Re: [PATCH] sh: fix fallout from ZERO_PAGE consolidation

[John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>]

Hi Mike,

On Fri, 2026-04-17 at 12:56 +0200, John Paul Adrian Glaubitz wrote:
> On Fri, 2026-04-17 at 13:32 +0300, Mike Rapoport wrote:
> > From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> > 
> > Consolidation of empty_zero_page declarations broke boot on sh.
> > 
> > sh stores its initial boot parameters in a page reserved in
> > arch/sh/kernel/head_32.S. Before commit 6215d9f4470f ("arch, mm:
> > consolidate empty_zero_page") this page was referenced in C code as an
> > array and after that commit it is referenced as a pointer.
> > 
> > This causes wrong code generation and boot hang.
> > 
> > Declare boot_params_page as an array to fix the issue.
> > 
> > Reported-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> > Tested-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> > Fixes: 6215d9f4470f ("arch, mm: consolidate empty_zero_page")
> > Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> > ---
> >  arch/sh/include/asm/setup.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/sh/include/asm/setup.h b/arch/sh/include/asm/setup.h
> > index 63c9efc06348..8488f76b48b4 100644
> > --- a/arch/sh/include/asm/setup.h
> > +++ b/arch/sh/include/asm/setup.h
> > @@ -7,7 +7,7 @@
> >  /*
> >   * This is set up by the setup-routine at boot-time
> >   */
> > -extern unsigned char *boot_params_page;
> > +extern unsigned char boot_params_page[];
> >  #define PARAM boot_params_page
> >  
> >  #define MOUNT_ROOT_RDONLY (*(unsigned long *) (PARAM+0x000))
> > 
> > base-commit: 43cfbdda5af60ffc6272a7b8c5c37d1d0a181ca9
> 
> Thanks, I'll try to test this patch this weekend and will pick it up for v7.1.
> I have already collected a number of patches for v7.1 with my Reviewed-by.

I just realized that this patch actually depends on 6215d9f4470f ("arch, mm:
consolidate empty_zero_page"), so I cannot take it directly into my tree now.

Shall we wait for v7.0-rc1 then, so I can pick it up as a regression fix?

Thanks,
Adrian

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