Messages in this thread | | | Subject | Re: [PATCH 03/23] perf: Add ability to attach user level registers dump to sample | From | Peter Zijlstra <> | Date | Wed, 27 Jun 2012 17:25:29 +0200 |
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On Wed, 2012-06-27 at 17:24 +0200, Frederic Weisbecker wrote: > On Wed, Jun 27, 2012 at 05:13:44PM +0200, Stephane Eranian wrote: > > On Wed, Jun 27, 2012 at 5:11 PM, Frederic Weisbecker <fweisbec@gmail.com> wrote: > > > On Tue, Jun 19, 2012 at 05:47:54PM +0200, Jiri Olsa wrote: > > >> @@ -4061,6 +4105,19 @@ void perf_prepare_sample(struct perf_event_header *header, > > >> } > > >> header->size += size; > > >> } > > >> + > > >> + if (sample_type & PERF_SAMPLE_REGS_USER) { > > >> + /* regs dump available bool */ > > >> + int size = sizeof(u64); > > >> + > > >> + data->regs_user = perf_sample_regs_user(regs); > > >> + if (data->regs_user) { > > >> + u64 mask = event->attr.sample_regs_user; > > >> + size += hweight64(mask) * sizeof(u64); > > >> + } > > >> + > > >> + header->size += size; > > > > > > We'll need to remove the 64 bits registers for compat tasks but other than > > > that, it looks ok. > > You cannot do this. You cannot remove register values from under the hood. > > The only way the user has to parse the sample is the sample_regs_users bitmask. > > You have to return 0 for those unexisting regs for compat tasks. > > You mean fill unexisting reg values with 0? Yeah that works.
What does x32 look like? Is that still reported as a compat task? If so, we should record all registers and not 0 out anything.
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