[PATCH V2 0/2] kexec-tools: arm64: Enable D-cache in purgatory

[panand@redhat.com (Pratyush Anand)]

Hi James and All,

Any feedback/review comment on it?

~Pratyush

On Monday 19 December 2016 12:43 PM, Pratyush Anand wrote:
> It takes more that 2 minutes to verify SHA in purgatory when vmlinuz image
> is around 13MB and initramfs is around 30MB. It takes more than 20 second
> even when we have -O2 optimization enabled. However, if dcache is enabled
> during purgatory execution then, it takes just a second in SHA
> verification.
>
> Therefore, these patches adds support for dcache enabling facility during
> purgatory execution.
>
> Although I have simplified the logic a bit now, however I understand that
> there are reservations for introducing this complexity for gaining few
> seconding of execution time during kexec or crash reboot.  But, I believe
> if d-cache enabling code is stable enough then there should not be any
> hindrances to accept it. So, please give it a try with your platform and
> let me know if you see any issue or it does not work. I am still open to
> improve it further if needed.
>
> Changes since V1:
> 	- Moved page table creation logic from purgatory to kexec code.
> 	- Only 4K page table is supported, with 48 bit VA and 2M block size
> 	- if platform supports a 4K page size, then D-cache is always
> 	  enabled now.
>
> Pratyush Anand (2):
>   kexec: arm64: create identity page table to be used in purgatory
>   arm64: enable d-cache support during purgatory sha verification
>
>  kexec/arch/arm64/kexec-arm64.c         | 152 ++++++++++++++++++
>  purgatory/arch/arm64/Makefile          |   1 +
>  purgatory/arch/arm64/cache.S           | 281 +++++++++++++++++++++++++++++++++
>  purgatory/arch/arm64/purgatory-arm64.c |   5 +
>  4 files changed, 439 insertions(+)
>  create mode 100644 purgatory/arch/arm64/cache.S
>