Strange reports of perf events on powerpc 83xx

[Joakim Tjernlund]

On Thu, 2015-08-27 at 15:58 +0200, leroy christophe wrote:
> Hi,
> 
> Has anybody already used 'perf' tool on powerpc MPC83xx ?
> 
> I have been succesfully using perf on MPC8xx, but on MPC83xx I get 
> something strange.
> 
> perf record/report reports addresses on user stack, as if it was mixing 
> up D accesses and I accesses.
> 
> Any idea of what the problem can be ?

We are also experiencing strange addresses on 83xx, did find the cause
of this problem?

We are using Linux 4.1.0

> 
> # Samples: 8K of event 'cpu-clock'
> # Event count (approx.): 2196000000
> #
> # Overhead  Command       Shared Object       Symbol
> # ........  ............  .................. 
> ............................................
> #
>       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
>       1.22%  perf_reseau4  [unknown]           [k] 0x7ffffdaa
>       1.21%  perf_reseau4  [unknown]           [k] 0x7ffffd96
>       1.18%  perf_reseau4  [unknown]           [k] 0x7ffffda7
>       1.17%  perf_reseau4  [unknown]           [k] 0x7ffffd8d
>       1.17%  perf_reseau4  [unknown]           [k] 0x7ffffd99
>       1.13%  perf_reseau4  [unknown]           [k] 0x7ffffd90
>       1.13%  perf_reseau4  [unknown]           [k] 0x7ffffda2
>       1.12%  perf_reseau4  [kernel.kallsyms]   [k] __local_bh_enable_ip
>       1.12%  perf_reseau4  [unknown]           [k] 0x7ffffd9c
>       1.12%  perf_reseau4  [unknown]           [k] 0x7ffffd9e
>       1.10%  perf_reseau4  [unknown]           [k] 0x7ffffda0
>       1.08%  perf_reseau4  [unknown]           [k] 0x7ffffd9f
>       1.08%  perf_reseau4  [unknown]           [k] 0x7ffffda6
>       1.05%  perf_reseau4  [unknown]           [k] 0x7ffffda8
>       1.02%  perf_reseau4  [unknown]           [k] 0x7ffffd9a
>       1.01%  perf_reseau4  [unknown]           [k] 0x7ffffdb0
>       1.00%  perf_reseau4  [unknown]           [k] 0x7ffffd89
>       1.00%  perf_reseau4  [unknown]           [k] 0x7ffffd8b
>       1.00%  perf_reseau4  [unknown]           [k] 0x7ffffdac