linux-kernel - Re: Fix built-in early-load Intel microcode alignment

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Date:   Wed, 15 Jan 2020 02:27:05 +0000
From:   Luis Chamberlain <mcgrof@...nel.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Jari Ruusu <jari.ruusu@...il.com>, Borislav Petkov <bp@...en8.de>,
        Fenghua Yu <fenghua.yu@...el.com>, johannes.berg@...el.com,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        stable <stable@...r.kernel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Ohad Ben-Cohen <ohad@...ery.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        linux-remoteproc@...r.kernel.org
Subject: Re: Fix built-in early-load Intel microcode alignment

On Mon, Jan 13, 2020 at 11:44:25AM -0800, Linus Torvalds wrote:
> On Mon, Jan 13, 2020 at 7:47 AM Luis Chamberlain <mcgrof@...nel.org> wrote:
> >
> > So I'd like to determine first if we really need this. Then if so,
> > either add a new global config option, and worst comes to worst
> > figure out a way to do it per driver. I don't think we'd need it
> > per driver.
> 
> I really don't think we need to have a config option for some small
> alignment. Increasing the alignment unconditionally to 16 bytes won't
> hurt anybody.

Since you are confident in that, then simply bumping it to 16 bytes
seems fine by me.

> Now, whether there might be other firmware loaders that need even more
> alignment, that might be an interesting question, and if such an
> alignment would be _huge_ we might want to worry about actual memory
> waste.

I can only envision waste being considered due to alignent for remote
proc folks, who I *doubt* use the built-in stuff given the large size of
their blobs... but since you never know, better poke. So I've CC'd them.

> But 16-byte alignment for a fw blob? That's nothing.

Fine by me if we are sure it won't break anything and we hear no
complaints by remote proc folks.

  Luis