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 X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B0C2FC6197 for ; Fri, 8 Nov 2019 21:45:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E66E220869 for ; Fri, 8 Nov 2019 21:45:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731914AbfKHVph (ORCPT ); Fri, 8 Nov 2019 16:45:37 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:57222 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1728265AbfKHVph (ORCPT ); Fri, 8 Nov 2019 16:45:37 -0500 Received: (qmail 6968 invoked by uid 2102); 8 Nov 2019 16:45:36 -0500 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 8 Nov 2019 16:45:36 -0500 Date: Fri, 8 Nov 2019 16:45:36 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Andrey Konovalov cc: linux-usb@vger.kernel.org, , Greg Kroah-Hartman , Jonathan Corbet , Felipe Balbi , Dmitry Vyukov , Alexander Potapenko , Marco Elver Subject: Re: [PATCH 0/1] usb: gadget: add raw-gadget interface In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 8 Nov 2019, Andrey Konovalov wrote: > This patchset (currently a single patch) adds a new userspace interface > for the USB Gadget subsystem called USB Raw Gadget (I don't mind changing > the name to something else if there are better ideas). This is what > currently being used to enable coverage-buided USB fuzzing with syzkaller: > > https://github.com/google/syzkaller/blob/master/docs/linux/external_fuzzing_usb.md > > Initially I was using GadgetFS (together with the Dummy HCD/UDC module) > to perform emulation of USB devices for fuzzing, but later switched to a > custom written interface. The incentive to implement a different interface > was to provide a somewhat raw and direct access to the USB Gadget layer > for the userspace, where every USB request is passed to the userspace to > get a response. See documentation for the list of differences between > Raw Gadget and GadgetFS. > > This patchset has been pushed to the public Linux kernel Gerrit instance: > > https://linux-review.googlesource.com/c/linux/kernel/git/torvalds/linux/+/2144 > > Andrey Konovalov (1): > usb: gadget: add raw-gadget interface > > Documentation/usb/index.rst | 1 + > Documentation/usb/raw-gadget.rst | 60 ++ > drivers/usb/gadget/Kconfig | 9 + > drivers/usb/gadget/Makefile | 2 + > drivers/usb/gadget/raw.c | 1150 +++++++++++++++++++++++++++ As a general rule, gadget drivers don't go directly in drivers/usb/gadget. raw.c counts as a legacy driver (because it's not written to use the composite gadget framework), so it belongs in drivers/usb/gadget/legacy. That's where the gadgetfs driver lives, for example. Alan Stern > include/uapi/linux/usb/raw_gadget.h | 164 ++++ > 6 files changed, 1386 insertions(+) > create mode 100644 Documentation/usb/raw-gadget.rst > create mode 100644 drivers/usb/gadget/raw.c > create mode 100644 include/uapi/linux/usb/raw_gadget.h