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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 A6836C47259 for ; Mon, 4 May 2020 14:33:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 841B7206E6 for ; Mon, 4 May 2020 14:33:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="tQ4FdOoe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728997AbgEDOdi (ORCPT ); Mon, 4 May 2020 10:33:38 -0400 Received: from mail26.static.mailgun.info ([104.130.122.26]:50909 "EHLO mail26.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728187AbgEDOdi (ORCPT ); Mon, 4 May 2020 10:33:38 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1588602817; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=DNLUn6EQruMMMF99UWRP+mb1eNSt+jyIl1CBrxqPHaY=; b=tQ4FdOoew0AAKlBbi1QQlM5kcXWkglNBpgpYQVnivzMHAe/2QE7VzlQ6WVugmIj7CDqBJ06w ISVjdUzqnfXkGty3E7MWKa9QZjiKoKrP8L78nKbN3ja7czAlRggP3zauctEl9QMalHy0JntM g0LRRrY4w/CpI2HW+JbLcxu97Cs= X-Mailgun-Sending-Ip: 104.130.122.26 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5eb027c0.7f3110055a78-smtp-out-n01; Mon, 04 May 2020 14:33:36 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id D8CC9C433F2; Mon, 4 May 2020 14:33:35 +0000 (UTC) Received: from [10.226.58.28] (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: jhugo) by smtp.codeaurora.org (Postfix) with ESMTPSA id 241A5C433CB; Mon, 4 May 2020 14:33:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 241A5C433CB Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=jhugo@codeaurora.org Subject: Re: [PATCH v4 8/8] bus: mhi: core: Ensure non-zero session or sequence ID values are used To: Bhaumik Bhatt , mani@kernel.org Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, hemantk@codeaurora.org References: <1588386725-1165-1-git-send-email-bbhatt@codeaurora.org> <1588386725-1165-9-git-send-email-bbhatt@codeaurora.org> From: Jeffrey Hugo Message-ID: <2a249d99-b1e7-7943-0ed4-d5529f7abc33@codeaurora.org> Date: Mon, 4 May 2020 08:33:34 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <1588386725-1165-9-git-send-email-bbhatt@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/1/2020 8:32 PM, Bhaumik Bhatt wrote: > While writing any sequence or session identifiers, it is possible that > the host could write a zero value, whereas only non-zero values should > be supported writes to those registers. Ensure that the host does not > write a non-zero value for them and also log them in debug messages. > > Suggested-by: Jeffrey Hugo > Signed-off-by: Bhaumik Bhatt > --- > drivers/bus/mhi/core/boot.c | 15 +++++++-------- > drivers/bus/mhi/core/internal.h | 1 + > 2 files changed, 8 insertions(+), 8 deletions(-) > > diff --git a/drivers/bus/mhi/core/boot.c b/drivers/bus/mhi/core/boot.c > index e5fcde1..9fe9c59 100644 > --- a/drivers/bus/mhi/core/boot.c > +++ b/drivers/bus/mhi/core/boot.c > @@ -43,10 +43,7 @@ void mhi_rddm_prepare(struct mhi_controller *mhi_cntrl, > lower_32_bits(mhi_buf->dma_addr)); > > mhi_write_reg(mhi_cntrl, base, BHIE_RXVECSIZE_OFFS, mhi_buf->len); > - sequence_id = prandom_u32() & BHIE_RXVECSTATUS_SEQNUM_BMSK; > - > - if (unlikely(!sequence_id)) > - sequence_id = 1; > + sequence_id = (MHI_RANDOM_U32_NONZERO & BHIE_RXVECSTATUS_SEQNUM_BMSK); I don't think this math works. For example, if MHI_RANDOM_U32_NONZERO is 0x0FF0, and BHIE_RXVECSTATUS_SEQNUM_BMSK is 0xF, then sequence_id will end up being 0. -- Jeffrey Hugo Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.