perf tools: Fix empty version number when building outside of a git repo

When perf is built in a full source tree that is not a git repository,
e.g. from a kernel source tarball, `perf version` will print empty tag
and commit strings:

  $ perf version
  perf version

Currently the tag version is only generated from the root Makefile when
building in a git repository. If PERF-VERSION-FILE has not been
generated and the source tree is not in a git repository, then
PERF-VERSION-GEN will return an empty version.

The problem can be reproduced with the following steps:

  $ wget https://git.kernel.org/torvalds/t/linux-6.0-rc7.tar.gz
  $ tar -xf linux-6.0-rc7.tar.gz && cd linux-6.0-rc7
  $ make -C tools/perf
  $ tools/perf/perf -v
  perf version

Builds from tarballs generated with `make perf-tar-src-pkg` are not
impacted by this issue as PERF-VERSION-FILE is included in the archive.

The perf RPM provided by Fedora for 5.18+ is experiencing this problem.
Package build logs[0] show that the build is attempting to fall back on
PERF-VERSION-FILE, but it is not present.

To resolve this, revert back to the previous logic of using the kernel
Makefile version if not in a git repository and PERF-VERSION-FILE does
not exist.

[0] https://kojipkgs.fedoraproject.org/packages/kernel-tools/5.19.4/200.fc36/data/logs/x86_64/build.log

Fixes: 7572733b84997d23 ("perf tools: Fix version kernel tag")
Reviewed-by: John Garry <[email protected]>
Signed-off-by: Will Chandler <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions