DMB is a 32-bit System instruction.

Field descriptions

CP15DMB ignores the value in the register specified by the instruction encoding. Software does not have to write a value to the register before issuing this instruction.

Executing the CP15DMB instruction

Accesses to this instruction use the following encodings:

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

opc1opc2CRncoprocCRm
0b0000b1010b01110b11110b1010

if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && SCTLR_EL1.CP15BEN == '0' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCTLR_EL2.CP15BEN == '0' then UNDEFINED; elsif ELUsingAArch32(EL1) && SCTLR.CP15BEN == '0' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && HSTR_EL2.T7 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T7 == '1' then AArch32.TakeHypTrapException(0x03); else CP15DMB(); elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T7 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T7 == '1' then AArch32.TakeHypTrapException(0x03); elsif ELUsingAArch32(EL1) && SCTLR.CP15BEN == '0' then UNDEFINED; else CP15DMB(); elsif PSTATE.EL == EL2 then if HSCTLR.CP15BEN == '0' then UNDEFINED; else CP15DMB(); elsif PSTATE.EL == EL3 then CP15DMB();




13/12/2018 16:42; 6379d01c197f1d40720d32d0f84c419c9187c009

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