ICC_EOIR0

A PE writes to this register to inform the CPU interface that it has completed the processing of the specified Group 0 interrupt.

Configuration

AArch32 System register ICC_EOIR0 performs the same function as AArch64 System register ICC_EOIR0_EL1.

This register is present only when EL1 is capable of using AArch32 and GICv3 is implemented. Otherwise, direct accesses to ICC_EOIR0 are UNDEFINED.

Attributes

Field descriptions

Bits [31:24]

INTID, bits [23:0]

The INTID from the corresponding ICC_IAR0 access.

This field has either 16 or 24 bits implemented. The number of implemented bits can be found in ICC_CTLR.IDbits and ICC_MCTLR.IDbits. If only 16 bits are implemented, bits [23:16] of this register are RES0.

If the EOImode bit for the current Exception level and Security state is 0, a write to this register drops the priority for the interrupt, and also deactivates the interrupt.

If the EOImode bit for the current Exception level and Security state is 1, a write to this register only drops the priority for the interrupt. Software must write to ICC_DIR to deactivate the interrupt.

The appropriate EOImode bit varies as follows:

If EL3 is not implemented, the appropriate bit is ICC_CTLR.EOImode.
If EL3 is implemented and the software is executing in Monitor mode, the appropriate bit is ICC_MCTLR.EOImode_EL3.
If EL3 is implemented and the software is not executing in Monitor mode, the bit depends on the current Security state:
- If the software is executing in Secure state, the bit is ICC_CTLR.EOImode in the Secure instance of ICC_CTLR. This is an alias of ICC_MCTLR.EOImode_EL1S.
- If the software is executing in Non-secure state, the bit is ICC_CTLR.EOImode in the Non-secure instance of ICC_CTLR. This is an alias of ICC_MCTLR.EOImode_EL1NS.

Accessing ICC_EOIR0

A write to this register must correspond to the most recent valid read by this PE from an Interrupt Acknowledge Register, and must correspond to the INTID that was read from ICC_IAR0, otherwise the system behavior is UNPREDICTABLE. A valid read is a read that returns a valid INTID that is not a special INTID.

A write of a Special INTID is ignored. For more information, see 'Special INTIDs' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).

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

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

coproc	opc1	CRn	CRm	opc2
0b1111	0b000	0b1100	0b1000	0b001

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && SCR_EL3.FIQ == '1' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.FIQ == '1' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HSTR_EL2.T12 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && HSTR.T12 == '1' then AArch32.TakeHypTrapException(0x03); elsif ICC_SRE.SRE == '0' then UNDEFINED; elsif EL2Enabled() && !ELUsingAArch32(EL2) && ICH_HCR_EL2.TALL0 == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && ICH_HCR.TALL0 == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.FMO == '1' then ICV_EOIR0 = R[t]; elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.FMO == '1' then ICV_EOIR0 = R[t]; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.FIQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.FIQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch32.TakeMonitorTrapException(); else ICC_EOIR0 = R[t]; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && !ELUsingAArch32(EL3) && SCR_EL3.FIQ == '1' then UNDEFINED; elsif HaveEL(EL3) && EL3SDDUndefPriority() && ELUsingAArch32(EL3) && SCR.FIQ == '1' then UNDEFINED; elsif ICC_HSRE.SRE == '0' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.FIQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && SCR.FIQ == '1' then if EL3SDDUndef() then UNDEFINED; else AArch32.TakeMonitorTrapException(); else ICC_EOIR0 = R[t]; elsif PSTATE.EL == EL3 then if ICC_MSRE.SRE == '0' then UNDEFINED; else ICC_EOIR0 = R[t];

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								INTID

ICC_EOIR0, Interrupt Controller End Of Interrupt Register 0