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

"Arnd Bergmann" <[email protected]> Mon, 13 Jul 2026 17:38:53 +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]>

On Mon, Jul 13, 2026, at 15:55, Yeoreum Yun wrote:
> From: "David Hildenbrand (Arm)" <[email protected]>
>
> We don't want pgd_t to be an array, as it prohibits returning it from a
> function, like pgdp_get().

What should pgdp_get() return on ARM 2-stage page tables then?
Does it return just the first entry or concatenate the two?

> +typedef u64 pgdval_t;

> +static inline pmdval_t pgd_val(pgd_t pgd)
> +{
> +	return (*(pmdval_t (*)[2])&pgd)[0];
> +}

This could use a comment to explain what this actually
returns and why the second entry is discarded.

      Arnd