When DEBUG_INFO_DWARF5 is selected, pahole 1.21+ is required to enable
DEBUG_INFO_BTF.
When DEBUG_INFO_DWARF4 or DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT is selected,
DEBUG_INFO_BTF can be enabled without pahole installed, but a build error
will occur in scripts/link-vmlinux.sh:
LD .tmp_vmlinux1
BTF: .tmp_vmlinux1: pahole (pahole) is not available
Failed to generate BTF for vmlinux
Try to disable CONFIG_DEBUG_INFO_BTF
We did not guard DEBUG_INFO_BTF by PAHOLE_VERSION when previously
discussed [1].
However, commit 613fe1692377 ("kbuild: Add CONFIG_PAHOLE_VERSION")
added CONFIG_PAHOLE_VERSION after all. Now several CONFIG options, as
well as the combination of DEBUG_INFO_BTF and DEBUG_INFO_DWARF5, are
guarded by PAHOLE_VERSION.
The remaining compile-time check in scripts/link-vmlinux.sh now appears
to be an awkward inconsistency.
This commit adopts Nathan's original work.
[1]: https://lore.kernel.org/lkml/20210111180609.713998-1-natechancellor@xxxxxxxxx/
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Reviewed-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
---
Changes in v2:
- Reword the help message per Alan
lib/Kconfig.debug | 6 ++++--
scripts/link-vmlinux.sh | 12 ------------
2 files changed, 4 insertions(+), 14 deletions(-)
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 5e2f30921cb2..bdf822bc1bab 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -379,13 +379,15 @@ config DEBUG_INFO_BTF
depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
depends on BPF_SYSCALL
+ depends on PAHOLE_VERSION >= 116
depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
# pahole uses elfutils, which does not have support for Hexagon relocations
depends on !HEXAGON
help
Generate deduplicated BTF type information from DWARF debug info.
- Turning this on expects presence of pahole tool, which will convert
- DWARF type info into equivalent deduplicated BTF type info.
+ Turning this on requires pahole v1.16 or later (v1.21 or later to
+ support DWARF 5), which will convert DWARF type info into equivalent
+ deduplicated BTF type info.
config PAHOLE_HAS_SPLIT_BTF
def_bool PAHOLE_VERSION >= 119
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index cfffc41e20ed..53bd4b727e21 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -111,20 +111,8 @@ vmlinux_link()
# ${1} - vmlinux image
gen_btf()
{
- local pahole_ver
local btf_data=${1}.btf.o
- if ! [ -x "$(command -v ${PAHOLE})" ]; then
- echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
- return 1
- fi
-
- pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
- if [ "${pahole_ver}" -lt "116" ]; then
- echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16"
- return 1
- fi
-
info BTF "${btf_data}"
LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}
--
2.43.0
