From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Robert Richter <rric@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Jason Cooper <jason@lakedaemon.net>,
Marc Zyngier <marc.zyngier@arm.com>,
Robert Richter <rrichter@cavium.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] GICv3: Fixing 32 bit compatibility
Date: Tue, 9 Sep 2014 11:19:12 +0200 [thread overview]
Message-ID: <20140909091912.GQ23009@pengutronix.de> (raw)
In-Reply-To: <20140909091201.GA4527@rric.localhost>
On Tue, Sep 09, 2014 at 11:12:01AM +0200, Robert Richter wrote:
> On 09.09.14 10:00:42, Uwe Kleine-König wrote:
> > On Mon, Sep 08, 2014 at 04:11:19PM +0200, Robert Richter wrote:
>
> > > @@ -479,7 +479,7 @@ static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
> > > smp_wmb();
> > >
> > > for_each_cpu_mask(cpu, *mask) {
> > > - u64 cluster_id = cpu_logical_map(cpu) & ~0xffUL;
> > > + u64 cluster_id = cpu_logical_map(cpu) & ~0xffULL;
> > This doesn't change anything, does it?
>
> It does, not in 64 bit but in 32 bit there unsigned long is 32
> bit. So, bit masks are broken if you compile a 32 bit kernel.
Can you make an example where the result actually changes?
> > I wonder if it would be cleaner to use (u64)0xff here.
>
> No, that's ULL for. This is commonly used in x86 too.
I don't care much here, but I'd say ULL is to force an unsigned long
long. If you want to make it obvious that you want a 64bit value, a cast
to u64 makes this more clear.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
next prev parent reply other threads:[~2014-09-09 9:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-08 14:11 [PATCH] GICv3: Fixing 32 bit compatibility Robert Richter
2014-09-08 14:24 ` Marc Zyngier
2014-09-14 5:55 ` Jason Cooper
2014-09-08 14:31 ` [PATCH] ITS: " Robert Richter
2014-09-09 8:00 ` [PATCH] GICv3: " Uwe Kleine-König
2014-09-09 9:12 ` Robert Richter
2014-09-09 9:19 ` Uwe Kleine-König [this message]
2014-09-09 9:26 ` Robert Richter
2014-09-09 9:43 ` Uwe Kleine-König
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