From patchwork Wed Mar 31 20:54:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 12176283 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,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 555D8C433B4 for ; Wed, 31 Mar 2021 20:55:54 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 9329760BBB for ; Wed, 31 Mar 2021 20:55:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9329760BBB 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-21102-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 11524 invoked by uid 550); 31 Mar 2021 20:55:19 -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 11347 invoked from network); 31 Mar 2021 20:55:17 -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=WPzOZI/7h/nIlJykeZPJIx0pP8kh07MzAyzEZatHRuIhHB97Us6jbJeY/UYOlmqOhI I0ecVNwtacYNG9lms+cBmhaFNl0rIzXFYDD0LRCOvReTo3zRWs7cC3oUH7692A+ZDVVi 2gGuQxNlOLAX8UFE9I1BxL/Nh/X2RmBxs4Bxw= 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=Si7FKvgWxNkHdMKz+4ViDR48f8ZQoOeIqPxd5tIxyKxJoxgyI6NJpwcq5c1ixeD3Ob goOP4aDhRZuYOFEypnMPOAt0clCa9NgT4ju19C2BGXuKWMwt3ilUfa4zIgKMPNZIIk3A kkEV/monG1CRulG9TuV5Y1tTrFDszDuE8ge6GqpNdu7Pu32TNQ10SpphRUWXn+7jfui5 2z9IlTJr35InKqZA+X34z94AXdzP4agQtyHjsA8Qb8yyXiCyD685+2V/4Y9caLHCJAEx 9re9c1P7rJbTvp5J5LKeYRzoLRyzrXz5InNM5MtpriE9O4tcO0hRx1qxox8n99OEcH2/ XUoQ== X-Gm-Message-State: AOAM533RH7GpErqYHfxXEOpY6AYnMPphxRg3fgCD8aFkPsIai42weTsJ UxNAt/qsISgKPSRKyYLlVS8QSQ== X-Google-Smtp-Source: ABdhPJwjc+yR/F1HFGbsO3JvcN74Eaz7ocQ4vidQqR9lLlweYVUpN1FMKcKww5c8xRtm5T99yzj42g== X-Received: by 2002:a63:4f56:: with SMTP id p22mr4811122pgl.224.1617224106052; Wed, 31 Mar 2021 13:55:06 -0700 (PDT) From: Kees Cook To: Will Deacon Cc: Kees Cook , Peter Zijlstra , Catalin Marinas , Mark Rutland , Thomas Gleixner , Elena Reshetova , x86@kernel.org, Andy Lutomirski , 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 v9 1/6] jump_label: Provide CONFIG-driven build state defaults Date: Wed, 31 Mar 2021 13:54:53 -0700 Message-Id: <20210331205458.1871746-2-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210331205458.1871746-1-keescook@chromium.org> References: <20210331205458.1871746-1-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=iQIzBAABCgAdFiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmBk4aEACgkQiXL039xtwCaqhg/+KwH hAw/wsPS1SeVqGJmKPfdQr82hCM0Ml7SVm9J6WipR0nxoHNTRoTq5fJgQ/HAKX35mqAAL3tYGqBi0 2+4WfT2O7DCmcfB4kxHIAZPP1QJPHiUWqb+fNCgutJ9rorMb8tWzDisghAXGGA5mLJTb+e3za84Mg Tz11kRO6uL8orQe4PDGMbtu4ZCR98bQV+/s0SJ2edzBC6JEfXsZGQR+aVB8IXsP7SLf4m7cqs+xko 0HsCJcGnkdPob7OY3xJ5xX638TmezTLmrLymvZQF/3nSqc6H9sGuaiM3d+AM23zJ3MCY6ZlyJXvV8 GzbL/fy12rUa+H/CHYoxEjJJDyopHQQOf677UExOEVO+E4cujeCRzdKv5dGhmFIcpDsFb7FlVCloU ORxvUCgvTSBkWF3qpl9OVmYHU6SKzdG4TU/awDvK6NojCgqhZpoIKjFDsImZzpta59PWF0iJQY7XJ jEq3UVi32y1V10znVqFCRaTTsYnknmSRGohaJqK9aIN29Ua/iBZooygQSNVS0ae3NR3YEQRHRoEZV kgil7zpFlzwuBxrLHrYvvKq3r0q0H4hsoDpFHgHGDZaTXKU4EXWsZ66xrOPJi0r6R9a8pYf+QDjxC cqQfU25fy65WH6DRJBFFXm3eRu/MP8OcVb83DQXHPhdKGC0lf0O4/2ELWKbU5SbM= 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 */