linux-kernel - Re: [PATCH 0/5] replace magic numbers in GDT descriptors

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Message-ID: <ZYK66eEcRgdPOeWa@gmail.com>
Date: Wed, 20 Dec 2023 10:59:05 +0100
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...uxfoundation.org>
Cc: Vegard Nossum <vegard.nossum@...cle.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
	Brian Gerst <brgerst@...il.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 0/5] replace magic numbers in GDT descriptors


* Linus Torvalds <torvalds@...uxfoundation.org> wrote:

> On Tue, 19 Dec 2023 at 07:12, Vegard Nossum <vegard.nossum@...cle.com> wrote:
> >
> > Vegard Nossum (5):
> >   x86: provide new infrastructure for GDT descriptors
> >   x86: replace magic numbers in GDT descriptors, part 1
> >   x86: replace magic numbers in GDT descriptors, part 2
> >   x86: always set A (accessed) flag in GDT descriptors
> >   x86: add DB flag to 32-bit percpu GDT entry
> 
> All these patches look fine to me, but I will again leave it to the
> x86 maintainers whether they want to apply them. But feel free to add
> my Ack if y ou do.

Thanks - I've applied your acks. These are obviously useful cleanups,
so no objections whatsoever.

> The end result does look a *lot* more legible, with something like
> 
>    DESC_DATA64 | DESC_USER
> 
> instead of just a raw number like 0xc0f3.
>
> So while this is unlikely to be a maintenance burden (since we look at
> these things so seldom, and they never really change), I think it's a
> nice readability improvement.

Yeah, absolutely.

> The fact that Vegard found two oddities while doing this series just
> reinforces that readability issue. Neither of them were bugs, but they
> were odd inconsistencies.

Indeed ...

Thanks,

	Ingo