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 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 A0483EB64D7 for ; Wed, 28 Jun 2023 16:53:54 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=vYXY3NHfPZ40w+ZXy/lZPLp+XSPrCRR5Xv0xavXycFA=; b=blbGoJUR+OUdmN 8qyiNlzHDUTAPXYPHgjUo3GhNNe+vy6HyNJVmsE2v2XzUs5SFBZJlSSwdBbODtL08nz53yQVJ/+u4 8DOYw8NJqwld7P5O7V5Hl6Rp32U02eDaF5F0oQVT/SxyDSbkc54uvvYPF3szIxf3tUMCxaip3HoE1 G4uYz1fh2pquGM1HiH+MIEvWMTyLNe93Zzm+a6NVVOdQXXGSWJJK9QzX77umeSZuzzlNTPQKkUr5m lAMckinbpZl6Y1dIbkxCLoYpgkIW5HzqwposnPHn/azTwYgqCxTeRB3fsQGWnKEN/IZGenZbX/2Ma 88113poPbpEinTdWQzyQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qEYQ2-00GCvD-0x; Wed, 28 Jun 2023 16:53:26 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qEYPy-00GCpR-1U for linux-arm-kernel@lists.infradead.org; Wed, 28 Jun 2023 16:53:24 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E94EE61354; Wed, 28 Jun 2023 16:53:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFC8EC433C8; Wed, 28 Jun 2023 16:53:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1687971201; bh=gozokXz2eVh6fctzR506kgwTFWCpOKR95WNjlihKjp0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XSAZJUru2/LERqubKZhN960vjbBGOsstoqQchktqgk2eAmAtD04A8rchUv6KtMPCO bluJTB4rl9FsREuSLLbvkM+kuLVOwWaqtIpM5FPIWWt2zmRAH96RiEjex7HjZ2P52U 90KKlCAHvvTURFden0f0Wv5p/9azoOifGjIJdo/I= Date: Wed, 28 Jun 2023 18:53:18 +0200 From: Greg KH To: Mukesh Ojha Cc: corbet@lwn.net, agross@kernel.org, andersson@kernel.org, konrad.dybcio@linaro.org, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, keescook@chromium.org, tony.luck@intel.com, gpiccoli@igalia.com, mathieu.poirier@linaro.org, catalin.marinas@arm.com, will@kernel.org, linus.walleij@linaro.org, andy.shevchenko@gmail.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-hardening@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org Subject: Re: [PATCH v4 00/21] Add Qualcomm Minidump kernel driver related support Message-ID: <2023062812-exporter-facing-aaf9@gregkh> References: <1687955688-20809-1-git-send-email-quic_mojha@quicinc.com> <2023062814-chance-flounder-f002@gregkh> <10dd2ead-758a-89f0-cda4-70ae927269eb@quicinc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <10dd2ead-758a-89f0-cda4-70ae927269eb@quicinc.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230628_095322_606135_C3F7B826 X-CRM114-Status: GOOD ( 35.00 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jun 28, 2023 at 09:50:00PM +0530, Mukesh Ojha wrote: > > > On 6/28/2023 9:15 PM, Greg KH wrote: > > On Wed, Jun 28, 2023 at 06:04:27PM +0530, Mukesh Ojha wrote: > > > Minidump is a best effort mechanism to collect useful and predefined data > > > for first level of debugging on end user devices running on Qualcomm SoCs. > > > It is built on the premise that System on Chip (SoC) or subsystem part of > > > SoC crashes, due to a range of hardware and software bugs. Hence, the > > > ability to collect accurate data is only a best-effort. The data collected > > > could be invalid or corrupted, data collection itself could fail, and so on. > > > > > > Qualcomm devices in engineering mode provides a mechanism for generating > > > full system ramdumps for post mortem debugging. But in some cases it's > > > however not feasible to capture the entire content of RAM. The minidump > > > mechanism provides the means for selecting which snippets should be > > > included in the ramdump. > > > > > > Minidump kernel driver implementation is divided into two parts for > > > simplicity, one is minidump core which can also be called minidump > > > frontend(As API gets exported from this driver for registration with > > > backend) and the other part is minidump backend i.e, where the underlying > > > implementation of minidump will be there. There could be different way > > > how the backend is implemented like Shared memory, Memory mapped IO > > > or Resource manager(gunyah) based where the guest region information is > > > passed to hypervisor via hypercalls. > > > > > > Minidump Client-1 Client-2 Client-5 Client-n > > > | | | | > > > | | ... | ... | > > > | | | | > > > | | | | > > > | | | | > > > | | | | > > > | | | | > > > | | | | > > > | +---+--------------+----+ | > > > +-----------+ qcom_minidump(core) +--------+ > > > | | > > > +------+-----+------+---+ > > > | | | > > > | | | > > > +---------------+ | +--------------------+ > > > | | | > > > | | | > > > | | | > > > v v v > > > +-------------------+ +-------------------+ +------------------+ > > > |qcom_minidump_smem | |qcom_minidump_mmio | | qcom_minidump_rm | > > > | | | | | | > > > +-------------------+ +-------------------+ +------------------+ > > > Shared memory Memory mapped IO Resource manager > > > (backend) (backend) (backend) > > > > > > > > > Here, we will be giving all analogy of backend with SMEM as it is the > > > only implemented backend at present but general idea remains the same. > > > > If you only have one "backend" then you don't need the extra compexity > > here at all, just remove that whole middle layer please and make this > > much simpler and smaller and easier to review and possibly accept. > > > > We don't add layers when they are not needed, and never when there is no > > actual user. If you need the extra "complexity" later, then add it > > later when it is needed as who knows when that will ever be. > > > > Please redo this series based on that, thanks. > > I already followed without this middle layer till v3 since without > the middle layer it will be end up with lot of code duplication if there > is another backend. But as this series does not have such a thing, only add it when needed please. Don't make us review a whole bunch of stuff that is not actually used here. Would you want to review such a thing? > We already have other backend implementation in the downstream, if you > want to see them, i will try to post them in upcoming series.. Ok, so if you already have it, yes, post it as part of the series, otherwise such a layer makes no sense. thanks, greg k-h _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel