4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Naveen N Rao <naveen@xxxxxxxxxx> [ 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> --- arch/powerpc/Makefile | 8 ++++++++ 1 file changed, 8 insertions(+) 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 -- 2.40.1
