[PATCH 8/8] arm64: irq: allow FIQs to be handled

[Joey Gouly]

Hi Mark,

On Fri, Feb 19, 2021 at 11:39:04AM +0000, Mark Rutland wrote:
> On contemporary platforms we don't use FIQ, and treat any stray FIQ as a
> fatal event. However, some platforms have an interrupt controller wired
> to FIQ, and need to handle FIQ as part of regular operation.
> 

[...]

> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index 0474cca9f1a9..a8290bd87a49 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -586,23 +586,23 @@ SYM_CODE_START(vectors)
>  
>  	kernel_ventry	1, sync				// Synchronous EL1h
>  	kernel_ventry	1, irq				// IRQ EL1h
> -	kernel_ventry	1, fiq_invalid			// FIQ EL1h
> +	kernel_ventry	1, fiq				// FIQ EL1h
>  	kernel_ventry	1, error			// Error EL1h
>  
>  	kernel_ventry	0, sync				// Synchronous 64-bit EL0
>  	kernel_ventry	0, irq				// IRQ 64-bit EL0
> -	kernel_ventry	0, fiq_invalid			// FIQ 64-bit EL0
> +	kernel_ventry	0, fiq				// FIQ 64-bit EL0
>  	kernel_ventry	0, error			// Error 64-bit EL0
>  
>  #ifdef CONFIG_COMPAT
>  	kernel_ventry	0, sync_compat, 32		// Synchronous 32-bit EL0
>  	kernel_ventry	0, irq_compat, 32		// IRQ 32-bit EL0
> -	kernel_ventry	0, fiq_invalid_compat, 32	// FIQ 32-bit EL0
> +	kernel_ventry	0, fiq_compat, 32		// FIQ 32-bit EL0
>  	kernel_ventry	0, error_compat, 32		// Error 32-bit EL0
>  #else
>  	kernel_ventry	0, sync_invalid, 32		// Synchronous 32-bit EL0
>  	kernel_ventry	0, irq_invalid, 32		// IRQ 32-bit EL0
> -	kernel_ventry	0, fiq_invalid, 32		// FIQ 32-bit EL0
> +	kernel_ventry	0, fiq, 32			// FIQ 32-bit EL0
>  	kernel_ventry	0, error_invalid, 32		// Error 32-bit EL0
>  #endif
>  SYM_CODE_END(vectors)

I believe you can now remove functions `el0_fiq_invalid` and `el0_fiq_invalid_compat`.
`el1_fiq_invalid` is still used by Synchronous EL1t, so can't be removed.

Thanks,
Joey