Re: [PATCH] clocksource: arch_timer: Fix arm64 platforms not booting

[Daniel Lezcano]

On 12/29/2014 08:13 PM, Mark Rutland wrote:
> [Adding Arnd]
>
> On Mon, Dec 29, 2014 at 08:35:09AM +0000, Christoffer Dall wrote:
> > On Sun, Dec 28, 2014 at 09:46:20PM +0000, Marc Zyngier wrote:
> > > On 2014-12-28 14:20, Christoffer Dall wrote:
> > > > Commit 0b46b8a718c6e ("clocksource: arch_timer: Fix code to...")
> > > > fixes
> > > > timer issues with certain ARMv7 platforms, but unfortunately breaks
> > > > arm64 platforms with hyp mode (EL2) enabled.
> > > >
> > > > The commit only sets arch_timer_use_virtual to false under
> > > > CONFIG_ARM,
> > > > but forgets that the config variable is also set in other code paths
> > > > (actually, right underneath the check in the patch) with detrimental
> > > > consequences as we've now introduced a direct early call to BUG() on
> > > > practically all arm64 platforms.
> > > >
> > > > One could argue that this code could be refactored to use different
> > > > variables for checking which *timer* to use and which *counter* to
> > > > use,
> > > > which seems to be the desired difference between ARM and arm64 in
> > > > this
> > > > case, but this approach fixes an urgent issue for now.
> > > >
> > > > Cc: Sonny Rao <sonnyrao@xxxxxxxxxxxx>
> > > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> > > > Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> > > > Cc: Olof Johansson <olof@xxxxxxxxx>
> > > > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> > > > Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
> > > > Cc: Yingjoe Chen <yingjoe.chen@xxxxxxxxxxxx>
> > > > Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
> > > > ---
> > > > This was apparently already discovered by Yingjoe Chen in this thread
> > > > https://lkml.org/lkml/2014/11/24/41 and Catalin recommended a similar
> > > > fix.
> > >
> > > I'm increasingly worried about the time it takes to get such critical
> > > fixes into the tree (arm64 is *dead* without it).
> > >
> > > What is holding this patch which, as far as I remember, has been posted
> > > by Catalin almost three weeks ago?
> > I didn't find that since I didn't think I'd have to go back that long on
> > lakml for something that breaks boot of an entire architecture.  Sorry
> > for the confusion of a second patch, but fwiw, I now spent another few
> > hours bisecting this, so I would really like to see this fix go into
> > mainline ASAP as well to save others the trouble.
>
> Last I knew, Arnd was going to take the fix [1], which has been in
> arm-soc's for-next and fixes branches for almost two weeks now. It
> didn't make it into the last pull req due to some confusion over who was
> going to take it.

I asked arm-soc team to take the fix because it was depending on a patch 
which was already in their tree [1].

Merry Christmas

  -- Daniel

[1] http://www.spinics.net/lists/arm-kernel/msg385704.html

> Arnd, what's the plan for getting this into mainline ASAP?
>
> Mark.
>
> [1] https://git.kernel.org/cgit/linux/kernel/git/arm/arm-soc.git/commit/?h=fixes&id=d6ad36913083d683aad4e02e53580c995f1a6ede


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