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Commit b1579872 authored by Naveen N Rao's avatar Naveen N Rao Committed by Greg Kroah-Hartman
Browse files

powerpc: Fail build if using recordmcount with binutils v2.37 

commit 25ea739ea1d4d3de41acc4f4eb2d1a97eee0eb75 upstream.

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@vger.kernel.org
Suggested-by: default avatarJoel Stanley <joel@jms.id.au>
Signed-off-by: default avatarNaveen N Rao <naveen@kernel.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230530061436.56925-1-naveen@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2b59740e

arch/powerpc/Makefile

+8 −0
Original line number Diff line number Diff line
@@ -425,3 +425,11 @@ 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