Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751733AbdFIK3k (ORCPT ); Fri, 9 Jun 2017 06:29:40 -0400 Received: from mga05.intel.com ([192.55.52.43]:46463 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751583AbdFIK3i (ORCPT ); Fri, 9 Jun 2017 06:29:38 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,317,1493708400"; d="asc'?scan'208";a="978741983" From: Felipe Balbi To: Alexander Shishkin , Steven Rostedt , Ingo Molnar Cc: Linux USB , linux-kernel@vger.kernel.org, Chunyan Zhang Subject: Re: [PATCH] usb: gadget: functions: add ftrace export over USB In-Reply-To: <20170609061327.17899-1-felipe.balbi@linux.intel.com> References: <20170609061327.17899-1-felipe.balbi@linux.intel.com> Date: Fri, 09 Jun 2017 13:28:51 +0300 Message-ID: <87mv9hqwt8.fsf@linux.intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2210 Lines: 55 --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Felipe Balbi writes: > Allow for ftrace data to be exported over a USB Gadget > Controller. With this, we have a potentially very fast pipe for > transmitting ftrace data to a Host PC for further analysis. > > Note that in order to decode the data, one needs access to kernel > symbols in order to convert binary data into function names and what > not. > > Signed-off-by: Felipe Balbi > --- > > I wanted to take this through the gadget tree, but there is a > dependency with a previous patch of mine adding and extra argument to > the ->write() function. Hoping someone else will take it. just as an extra note here. In order for this to be really useful, it would be nice to be able to control what is going to be traced over USB as well, but that means exporting a few extra functions to GPL drivers. Would that be okay? I could have a set of vendor-specific control requests to set buffer size and to read/write ftrace filter functions. The idea is that things like e.g. Android SDK could rely on this on debug builds and the SDK itself would make sure to keep a copy of vmlinux around to processing of the data coming through USB. =2D-=20 balbi --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEElLzh7wn96CXwjh2IzL64meEamQYFAlk6eGMACgkQzL64meEa mQbknw/+MTKMCRgVfQoEbx0kNuBKHgzN7OtzcGEYZC+PO+hSo3GD35rW8VhZrbMQ eb9NFrWylTZYw5/aGvsLlmlAAJbTRLwuY4i4mcRruzeYst8dFRWQq1LaRvZzdgd4 K9xuh3jyHNNT6xguGwp5zUSCZLsJ/k1Bj4q8tjnXt8ZiVF/SrnTYW03u8n7oh5Jo rzJZmcnO/drUZPh0+0qF7d0vdvDt53LC1qBHzELohUlOkR1JBs+dlSPeqFSsu48r m5xeHLlQGLFHwkvel7bk4k/AHFAZSQW6Vb2KqH+YzZ8wjzXgVFmBdHF3umA0R4/M 0IplHsGeAyodyeTROtMP0Oj+dVZCwESrLVSZP9L14ClCaZbKeW1rq0MgaNWb/Qxd XBeAYV/MtsTJ5rUFjB1fJYfUadi0GnhNCFIFUIMSyChgRTdZByGs6ooiKP0ilMcY bxEXGqw/tAYkETelcNy/0kAwkAl8dtazv5BSQAnFTVg1EmmwN/LqIPC6D+QRzx0Z uFNXkUwokN4sHz/p2ERMfbJT628nppUQE4Mzd6UghZ/O6AXwxBGEPd4vrLV44/2o zmi/RBWTwRaQxH3GoqGxyPOdsxvf4LWw3yD6p4LCRkPHnvA6OsQszLkPbPUYVa0g EBa22w1htPthkF96ldY7R28m9UrbT09eHN6FgTLXy0FQpNH52N0= =ejpg -----END PGP SIGNATURE----- --=-=-=--