On Wed, Jul 25, 2012 at 07:39:18PM +0200, Stephane Eranian wrote:
> On Sun, Jul 22, 2012 at 2:14 PM, Jiri Olsa <[email protected]> wrote:
SNIP
> > + if (sample_type & PERF_SAMPLE_REGS_USER) {
> > + u64 avail = (data->regs_user != NULL);
> > +
> > + /*
> > + * If there are no regs to dump, notice it through
> > + * first u64 being zero.
> > + */
> > + perf_output_put(handle, avail);
> > +
> The only role of avail is to report whether or not you've captured actual
> registers. Could it be used to report the sampled process ABI (32 vs. 64)
> instead? Something like:
> PERF_SAMPLE_REGS_ABI_NONE -> no regs captured (emulate your
> current behavior)
> PERF_SAMPLE_REGS_ABI_32 -> 32 bit ABI regs captured
> PERF_SAMPLE_REGS_ABI_64 -> 64 bit ABI regs captured
>
> That could help the tools interpret the register values.
Yes, I think that could help once we start dealing with compat tasks.
The current userspace code stays untouched, because it checks for
'avail != 0', which stays even with your change.
I think this could be sent later with all other fixes I'm already
working on. But I can work/send it preferentially before whole patchset
is taken if you like.
thanks,
jirka
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
