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From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Alexander Pateenok <pateenoc@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: Indirect call in vesafb driver
Date: Tue, 19 Mar 2019 16:46:51 +0000	[thread overview]
Message-ID: <20190319164651.4ec9e3d1@alans-desktop> (raw)
In-Reply-To: <20190313145418.bwta37cogo7a4qtt@K55DR>

On Wed, 13 Mar 2019 17:54:18 +0300
Alexander Pateenok <pateenoc@gmail.com> wrote:

> Hi,
> 
> There're several indirect calls in inline assembly in vesafb driver
> (drivers/video/fbdev/vesafb.c), and these calls cannot be automatically
> changed to retpolines. It's in vesafb_pan_display():
> 
>    73        __asm__ __volatile__(
>    74                "call *(%%edi)"
> 
> and in vesa_setpalette():
> 
>   113        __asm__ __volatile__(
>   114         "call *(%%esi)"
> 
> Is there need to use CALL_NOSPEC ?

Vesafb is from the time on the dinosaurs but yes any vesa bios code will
not be speculatively hardened. I'd also doubt anyone is actually using
vesafb in the first place but it should use nospec

Alan

  reply	other threads:[~2019-03-19 16:46 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-13 14:54 Indirect call in vesafb driver Alexander Pateenok
2019-03-19 16:46 ` Alan Cox [this message]
2019-03-20  8:26   ` Gerd Hoffmann

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