livepatch/klp-build: Require Clang assembler >= 20

Some special sections specify their ELF section entsize, for example:

  .pushsection section, "M", @progbits, 8

The entsize (8 in this example) is needed by objtool klp-diff for
extracting individual entries.

Clang assembler versions older than 20 silently ignore the above
construct and set entsize to 0, resulting in the following error:

  .discard.annotate_data: missing special section entsize or annotations

Add a klp-build check to prevent the use of Clang assembler versions
prior to 20.

Fixes: 24ebfcd65a ("livepatch/klp-build: Introduce klp-build script for generating livepatch modules")
Reported-by: Song Liu <song@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/957fd52e375d0e2cfa3ac729160da995084a7f5e.1769562556.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
This commit is contained in:
Josh Poimboeuf 2026-01-27 17:12:05 -08:00
parent 78c268f378
commit a8ff29f0ca

View file

@ -249,6 +249,10 @@ validate_config() {
[[ -v CONFIG_GCC_PLUGIN_RANDSTRUCT ]] && \
die "kernel option 'CONFIG_GCC_PLUGIN_RANDSTRUCT' not supported"
[[ -v CONFIG_AS_IS_LLVM ]] && \
[[ "$CONFIG_AS_VERSION" -lt 200000 ]] && \
die "Clang assembler version < 20 not supported"
return 0
}