Re: [PATCH v7 12/15] sh: Drop cache flush of the zero page at boot

[Geert Uytterhoeven]

On Fri, 29 May 2026 at 17:02, Ard Biesheuvel <ardb+git@xxxxxxxxxx> wrote:
> From: Ard Biesheuvel <ardb@xxxxxxxxxx>
>
> SuperH performs cache maintenance on the zero page during boot,
> presumably because before commit
>
>   6215d9f4470f ("arch, mm: consolidate empty_zero_page")
>
> the zero page did double duty as a boot params region, and was cleared
> separately, as it was not part of BSS. The memset() in question was
> dropped by that commit, but the __flush_wback_region() call remained.
>
> As empty_zero_page[] has been moved to BSS, it can be treated as any
> other BSS memory, and so the cache flush can be dropped.
>
> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
> Cc: Rich Felker <dalias@xxxxxxxx>
> Cc: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx>
> Cc: Mike Rapoport <rppt@xxxxxxxxxx>
> Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>

Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds