From patchwork Fri Mar 19 21:28:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 12151953 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=-24.0 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 B4A0BC433C1 for ; Fri, 19 Mar 2021 21:29:27 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 0A48660232 for ; Fri, 19 Mar 2021 21:29:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0A48660232 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-21007-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 16207 invoked by uid 550); 19 Mar 2021 21:28:53 -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 16041 invoked from network); 19 Mar 2021 21:28:50 -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=hNLL/iR5ciHz3nypbWaLIbBPySyhArn0Jn6KwOSnKW7StS7IyHeAh9dHsnn+rBVZuM SZXdTNSxwVKq50x5Xf1v8bhM7QBb3pZu9DXAAd2wnWgI9CSi2PqravtbBDaRX8BVIsHo Z26cDQYXGeG5i2SkY21uKSrrQC+cMtJEhj+u8= 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=ub/aV9zYjZMXtujzMnum/RdSUhjexAfrw1dmY1uKE7Xm8GtADK6hKqYyt+p3g7C/FI ai96WDwHJSFTYWVqe+YvaJEWhboAfUeTDryvcewzB8u+NPpR6KByGbLU9IV1/bl05SPu qIAbnJFAqRvsTOd8NfZzFGTitNHRMKe9e0/hvuefHwEJGfJLIoFexCK8cL7nBHj6Yigh NutfZMA4+/FHI8A9RUbXTVZF0aN+7n8MAMnWyn4q+9gxWEPlksgty8Z0vFT5i2vERhkJ ImgUD5UMRK7hMR6yL7RS4giheTmI9od+pyj9Aunj/X1WiwU/YbSmfk/Sr5245o26Woyu aTMQ== X-Gm-Message-State: AOAM532X/BGImzn7pVC6cPLd877a+xj066E411V0KFM0M7gLT33gMTpC b+ZDSPCA7An6olOmIdG/ngoFRQ== X-Google-Smtp-Source: ABdhPJyfUXAHNwViuz7nekDjbNriZkEy04Ykr/kaTbKMfCJtsvgOEgLVUNsmKw9hYWc1Hz7JsbqgUA== X-Received: by 2002:a17:902:6b43:b029:e6:3d73:e9fb with SMTP id g3-20020a1709026b43b02900e63d73e9fbmr16208336plt.37.1616189318964; Fri, 19 Mar 2021 14:28:38 -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 v7 1/6] jump_label: Provide CONFIG-driven build state defaults Date: Fri, 19 Mar 2021 14:28:30 -0700 Message-Id: <20210319212835.3928492-2-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210319212835.3928492-1-keescook@chromium.org> References: <20210319212835.3928492-1-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=iQIzBAABCgAdFiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmBVF4EACgkQiXL039xtwCYoKQ//WsO JhBKVKfDUIyIOwrMCU3Z/kRQjSwDXUlgTtwiYp36T0IJ3d76UirWkyQFSy0y5HMNMyGbGhto2ftzU 7iBhSN/U2EHLY80ksg28k/Xw8jFC36JeiIgqYDWJHbE6d5D5MDzR6+ubtytgB1aNhCuOpETM6HMkZ t5Ckc7Bk31LbOuKiVpG6nzLce4/BxOYq9vzWNPU8g7YB17QXuTDWgurYMwMXytg5uUR6vdCgOKeaH fNyC+StIV1Lj9LzoYgRQKXXYFXduWjWKZ3WcYpJfwgStKSe9uhM6MvfA3aW9W6f5+n/SQS7Yejt5E YYTBCKbMqEIHMuruza2MOMKuyIoK9bT1qvbzDJCEoCXh/DuiSUbdxpMMgtcwPdkxiHHkUPzhkIl7H DwQY5X+eVbPVxL8W9QoKeq+8d/Ve4ASwv4kzDFC65vq5+WI6sK0pQsT4u/3Rcu8sEf0GC25e4tELr 7R0tPXMOgYkGsKM9dVtfSLbQJjvHmaRWJmZrufU9nmYGQuavWsaVkQJTKMY2SkUevJNw+KxlrUCmz gsgT24T5dWCOZao0jTacVwTJ/WKm7vV7SnxTvandK270LFmG5gK/1USGGs8znRoMJPkDE4Ktfzruf pZUWQhHZoMIENQGhElqSlhCvcRS0QOcc9VmehZJGxju+EVvlYvvLM5JDtvaCjRnw= 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 */