On Fri, Sep 07, 2018 at 08:43:59PM +0200, Luc Van Oostenryck wrote: > On Fri, Sep 07, 2018 at 04:15:33PM +0200, Christophe LEROY wrote: > > Le 07/09/2018 à 15:58, Peter Zijlstra a écrit : > > > 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. > > Sparse is a bit weird about the exact underlying type used for enums. > > > Ah yes, it seems that GCC is happy. So sparse should be fixed instead ? > > I'll investigate (I suppose the same is given on x86-32). It's definitively a bug in sparse. A relatively nasty one and which open a can of worms. Fortunately, I had already looked at these problems in May, I just didn't had the time to push the patches. -- Luc
