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

Mike Rapoport <[email protected]> Sat, 30 May 2026 19:19:36 +0300
Newsgroups org.kernel.vger.linux-sh,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-hardening,org.kernel.vger.linux-kernel,org.kvack.linux-mm,org.ozlabs.lists.linuxppc-dev
Message-ID <[email protected]>
On Fri, May 29, 2026 at 05:02:03PM +0200, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <[email protected]>
> 
> 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 <[email protected]>
> Cc: Rich Felker <[email protected]>
> Cc: John Paul Adrian Glaubitz <[email protected]>
> Cc: Mike Rapoport <[email protected]>
> Cc: Geert Uytterhoeven <[email protected]>
> Signed-off-by: Ard Biesheuvel <[email protected]>

Acked-by: Mike Rapoport (Microsoft) <[email protected]>

> ---
>  arch/sh/mm/init.c | 3 ---
>  1 file changed, 3 deletions(-)

-- 
Sincerely yours,
Mike.