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

[Mark Rutland]

[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 at chromium.org>
> > >Cc: Catalin Marinas <catalin.marinas at arm.com>
> > >Cc: Daniel Lezcano <daniel.lezcano at linaro.org>
> > >Cc: Olof Johansson <olof at lixom.net>
> > >Cc: Mark Rutland <mark.rutland at arm.com>
> > >Cc: Catalin Marinas <catalin.marinas at arm.com>
> > >Cc: Marc Zyngier <marc.zyngier at arm.com>
> > >Cc: Yingjoe Chen <yingjoe.chen at mediatek.com>
> > >Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
> > >---
> > >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.

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