From patchwork Wed Jun 22 02:46:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chunyan Zhang X-Patchwork-Id: 9191767 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 4DB2A6075E for ; Wed, 22 Jun 2016 02:49:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 419262838C for ; Wed, 22 Jun 2016 02:49:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3639A28391; Wed, 22 Jun 2016 02:49:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED, T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id DDD20283E0 for ; Wed, 22 Jun 2016 02:49:46 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bFYDB-0002d7-LM; Wed, 22 Jun 2016 02:48:17 +0000 Received: from mail-pa0-x22c.google.com ([2607:f8b0:400e:c03::22c]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1bFYD9-0002Tq-1D for linux-arm-kernel@lists.infradead.org; Wed, 22 Jun 2016 02:48:15 +0000 Received: by mail-pa0-x22c.google.com with SMTP id bz2so12012111pad.1 for ; Tue, 21 Jun 2016 19:47:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=F4HWFejdh/Ugl98i8FXih7FsxA2PEzroOAPk5JwklIU=; b=HVAHKNdOrDe6GTrlca248gRRsXwQdOv7rHKMK4GBKHqV8zo2NLvxUcqYOrRmtWXfdq HDoSzY1BUg+zjykQr61q07QZSTDjrMv3UG+EXt258jZL9VhZD8X8e2l4cX+tY2AH2TVu yvwTiNUyzUzxA1MA4VZarTAaA0k8QK4e3Q+fk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=F4HWFejdh/Ugl98i8FXih7FsxA2PEzroOAPk5JwklIU=; b=eJt1ykbqqUugoxjw6fFlyc7CW+KhAClzj4lNO5jLaUZZ1uxtP2LSSmcS7vLMX8uYqO oSkLPg+LCwtoHXW/eLs7CkMh7soTuwmPa/IqO2tCOhgjbU8CMTWlEEm5WtIoq4X8AQFC 3QpPaS/WHzgNzQ3dh0CtoE1Ne6dMqO8lYuFnZwlDGYmuWlTqVaxlvvQtBFp+VUspDZqi d+hQTnHarTl7u1g5LVFm3EOXmFanKWPcJZXQnhNhAxJkg+VnbKVtkn+rc7qOitfnBuiL WN/5jXy6eU0lLFdXVl3IEsVdSTMFNzIdnsqq+EeYPv7gGU8Mh8rAkx+g0gty7mvpHL0H vJmA== X-Gm-Message-State: ALyK8tIrLeKje5FvKoLkszelkE29/pljrmAzXT6quxcGWnx1wtiZUeB3f8VdO+MbrvjdEzea X-Received: by 10.66.168.13 with SMTP id zs13mr31498215pab.68.1466563674289; Tue, 21 Jun 2016 19:47:54 -0700 (PDT) Received: from zcy-ubuntu.spreadtrum.com ([175.111.195.49]) by smtp.gmail.com with ESMTPSA id y70sm98867836pff.25.2016.06.21.19.47.49 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 21 Jun 2016 19:47:53 -0700 (PDT) From: Chunyan Zhang To: rostedt@goodmis.org, mathieu.poirier@linaro.org, alexander.shishkin@linux.intel.com, mingo@redhat.com Subject: [PATCH V2 1/4] trace: Introduce an output interface from ftrace to STM Date: Wed, 22 Jun 2016 10:46:50 +0800 Message-Id: <1466563613-31578-2-git-send-email-zhang.chunyan@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1466563613-31578-1-git-send-email-zhang.chunyan@linaro.org> References: <1466563613-31578-1-git-send-email-zhang.chunyan@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160621_194815_104676_D42D34E6 X-CRM114-Status: GOOD ( 19.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: zhang.lyra@gmail.com, linux-kernel@vger.kernel.org, tor@ti.com, philippe.langlais@st.com, mike.leach@arm.com, nicolas.guion@st.com, linux-arm-kernel@lists.infradead.org, maxime.coquelin@st.com MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP This patch is introducing a new output to print Ftrace messages to STM buffer when the traces happen. In order to reduce the effect on timing overhead as much as possible, only the current function and its parent's instruction pointer will be recorded into STM. This idea was first introduced by Philippe Langlais at ST-Microelectronics a long time ago[1]. [1] http://thread.gmane.org/gmane.linux.kernel/1114274/focus=1114275 Signed-off-by: Chunyan Zhang --- include/linux/stm.h | 7 +++++++ include/linux/trace_output_stm.h | 17 +++++++++++++++++ kernel/trace/Makefile | 1 + kernel/trace/trace_output_stm.c | 41 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 66 insertions(+) create mode 100644 include/linux/trace_output_stm.h create mode 100644 kernel/trace/trace_output_stm.c diff --git a/include/linux/stm.h b/include/linux/stm.h index 8369d8a..2b6639a 100644 --- a/include/linux/stm.h +++ b/include/linux/stm.h @@ -129,6 +129,13 @@ struct stm_source_data { void (*unlink)(struct stm_source_data *data); }; +struct stm_ftrace { + struct stm_source_data data; + void (*write)(struct stm_source_data *data, const char *buf, + unsigned int len, unsigned int chan); + bool available; +}; + int stm_source_register_device(struct device *parent, struct stm_source_data *data); void stm_source_unregister_device(struct stm_source_data *data); diff --git a/include/linux/trace_output_stm.h b/include/linux/trace_output_stm.h new file mode 100644 index 0000000..7edc680 --- /dev/null +++ b/include/linux/trace_output_stm.h @@ -0,0 +1,17 @@ +#ifndef __TRACE_OUTPUT_STM_H +#define __TRACE_OUTPUT_STM_H + +#include + +#if IS_ENABLED(CONFIG_STM_SOURCE_FTRACE) +struct stm_ftrace; +extern void +trace_func_to_stm(unsigned long ip, unsigned long parent_ip); +extern void trace_add_output(struct stm_ftrace *stm); +extern void trace_rm_output(void); +#else +static inline void +trace_func_to_stm(unsigned long ip, unsigned long parent_ip) {} +#endif + +#endif /* __TRACE_OUTPUT_STM_H */ diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 979e7bf..5330803 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -69,4 +69,5 @@ obj-$(CONFIG_UPROBE_EVENT) += trace_uprobe.o obj-$(CONFIG_TRACEPOINT_BENCHMARK) += trace_benchmark.o +obj-$(CONFIG_TRACING) += trace_output_stm.o libftrace-y := ftrace.o diff --git a/kernel/trace/trace_output_stm.c b/kernel/trace/trace_output_stm.c new file mode 100644 index 0000000..dc04952 --- /dev/null +++ b/kernel/trace/trace_output_stm.c @@ -0,0 +1,41 @@ +/* + * Output interface from Ftrace to STM buffer + * Copyright (c) 2016, Linaro Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#include + +/* Offset above the start channel number */ +#define STM_FTRACE_CHAN 0 + +static struct stm_ftrace *trace_output; + +void trace_func_to_stm(unsigned long ip, unsigned long parent_ip) +{ + unsigned long ip_array[2] = {ip, parent_ip}; + + if (trace_output) + trace_output->write(&trace_output->data, (char *)ip_array, + sizeof(unsigned long) * 2, STM_FTRACE_CHAN); +} + +void trace_add_output(struct stm_ftrace *stm) +{ + trace_output = stm; +} +EXPORT_SYMBOL_GPL(trace_add_output); + +void trace_rm_output(void) +{ + trace_output = NULL; +} +EXPORT_SYMBOL_GPL(trace_rm_output);