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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 55ED0C10F27 for ; Mon, 9 Mar 2020 19:05:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 32EF9215A4 for ; Mon, 9 Mar 2020 19:05:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583780713; bh=h8NlL0BNWOOzGjbattsQHdPTR/D98Gipr0p/Cf1gauo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=a+XvVHyUyOFajQR6rAj11o0JszK3dQA++BGZjhwTuCrDiHLt3rjTqKf8oZYI5u4P9 ehE0htTu27klUlN4YFWblnuWySoOP/MIR57+UgUhSG0vkn4nRqK4J8hMhuua+t+QTj YG26NZ/UNNhiF7vpbTQcD98yRvEn0cZk0zzeGBDc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727789AbgCITFL (ORCPT ); Mon, 9 Mar 2020 15:05:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:47878 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727562AbgCITE1 (ORCPT ); Mon, 9 Mar 2020 15:04:27 -0400 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CF29021655; Mon, 9 Mar 2020 19:04:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583780667; bh=h8NlL0BNWOOzGjbattsQHdPTR/D98Gipr0p/Cf1gauo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IAd2hde4Obj2yUyEKiuD+RNlHhu9QkfyY8Nth3FZj/IclaMTSj/ebOWqxlv45Y85D blN8y9OUDB9g57RMkn0YUQDlHK1g1sl0hr/mMJJvzeclAp/H4QLxlLtmjsd2ivSoIL mZcz2bxPEMPjZJcSyDIdXq+KYMU3BAEG+l6rCRes= From: paulmck@kernel.org To: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, kernel-team@fb.com, mingo@kernel.org Cc: elver@google.com, andreyknvl@google.com, glider@google.com, dvyukov@google.com, cai@lca.pw, boqun.feng@gmail.com, "Paul E . McKenney" Subject: [PATCH kcsan 19/32] kcsan: Expose core configuration parameters as module params Date: Mon, 9 Mar 2020 12:04:07 -0700 Message-Id: <20200309190420.6100-19-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20200309190359.GA5822@paulmck-ThinkPad-P72> References: <20200309190359.GA5822@paulmck-ThinkPad-P72> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marco Elver 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 Signed-off-by: Paul E. McKenney --- 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 87ef01e..498b1eb 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); } -- 2.9.5