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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 10D2EC43441 for ; Fri, 12 Oct 2018 05:23:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AED682086A for ; Fri, 12 Oct 2018 05:22:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="iCzfxxlE"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="AJSSxy67" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AED682086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727427AbeJLMxi (ORCPT ); Fri, 12 Oct 2018 08:53:38 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:45454 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726731AbeJLMxi (ORCPT ); Fri, 12 Oct 2018 08:53:38 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 1CF6160B7A; Fri, 12 Oct 2018 05:22:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1539321777; bh=PQk4ghll7M2SlTQ8n/VNfrOZYpnVO76DMikfP4DLB9I=; h=From:To:References:In-Reply-To:Subject:Date:From; b=iCzfxxlEE9Vy+J1NWZbzpFA4bX8SD78p81pqg5pZCG6swxm3THUxac+ybB2sDvlTW VI9gut+miIFHyRMmb9SbS1KwZqDNSZBWfnYnVDLqNXLsNpcTOrYJ9bfIB/NgiGgOxm kUPEQj43MA0ILPBxf8HKHCi+wKUzFiebYYgXm5M0= Received: from tbhardwa (blr-c-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: tbhardwa@codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 55EF260316; Fri, 12 Oct 2018 05:22:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1539321776; bh=PQk4ghll7M2SlTQ8n/VNfrOZYpnVO76DMikfP4DLB9I=; h=From:To:References:In-Reply-To:Subject:Date:From; b=AJSSxy679V7gS11r/wPLkz8TV9fgmt8lG6TL3Zgmv0k7c/pKpwwZE2YXpYQwxDy4c MUBIZRx5vP98ab1U5Zr9mBUH6W7LAJiAI8D/bZaShck73WWgwyLFo960t382qrLrfK oApev25vqE4JLsQlH2/EWLnoPD9+jGTyBp+hmRVg= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 55EF260316 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=tbhardwa@codeaurora.org From: To: "'Zhang, Ning A'" , , References: <1539313441.21249.3.camel@intel.com> <1539318782.21249.7.camel@intel.com> In-Reply-To: <1539318782.21249.7.camel@intel.com> Subject: RE: question about V4L2_MEMORY_USERPTR on 64bit applications Date: Fri, 12 Oct 2018 10:52:51 +0530 Message-ID: <000601d461eb$a1f7afc0$e5e70f40$@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Outlook 16.0 Content-Language: en-us Thread-Index: AQIZOT1Qp2mifVHgqOiMlO5tZ7T4WgG2r2gYpIOuUQA= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 64 bit kernel have 64 bit long(not 32 bit), which is not the case with = userspace (in 64 bit userspace long is 32-bit). Probably thig got you = confused. -----Original Message----- From: linux-media-owner@vger.kernel.org = On Behalf Of Zhang, Ning A Sent: Friday, October 12, 2018 10:03 AM To: linux-kernel@vger.kernel.org; linux-media@vger.kernel.org Subject: Re: question about V4L2_MEMORY_USERPTR on 64bit applications sorry for wrong question, I really meet memory address truncated issue, = when use V4L2 kernel APIs. in a kernel thread created by kernel_thread() I vm_mmap a shmem_file to = addr: 00007ffff7fa8000 and queue it to V4L2, after dequeue it, and I = find the address is truncated to 00000000f7fa8000 I use __u64 {aka long long unsigned int} to save address, and I find = userptr is unsigned long, wrongly think it as "data truncated" and a lot of __u32 in this structure. everything works fine, but I still don't understand why high 32bit be = 0.. BR. Ning. =E5=9C=A8 2018-10-12=E4=BA=94=E7=9A=84 11:04 +0800=EF=BC=8CZhang = Ning=E5=86=99=E9=81=93=EF=BC=9A > Hi, >=20 > I have question about V4L2_MEMORY_USERPTR on 64bit applications. >=20 > struct v4l2_buffer { > __u32 index; > __u32 type; > __u32 bytesused; > __u32 flags; > __u32 field; > struct timeval timestamp; > struct v4l2_timecode timecode; > __u32 sequence; >=20 > /* memory location */ > __u32 memory; > union { > __u32 offset; > unsigned long userptr; <<<--- this is a 32bit addr. > struct v4l2_plane *planes; > __s32 fd; > } m; > __u32 length; > __u32 reserved2; > __u32 reserved; > }; >=20 > when use a 64bit application, memory from malloc is 64bit address. > memory from GPU (eg, intel i915) are also 64bit address. >=20 > when use these kind of memory as V4L2_MEMORY_USERPTR, address will be=20 > truncated into 32bit. >=20 > this would be error, but actually not. I really don't understand. >=20 > BR. > Ning.