linux-kernel - Re: [PATCH RFC] arm64: improve display about CPU architecture in cpuinfo

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Date:   Mon, 07 Mar 2022 08:45:05 +0000
From:   Marc Zyngier <maz@...nel.org>
To:     Rongwei Wang <rongwei.wang@...ux.alibaba.com>
Cc:     catalin.marinas@....com, will@...nel.org, joey.gouly@....com,
        mark.rutland@....com, akpm@...ux-foundation.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC] arm64: improve display about CPU architecture in cpuinfo

On Mon, 07 Mar 2022 03:04:17 +0000,
Rongwei Wang <rongwei.wang@...ux.alibaba.com> wrote:
> 
> Now, it is unsuitable for both ARMv8 and ARMv9 to show a
> fixed string "CPU architecture: 8" in /proc/cpuinfo.

Please read the various threads that have been going on over the past
10+ years about *why* we don't allow this sort of change (TL;DR: it
breaks userspace, and we don't do that).

Also, there is no material difference between v8 and v9 that would be
observable from userspace outside of the "Features:" line. And if that
doesn't convince you, just think of '8' as the number of bytes used by
a virtual address. You can't make that a '9'. Yet.

	M.

-- 
Without deviation from the norm, progress is not possible.