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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 12060C48BE5 for ; Sat, 19 Jun 2021 06:29:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA11E611B0 for ; Sat, 19 Jun 2021 06:29:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233901AbhFSGbl (ORCPT ); Sat, 19 Jun 2021 02:31:41 -0400 Received: from mail.loongson.cn ([114.242.206.163]:45474 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S233081AbhFSGbh (ORCPT ); Sat, 19 Jun 2021 02:31:37 -0400 Received: from linux.localdomain (unknown [113.200.148.30]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Dx70DBjs1gXRcUAA--.23357S3; Sat, 19 Jun 2021 14:29:22 +0800 (CST) From: Tiezhu Yang To: Steven Rostedt , Ingo Molnar , Jonathan Corbet Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Xuefeng Li Subject: [RFC PATCH 1/2] ftrace: Introduce cmdline argument ftrace_disabled Date: Sat, 19 Jun 2021 14:29:19 +0800 Message-Id: <1624084160-3342-2-git-send-email-yangtiezhu@loongson.cn> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1624084160-3342-1-git-send-email-yangtiezhu@loongson.cn> References: <1624084160-3342-1-git-send-email-yangtiezhu@loongson.cn> X-CM-TRANSID: AQAAf9Dx70DBjs1gXRcUAA--.23357S3 X-Coremail-Antispam: 1UD129KBjvdXoWrtw1DZFykWrWrCF4rJF4ktFb_yoWkGrX_XF srX3WDXr13Cw1vyw1rX3yrZry0gw1IgF4q9w1xKry5J3W8J3y5Ka13XwnIy3Wvgr40qF9x Ar47Jr15KF4fGjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbhxFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUGwA2048vs2IY02 0Ec7CjxVAFwI0_JFI_Gr1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1l84 ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AKxVWxJr0_GcWl e2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI 8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwAC jcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc2xSY4AK67AK6r47MxAIw2 8IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4l x2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUAVWUtwCIc40Y0x0EwIxGrw CI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI 42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z2 80aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUjLZ2DUUUUU== X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If set CONFIG_FUNCTION_TRACER=y, we can use the following command to disable ftrace after boot up: echo 0 > /proc/sys/kernel/ftrace_enabled ftrace_disabled is much stronger than ftrace_enabled, introduce a new cmdline argument ftrace_disabled for user to control whether to disable ftrace when boot up. Signed-off-by: Tiezhu Yang --- kernel/trace/ftrace.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 72ef4dc..a015699 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5517,6 +5517,14 @@ static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata; /* Used by function selftest to not test if filter is set */ bool ftrace_filter_param __initdata; +static int __init set_ftrace_disabled(char *str) +{ + pr_info("Set ftrace_disabled to disable ftrace\n"); + ftrace_disabled = 1; + return 1; +} +__setup("ftrace_disabled", set_ftrace_disabled); + static int __init set_ftrace_notrace(char *str) { ftrace_filter_param = true; -- 2.1.0