From mboxrd@z Thu Jan 1 00:00:00 1970 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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 ADAB2C2BA83 for ; Fri, 7 Feb 2020 18:59:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 77B952464B for ; Fri, 7 Feb 2020 18:59:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="nP+4sZ11" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727065AbgBGS7T (ORCPT ); Fri, 7 Feb 2020 13:59:19 -0500 Received: from mail-wr1-f73.google.com ([209.85.221.73]:51336 "EHLO mail-wr1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726900AbgBGS7T (ORCPT ); Fri, 7 Feb 2020 13:59:19 -0500 Received: by mail-wr1-f73.google.com with SMTP id c6so107490wrm.18 for ; Fri, 07 Feb 2020 10:59:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=nR+y9oL83JIGNZtIre6/euwCwaqJGCzYCr1D5UPHiH4=; b=nP+4sZ11+bPG7CKNNsIVXFVgJ9RV5HxfeJX1ANQYSQalovtR9KJ+XgtL6djX225oDc x58UXUaq7HZDzRZ9nuES1dj8iSUziSjL5xgYygFjwPUPyqzk7El3+awQLU3A7fBP36qd JKAxgMLGh7j7ynfzYadsnJ7oLZnz0TkreQkG1/AHWLk8eYX7D6bPHi9/EYzDpeG+oLKz SUW3eE0nnnW33XJ2+hRlc732/wuptyj6hsuyRwfbCVmA1ewjVa/FHEw1pVJNyp6toL0I nrZdkG5U4PQTwvH6xD7XH49QTFyX1LejcaEZ8zd+YeeU31kQcE+Is12v1vAmHKc4qbE4 I9ew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=nR+y9oL83JIGNZtIre6/euwCwaqJGCzYCr1D5UPHiH4=; b=S0q+aNt4ZPf9w0s8+Iu0y4Z9Y24Nr4Vf4TuZ6B2bK8w7Hzl3lsMokGf0NYaAybVCwb gW78A53RMGtAgoaG1BtNKkG6JgoFU3OaYdv6VP38QE6BxOWqyGf4SU/yotI6vtFzfOmA /4ffhndOhmHMKjuOiw41Lhl9uqN3PjX6/FEYWH00P7ZCdFUwhALv9LM/8258zwofUK2O cazwHpRstTpJaoZVtfveuK7zFyILCPXpc/DSsE0r5P6XURYtC4lEEfWqaZhjXgYl+XwD +rqBU5tLQ1oZ20byIUW60ZYA/N1xR/Zsee9twzlq2d7jia/8MUz36UfZqpBcvnE3QmBg XO4A== X-Gm-Message-State: APjAAAWvqkrWFWc0NbkndmanmBTfXj6fMozo18VneXOL8/bANqDCRnCb iM4zTFZr1dD1jJxTNpx4gcfCmgKTMQ== X-Google-Smtp-Source: APXvYqyf/g7zk1EO7HKJUQGSGYz/6bLPHYZzw4JG7fqMMjAq1bcJGTMVNQqgTVaiEexiNoXYKWBxs6fC4g== X-Received: by 2002:a5d:40d1:: with SMTP id b17mr400665wrq.93.1581101956137; Fri, 07 Feb 2020 10:59:16 -0800 (PST) Date: Fri, 7 Feb 2020 19:59:10 +0100 Message-Id: <20200207185910.162512-1-elver@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.25.0.341.g760bfbb309-goog Subject: [PATCH] kcsan: Expose core configuration parameters as module params From: Marco Elver To: elver@google.com Cc: paulmck@kernel.org, andreyknvl@google.com, glider@google.com, dvyukov@google.com, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, Qian Cai Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This adds early_boot, udelay_{task,interrupt}, and skip_watch as module params. The latter parameters are useful to modify at runtime to tune KCSAN's performance on new systems. This will also permit auto-tuning these parameters to maximize overall system performance and KCSAN's race detection ability. None of the parameters are used in the fast-path and referring to them via static variables instead of CONFIG constants will not affect performance. Signed-off-by: Marco Elver Cc: Qian Cai --- kernel/kcsan/core.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c index 87ef01e40199d..498b1eb3c1cda 100644 --- a/kernel/kcsan/core.c +++ b/kernel/kcsan/core.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -16,6 +17,20 @@ #include "encoding.h" #include "kcsan.h" +static bool kcsan_early_enable = IS_ENABLED(CONFIG_KCSAN_EARLY_ENABLE); +static unsigned int kcsan_udelay_task = CONFIG_KCSAN_UDELAY_TASK; +static unsigned int kcsan_udelay_interrupt = CONFIG_KCSAN_UDELAY_INTERRUPT; +static long kcsan_skip_watch = CONFIG_KCSAN_SKIP_WATCH; + +#ifdef MODULE_PARAM_PREFIX +#undef MODULE_PARAM_PREFIX +#endif +#define MODULE_PARAM_PREFIX "kcsan." +module_param_named(early_enable, kcsan_early_enable, bool, 0); +module_param_named(udelay_task, kcsan_udelay_task, uint, 0644); +module_param_named(udelay_interrupt, kcsan_udelay_interrupt, uint, 0644); +module_param_named(skip_watch, kcsan_skip_watch, long, 0644); + bool kcsan_enabled; /* Per-CPU kcsan_ctx for interrupts */ @@ -239,9 +254,9 @@ should_watch(const volatile void *ptr, size_t size, int type) static inline void reset_kcsan_skip(void) { - long skip_count = CONFIG_KCSAN_SKIP_WATCH - + long skip_count = kcsan_skip_watch - (IS_ENABLED(CONFIG_KCSAN_SKIP_WATCH_RANDOMIZE) ? - prandom_u32_max(CONFIG_KCSAN_SKIP_WATCH) : + prandom_u32_max(kcsan_skip_watch) : 0); this_cpu_write(kcsan_skip, skip_count); } @@ -253,8 +268,7 @@ static __always_inline bool kcsan_is_enabled(void) static inline unsigned int get_delay(void) { - unsigned int delay = in_task() ? CONFIG_KCSAN_UDELAY_TASK : - CONFIG_KCSAN_UDELAY_INTERRUPT; + unsigned int delay = in_task() ? kcsan_udelay_task : kcsan_udelay_interrupt; return delay - (IS_ENABLED(CONFIG_KCSAN_DELAY_RANDOMIZE) ? prandom_u32_max(delay) : 0); @@ -527,7 +541,7 @@ void __init kcsan_init(void) * We are in the init task, and no other tasks should be running; * WRITE_ONCE without memory barrier is sufficient. */ - if (IS_ENABLED(CONFIG_KCSAN_EARLY_ENABLE)) + if (kcsan_early_enable) WRITE_ONCE(kcsan_enabled, true); } -- 2.25.0.341.g760bfbb309-goog