Re: [PATCH v3] RISC-V: Fix Maximum Physical Memory 2GiB option for 64bit systems

[Christoph Hellwig]

On Fri, Apr 05, 2019 at 05:49:34AM +0000, Anup Patel wrote:
> The Maximum Physical Memory 2GiB option for 64bit systems is currently
> broken because kernel hangs at boot-time when this option is enabled
> and the underlying system has more than 2GiB memory.
> 
> This issue can be easily reproduced on SiFive Unleashed board where
> we have 8GiB of memory.
> 
> This patch fixes above issue by removing unusable memory region in
> setup_bootmem().
> 
> Signed-off-by: Anup Patel <anup.patel@xxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>

Btw, what is the rationale behind even offering the 2GiB option and
the medlow model on 64-bit?  Do we reall have use cases where the
slightly more effient generated code matters so much to keep up
the support burden of this mostly unused and unusual configuration?