Re: [PATCH] GICv3: Fixing 32 bit compatibility

From: Robert Richter
Date: Tue Sep 09 2014 - 05:12:28 EST


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.

> I wonder if it would be cleaner to use (u64)0xff here.

No, that's ULL for. This is commonly used in x86 too.

-Robert
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/