Re: [RFC V1 08/16] arm64/mm: Convert READ_ONCE() as pgdp_get() while accessing PGD

Anshuman Khandual
2026-04-10T05:30:32Z

On 08/04/26 5:49 PM, David Hildenbrand (Arm) wrote:
> On 2/24/26 06:11, Anshuman Khandual wrote:
>> Convert all READ_ONCE() based PGD accesses as pgdp_get() instead which will
>> support both D64 and D128 translation regime going forward.
>
> Please mention here why you move p4d_offset_phys/p4d_offset. (same
> applies to other patches)

Will do that.

>
> Do we get additional function calls that might degrade some page table
> walkers?

Sorry did not get it. Are you asking if D128 adds new page table
function paths thus increasing memory access latency etc ?

>
> Same comment regarding BUG_ON.
>

As mentioned earlier it might be better to have a separate change
converting similar BUG_ON() in various arm64 page table helpers.