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

[Suzuki K Poulose <suzuki.poulose@arm.com>]

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@kernel.org>
>> Cc: Len Brown <lenb@kernel.org>
>> Cc: Pavel Machek <pavel@kernel.org>
>> Cc: linux-pm@vger.kernel.org
>> Cc: Sudeep Holla <sudeep.holla@kernel.org>
>> Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> 
> 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@arm.com>
> 
> 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.
>