linux-kernel - Re: [tip: x86/urgent] x86/traps: Initialize DR7 by writing its architectural reset value

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Message-ID: <20250626090439.GBaF0NJ34n065_4vb-@fat_crate.local>
Date: Thu, 26 Jun 2025 11:04:39 +0200
From: Borislav Petkov <bp@...en8.de>
To: "Xin Li (Intel)" <xin@...or.com>
Cc: linux-kernel@...r.kernel.org, linux-tip-commits@...r.kernel.org,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin (Intel)" <hpa@...or.com>,
	Sohil Mehta <sohil.mehta@...el.com>,
	"Peter Zijlstra (Intel)" <peterz@...radead.org>,
	Sean Christopherson <seanjc@...gle.com>, stable@...r.kernel.org,
	x86@...nel.org
Subject: Re: [tip: x86/urgent] x86/traps: Initialize DR7 by writing its
 architectural reset value

On Tue, Jun 24, 2025 at 08:35:22PM -0000, tip-bot2 for Xin Li (Intel) wrote:
> The following commit has been merged into the x86/urgent branch of tip:
> 
> Commit-ID:     fa7d0f83c5c4223a01598876352473cb3d3bd4d7
> Gitweb:        https://git.kernel.org/tip/fa7d0f83c5c4223a01598876352473cb3d3bd4d7
> Author:        Xin Li (Intel) <xin@...or.com>
> AuthorDate:    Fri, 20 Jun 2025 16:15:04 -07:00
> Committer:     Dave Hansen <dave.hansen@...ux.intel.com>
> CommitterDate: Tue, 24 Jun 2025 13:15:52 -07:00
> 
> x86/traps: Initialize DR7 by writing its architectural reset value
> 
> Initialize DR7 by writing its architectural reset value to always set
> bit 10, which is reserved to '1', when "clearing" DR7 so as not to
> trigger unanticipated behavior if said bit is ever unreserved, e.g. as
> a feature enabling flag with inverted polarity.

OMG, who wrote that "text"? 

I asked AI to simplify it:

"Set DR7 to its standard reset value and always make sure bit 10 is set to 1.
This prevents unexpected issues if bit 10 later becomes a feature flag that is
active when cleared."

It sure does read better and I can understand what you're trying to say.

So can we *please* use simple, declarative sentences in our commit messages
and not perpetuate the SDM?

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette