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DC IVAC, Data or unified Cache line Invalidate by VA to PoC

The DC IVAC characteristics are:

Purpose

Invalidate data cache by address to Point of Coherency.

When ARMv8.5-MemTag is implemented, this instruction might invalidate Allocation Tags from caches. When it invalidates Allocation Tags from caches, it also cleans them.

Configuration

AArch64 System instruction DC IVAC performs the same function as AArch32 System instruction DCIMVAC.

Attributes

DC IVAC is a 64-bit System instruction.

Field descriptions

The DC IVAC input value bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
Virtual address to use
Virtual address to use
313029282726252423222120191817161514131211109876543210

Bits [63:0]

Virtual address to use. No alignment restrictions apply to this VA.

Executing the DC IVAC instruction

When the instruction is executed, it can generate a watchpoint, which is prioritized in the same way as other watchpoints. If a watchpoint is generated, the CM bit in the ESR_ELx.ISS field is set to 1.

This instruction requires write access permission to the VA, otherwise it generates a Permission Fault, subject to the constraints described in 'Permission fault' in the Arm® Architecture Reference Manual, Armv8, for Armv8-A architecture profile.

Execution of this instruction might require an address translation from VA to PA, and that translation might fault. For more information, see 'The data cache maintenance instruction (DC)' in the Arm® Architecture Reference Manual, Armv8, for Armv8-A architecture profile.

Accesses to this instruction use the following encodings:

DC IVAC, <Xt>

op0op1CRnCRmop2
0b010b0000b01110b01100b001
if PSTATE.EL == EL0 then
    UNDEFINED;
elsif PSTATE.EL == EL1 then
    if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TPCP == '1' then
        AArch64.SystemAccessTrap(EL2, 0x18);
    elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<DC,VM> != '00' then
        DC_CIVAC(X[t]);
    else
        DC_IVAC(X[t]);
elsif PSTATE.EL == EL2 then
    DC_IVAC(X[t]);
elsif PSTATE.EL == EL3 then
    DC_IVAC(X[t]);
              


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