ARM64: hibernation: How to use hibernation/suspend-to-disk on ARMv8?

ARM64: hibernation: How to use hibernation/suspend-to-disk on ARMv8?

[George Bush]

Hi all

I notice we have hibernation.c in arm/kernel, however, I don't find it in arm64.
Does it mean arm64 do not support hibernation/suspend-to-disk function?

I tried some path to search the reason, but found nothing, they all say arm64
has the backward compatibility. So I send this email to the community and
hope to get the reason.
Thanks!

I ported the arm hibernation.c to arm64/kernel(with LP64), but failed in a
strange way. When I do resume, the arch_restore_image() get a page_fault
when it calls the copy_page(), like:
"Unable to handle kernel paging request at virtual address 0xffffffbc055c3fa8"
I'm sure the copy_page()'s parameters is in the memory area, why and how
I get the strange address 0xffffffbc055c3fa8?

vmalloc:         0xffffff8000000000 - 0xffffffbb00000000
vmemmap:     0xffffffbc01400000 - 0xffffffbc04f88000
modules:       0xffffffbffc000000   -  0xffffffc000000000
memory:        0xffffffc000000000 - 0xffffffc0be800000


Look forward to your reply, thanks!

ARM64: hibernation: How to use hibernation/suspend-to-disk on ARMv8?

[Amit Kucheria]

(Fixing Sebastian's email address)

On Sat, Jan 10, 2015 at 8:44 PM, George Bush <georgebush815@gmail.com> wrote:
> Hi all
>
> I notice we have hibernation.c in arm/kernel, however, I don't find it in arm64.
> Does it mean arm64 do not support hibernation/suspend-to-disk function?

Correct. arm64 is a separate architecture and will need to implement
something similar to SHA 603fb42a66499ab353466c7afa3d38beea20a8a9.

> I tried some path to search the reason, but found nothing, they all say arm64
> has the backward compatibility. So I send this email to the community and
> hope to get the reason.
> Thanks!
>
> I ported the arm hibernation.c to arm64/kernel(with LP64), but failed in a
> strange way. When I do resume, the arch_restore_image() get a page_fault
> when it calls the copy_page(), like:

I'm afraid I can't help with the memory management aspects of arm64
but you've cc'ed the right people who'd know.

> "Unable to handle kernel paging request at virtual address 0xffffffbc055c3fa8"
> I'm sure the copy_page()'s parameters is in the memory area, why and how
> I get the strange address 0xffffffbc055c3fa8?
>
> vmalloc:         0xffffff8000000000 - 0xffffffbb00000000
> vmemmap:     0xffffffbc01400000 - 0xffffffbc04f88000
> modules:       0xffffffbffc000000   -  0xffffffc000000000
> memory:        0xffffffc000000000 - 0xffffffc0be800000
>

ARM64: hibernation: How to use hibernation/suspend-to-disk on ARMv8?

[Lorenzo Pieralisi]

On Sat, Jan 10, 2015 at 03:14:33PM +0000, George Bush wrote:
> Hi all
> 
> I notice we have hibernation.c in arm/kernel, however, I don't find it in arm64.
> Does it mean arm64 do not support hibernation/suspend-to-disk function?

Yes, not at the moment, but we have planned to implement it.

> I tried some path to search the reason, but found nothing, they all say arm64
> has the backward compatibility. So I send this email to the community and
> hope to get the reason.
> Thanks!
> 
> I ported the arm hibernation.c to arm64/kernel(with LP64), but failed in a
> strange way. When I do resume, the arch_restore_image() get a page_fault
> when it calls the copy_page(), like:
> "Unable to handle kernel paging request at virtual address 0xffffffbc055c3fa8"
> I'm sure the copy_page()'s parameters is in the memory area, why and how
> I get the strange address 0xffffffbc055c3fa8?
> 
> vmalloc:         0xffffff8000000000 - 0xffffffbb00000000
> vmemmap:     0xffffffbc01400000 - 0xffffffbc04f88000
> modules:       0xffffffbffc000000   -  0xffffffc000000000
> memory:        0xffffffc000000000 - 0xffffffc0be800000
> 
> 
> Look forward to your reply, thanks!

We need your patch, kernel version, config file, your board/SoC HW details
before even assuming what is happening. Please provide them and I
am happy to help you implement suspend-to-disk on arm64 properly.

Thanks,
Lorenzo