Re: [PATCH v22 07/10] kernel: hibernate: Add an arch hook for preventing hiberation

[Suzuki K Poulose]

On 02/10/2026 12:03, Catalin Marinas wrote:
> On Fri, Oct 02, 2026 at 07:15:03AM +0100, Suzuki K Poulose wrote:
> > Add a hook to allow arch code disable hibernation. On arm64, with an RMM active,
> > there could be pages that are delegated to the "Realm" security state. Any
> > access to them are fatal (e.g., hibernate save image or restoring an image to
> > a delegated page). pKVM host also has its restrictions on enabling hibernation.
> >
> > Add a weak arch hook to let the architectures have a say.
> >
> > Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
> > Cc: Len Brown <lenb@xxxxxxxxxx>
> > Cc: Pavel Machek <pavel@xxxxxxxxxx>
> > Cc: linux-pm@xxxxxxxxxxxxxxx
> > Cc: Sudeep Holla <sudeep.holla@xxxxxxxxxx>
> > Suggested-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>
> Nit: the subject prefix for kernel/power/ usually is
>
> 	PM: hibernate: ....
>
> I can fix it locally, no need to respin (and probably the wrap the long
> lines in the commit log, we tend to keep them shorter).

Ack, I will take care of that in the future.


> > ---
> >   include/linux/suspend.h  | 1 +
> >   kernel/power/hibernate.c | 8 +++++++-
> >   2 files changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/linux/suspend.h b/include/linux/suspend.h
> > index b02876f1ae38a..a3815027773c5 100644
> > --- a/include/linux/suspend.h
> > +++ b/include/linux/suspend.h
> > @@ -401,6 +401,7 @@ int hibernate_quiet_exec(int (*func)(void *data), void *data);
> >   int hibernate_resume_nonboot_cpu_disable(void);
> >   int arch_hibernation_header_save(void *addr, unsigned int max_size);
> >   int arch_hibernation_header_restore(void *addr);
> > +bool arch_hibernation_available(void);
> >   
> >   #else /* CONFIG_HIBERNATION */
> >   static inline void register_nosave_region(unsigned long b, unsigned long e) {}
> > diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> > index d2479c69d71a4..9d9d53828542f 100644
> > --- a/kernel/power/hibernate.c
> > +++ b/kernel/power/hibernate.c
> > @@ -106,11 +106,17 @@ bool hibernation_in_progress(void)
> >   	return !atomic_read(&hibernate_atomic);
> >   }
> >   
> > +__weak bool arch_hibernation_available(void)
> > +{
> > +	return true;
> > +}
> > +
> >   bool hibernation_available(void)
> >   {
> >   	return nohibernate == 0 &&
> >   		!security_locked_down(LOCKDOWN_HIBERNATION) &&
> > -		!secretmem_active() && !cxl_mem_active();
> > +		!secretmem_active() && !cxl_mem_active() &&
> > +		arch_hibernation_available();
>
> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
>
> Raphael, any objection to this patch going in through the arm64 tree? It
> matches the style of other __weak functions in this file.

Thanks Catalin

Suzuki

> Thanks.