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 B5BF4CAC5B0 for ; Thu, 2 Oct 2025 06:44:42 +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:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject: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=z8nNNnRxxYoNK55Efclobl1KCAWYm0aw/y/tYmD83WY=; b=ueneWQ92lFYPYq xV6MN45iHIQsDWwrSqrjDahBg3fTmKkeIY1PV7LmiJ8fgvtWPxswPPjUGvJRsjyHhpv0GYwybdZLQ VvozRCwdAVGiEIuYBN0bfg7KeT6R1TVOGfHY9KkCjWk3lTLuxC4yGuhO9KG9wvBBGE0dtYoEn5OnV Fa5XeWbDfS145oME6ZEdmvT0HfCz1c1+Ky79hPDd1lOjrNHdv8QKcWs5pyZB33NkoKMVkSO8yKO1i NeUMT5+fBeDjSk9+V9PPmLdlNSGHIzC/tmM/N5PkD5SzL9B0W90I25PHO6JnIMu19aKsnRyqniYjh sDCY9ovmpNVhPoZtbv6A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v4D3M-00000009kXR-1bfS; Thu, 02 Oct 2025 06:44:36 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v4D3K-00000009kXC-3jSu for linux-riscv@lists.infradead.org; Thu, 02 Oct 2025 06:44:34 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id E957F61E36; Thu, 2 Oct 2025 06:44:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 103B2C4CEF4; Thu, 2 Oct 2025 06:44:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1759387473; bh=JnBN7j5droh3H2pGNS2Yqug4bI9vWf9w2jtC9CcI0Rs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UG58CB2rWtiMXRchCHwWLofkmsXLn3fKVtWNW04+7L9eNEENg/qRLNowFt/vG/bys 3HXtuDxQ1SRoqd+ysPhnEt6fgHCd+OulYKaYQCDquJ7AY+CZngGKkBZ70hzSWs67BA A9dHrIL04xDuCGqWZ5BGnqJ4rryPEuxYsAYKsM6c= Date: Thu, 2 Oct 2025 08:44:30 +0200 From: Greg KH To: Anup Patel Subject: Re: [PATCH 00/11] Linux RISC-V trace framework and drivers Message-ID: <2025100255-catcall-drinkable-23f5@gregkh> References: <20251002060732.100213-1-apatel@ventanamicro.com> <2025100208-challenge-protrude-d6c3@gregkh> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Ian Rogers , Atish Patra , Alexander Shishkin , linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Liang Kan , Rob Herring , Alexandre Ghiti , Anup Patel , Peter Zijlstra , Andrew Jones , devicetree@vger.kernel.org, Conor Dooley , Paul Walmsley , Mayuresh Chitale , Namhyung Kim , Ingo Molnar , Adrian Hunter , Palmer Dabbelt , Jiri Olsa , Krzysztof Kozlowski Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org T24gVGh1LCBPY3QgMDIsIDIwMjUgYXQgMTI6MDk6MjNQTSArMDUzMCwgQW51cCBQYXRlbCB3cm90 ZToKPiBPbiBUaHUsIE9jdCAyLCAyMDI1IGF0IDExOjU24oCvQU0gR3JlZyBLSCA8Z3JlZ2toQGxp bnV4Zm91bmRhdGlvbi5vcmc+IHdyb3RlOgo+ID4KPiA+IE9uIFRodSwgT2N0IDAyLCAyMDI1IGF0 IDExOjM3OjIxQU0gKzA1MzAsIEFudXAgUGF0ZWwgd3JvdGU6Cj4gPiA+IFRoaXMgc2VyaWVzIGFk ZHMgaW5pdGlhbCBzdXBwb3J0IGZvciBSSVNDLVYgdHJhY2UgZnJhbWV3b3JrIGFuZCBkcml2ZXJz Lgo+ID4gPiBUaGUgUklTQy1WIHRyYWNlIHYxLjAgc3BlY2lmaWNhdGlvbiBpcyBhbHJlYWR5IHJh dGlmaWVkIGFuZCBjYW4gYmUgZm91bmQgYXQ6Cj4gPiA+IGh0dHBzOi8vZ2l0aHViLmNvbS9yaXNj di1ub24taXNhL2UtdHJhY2UtZW5jYXAvcmVsZWFzZXMvdGFnL3YxLjAuMC1yYXRpZmllZAo+ID4g PiBodHRwczovL2dpdGh1Yi5jb20vcmlzY3Ytbm9uLWlzYS90Zy1uZXh1cy10cmFjZS9yZWxlYXNl cy90YWcvMS4wX1JhdGlmaWVkCj4gPiA+Cj4gPiA+IFRoZSBSSVNDLVYgdHJhY2UgZnJhbWV3b3Jr IGFuZCBkcml2ZXJzIGFyZSBkZXNpZ25lZCB0byBiZSBhZ25vc3RpYyB0byB0aGUKPiA+ID4gdW5k ZXJseWluZyB0cmFjZSBwcm90b2NvbCBoZW5jZSBib3RoIFJJU0MtViBFLXRyYWNlIGFuZCBSSVND LVYgTi10cmFjZSBzaG91bGQKPiA+ID4gd29yayBmaW5lLiBUaGUgZGlzY292ZXJ5IG9mIHRyYWNl IHByb3RvY2wgcGFyYW1ldGVycyBhcmUgbGVmdCB0byB1c2VyLXNwYWNlCj4gPiA+IHRyYWNlIGRl Y29kZXIuCj4gPiA+Cj4gPiA+IEluIHRoZXIgZnV0dXJlLCB0aGVyZSB3aWxsIGJlIHN1YnNlcXVl bnQgc2VyaWVzIGFkZGluZzoKPiA+ID4gMSkgU3lzZnMgc3VwcG9ydAo+ID4KPiA+IHdoeSBkb2Vz ICJ0cmFjZSIgbmVlZCBzeXNmcyBzdXBwb3J0PyAgTm8gb3RoZXIgY3B1IHBsYXRmb3JtIHVzZXMg dGhhdAo+ID4gdG9kYXksIHNvIHdoeSBpcyBhIG5ldyB1c2VyL2tlcm5lbCBhcGkgbmVlZGVkPwo+ IAo+IFdlIHNhdyB0cmFjZSBzdXBwb3J0IGZvciBvdGhlciBhcmNoaXRlY3R1cmVzIChlLmcuIEFS TSBjb3Jlc2lnaHQpIGFsbG93aW5nCj4gdHJhY2Ugc3RhcnQvc3RvcCB0aHJvdWdoIHN5c2ZzLiBJ ZiB0aGlzIGlzIGFuIG9ic29sZXRlIG9yIG5vdCBwcmVmZXJyZWQgYXBwcm9hY2gKPiB0aGVuIHdl IHdpbGwgZGVwcmlvcml0aXplIGFuZCBwb3NzaWJseSBuZXZlciBhZGQgaXQuCgpXaHkgaXMgdGhh dCBuZWVkZWQgZm9yIGNvcmVzaWdodCBhbmQgb3RoZXIgYXJjaGVzIGRvIG5vdCBuZWVkIGl0PwpQ ZXJoYXBzIGl0IHNob3VsZCBiZSBkZWxldGVkIGZyb20gdGhhdCBjb2RlYmFzZSBpbnN0ZWFkPwoK dGhhbmtzLAoKZ3JlZyBrLWgKCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fCmxpbnV4LXJpc2N2IG1haWxpbmcgbGlzdApsaW51eC1yaXNjdkBsaXN0cy5pbmZy YWRlYWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGluZm8vbGlu dXgtcmlzY3YK From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C91641339A4; Thu, 2 Oct 2025 06:44:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759387473; cv=none; b=o3BgUNfiZofsAm4uZAeswL70pjNpAJAS9KdWSPnCCjrzERTmQGcxkd5z5rofB460IzZE7ronHEgE6FIG/d0G+TsXxuw9qC/VddsHjptryDXAYW5GouBjfq517Krr3EKXnOALGdDtIExA0DOxiT0rRhRMMktJUJhybwZoAniNQVI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759387473; c=relaxed/simple; bh=JnBN7j5droh3H2pGNS2Yqug4bI9vWf9w2jtC9CcI0Rs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=O5zJnvTvpFDLXR2BnX0lHZRdwbYd5Kpioz5HyNslL/y2sYN8YLq5myaHiCPpgk5VlROjH1sY7RVCAPuqP8UuMjZ84tS5+XScsJ0TPzMBFA+nlf4W/zKVMaZKefSPcfWUqab9++r5YffU/raPtqUS7/0JUgDgY2KCA7PkXSuZGGY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UG58CB2r; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="UG58CB2r" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 103B2C4CEF4; Thu, 2 Oct 2025 06:44:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1759387473; bh=JnBN7j5droh3H2pGNS2Yqug4bI9vWf9w2jtC9CcI0Rs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UG58CB2rWtiMXRchCHwWLofkmsXLn3fKVtWNW04+7L9eNEENg/qRLNowFt/vG/bys 3HXtuDxQ1SRoqd+ysPhnEt6fgHCd+OulYKaYQCDquJ7AY+CZngGKkBZ70hzSWs67BA A9dHrIL04xDuCGqWZ5BGnqJ4rryPEuxYsAYKsM6c= Date: Thu, 2 Oct 2025 08:44:30 +0200 From: Greg KH To: Anup Patel Cc: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Paul Walmsley , Palmer Dabbelt , Alexander Shishkin , Ian Rogers , Alexandre Ghiti , Peter Zijlstra , Ingo Molnar , Namhyung Kim , Mark Rutland , Jiri Olsa , Adrian Hunter , Liang Kan , Mayuresh Chitale , Anup Patel , Atish Patra , Andrew Jones , Sunil V L , linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 00/11] Linux RISC-V trace framework and drivers Message-ID: <2025100255-catcall-drinkable-23f5@gregkh> References: <20251002060732.100213-1-apatel@ventanamicro.com> <2025100208-challenge-protrude-d6c3@gregkh> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Oct 02, 2025 at 12:09:23PM +0530, Anup Patel wrote: > On Thu, Oct 2, 2025 at 11:56 AM Greg KH wrote: > > > > On Thu, Oct 02, 2025 at 11:37:21AM +0530, Anup Patel wrote: > > > This series adds initial support for RISC-V trace framework and drivers. > > > The RISC-V trace v1.0 specification is already ratified and can be found at: > > > https://github.com/riscv-non-isa/e-trace-encap/releases/tag/v1.0.0-ratified > > > https://github.com/riscv-non-isa/tg-nexus-trace/releases/tag/1.0_Ratified > > > > > > The RISC-V trace framework and drivers are designed to be agnostic to the > > > underlying trace protocol hence both RISC-V E-trace and RISC-V N-trace should > > > work fine. The discovery of trace protocl parameters are left to user-space > > > trace decoder. > > > > > > In ther future, there will be subsequent series adding: > > > 1) Sysfs support > > > > why does "trace" need sysfs support? No other cpu platform uses that > > today, so why is a new user/kernel api needed? > > We saw trace support for other architectures (e.g. ARM coresight) allowing > trace start/stop through sysfs. If this is an obsolete or not preferred approach > then we will deprioritize and possibly never add it. Why is that needed for coresight and other arches do not need it? Perhaps it should be deleted from that codebase instead? thanks, greg k-h