Messages in this thread | | | Date | Thu, 01 Nov 2007 12:12:35 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86: show cpuinfo only for online CPUs |
| |
Glauber de Oliveira Costa wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Andreas Herrmann3 escreveu: >> On Thu, Nov 01, 2007 at 06:35:43PM +0100, Andreas Herrmann3 wrote: >>> On Thu, Nov 01, 2007 at 03:12:25PM -0200, Glauber de Oliveira Costa wrote: >>>> So it could even work, but as accident. Unless I'm wrong about it, I'd >>>> prefer to see an explicit attribution of cpu_index = 0 somewhere for the >>>> boot cpu. >>> Hmm, will look at this as well. >> BTW, isn't it zero initialized anyway? >> So, no need to explicitely set cpuinfo->cpu_index=0 for the boot cpu. > > Well, it should be, but as far as I know it is not exactly a guarantee > given by all compilers. So it should be safer to do it explicitly, with > no prejudice. Unless it's really guaranteed. If it is, yeah, no need.
Any uninitialized field in a static section (.data or .bss) is guaranteed to be initialized to zero. This is guaranteed by the C standard. In the former case, it is the responsibility of the compiler and in the latter by the runtime.
The Linux percpu handling creates a .data.percpu section which is then replicated into each of the CPU data blocks; thus, percpu data counts as static data for this purpose, and initialization is guaranteed.
-hpa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |