kbuild: fix CONFIG_TRIM_UNUSED_KSYMS build for ppc64
Stephen Rothwell reported a build error on ppc64 when CONFIG_TRIM_UNUSED_KSYMS is enabled. Jessica Yu pointed out the cause of the error with the reference to the ppc64 ELF ABI: "Symbol names with a dot (.) prefix are reserved for holding entry point addresses. The value of a symbol named ".FN", if it exists, is the entry point of the function "FN". As it turned out, CONFIG_TRIM_UNUSED_KSYMS has never worked for ppc64, but this issue has been unnoticed until recently because this option depends on !UNUSED_SYMBOLS hence is disabled by all{mod,yes}config. (Then, it was uncovered by another patch removing UNUSED_SYMBOLS.) Removing the dot prefix in scripts/gen_autoksyms.sh fixes the issue. Please note it must be done before 'sort -u' because modules have both ._mcount and _mcount undefined when CONFIG_FUNCTION_TRACER=y. Link: https://lore.kernel.org/lkml/20210209210843.3af66662@canb.auug.org.au/ Reported-by:Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by:
Masahiro Yamada <masahiroy@kernel.org> Tested-by:
Jessica Yu <jeyu@kernel.org>
parent
92bf2261
Please register or sign in to comment