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Date: Mon, 13 Jul 2026 09:07:45 -0400
From: Eric Biggers <ebiggers@kernel.org>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: demiobenour@gmail.com, Russell King <linux@armlinux.org.uk>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-crypto@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v2] drivers/crypto: Mark QCE as BROKEN
Message-ID: <20260713130745.GA2254@quark>
References: <20260712-qce-broken-v2-1-b2dfff47f7f5@gmail.com>
 <2026071312-uncover-refining-8cac@gregkh>
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In-Reply-To: <2026071312-uncover-refining-8cac@gregkh>

On Mon, Jul 13, 2026 at 06:47:07AM +0200, Greg KH wrote:
> On Sun, Jul 12, 2026 at 05:31:31PM -0400, Demi Marie Obenour via B4 Relay wrote:
> > From: Demi Marie Obenour <demiobenour@gmail.com>
> > 
> > This driver is harmful:
> > 
> > - It is much slower than the CPU [1] [2].
> > - It Has a history of bugs [2] [3].
> > - It does not have exclusive access to the hardware [4], causing races
> >   with the secure world.
> > - It register its implementations with too low a cra_priority for them
> >   to be actually used [5].
> > 
> > Therefore, disable it to ensure that nobody builds it into kernels they
> > intend to ship.
> > 
> > In the future, the driver will be used for processing restricted media
> > content.  However, the kernel does not currently support this.  Since
> > the driver will have future uses, allow building it if COMPILE_TEST is
> > enabled.
> 
> Why not just delete it now, and then bring it back when it is needed in
> the future?  Otherwise this will just trip up the static code checkers
> who will attempt to "fix" things in it.

That makes sense to me, but Qualcomm pushed back on deletion:
https://lore.kernel.org/linux-crypto/20260602-qcom-qce-broken-v1-1-a4ef756089e0@oss.qualcomm.com/

But I've still not seen any evidence that this driver is useful for
anything or has any users.  Even Qualcomm seems to be unwilling to make
such claims; they only claim that the IP is used (i.e., not in Linux)
and that new features are planned.

- Eric