Re: [PATCH] powerpc/book3s32: Only select PPC_HAVE_PMU on e600

[christophe leroy]

Le 04/09/2015 18:43, Scott Wood a écrit :
> On Thu, Sep 03, 2015 at 11:27:03AM +0200, Christophe Leroy wrote:
> > On PPC832x, perf record/report reports martian addresses
> >
> >       2.62%  perf_reseau4  libpthread-2.18.so  [.] __libc_send
> >       2.56%  perf_reseau4  [kernel.kallsyms]   [k] __ip_make_skb
> >       1.62%  perf_reseau4  [kernel.kallsyms]   [k] __ip_append_data.isra.39
> >       1.55%  perf_reseau4  [kernel.kallsyms]   [k] ip_finish_output
> >       1.33%  perf_reseau4  [unknown]           [k] 0x7ffffd94
> >       1.33%  perf_reseau4  [unknown]           [k] 0x7ffffd95
> >       1.28%  perf_reseau4  [unknown]           [k] 0x7ffffd97
> >       1.26%  perf_reseau4  [unknown]           [k] 0x7ffffda3
> >       1.24%  perf_reseau4  [unknown]           [k] 0x7ffffd98
> >       1.22%  perf_reseau4  [unknown]           [k] 0x7ffffd92
> >       1.22%  perf_reseau4  [unknown]           [k] 0x7ffffd9b
> >       [.....]
> >
> > This is due to function perf_instruction_pointer() reading SPR SIAR
> > which doesn't exist on e300 core. The perf_instruction_pointer() is
> > redefined in arch/powerpc/perf/core-book3s.c when CONFIG_PPC_PERF_CTRS
> > is selected.
> >
> > This patch moves the selection of CONFIG_PPC_HAVE_PMU in 86xx section
> > so that CONFIG_PPC_PERF_CTRS won't be selected for other 6xx powerpc
> >
> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
> So, what happens when a kernel is built that supports both 83xx and 86xx?
Right, so should we define a processor feature for it ?
> Plus, it's e300, not e600, that is the exception among 6xx-style cores.
Is it ? I've been looking for special register SIAR (spr 955) in several 
6xx reference manuals.
82xx doesn't have it, 52xx and 512x don't have it.
I found it only in the 86xx
Which other family has it ?

Christophe

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