DC CGVAC, Data, Allocation Tag or unified Cache line Clean of Allocation Tags by VA to PoC
The DC CGVAC characteristics are:
Purpose
Clean Allocation Tags in data cache by address to Point of Coherency.
Configuration
This instruction is present only when ARMv8.5-MemTag is implemented. Otherwise, direct accesses to DC CGVAC are UNDEFINED.
Attributes
DC CGVAC is a 64-bit System instruction.
Field descriptions
The DC CGVAC input value bit assignments are:
| 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 |
| Virtual address to use | |||||||||||||||||||||||||||||||
| Virtual address to use | |||||||||||||||||||||||||||||||
| 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 |
Bits [63:0]
Virtual address to use. No alignment restrictions apply to this VA.
Executing the DC CGVAC instruction
If EL0 access is enabled, when executed at EL0, this instruction requires read access permission to the VA, otherwise it generates a Permission Fault, subject to the constraints described in 'Permission fault'.
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)'.
Accesses to this instruction use the following encodings:
DC CGVAC, <Xt>
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b01 | 0b011 | 0b0111 | 0b1010 | 0b011 |
if PSTATE.EL == EL0 then
if !ELUsingAArch32(EL1) && !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && SCTLR_EL1.UCI == '0' then
if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
else
AArch64.SystemAccessTrap(EL1, 0x18);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> != '11' && HCR_EL2.TPCP == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
elsif EL2Enabled() && !ELUsingAArch32(EL1) && HCR_EL2.<E2H,TGE> != '11' && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGITR_EL2.DCCVAC == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.<E2H,TGE> == '11' && SCTLR_EL2.UCI == '0' then
AArch64.SystemAccessTrap(EL2, 0x18);
else
DC_CGVAC(X[t]);
elsif PSTATE.EL == EL1 then
if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TPCP == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
elsif EL2Enabled() && !ELUsingAArch32(EL2) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGITR_EL2.DCCVAC == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
else
DC_CGVAC(X[t]);
elsif PSTATE.EL == EL2 then
DC_CGVAC(X[t]);
elsif PSTATE.EL == EL3 then
DC_CGVAC(X[t]);