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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1CE66C433EF for ; Tue, 24 May 2022 03:59:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234092AbiEXD7t (ORCPT ); Mon, 23 May 2022 23:59:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233309AbiEXD7r (ORCPT ); Mon, 23 May 2022 23:59:47 -0400 Received: from alexa-out.qualcomm.com (alexa-out.qualcomm.com [129.46.98.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CB0A4EA21; Mon, 23 May 2022 20:59:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1653364786; x=1684900786; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=JtQtked8sKOZnAnbX7HvpbDPMaLU9/DINVcMbDa20Ac=; b=YwwUePaTheA5QGBsEQoZrTlddgDvfmVzkh7S8XcFD66wjRvzCix6UEg/ F7kMM8lQOl7pDLdphPRzoUd0TEpu0O4m8CmnFpz9VlgyF51GMps4fmMgE 1LUwnEC1pWzwGpq1l7l6MAyJLrBzJe/rDqDa2JzjgTxp54R4BpaJMInnM s=; Received: from ironmsg09-lv.qualcomm.com ([10.47.202.153]) by alexa-out.qualcomm.com with ESMTP; 23 May 2022 20:59:46 -0700 X-QCInternal: smtphost Received: from nasanex01c.na.qualcomm.com ([10.47.97.222]) by ironmsg09-lv.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 May 2022 20:59:46 -0700 Received: from nalasex01a.na.qualcomm.com (10.47.209.196) by nasanex01c.na.qualcomm.com (10.47.97.222) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Mon, 23 May 2022 20:59:45 -0700 Received: from [10.50.42.127] (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Mon, 23 May 2022 20:59:41 -0700 Message-ID: <5544ba12-8a7a-3bc5-1416-c8c707500c9d@quicinc.com> Date: Tue, 24 May 2022 09:29:38 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [PATCHv15 5/9] lib: Add register read/write tracing support Content-Language: en-US To: , CC: , , , , , , , , , , References: From: Sai Prakash Ranjan In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Steve, On 5/18/2022 10:14 PM, Sai Prakash Ranjan wrote: > From: Prasad Sodagudi > > Generic MMIO read/write i.e., __raw_{read,write}{b,l,w,q} accessors > are typically used to read/write from/to memory mapped registers > and can cause hangs or some undefined behaviour in following few > cases, > > * If the access to the register space is unclocked, for example: if > there is an access to multimedia(MM) block registers without MM > clocks. > > * If the register space is protected and not set to be accessible from > non-secure world, for example: only EL3 (EL: Exception level) access > is allowed and any EL2/EL1 access is forbidden. > > * If xPU(memory/register protection units) is controlling access to > certain memory/register space for specific clients. > > and more... > > Such cases usually results in instant reboot/SErrors/NOC or interconnect > hangs and tracing these register accesses can be very helpful to debug > such issues during initial development stages and also in later stages. > > So use ftrace trace events to log such MMIO register accesses which > provides rich feature set such as early enablement of trace events, > filtering capability, dumping ftrace logs on console and many more. > > Sample output: > > rwmmio_write: __qcom_geni_serial_console_write+0x160/0x1e0 width=32 val=0xa0d5d addr=0xfffffbfffdbff700 > rwmmio_post_write: __qcom_geni_serial_console_write+0x160/0x1e0 width=32 val=0xa0d5d addr=0xfffffbfffdbff700 > rwmmio_read: qcom_geni_serial_poll_bit+0x94/0x138 width=32 addr=0xfffffbfffdbff610 > rwmmio_post_read: qcom_geni_serial_poll_bit+0x94/0x138 width=32 val=0x0 addr=0xfffffbfffdbff610 > > Signed-off-by: Prasad Sodagudi > Co-developed-by: Sai Prakash Ranjan > Signed-off-by: Sai Prakash Ranjan > --- > arch/Kconfig | 3 ++ > arch/arm64/Kconfig | 1 + > include/trace/events/rwmmio.h | 97 +++++++++++++++++++++++++++++++++++ > lib/Kconfig | 7 +++ > lib/Makefile | 2 + > lib/trace_readwrite.c | 47 +++++++++++++++++ > 6 files changed, 157 insertions(+) > create mode 100644 include/trace/events/rwmmio.h > create mode 100644 lib/trace_readwrite.c How does this version look? Thanks, Sai