From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@armlinux.org.uk (Russell King - ARM Linux) Date: Tue, 13 Nov 2018 09:20:13 +0000 Subject: [RFC PATCH 01/13] arm: Fix mutual exclusion in arch_gettimeoffset In-Reply-To: References: <20181112083422.GA19695@infradead.org> Message-ID: <20181113092012.GI30658@n2100.armlinux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 > > > > 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