This is a note to let you know that I've just added the patch titled
powerpc: Fail build if using recordmcount with binutils v2.37
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-fail-build-if-using-recordmcount-with-binuti.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 04a4de89e3ea5dbe11440226e243c96b0dfd2b15
Author: Naveen N Rao <naveen@xxxxxxxxxx>
Date: Tue May 30 11:44:36 2023 +0530
powerpc: Fail build if using recordmcount with binutils v2.37
[ Upstream commit 25ea739ea1d4d3de41acc4f4eb2d1a97eee0eb75 ]
binutils v2.37 drops unused section symbols, which prevents recordmcount
from capturing mcount locations in sections that have no non-weak
symbols. This results in a build failure with a message such as:
Cannot find symbol for section 12: .text.perf_callchain_kernel.
kernel/events/callchain.o: failed
The change to binutils was reverted for v2.38, so this behavior is
specific to binutils v2.37:
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=c09c8b42021180eee9495bd50d8b35e683d3901b
Objtool is able to cope with such sections, so this issue is specific to
recordmcount.
Fail the build and print a warning if binutils v2.37 is detected and if
we are using recordmcount.
Cc: stable@xxxxxxxxxxxxxxx
Suggested-by: Joel Stanley <joel@xxxxxxxxx>
Signed-off-by: Naveen N Rao <naveen@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://msgid.link/20230530061436.56925-1-naveen@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 2fad158173485..daddada1a3902 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -439,3 +439,11 @@ checkbin:
echo -n '*** Please use a different binutils version.' ; \
false ; \
fi
+ @if test "x${CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT}" = "xy" -a \
+ "x${CONFIG_LD_IS_BFD}" = "xy" -a \
+ "${CONFIG_LD_VERSION}" = "23700" ; then \
+ echo -n '*** binutils 2.37 drops unused section symbols, which recordmcount ' ; \
+ echo 'is unable to handle.' ; \
+ echo '*** Please use a different binutils version.' ; \
+ false ; \
+ fi
