Re: [PATCH 1/3] csky: Fixup arch_get_unmapped_area() implementation

[Christoph Hellwig]

> +/*
> + * We need to ensure that shared mappings are correctly aligned to
> + * avoid aliasing issues with VIPT caches.  We need to ensure that
> + * a specific page of an object is always mapped at a multiple of
> + * SHMLBA bytes.
> + *
> + * We unconditionally provide this function for all cases.
> + */

On something unrelated: If csky has virtually indexed caches you also
need to implement the flush_kernel_vmap_range and
invalidate_kernel_vmap_range functions to avoid data corruption when
doing I/O on vmalloc/vmap ranges.