Version 1.24 of pahole has the capability to exclude compilation units (CUs) of specific languages [1] [2]. Rust, as of writing, is not currently supported by pahole and if it's used with a build that has BTF debugging enabled it results in malformed kernel and module binaries [3]. So it's better for pahole to exclude Rust CUs until support for it arrives. Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=49358dfe2aaae4e90b072332c3e324019826783f [1] Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4 [2] Link: https://github.com/Rust-for-Linux/linux/issues/735 [3] Co-developed-by: Eric Curtin <ecurtin@xxxxxxxxxx> Signed-off-by: Eric Curtin <ecurtin@xxxxxxxxxx> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@xxxxxxxxx> --- V2 -> V3: Enable pahole option upon comparing with version 1.24 V1 -> V2: Removed dependency on auto.conf init/Kconfig | 2 +- lib/Kconfig.debug | 9 +++++++++ scripts/pahole-flags.sh | 4 ++++ 3 files changed, 14 insertions(+), 1 deletion(-) diff --git a/init/Kconfig b/init/Kconfig index 694f7c160c9c..360aef8d7292 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1913,7 +1913,7 @@ config RUST depends on !MODVERSIONS depends on !GCC_PLUGINS depends on !RANDSTRUCT - depends on !DEBUG_INFO_BTF + depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE select CONSTRUCTORS help Enables Rust support in the kernel. diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index ea4c903c9868..d473d491e709 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -364,6 +364,15 @@ config PAHOLE_HAS_BTF_TAG btf_decl_tag) or not. Currently only clang compiler implements these attributes, so make the config depend on CC_IS_CLANG. +config PAHOLE_HAS_LANG_EXCLUDE + def_bool PAHOLE_VERSION >= 124 + help + Support for the --lang_exclude flag which makes pahole exclude + compilation units from the supplied language. Used in Kbuild to + omit Rust CUs which are not supported in version 1.24 of pahole, + otherwise it would emit malformed kernel and module binaries when + using DEBUG_INFO_BTF_MODULES. + config DEBUG_INFO_BTF_MODULES def_bool y depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh index 0d99ef17e4a5..1f1f1d397c39 100755 --- a/scripts/pahole-flags.sh +++ b/scripts/pahole-flags.sh @@ -19,5 +19,9 @@ fi if [ "${pahole_ver}" -ge "122" ]; then extra_paholeopt="${extra_paholeopt} -j" fi +if [ "${pahole_ver}" -ge "124" ]; then + # see PAHOLE_HAS_LANG_EXCLUDE + extra_paholeopt="${extra_paholeopt} --lang_exclude=rust" +fi echo ${extra_paholeopt} -- 2.39.0
