From mboxrd@z Thu Jan 1 00:00:00 1970 From: robert.richter@caviumnetworks.com (Robert Richter) Date: Tue, 9 Sep 2014 11:26:53 +0200 Subject: [PATCH] GICv3: Fixing 32 bit compatibility In-Reply-To: <20140909091912.GQ23009@pengutronix.de> References: <1410185480-5153-1-git-send-email-rric@kernel.org> <20140909080042.GO23009@pengutronix.de> <20140909091201.GA4527@rric.localhost> <20140909091912.GQ23009@pengutronix.de> Message-ID: <20140909092653.GC4588@rric.localhost> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 09.09.14 11:19:12, Uwe Kleine-K?nig wrote: > On Tue, Sep 09, 2014 at 11:12:01AM +0200, Robert Richter wrote: > > On 09.09.14 10:00:42, Uwe Kleine-K?nig 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? Upper 32 bits will be cleared above. > > > 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. ULL is no cast at all. -Robert