From patchwork Fri Dec 22 19:51:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Graf X-Patchwork-Id: 13503784 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E4AF7C4706C for ; Fri, 22 Dec 2023 19:53:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=GVLZeu5lBNyNjnrTBAj9im9YaUX+LMyboufQKEF0BuQ=; b=2NnJoS+4bINIuj kqHb0nDhMESE9RVcxYycngh11eKhL9HK8+xduskWH5/qMz683nFH1znbW9nJ04+Mt29xiV30JPdIJ TFFdalC6wp4Fw/1UGiDXTfaHoljV2PaJ7JcAu39HJL2cgY2tHyFCnhGRh7ZuU+thscxkZEKki0uUC WPQ0OGTs5V+pJG1u2R2AGgkl9i8FT5JioChXVdovnkA17tfrzSa2ijjl9ggQI5H7n6EF9Muy9ICz2 4h2b3DeeviaV4wYtAmsgeFhfdCDPBGg3H9bb90P45BGwPNnXHgIlwyICoKlaxE7OfOKPM+QmpMzL2 +xJLzmL/YSuiV4qxZCug==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rGlZl-006l9d-0q; Fri, 22 Dec 2023 19:52:53 +0000 Received: from smtp-fw-52002.amazon.com ([52.119.213.150]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rGlZY-006kyT-04; Fri, 22 Dec 2023 19:52:43 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1703274760; x=1734810760; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=qmhUZjf5F0irRMFPH4YUunFpNZODTBv7SKMl/vOJmCU=; b=DZRtWwrHDbeJZ7Kiu3qm0w1oqMzmDwUgILe68nCq3rnvP8iIAmvFKR7g EeCqvMM14rOzGHaBMcpBn4nfvfAGp7++DRi8C78/ATDQ6gamcz7BDsceo J8yb88i+4wsUT07oREBsaqzbz7bGNmKVBS0BRC7/94nIRfgXzSlHZ8aD2 I=; X-IronPort-AV: E=Sophos;i="6.04,297,1695686400"; d="scan'208";a="602627243" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-iad-1d-m6i4x-25ac6bd5.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-52002.iad7.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Dec 2023 19:52:39 +0000 Received: from smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev (iad7-ws-svc-p70-lb3-vlan2.iad.amazon.com [10.32.235.34]) by email-inbound-relay-iad-1d-m6i4x-25ac6bd5.us-east-1.amazon.com (Postfix) with ESMTPS id E5434498C1; Fri, 22 Dec 2023 19:52:31 +0000 (UTC) Received: from EX19MTAUWB001.ant.amazon.com [10.0.7.35:18611] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.6.30:2525] with esmtp (Farcaster) id 881e61d8-d7c5-43dd-85b6-cb73d6682b26; Fri, 22 Dec 2023 19:52:30 +0000 (UTC) X-Farcaster-Flow-ID: 881e61d8-d7c5-43dd-85b6-cb73d6682b26 Received: from EX19D020UWC004.ant.amazon.com (10.13.138.149) by EX19MTAUWB001.ant.amazon.com (10.250.64.248) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Fri, 22 Dec 2023 19:52:30 +0000 Received: from dev-dsk-graf-1a-5ce218e4.eu-west-1.amazon.com (10.253.83.51) by EX19D020UWC004.ant.amazon.com (10.13.138.149) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Fri, 22 Dec 2023 19:52:26 +0000 From: Alexander Graf To: CC: , , , , , , , Eric Biederman , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , "Rob Herring" , Steven Rostedt , "Andrew Morton" , Mark Rutland , "Tom Lendacky" , Ashish Kalra , James Gowans , Stanislav Kinsburskii , , , , Anthony Yznaga , Usama Arif , David Woodhouse , Benjamin Herrenschmidt Subject: [PATCH v2 11/17] tracing: Introduce kho serialization Date: Fri, 22 Dec 2023 19:51:38 +0000 Message-ID: <20231222195144.24532-6-graf@amazon.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20231222195144.24532-1-graf@amazon.com> References: <20231222193607.15474-1-graf@amazon.com> <20231222195144.24532-1-graf@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.253.83.51] X-ClientProxiedBy: EX19D042UWA003.ant.amazon.com (10.13.139.44) To EX19D020UWC004.ant.amazon.com (10.13.138.149) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231222_115240_197882_36AB0304 X-CRM114-Status: GOOD ( 15.89 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org We want to be able to transfer ftrace state from one kernel to the next. To start off with, let's establish all the boiler plate to get a write hook when KHO wants to serialize and fill out basic data. Follow-up patches will fill in serialization of ring buffers and events. Signed-off-by: Alexander Graf --- v1 -> v2: - Remove ifdefs --- kernel/trace/trace.c | 47 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 199df497db07..6ec31879b4eb 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include #include @@ -866,6 +867,8 @@ static struct tracer *trace_types __read_mostly; */ DEFINE_MUTEX(trace_types_lock); +static bool trace_in_kho; + /* * serialize the access of the ring buffer * @@ -10560,12 +10563,56 @@ void __init early_trace_init(void) init_events(); } +static int trace_kho_notifier(struct notifier_block *self, + unsigned long cmd, + void *v) +{ + const char compatible[] = "ftrace-v1"; + void *fdt = v; + int err = 0; + + switch (cmd) { + case KEXEC_KHO_ABORT: + if (trace_in_kho) + mutex_unlock(&trace_types_lock); + trace_in_kho = false; + return NOTIFY_DONE; + case KEXEC_KHO_DUMP: + /* Handled below */ + break; + default: + return NOTIFY_BAD; + } + + if (unlikely(tracing_disabled)) + return NOTIFY_DONE; + + err |= fdt_begin_node(fdt, "ftrace"); + err |= fdt_property(fdt, "compatible", compatible, sizeof(compatible)); + err |= fdt_end_node(fdt); + + if (!err) { + /* Hold all future allocations */ + mutex_lock(&trace_types_lock); + trace_in_kho = true; + } + + return err ? NOTIFY_BAD : NOTIFY_DONE; +} + +static struct notifier_block trace_kho_nb = { + .notifier_call = trace_kho_notifier, +}; + void __init trace_init(void) { trace_event_init(); if (boot_instance_index) enable_instances(); + + if (IS_ENABLED(CONFIG_FTRACE_KHO)) + register_kho_notifier(&trace_kho_nb); } __init static void clear_boot_tracer(void)