From patchwork Tue Mar 30 20:57:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 12173719 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-23.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F136C433DB for ; Tue, 30 Mar 2021 20:58:27 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 9BE17619C5 for ; Tue, 30 Mar 2021 20:58:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9BE17619C5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-21085-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 5228 invoked by uid 550); 30 Mar 2021 20:58:07 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 5156 invoked from network); 30 Mar 2021 20:58:06 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=9ijlYcKqhmRnIjh3GfaZu6VzSGgGwccaBk76YZfh88U=; b=FE7kn9uccaNwZUZ65DKIqMMeCF4L8T5uHj+6rAX1M16+hIAiROMPCoW0ANbpyvkauA zNm2OopXkQ6LAOsRPbIK640iKsOLSDOOggNsbZdq6eYIsT34pwdagUeVUvG7xjxhyCBj zo84r5YxnuOMKbimr0OM8w19pz/qkGBGzGeOI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=9ijlYcKqhmRnIjh3GfaZu6VzSGgGwccaBk76YZfh88U=; b=R2NSFVj/gz/Isd6Z353hIdYBdiYTx9KrY76INs8wuj5bem0TdzlM/NVR9x0/geW6oF KK7Hg610v/bs1ZOIxsan3NT1aLkG8FACa1fkV2u1DBHoeGm4xOiGlwZUXlY3lnQWYVN7 JEnszosurfkaJYwhkugSb5j3NJoZkHKtCJtKnepSzv+CZSqzu80ostrF+94zE+1jD32m zBfMAIfmsYfy/gC7BQAGTfuxIL72YvxAXVFoiombxnEt4E3Y3gTU9ZuA565vtEimU+2H Qq7WBMzQiKgZhJ8XOpJ4mjD6muWPDNfYAHEw6sE2zJweenu/Y+gLYIZ/dNeTm7CjGzr6 qTHQ== X-Gm-Message-State: AOAM531AAOSMD6SYqacwGV9eGhGO8GFkGzu6e74do8cxjlZxUouuJR97 EZCkCWKa8m1UrAurwuHF+Cuydg== X-Google-Smtp-Source: ABdhPJxKiSYrHQGcEilxb2Xm7psWt7RDOXuAoFkC/UflndAY9YjgBstIUNwwje4/jGjMrGhbk14LkA== X-Received: by 2002:a17:90b:38f:: with SMTP id ga15mr170436pjb.149.1617137874107; Tue, 30 Mar 2021 13:57:54 -0700 (PDT) From: Kees Cook To: Thomas Gleixner Cc: Kees Cook , Peter Zijlstra , Elena Reshetova , x86@kernel.org, Andy Lutomirski , Catalin Marinas , Will Deacon , Mark Rutland , Alexander Potapenko , Alexander Popov , Ard Biesheuvel , Jann Horn , Vlastimil Babka , David Hildenbrand , Mike Rapoport , Andrew Morton , Jonathan Corbet , Randy Dunlap , kernel-hardening@lists.openwall.com, linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v8 1/6] jump_label: Provide CONFIG-driven build state defaults Date: Tue, 30 Mar 2021 13:57:45 -0700 Message-Id: <20210330205750.428816-2-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210330205750.428816-1-keescook@chromium.org> References: <20210330205750.428816-1-keescook@chromium.org> MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; g=aa54c44d1d71b9550d6015efc734f667917094a1; i=Vishx6UyAXwYzcnoSyP+eBB3iQyx+/i5smsbQfc0cnA=; m=vc4sSYlf+uaSlLSFP5TpbQv56VaSRpBLpRuMltXaB4Q=; p=mNH2Bo/K9vrGz9sBtTDV8UFO0eJ8yv8BbR/DeIaO1es= X-Patch-Sig: m=pgp; i=keescook@chromium.org; s=0x0x8972F4DFDC6DC026; b=iQIzBAABCgAdFiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmBjkMwACgkQiXL039xtwCaWexAAp34 ok/GqKys22n/+Xt+9QrE/sBFj+uvgYjI14mqH/xkZoouYd5+myYJn0h/B8R83n48nwB7KdYtukzVv nSela//6I+ohCNhjgEt1TmUc81qTISl5q5mxbq/+IAPNVqlXEYCpTcSFkBbr5tbXOoOrbkI87vrja az8w6YyJGWbCBm/PpNK/FqvgxnWKMmJbomwDiBeWSgEfJUSD/M/r6PV1RhbK2mt7AniDqOPJ/oRG0 VB6GcbfW106hXfwKjmeqoce8yTv7YrC4mYL5sKA0yV/H62mmU9vkUtd+/0x07Cg1iXFAbg3bkDu/i hQkdH1ZBkjnjcWQJ6pvYBfHR+5Fblp8ibFwpPJc/hJmGkzxTde5pAlM3s4FMdtv++qD7bvL2tdXIS kzkw4HJRrjKMET9L3sAWvlSZgUTAip8wslmfIZUVea7HUy5ypoFIvSxHL5BNOGiTBp0zWwvXAzNt1 PTrOAP9fZKIsGI0Nj6laG2wpUdzjTpYcjfNxIPtygIIqheWGFwHwPYpWV0g8700cR/heR7qoBa0zt nrQX1WU7AUkaYROLg1QVWr13bMVlZZuDsSPfvsu3yo8alzHhY8xaryuKCwuTzY8ResHzU6XIqkmJb J1b8qCZ973eAn1T3KbVOk18YcqsShZ8C4SwIbyGOuesFrhes7bPZf/GqTx2MNcoU= As shown in jump_label.h[1], choosing the initial state of static branches changes the assembly layout. If the condition is expected to be likely it's inline, and if unlikely it is out of line via a jump. A few places in the kernel use (or could be using) a CONFIG to choose the default state, which would give a small performance benefit to their compile-time declared default. Provide the infrastructure to do this. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/jump_label.h?h=v5.11#n398 Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/lkml/20200324220641.GT2452@worktop.programming.kicks-ass.net/ Signed-off-by: Kees Cook --- include/linux/jump_label.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index d92691262f51..05f5554d860f 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -382,6 +382,21 @@ struct static_key_false { [0 ... (count) - 1] = STATIC_KEY_FALSE_INIT, \ } +#define _DEFINE_STATIC_KEY_1(name) DEFINE_STATIC_KEY_TRUE(name) +#define _DEFINE_STATIC_KEY_0(name) DEFINE_STATIC_KEY_FALSE(name) +#define DEFINE_STATIC_KEY_MAYBE(cfg, name) \ + __PASTE(_DEFINE_STATIC_KEY_, IS_ENABLED(cfg))(name) + +#define _DEFINE_STATIC_KEY_RO_1(name) DEFINE_STATIC_KEY_TRUE_RO(name) +#define _DEFINE_STATIC_KEY_RO_0(name) DEFINE_STATIC_KEY_FALSE_RO(name) +#define DEFINE_STATIC_KEY_MAYBE_RO(cfg, name) \ + __PASTE(_DEFINE_STATIC_KEY_RO_, IS_ENABLED(cfg))(name) + +#define _DECLARE_STATIC_KEY_1(name) DECLARE_STATIC_KEY_TRUE(name) +#define _DECLARE_STATIC_KEY_0(name) DECLARE_STATIC_KEY_FALSE(name) +#define DECLARE_STATIC_KEY_MAYBE(cfg, name) \ + __PASTE(_DECLARE_STATIC_KEY_, IS_ENABLED(cfg))(name) + extern bool ____wrong_branch_error(void); #define static_key_enabled(x) \ @@ -482,6 +497,10 @@ extern bool ____wrong_branch_error(void); #endif /* CONFIG_JUMP_LABEL */ +#define static_branch_maybe(config, x) \ + (IS_ENABLED(config) ? static_branch_likely(x) \ + : static_branch_unlikely(x)) + /* * Advanced usage; refcount, branch is enabled when: count != 0 */