powerpc: Fail build if using recordmcount with binutils v2.37
authorNaveen N Rao <naveen@kernel.org>
Tue, 30 May 2023 06:14:36 +0000 (11:44 +0530)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 23 Jul 2023 11:49:32 +0000 (13:49 +0200)
commit16eceb395994f2eb004938d4b58e405e7dd4dd94
treedfeca35f978f71f0f752a6f6460eec656ce2274c
parent5aea2ac374560ee9bb13e32f4c06143fe95d330d
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: Joel Stanley <joel@jms.id.au>
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230530061436.56925-1-naveen@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/powerpc/Makefile