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=-8.0 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 D8912C47247 for ; Thu, 30 Apr 2020 15:12:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B6F3B20661 for ; Thu, 30 Apr 2020 15:12:47 +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="raszGkcn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726840AbgD3PMp (ORCPT ); Thu, 30 Apr 2020 11:12:45 -0400 Received: from mail27.static.mailgun.info ([104.130.122.27]:27315 "EHLO mail27.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726419AbgD3PMp (ORCPT ); Thu, 30 Apr 2020 11:12:45 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1588259564; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=+Elf3SEuakpHyKtLd2fhgPxNApOMvDXgdZ23op/04/o=; b=raszGkcn6qzpFgcSrQbSvrgY/iEOabQmzBBmLRQhTams+tp+FfwXWwXzO+prVVv3AzyVHSoq 3HY47lRAoDFRBtQVyoA+BhZ+LYMlw7ks9R+d47ORvox+7XTsUu61Dkma6T4cffOSsaCx8IRQ CxA6UIBJfdtSDirts/HSgy5i1HA= X-Mailgun-Sending-Ip: 104.130.122.27 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== 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 5eaaeae7.7f2dc00b1998-smtp-out-n03; Thu, 30 Apr 2020 15:12:39 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 38A40C433CB; Thu, 30 Apr 2020 15:12:39 +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 AA60CC432C2; Thu, 30 Apr 2020 15:12:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org AA60CC432C2 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 v3 9/9] bus: mhi: core: Ensure non-zero session or sequence ID values To: Bhaumik Bhatt , mani@kernel.org Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, hemantk@codeaurora.org References: <1588193551-31439-1-git-send-email-bbhatt@codeaurora.org> <1588193551-31439-10-git-send-email-bbhatt@codeaurora.org> From: Jeffrey Hugo Message-ID: Date: Thu, 30 Apr 2020 09:12:35 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <1588193551-31439-10-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-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 4/29/2020 2:52 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 are > supported writes to those registers. Ensure that host does not write a > non-zero value for those cases. > > Signed-off-by: Bhaumik Bhatt > --- > drivers/bus/mhi/core/boot.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/bus/mhi/core/boot.c b/drivers/bus/mhi/core/boot.c > index 0bc9c50..c9971d4 100644 > --- a/drivers/bus/mhi/core/boot.c > +++ b/drivers/bus/mhi/core/boot.c > @@ -199,6 +199,9 @@ static int mhi_fw_load_amss(struct mhi_controller *mhi_cntrl, > mhi_write_reg(mhi_cntrl, base, BHIE_TXVECSIZE_OFFS, mhi_buf->len); > > sequence_id = prandom_u32() & BHIE_TXVECSTATUS_SEQNUM_BMSK; > + if (unlikely(!sequence_id)) > + sequence_id = 1; Seems like you could use prandom_u32_max(), and add 1 to the result to eliminate the conditional. What do you think? > + > mhi_write_reg_field(mhi_cntrl, base, BHIE_TXVECDB_OFFS, > BHIE_TXVECDB_SEQNUM_BMSK, BHIE_TXVECDB_SEQNUM_SHFT, > sequence_id); > @@ -254,6 +257,9 @@ static int mhi_fw_load_sbl(struct mhi_controller *mhi_cntrl, > lower_32_bits(dma_addr)); > mhi_write_reg(mhi_cntrl, base, BHI_IMGSIZE, size); > session_id = prandom_u32() & BHI_TXDB_SEQNUM_BMSK; > + if (unlikely(!session_id)) > + session_id = 1; > + > mhi_write_reg(mhi_cntrl, base, BHI_IMGTXDB, session_id); > read_unlock_bh(pm_lock); > > -- Jeffrey Hugo Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.