[PATCH] sh: fix fallout from ZERO_PAGE consolidation

[PATCH] sh: fix fallout from ZERO_PAGE consolidation

[Mike Rapoport]

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
-- 
2.53.0

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

[John Paul Adrian Glaubitz]

Hi Mike,

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.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

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

[John Paul Adrian Glaubitz]

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

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

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

[Mike Rapoport]

Hi Adrian,

On Sat, Apr 18, 2026 at 10:33:56AM +0200, John Paul Adrian Glaubitz wrote:
> On Fri, 2026-04-17 at 12:56 +0200, John Paul Adrian Glaubitz wrote:
> > > 
> > > 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?
 
Or we can ask Andrew to pick it via mm tree.

> Thanks,
> Adrian

-- 
Sincerely yours,
Mike.

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

[John Paul Adrian Glaubitz]

Hi Mike,

On Sat, 2026-04-18 at 13:34 +0300, Mike Rapoport wrote:
> Hi Adrian,
> 
> On Sat, Apr 18, 2026 at 10:33:56AM +0200, John Paul Adrian Glaubitz wrote:
> > On Fri, 2026-04-17 at 12:56 +0200, John Paul Adrian Glaubitz wrote:
> > > > 
> > > > 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?
>  
> Or we can ask Andrew to pick it via mm tree.

Let me take it for v7.0-rc2, so I can take more time for testing the patch.

Thanks,
Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

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

[Artur Rojek]

On 2026-04-17 12:32, 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>

I confirm this fixes boot issues on SEGA Dreamcast (sh4).

Tested-by: Artur Rojek <contact@artur-rojek.eu>

> ---
>  arch/sh/include/asm/setup.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> 
> base-commit: 43cfbdda5af60ffc6272a7b8c5c37d1d0a181ca9
> 
> 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))