| Message ID | 20210211061416.3747231-1-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kbuild: fix CONFIG_TRIM_UNUSED_KSYMS build for ppc64 | expand |
+++ Masahiro Yamada [11/02/21 15:14 +0900]: >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, >which 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> Thanks a lot for the quick fix. This fixes the ppc64 build issue on my end: Tested-by: Jessica Yu <jeyu@kernel.org> Do you plan to take this through the kbuild tree? If so, please let me know when you've applied it, then I can undo the temporary workaround I currently have in modules-next. Thank you! Jessica
On Thu, Feb 11, 2021 at 7:43 PM Jessica Yu <jeyu@kernel.org> wrote: > > +++ Masahiro Yamada [11/02/21 15:14 +0900]: > >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, > >which 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> > > Thanks a lot for the quick fix. This fixes the ppc64 build issue on my end: > > Tested-by: Jessica Yu <jeyu@kernel.org> > > Do you plan to take this through the kbuild tree? If so, please let me > know when you've applied it, then I can undo the temporary workaround > I currently have in modules-next. > > Thank you! > > Jessica Applied to linux-kbuild/fixes.
diff --git a/scripts/gen_autoksyms.sh b/scripts/gen_autoksyms.sh index 16c0b2ddaa4c..d54dfba15bf2 100755 --- a/scripts/gen_autoksyms.sh +++ b/scripts/gen_autoksyms.sh @@ -43,6 +43,9 @@ EOT sed 's/ko$/mod/' $modlist | xargs -n1 sed -n -e '2{s/ /\n/g;/^$/!p;}' -- | cat - "$ksym_wl" | +# Remove the dot prefix for ppc64; symbol names with a dot (.) hold entry +# point addresses. +sed -e 's/^\.//' | sort -u | sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file"
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, which 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> --- scripts/gen_autoksyms.sh | 3 +++ 1 file changed, 3 insertions(+)