linux-kernel - Re: [PATCH V3] arm64/mm: Define PTDESC

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Message-Id: <174197745246.735540.15365076503205188211.b4-ty@arm.com>
Date: Fri, 14 Mar 2025 18:37:39 +0000
From: Catalin Marinas <catalin.marinas@....com>
To: linux-arm-kernel@...ts.infradead.org,
	Anshuman Khandual <anshuman.khandual@....com>
Cc: Will Deacon <will@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Andrey Ryabinin <ryabinin.a.a@...il.com>,
	Alexander Potapenko <glider@...gle.com>,
	Andrey Konovalov <andreyknvl@...il.com>,
	Dmitry Vyukov <dvyukov@...gle.com>,
	Ard Biesheuvel <ardb@...nel.org>,
	Ryan Roberts <ryan.roberts@....com>,
	linux-kernel@...r.kernel.org,
	kasan-dev@...glegroups.com
Subject: Re: [PATCH V3] arm64/mm: Define PTDESC_ORDER

On Tue, 11 Mar 2025 10:27:10 +0530, Anshuman Khandual wrote:
> Address bytes shifted with a single 64 bit page table entry (any page table
> level) has been always hard coded as 3 (aka 2^3 = 8). Although intuitive it
> is not very readable or easy to reason about. Besides it is going to change
> with D128, where each 128 bit page table entry will shift address bytes by
> 4 (aka 2^4 = 16) instead.
> 
> Let's just formalise this address bytes shift value into a new macro called
> PTDESC_ORDER establishing a logical abstraction, thus improving readability
> as well. While here re-organize EARLY_LEVEL macro along with its dependents
> for better clarity. This does not cause any functional change. Also replace
> all (PAGE_SHIFT - PTDESC_ORDER) instances with PTDESC_TABLE_SHIFT.
> 
> [...]

Applied to arm64 (for-next/pgtable-cleanups), thanks!

[1/1] arm64/mm: Define PTDESC_ORDER
      https://git.kernel.org/arm64/c/51ecb29f7a65

-- 
Catalin