[PATCH 3/5] ARM: Disable FAST_GUP on PREEMPT_RT if HIGHPTE is also enabled.

[Arnd Bergmann]

On Wed, Oct 29, 2025, at 16:59, Sebastian Andrzej Siewior wrote:
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -105,7 +105,7 @@ config ARM
>  	select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
>  	select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU
>  	select HAVE_EXIT_THREAD
> -	select HAVE_GUP_FAST if ARM_LPAE
> +	select HAVE_GUP_FAST if ARM_LPAE && !(PREEMPT_RT && HIGHPTE)
>  	select HAVE_FUNCTION_ERROR_INJECTION
>  	select HAVE_FUNCTION_GRAPH_TRACER
>  	select HAVE_FUNCTION_GRAPH_FREGS

I would still prefer the version I posted previous at

https://lore.kernel.org/all/20241210160556.2341497-3-arnd@kernel.org/

disabling HIGHPTE when PREEMPT_RT is enabled.

     Arnd