IFAR, Instruction Fault Address Register

The IFAR characteristics are:

Purpose

Holds the virtual address of the faulting address that caused a synchronous Prefetch Abort exception.

This register is part of the Exception and fault handling registers functional group.

Configuration

AArch32 System register IFAR (NS) is architecturally mapped to AArch64 System register FAR_EL1[63:32] .

AArch32 System register IFAR (S) is architecturally mapped to AArch32 System register HIFAR when EL2 is implemented.

AArch32 System register IFAR (S) is architecturally mapped to AArch64 System register FAR_EL2[63:32] when EL2 is implemented.

RW fields in this register reset to architecturally UNKNOWN values.

Attributes

IFAR is a 32-bit register.

Field descriptions

The IFAR bit assignments are:

313029282726252423222120191817161514131211109876543210
VA of faulting address of synchronous Prefetch Abort exception

Bits [31:0]

VA of faulting address of synchronous Prefetch Abort exception.

Accessing the IFAR

This register can be read using MRC with the following syntax:

MRC <syntax>

This register can be written using MCR with the following syntax:

MCR <syntax>

This syntax uses the following encoding in the System instruction encoding space:

<syntax> opc1opc2CRncoprocCRm
p15, 0, <Rt>, c6, c0, 2000010011011110000

Accessibility

The register is accessible as follows:

Configuration Control Accessibility Instance
E2HTGENSEL0EL1EL2EL3
EL3 using AArch32xx0 - n/a n/a RWIFAR_s
EL3 not implemented xx0 - RW n/a n/a IFAR
EL3 not implemented x01 - RWRW n/a IFAR
EL3 not implemented x11 - n/a RW n/a IFAR
EL3 using AArch64xx0 - RW n/a n/a IFAR
EL3 using AArch64x01 - RWRW n/a IFAR
EL3 using AArch64x11 - n/a RW n/a IFAR
EL3 using AArch32x01 - RWRWRWIFAR_ns
EL3 using AArch32x11 - n/a RWRWIFAR_ns

This table applies to all instructions that can access this register.

Traps and enables

For a description of the prioritization of any generated exceptions, see section G1.11.2 (Exception priority order) in the ARM® Architecture Reference Manual, ARMv8, for ARMv8-A architecture profile for exceptions taken to AArch32 state, and section D1.13.2 (Synchronous exception prioritization) for exceptions taken to AArch64 state. Subject to the prioritization rules, the following traps and enables are applicable when accessing this register.

When EL2 is implemented and is using AArch64 and SCR_EL3.NS==1 && HCR_EL2.E2H==0 :

When EL2 is implemented and is using AArch64 and SCR_EL3.NS==1 && HCR_EL2.E2H==1 && HCR_EL2.TGE==0 :

When EL2 is implemented and is using AArch32 and SCR_EL3.NS==1 :




18/04/2017 17:00

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