[PATCH] arm64: add unlikely hint to MTE async fault check in el0_svc_common

[Will Deacon]

On Fri, Sep 19, 2025 at 11:33:27AM +0800, Li Qiang wrote:
> Add unlikely() hint to the _TIF_MTE_ASYNC_FAULT flag check in
> el0_svc_common() since asynchronous MTE faults are expected to be
> rare occurrences during normal system call execution.
> 
> This optimization helps the compiler to improve instruction caching
> and branch prediction for the common case where no asynchronous
> MTE faults are pending, while maintaining correct behavior for
> the exceptional case where such faults need to be handled prior
> to system call execution.
> 
> Signed-off-by: Li Qiang <liqiang01 at kylinos.cn>
> ---
>  arch/arm64/kernel/syscall.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Does this result in a measurable performance difference?

Will