bpf: Add --skip_encoding_btf_inconsistent_proto, --btf_gen_optimized to pahole flags...

commit 7b99f75942da332e3f4f865e55a10fec95a30d4f upstream.

v1.25 of pahole supports filtering out functions with multiple inconsistent
function prototypes or optimized-out parameters from the BTF representation.
These present problems because there is no additional info in BTF saying which
inconsistent prototype matches which function instance to help guide attachment,
and functions with optimized-out parameters can lead to incorrect assumptions
about register contents.

So for now, filter out such functions while adding BTF representations for
functions that have "."-suffixes (foo.isra.0) but not optimized-out parameters.
This patch assumes that below linked changes land in pahole for v1.25.

Issues with pahole filtering being too aggressive in removing functions
appear to be resolved now, but CI and further testing will confirm.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230510130241.1696561-1-alan.maguire@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
[ small context conflict because of not backported --lang_exclude=rust
option, which is not needed in 5.15 ]
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh
index d38fa6d84d62a60bcff9805c8b1184bc69e0162a..5c724f6971009d2836f88a7b72bdd966a4ec79f5 100755 (executable)
--- a/scripts/pahole-flags.sh
+++ b/scripts/pahole-flags.sh
@@ -20,5 +20,8 @@ fi
 if [ "${pahole_ver}" -ge "124" ]; then
        extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_enum64"
 fi
+if [ "${pahole_ver}" -ge "125" ]; then
+       extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_inconsistent_proto --btf_gen_optimized"
+fi
 
 echo ${extra_paholeopt}