From patchwork Wed Oct 18 13:42:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicola Vetrini X-Patchwork-Id: 13427105 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1E9CCCDB47E for ; Wed, 18 Oct 2023 13:42:44 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.618580.962392 (Exim 4.92) (envelope-from ) id 1qt6oW-0005Lh-51; Wed, 18 Oct 2023 13:42:20 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 618580.962392; Wed, 18 Oct 2023 13:42:20 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qt6oW-0005La-1s; Wed, 18 Oct 2023 13:42:20 +0000 Received: by outflank-mailman (input) for mailman id 618580; Wed, 18 Oct 2023 13:42:18 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qt6oU-0005LK-6r for xen-devel@lists.xenproject.org; Wed, 18 Oct 2023 13:42:18 +0000 Received: from support.bugseng.com (mail.bugseng.com [162.55.131.47]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 264254e2-6dbc-11ee-9b0e-b553b5be7939; Wed, 18 Oct 2023 15:42:16 +0200 (CEST) Received: from nico.bugseng.com (unknown [147.123.100.131]) by support.bugseng.com (Postfix) with ESMTPSA id 0BB714EE0739; Wed, 18 Oct 2023 15:42:13 +0200 (CEST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 264254e2-6dbc-11ee-9b0e-b553b5be7939 From: Nicola Vetrini To: xen-devel@lists.xenproject.org Cc: sstabellini@kernel.org, michal.orzel@amd.com, xenia.ragiadakou@amd.com, ayan.kumar.halder@amd.com, consulting@bugseng.com, jbeulich@suse.com, andrew.cooper3@citrix.com, roger.pau@citrix.com, Nicola Vetrini , Simone Ballarin , Doug Goldstein , George Dunlap , Julien Grall , Wei Liu Subject: [XEN PATCH][for-4.19 v3] xen: address violations of Rule 11.9 Date: Wed, 18 Oct 2023 15:42:11 +0200 Message-Id: X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 The constant 0 is used instead of NULL in '__ACCESS_ONCE' as a compile-time check to detect non-scalar types; its usage for this purpose is deviated. Furthermore, the 'typeof_field' macro is introduced as a general way to access the type of a struct member without declaring a variable of struct type. Both this macro and 'sizeof_field' are moved to 'xen/macros.h'. No functional change intended. Signed-off-by: Nicola Vetrini Reviewed-by: Jan Beulich Reviewed-by: Stefano Stabellini --- Changes in v2: - added entry in deviations.rst Changes in v3: - dropped access_field - moved macro to macros.h --- automation/eclair_analysis/ECLAIR/deviations.ecl | 9 +++++++++ docs/misra/deviations.rst | 5 +++++ xen/include/xen/compiler.h | 8 -------- xen/include/xen/kernel.h | 2 +- xen/include/xen/macros.h | 16 ++++++++++++++++ 5 files changed, 31 insertions(+), 9 deletions(-) diff --git a/automation/eclair_analysis/ECLAIR/deviations.ecl b/automation/eclair_analysis/ECLAIR/deviations.ecl index fa56e5c00a27..28d9c37bedb2 100644 --- a/automation/eclair_analysis/ECLAIR/deviations.ecl +++ b/automation/eclair_analysis/ECLAIR/deviations.ecl @@ -246,6 +246,15 @@ constant expressions are required.\"" "any()"} -doc_end +# +# Series 11 +# + +-doc_begin="This construct is used to check if the type is scalar, and for this purpose the use of 0 as a null pointer constant is deliberate." +-config=MC3R1.R11.9,reports+={deliberate, "any_area(any_loc(any_exp(macro(^__ACCESS_ONCE$))))" +} +-doc_end + # # Series 13 # diff --git a/docs/misra/deviations.rst b/docs/misra/deviations.rst index ee7aed0609d2..1b00e4e3e9b7 100644 --- a/docs/misra/deviations.rst +++ b/docs/misra/deviations.rst @@ -199,6 +199,11 @@ Deviations related to MISRA C:2012 Rules: See automation/eclair_analysis/deviations.ecl for the full explanation. - Tagged as `safe` for ECLAIR. + * - R11.9 + - __ACCESS_ONCE uses a 0 as a null pointer constant to check if a type is + scalar, therefore its usage for this purpose is allowed. + - Tagged as `deliberate` for ECLAIR. + * - R13.5 - All developers and reviewers can be safely assumed to be well aware of the short-circuit evaluation strategy for logical operators. diff --git a/xen/include/xen/compiler.h b/xen/include/xen/compiler.h index dd99e573083f..a8be1f19cfc2 100644 --- a/xen/include/xen/compiler.h +++ b/xen/include/xen/compiler.h @@ -109,14 +109,6 @@ #define offsetof(a,b) __builtin_offsetof(a,b) -/** - * sizeof_field(TYPE, MEMBER) - * - * @TYPE: The structure containing the field of interest - * @MEMBER: The field to return the size of - */ -#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER)) - #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L #define alignof __alignof__ #endif diff --git a/xen/include/xen/kernel.h b/xen/include/xen/kernel.h index 46b3c9c02625..2c5ed7736c99 100644 --- a/xen/include/xen/kernel.h +++ b/xen/include/xen/kernel.h @@ -51,7 +51,7 @@ * */ #define container_of(ptr, type, member) ({ \ - typeof( ((type *)0)->member ) *__mptr = (ptr); \ + typeof_field(type, member) *__mptr = (ptr); \ (type *)( (char *)__mptr - offsetof(type,member) );}) /* diff --git a/xen/include/xen/macros.h b/xen/include/xen/macros.h index d0caae7db298..457c84b9d1a0 100644 --- a/xen/include/xen/macros.h +++ b/xen/include/xen/macros.h @@ -54,6 +54,22 @@ #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]) + __must_be_array(x)) +/** + * typeof_field(type, member) + * + * @type: The structure containing the field of interest + * @member: The field whose type is returned + */ +#define typeof_field(type, member) typeof(((type *)NULL)->member) + +/** + * sizeof_field(type, member) + * + * @type: The structure containing the field of interest + * @member: The field to return the size of + */ +#define sizeof_field(type, member) sizeof(((type *)NULL)->member) + #endif /* __ASSEMBLY__ */ #endif /* __MACROS_H__ */