From: Masahiro Yamada masahiroy@kernel.org
[ Upstream commit 29500f15b54b63ad0ea60b58e85144262bd24df2 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- scripts/gen_autoksyms.sh | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/scripts/gen_autoksyms.sh b/scripts/gen_autoksyms.sh index 16c0b2ddaa4c9..d54dfba15bf25 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"