lkml.org 
[lkml]   [2018]   [Nov]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH 01/13] arm: Fix mutual exclusion in arch_gettimeoffset
On Tue, Nov 13, 2018 at 02:39:00PM +1100, Finn Thain wrote:
> On Mon, 12 Nov 2018, Christoph Hellwig wrote:
>
> > On Mon, Nov 12, 2018 at 03:12:39PM +1100, Finn Thain wrote:
> > > Implementations of arch_gettimeoffset are generally not re-entrant and
> > > assume that interrupts have been disabled. Unfortunately this
> > > pre-condition got broken in v2.6.32.
> > >
> > > Fixes: 5cfc8ee0bb51 ("ARM: convert arm to arch_gettimeoffset()")
> > > Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
> >
> > This looks like a sensible fix for -stable backporting. But with m68k
> > converted over it might be time for these two arm platforms to either
> > be converted to the clocksource API or to be dropped..
> >
>
> You could remove the old arch_gettimeoffset API without dropping any
> platforms.
>
> If no-one converts a given platform to the clocksource API it would mean
> that the default 'jiffies' clocksource will get used on that platform.
>
> Clock resolution and timer precision would be degraded, but that might not
> matter.
>
> Anyway, if someone who has this hardware is willing to test a clocksource
> API conversion, they can let me know and I'll attempt that patch.

There's reasons why that's not appropriate - such as not having two
separate timers in order to supply a clocksource and separate clock
event.

Not all hardware is suited to the clocksource + clockevent idea.

--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up

\
 
 \ /
  Last update: 2018-11-13 10:21    [W:0.056 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site