From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F3CF73C2F; Wed, 21 Feb 2024 13:47:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708523259; cv=none; b=o91fFrFxvlc/17/px4HzS9zMvjdmNhVeqglTwFxdkr3m82qrD7DYsVI6qzX6Shbm2LEgclQImwt3r4j8saxIHE1wL4i1xDezfIBrJwPvZYeZmI+Mh0J+3F22znvrp6/q59xOTH+8SkHwf/qHDDOrloXUuoUer3uw37Rkxc7I/lY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708523259; c=relaxed/simple; bh=ohK9PlLIN7TmNElA2isQX3j8J0hl3G96l7/3YtitKEs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=F3s+soFzQ7L/jah8XuZ9dVxDNtwYksd7xsvHwvuxyYRxV9Q2iUdKLx2OlZsQQ2Au1kQfcVBDdk3BZEWe/tkdeQUsSlGiC1HRvn21wNMynVLpqSqd/2dXj1+UpaVHn9iffN9lW4nAEykYrTsx950HatO81kHbfsqE51QYP15Z3fQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=SGeyQNBM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="SGeyQNBM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F22F2C433F1; Wed, 21 Feb 2024 13:47:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1708523258; bh=ohK9PlLIN7TmNElA2isQX3j8J0hl3G96l7/3YtitKEs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SGeyQNBMBsCmFlOftNFs7+jeW/LZoJWueoGhl1+KsTkJRHmn/zEoVtg7UDAwAVBfW dcs0EsfGTJju40lVXTC4lCv/5XN86co1RmZtrSJqnpsTW/yzddsfxb+CH3ZqmcOyd8 F1wVc5mImmxF8kLTJt6BX9FH3hinH6s3lLKQuYN8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masahiro Yamada , Nathan Chancellor , Fangrui Song , Nicolas Schier , Kees Cook , Justin Stitt Subject: [PATCH 5.15 380/476] kbuild: Fix changing ELF file type for output of gen_btf for big endian Date: Wed, 21 Feb 2024 14:07:11 +0100 Message-ID: <20240221130022.096353982@linuxfoundation.org> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240221130007.738356493@linuxfoundation.org> References: <20240221130007.738356493@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nathan Chancellor commit e3a9ee963ad8ba677ca925149812c5932b49af69 upstream. Commit 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") changed the ELF type of .btf.vmlinux.bin.o to ET_REL via dd, which works fine for little endian platforms: 00000000 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| -00000010 03 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| +00000010 01 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| However, for big endian platforms, it changes the wrong byte, resulting in an invalid ELF file type, which ld.lld rejects: 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| +00000010 01 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| Type: : 103 ld.lld: error: .btf.vmlinux.bin.o: unknown file type Fix this by updating the entire 16-bit e_type field rather than just a single byte, so that everything works correctly for all platforms and linkers. 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| +00000010 00 01 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| Type: REL (Relocatable file) While in the area, update the comment to mention that binutils 2.35+ matches LLD's behavior of rejecting an ET_EXEC input, which occurred after the comment was added. Cc: stable@vger.kernel.org Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") Link: https://github.com/llvm/llvm-project/pull/75643 Suggested-by: Masahiro Yamada Signed-off-by: Nathan Chancellor Reviewed-by: Fangrui Song Reviewed-by: Nicolas Schier Reviewed-by: Kees Cook Reviewed-by: Justin Stitt Signed-off-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman --- scripts/link-vmlinux.sh | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -236,8 +236,13 @@ gen_btf() ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \ --strip-all ${1} ${2} 2>/dev/null # Change e_type to ET_REL so that it can be used to link final vmlinux. - # Unlike GNU ld, lld does not allow an ET_EXEC input. - printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none + # GNU ld 2.35+ and lld do not allow an ET_EXEC input. + if is_enabled CONFIG_CPU_BIG_ENDIAN; then + et_rel='\0\1' + else + et_rel='\1\0' + fi + printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none } # Create ${2} .S file with all symbols from the ${1} object file