Re: [RFC PATCH 02/34] ARM: mm: make 2-level pgd_t a scalar

"David Hildenbrand (Arm)" <[email protected]> Mon, 13 Jul 2026 18:26:16 +0200

Newsgroups	org.kernel.vger.linux-csky,dev.linux.lists.loongarch,org.infradead.lists.kvm-riscv,org.infradead.lists.linux-riscv,org.kernel.vger.linux-arch,org.kernel.vger.linux-kernel,org.kernel.vger.linux-m68k,org.kernel.vger.linux-mips,org.kernel.vger.linux-openrisc,org.kvack.linux-mm
Message-ID	<[email protected]>

>  * |        |
>  * +--------+
>  * |        |       +------------+ +0
>  * +- - - - +       | Linux pt 0 |
>  * |        |       +------------+ +1024
>  * +--------+ +0    | Linux pt 1 |
>  * |        |-----> +------------+ +2048
>  * +- - - - + +4    |  h/w pt 0  |
>  * |        |-----> +------------+ +3072
>  * +--------+ +8    |  h/w pt 1  |
>  * |        |       +------------+ +4096
>  *
> 
> So we interpret two 32bit entries as a pair (64bit value). Together they span
> 2x256 values.
> 
> Then we make PTRS_PER_PTE = 512, to iterate all of them (both pairs).
> 
> Let me do some more digging to come up with something I can confidentially

"with confidence", not confidentially :)

-- 
Cheers,

David