Messages in this thread | | | Subject | Re: [RFC][PATCH 07/11] perf: Provide PERF_SAMPLE_REGS | From | Peter Zijlstra <> | Date | Wed, 03 Mar 2010 20:18:30 +0100 |
| |
On Wed, 2010-03-03 at 09:55 -0800, David Miller wrote: > From: Stephane Eranian <eranian@google.com> > Date: Wed, 3 Mar 2010 09:49:33 -0800 > > > On Wed, Mar 3, 2010 at 9:39 AM, Peter Zijlstra <peterz@infradead.org> wrote: > >> On Wed, 2010-03-03 at 09:30 -0800, Stephane Eranian wrote: > >>> This assumes struct pt_regs is somehow exported to userland. > >>> Is that the case? > >> > >> I seems to have understood they were, and asm/ptrace.h seems to agree > >> with that, it has !__KERNEL__ definitions for struct pt_regs. > >> > > Seems to be the case, indeed. > > BTW, how are you going to cope with compat systems? > > If I build 'perf' on a sparc64 kernel build, it's going to get the > 64-bit pt_regs. So I can't then use that binary on a sparc box > running a 32-bit kernel. > > And vice versa. > > And more generally aren't we supposed to be able to eventually analyze > perf dumps on any platform not just the one 'perf' was built under? > > We'll need to do something about the encoding of pt_regs, therefore.
Hrm, yes,.. what I can do for the moment is 'cheat' and make the raw PEBS record available through PERF_SAMPLE_RAW (that also has CAP_ADMIN, which I guess is a good idea for full reg sets), and then we can work out how to expose pt_regs later.
If someone has a better suggestion than this, which is basically blurp out host native pt_regs and cope, please tell ;-)
| |