From patchwork Tue Oct 13 23:48:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11836227 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0EBC8921 for ; Tue, 13 Oct 2020 23:48:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BF86B21D7F for ; Tue, 13 Oct 2020 23:48:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="JFA016Z7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF86B21D7F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C54F06B0075; 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Tue, 13 Oct 2020 23:48:03 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5DC3C21D7A; Tue, 13 Oct 2020 23:48:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602632882; bh=1IE0rXmrIv5WEpxIUQFbF+jl/alNJTZrKr0kJ0mM3ao=; h=Date:From:To:Subject:In-Reply-To:From; b=JFA016Z7tWF4TmfyvM8J/O17jgETStu9tYsT9jjGrXOLlS2dTcRoFV0SfAmJCON88 KDBAQnw7FXtZsminykfsM2OgPZuSdnvfRoE00o+EJAPChDJBIET6YHvJFiIvbJkvOP f92uN25V4oNdQ1TpiuOmowUyVHR1Olnxiv7JCawk= Date: Tue, 13 Oct 2020 16:48:01 -0700 From: Andrew Morton To: akpm@linux-foundation.org, gregkh@linuxfoundation.org, jeyu@kernel.org, keescook@chromium.org, linux-mm@kvack.org, lkp@intel.com, maennich@google.com, mm-commits@vger.kernel.org, natechancellor@gmail.com, ndesaulniers@google.com, torvalds@linux-foundation.org, will@kernel.org, yamada.masahiro@socionext.com Subject: [patch 009/181] export.h: fix section name for CONFIG_TRIM_UNUSED_KSYMS for Clang Message-ID: <20201013234801.zMU594pMt%akpm@linux-foundation.org> In-Reply-To: <20201013164658.3bfd96cc224d8923e66a9f4e@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Nick Desaulniers Subject: export.h: fix section name for CONFIG_TRIM_UNUSED_KSYMS for Clang When enabling CONFIG_TRIM_UNUSED_KSYMS, the linker will warn about the orphan sections: (".discard.ksym") is being placed in '".discard.ksym"' repeatedly when linking vmlinux. This is because the stringification operator, `#`, in the preprocessor escapes strings. GCC and Clang differ in how they treat section names that contain \". The portable solution is to not use a string literal with the preprocessor stringification operator. Link: https://bugs.llvm.org/show_bug.cgi?id=42950 Link: https://github.com/ClangBuiltLinux/linux/issues/1166 Link: https://lkml.kernel.org/r/20200929190701.398762-1-ndesaulniers@google.com Fixes: commit bbda5ec671d3 ("kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS") Signed-off-by: Nick Desaulniers Reported-by: kbuild test robot Suggested-by: Kees Cook Reviewed-by: Kees Cook Cc: Nathan Chancellor Cc: Masahiro Yamada Cc: Matthias Maennich Cc: Jessica Yu Cc: Greg Kroah-Hartman Cc: Will Deacon Signed-off-by: Andrew Morton --- include/linux/export.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/export.h~exporth-fix-section-name-for-config_trim_unused_ksyms-for-clang +++ a/include/linux/export.h @@ -130,7 +130,7 @@ struct kernel_symbol { * discarded in the final link stage. */ #define __ksym_marker(sym) \ - static int __ksym_marker_##sym[0] __section(".discard.ksym") __used + static int __ksym_marker_##sym[0] __section(.discard.ksym) __used #define __EXPORT_SYMBOL(sym, sec, ns) \ __ksym_marker(sym); \