From: Peter Zijlstra <peterz@infradead.org>
To: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] perf: enum overflow in uapi/linux/perf_event.h
Date: Fri, 7 Sep 2018 15:58:17 +0200 [thread overview]
Message-ID: <20180907135817.GF24106@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <ae32181d-37b2-1a13-3c72-66775e05ff88@c-s.fr>
On Fri, Sep 07, 2018 at 01:50:18PM +0000, Christophe Leroy wrote:
>
>
> On 09/07/2018 01:42 PM, Peter Zijlstra wrote:
> > On Fri, Sep 07, 2018 at 01:27:19PM +0000, Christophe Leroy wrote:
> > > On PPC32, enums are 32 bits, so __PERF_SAMPLE_CALLCHAIN_EARLY is
> > > out of scope. The following sparse warning is encountered:
> > >
> > > CHECK arch/powerpc/kernel/process.c
> > > ./include/uapi/linux/perf_event.h:147:56: warning: cast truncates bits from constant value (8000000000000000 becomes 0)
> >
> > Urgh... what compiler is that? I've not seen anything like that from the
> > build bots.
> >
>
> [root@pc16082vm linux-powerpc]# sparse --version
> 0.5.2
>
> [root@pc16082vm linux-powerpc]# ppc-linux-gcc --version
> ppc-linux-gcc (GCC) 5.4.0
Ah, that's a sparse warning. But does your GCC agree? The thing is,
sparse uses the C enum spec, but I suspect GCC uses the C++ enum spec
and it all works fine.
next prev parent reply other threads:[~2018-09-07 13:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-07 13:27 [PATCH] perf: enum overflow in uapi/linux/perf_event.h Christophe Leroy
2018-09-07 13:42 ` Peter Zijlstra
2018-09-07 13:50 ` Christophe Leroy
2018-09-07 13:58 ` Peter Zijlstra [this message]
2018-09-07 14:13 ` Peter Zijlstra
2018-09-07 14:15 ` Christophe LEROY
2018-09-07 14:23 ` Peter Zijlstra
2018-09-07 18:43 ` Luc Van Oostenryck
2018-09-07 23:55 ` Luc Van Oostenryck
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