Re: [PATCH] perf test: Skip test 68 for Powerpc

[Ravi Bangoria]

On 12/9/20 11:19 PM, Arnaldo Carvalho de Melo wrote:
> Em Tue, Dec 08, 2020 at 10:32:33PM +0530, Ravi Bangoria escreveu:
> > On 12/8/20 8:13 PM, Thomas Richter wrote:
> > > On 12/7/20 5:35 PM, Arnaldo Carvalho de Melo wrote:
> > > > Em Tue, Nov 24, 2020 at 03:04:53PM +0530, Ravi Bangoria escreveu:
> > > > > On 11/19/20 7:20 PM, Kajol Jain wrote:
> > > > > > Commit ed21d6d7c48e6e ("perf tests: Add test for PE binary format support")
> > > > > > adds a WINDOWS EXE file named tests/pe-file.exe, which is
> > > > > > examined by the test case 'PE file support'. As powerpc doesn't support
> > > > > > it, we are skipping this test.
>
> > > > > > Result in power9 platform before this patach:
> > > > > > [command]# ./perf test -F 68
> > > > > > 68: PE file support                               : Failed!
>
> > > > > > Result in power9 platform after this patch:
> > > > > > [command]# ./perf test -F 68
> > > > > > 68: PE file support                               : Skip
>
> > > > > > Signed-off-by: Kajol Jain <kjain@xxxxxxxxxxxxx>
>
> > > > > Reviewed-by: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxx>
>
> > > > But why is it failing? I.e. what is that
>
> > > >    perf test -v -F 68
>
> > > > outputs?
>
> > > > Using 'perf report' on a perf.data file containing samples in such
> > > > binaries, collected on x86 should work on whatever workstation a
> > > > developer uses.
>
> > > > Say, on a MacBook aarch64 one can look at a perf.data file collected on
> > > > a x86_64 system where Wine running a PE binary was present.
>
> > > What is the distro you are using?
> > > I observed the same issue on s390 but this was fixed for fedora33 somehow.
> > > The error just went away after a dnf update....
>
> > > [root@m35lp76 perf]# cat /etc/fedora-release
> > > Fedora release 33 (Thirty Three)
> > > [root@m35lp76 perf]# ./perf test -F 68
> > > 68: PE file support                                                 : Ok
> > > [root@m35lp76 perf]#
>
> > > However on my fedora32 machine it still fails:
> > > [root@t35lp46 perf]# cat /etc/fedora-release
> > > Fedora release 32 (Thirty Two)
> > > [root@t35lp46 perf]# ./perf test -F 68
> > > 68: PE file support                                                 : FAILED!
> > > [root@t35lp46 perf]#
> > >
> > > Note that I am running the same kernel on both machines: linux 5.10.0rc7 downloaded
> > > this morning.
> >
> > Ok that's interesting. I don't see that on powerpc.
> >
> > Fedora 32 with 5.10.0-rc2+ kernel:
> >
> >    $ ./perf test -vv -F 68
> >    68: PE file support                                                 :
> >    --- start ---
> >    filename__read_build_id: cannot read ./tests/pe-file.exe bfd file.
> >    FAILED tests/pe-file-parsing.c:40 Failed to read build_id
> >    ---- end ----
> >    PE file support: FAILED!
> >
> > Fedora 33 with 5.10.0-rc3 kernel:
> >
> >    $ ./perf test -vv -F 68
> >    68: PE file support                                                 :
> >    --- start ---
> >    filename__read_build_id: cannot read ./tests/pe-file.exe bfd file.
> >    FAILED tests/pe-file-parsing.c:40 Failed to read build_id
> >    ---- end ----
> >    PE file support: FAILED!
> >
> > Ubuntu 18.04.5 with 4.15.0-126-generic kernel:
> >
> >    $ ./perf test -vv -F 68
> >    68: PE file support                                                 :
> >    --- start ---
> >    filename__read_build_id: cannot read ./tests/pe-file.exe bfd file.
> >    FAILED tests/pe-file-parsing.c:41 Failed to read build_id
> >    ---- end ----
> >    PE file support: FAILED!
> >
> >
> > I assumed bfd is not capable to parse PE files on powerpc. Though,
> > I didn't check it in more detail. I'll look into it tomorrow.
>
> Humm, so this is something related to installation? I.e. that
> pe-file.exe isn't being found...
>
> It first assumes that the developers are in the tools/perf/ directory,
> can you please add the patch below and see if it helps?

I'm using upstream perf from tools/perf/

I checked bfd code and it's bfd_check_format() who is returning error
"bfd_error_file_not_recognized".

I cross verified with objdump as well:

On x86:

  $ objdump -d ./tests/pe-file.exe
  ./tests/pe-file.exe:     file format pei-x86-64
    
  Disassembly of section .text:
  
  0000000000401000 <__mingw_invalidParameterHandler>:
    401000:       c3                      retq
    401001:       66 66 2e 0f 1f 84 00    data16 nopw %cs:0x0(%rax,%rax,1)
    401008:       00 00 00 00
    40100c:       0f 1f 40 00             nopl   0x0(%rax)

On powerpc:

  $ objdump -d ./tests/pe-file.exe
  objdump: ./tests/pe-file.exe: file format not recognized

Objdump is also returning *same* error.

I dig more into bfd logs and found that Powerpc PE support was removed
recently (Jul 2020) with this commit:
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=fe49679d5193f6ff7cfd333e30883d293112a3d1

Ravi