ICC_PMR, Interrupt Controller Interrupt Priority Mask Register
The ICC_PMR characteristics are:
Purpose
Provides an interrupt priority filter. Only interrupts with a higher priority than the value in this register are signaled to the PE.
Configuration
AArch32 System register ICC_PMR bits [31:0] are architecturally mapped to AArch64 System register ICC_PMR_EL1[31:0] .
This register is present only when AArch32 is supported at any Exception level. Otherwise, direct accesses to ICC_PMR are UNDEFINED.
To allow software to ensure appropriate observability of actions initiated by GIC register accesses, the PE and CPU interface logic must ensure that writes to this register are self-synchronising. This ensures that no interrupts below the written PMR value will be taken after a write to this register is architecturally executed. For more information, see 'Observability of the effects of accesses to the GIC registers' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).
Attributes
ICC_PMR is a 32-bit register.
Field descriptions
The ICC_PMR bit assignments are:
Bits [31:8]
Reserved, RES0.
Priority, bits [7:0]
The priority mask level for the CPU interface. If the priority of an interrupt is higher than the value indicated by this field, the interface signals the interrupt to the PE.
The possible priority field values are as follows:
Implemented priority bits | Possible priority field values | Number of priority levels |
---|---|---|
[7:0] | 0x00-0xFF (0-255), all values | 256 |
[7:1] | 0x00-0xFE (0-254), even values only | 128 |
[7:2] | 0x00-0xFC (0-252), in steps of 4 | 64 |
[7:3] | 0x00-0xF8 (0-248), in steps of 8 | 32 |
[7:4] | 0x00-0xF0 (0-240), in steps of 16 | 16 |
Unimplemented priority bits are RAZ/WI.
This field resets to 0.
Accessing the ICC_PMR
Accesses to this register use the following encodings:
MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}
coproc | opc1 | CRn | CRm | opc2 |
---|---|---|---|---|
0b1111 | 0b000 | 0b0100 | 0b0110 | 0b000 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then UNDEFINED; elsif Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.<IRQ,FIQ> == '11' 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 EL2Enabled() && !ELUsingAArch32(EL2) && ICH_HCR_EL2.TC == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && ICH_HCR.TC == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.FMO == '1' then return ICV_PMR; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.IMO == '1' then return ICV_PMR; elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.FMO == '1' then return ICV_PMR; elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.IMO == '1' then return ICV_PMR; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.<IRQ,FIQ> == '11' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch32.TakeMonitorTrapException(); else return ICC_PMR; elsif PSTATE.EL == EL2 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then UNDEFINED; elsif Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && ELUsingAArch32(EL3) && SCR.<IRQ,FIQ> == '11' then UNDEFINED; elsif ICC_HSRE.SRE == '0' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && SCR.<IRQ,FIQ> == '11' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch32.TakeMonitorTrapException(); else return ICC_PMR; elsif PSTATE.EL == EL3 then if ICC_MSRE.SRE == '0' then UNDEFINED; else return ICC_PMR;
MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}
coproc | opc1 | CRn | CRm | opc2 |
---|---|---|---|---|
0b1111 | 0b000 | 0b0100 | 0b0110 | 0b000 |
if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then UNDEFINED; elsif Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.<IRQ,FIQ> == '11' 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 EL2Enabled() && !ELUsingAArch32(EL2) && ICH_HCR_EL2.TC == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x03); elsif EL2Enabled() && ELUsingAArch32(EL2) && ICH_HCR.TC == '1' then AArch32.TakeHypTrapException(0x03); elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.FMO == '1' then ICV_PMR = R[t]; elsif EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.IMO == '1' then ICV_PMR = R[t]; elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.FMO == '1' then ICV_PMR = R[t]; elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.IMO == '1' then ICV_PMR = R[t]; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && PSTATE.M != M32_Monitor && SCR.<IRQ,FIQ> == '11' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch32.TakeMonitorTrapException(); else ICC_PMR = R[t]; elsif PSTATE.EL == EL2 then if Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && !ELUsingAArch32(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then UNDEFINED; elsif Halted() && HaveEL(EL3) && EDSCR.SDD == '1' && boolean IMPLEMENTATION_DEFINED "EL3 trap priority when SDD == '1'" && ELUsingAArch32(EL3) && SCR.<IRQ,FIQ> == '11' then UNDEFINED; elsif ICC_HSRE.SRE == '0' then UNDEFINED; elsif HaveEL(EL3) && !ELUsingAArch32(EL3) && SCR_EL3.<IRQ,FIQ> == '11' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch64.AArch32SystemAccessTrap(EL3, 0x03); elsif HaveEL(EL3) && ELUsingAArch32(EL3) && SCR.<IRQ,FIQ> == '11' then if Halted() && EDSCR.SDD == '1' then UNDEFINED; else AArch32.TakeMonitorTrapException(); else ICC_PMR = R[t]; elsif PSTATE.EL == EL3 then if ICC_MSRE.SRE == '0' then UNDEFINED; else ICC_PMR = R[t];