[PATCH v6 13/15] sh: cast away constness from the zero page when flushing it from the cache

[Geert Uytterhoeven]

On Tue, 26 May 2026 at 20:05, Ard Biesheuvel <ardb+git at google.com> wrote:
> From: Ard Biesheuvel <ardb at kernel.org>
>
> SH performs cache maintenance on the zero page during boot, presumably
> to ensure that any clearing of BSS that has occurred at startup is
> visible to other CPUs and DMA devices.
>
> The __flush_wback_region() function takes a void* argument, which is
> conceptually sound, but given that empty_zero_page[] must never be
> modified, it is being repainted as const, making it incompatible with a
> void* formal parameter.
>
> Given the above, and the fact that __flush_wback_region() is in fact a
> function pointer variable with multiple implementations, take the easy
> way out, and cast away the constness in this particular invocation.
>
> Cc: Yoshinori Sato <ysato at users.sourceforge.jp>
> Cc: Rich Felker <dalias at libc.org>
> Cc: John Paul Adrian Glaubitz <glaubitz at physik.fu-berlin.de>
> Signed-off-by: Ard Biesheuvel <ardb at kernel.org>

Reviewed-by: Geert Uytterhoeven <geert+renesas at glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

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