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=-19.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 4FDFCC32750 for ; Tue, 13 Aug 2019 20:43:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B28C20665 for ; Tue, 13 Aug 2019 20:43:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FNpL+MFo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726465AbfHMUnQ (ORCPT ); Tue, 13 Aug 2019 16:43:16 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:41141 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725944AbfHMUnP (ORCPT ); Tue, 13 Aug 2019 16:43:15 -0400 Received: by mail-pf1-f195.google.com with SMTP id 196so5094952pfz.8 for ; Tue, 13 Aug 2019 13:43:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wedeTRt18LF5MmeSQANDHDmPkQrZQasBte+17UN0Uok=; b=FNpL+MFoqL+CcbHGv3P3AIhLuDCKtOB3CCpbeOGWU5vhyTaCG9qwLCYvaz6mUgbR43 9xMtJAuL9M3SuJ0+Qpk5iAA1D4ghWpwCAPgSvp16oH29zAme0N1tfz0OKvmvg1NLjyws eF7Gd21hpRW+x0sxix7tGlh5f3/LDDqCCtNk1YzSfXbtKPBexB3yAT1bFw1P4iJnPZb1 cbESvgGTDDDa2ZyEFZCqe5vtrtBLAVNSSteMU0wp9Cte58POwIFnn05tfFj5d7GDB/WX ZkSmGyLjt8X0gmWR2u2E1MVP8h8QgNAXM4eEQP2fhaMI5LQAeV421Z7zLEen1D4tmeDm ABKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=wedeTRt18LF5MmeSQANDHDmPkQrZQasBte+17UN0Uok=; b=a/HqkqXZioCOzsrIOAmpSE6WOOQ8X+JzIEm7UEEn7GIifA4eOCd8zsUlcGtUUcwlp8 98wcEUdo27alcQxBYJurjKk9K6Nrjo7PQlYcpUBdxh52ZQfai+tsIazjCS7B+NyyuWiH WNyKt2FDLNdxF8iI6ZXXwk96nNXJtoC36SgXDAAYimJThKR5Oe2JZZsgUhUmgAeI4J/0 LZN3NsualmucTCDYHzAqYK91UR950iL2Y1iMurqDY1QeRu09hmOzTxQSg6HO+DRVw7OD 455yPFG3W4hhVy+65tY5oWzZKWPnglDhjYHUXqrGy9+SsJVrLBOOIh/BPQzmf4Nd66z1 9KgA== X-Gm-Message-State: APjAAAUHchivnSyO2e+HQtv64+sjuFfRSeSAezSRofKvEpn+F9T+cv90 wFI5oLFW7QywcSW78WsW5ZYYVODnN4uBY1tAsoLdDw== X-Google-Smtp-Source: APXvYqxhtzYE0QLYkYDVy2cD7X7/qEOHczJKl5d7ACHw1m+SOe+brERicZvIdCM8ZZTtSbo171hwe2clAfFqC+rqRLs= X-Received: by 2002:a17:90a:ac02:: with SMTP id o2mr3955419pjq.134.1565728994589; Tue, 13 Aug 2019 13:43:14 -0700 (PDT) MIME-Version: 1.0 References: <20190813173448.109859-1-nhuck@google.com> In-Reply-To: <20190813173448.109859-1-nhuck@google.com> From: Nick Desaulniers Date: Tue, 13 Aug 2019 13:43:03 -0700 Message-ID: Subject: Re: [PATCH v2] dmaengine: mv_xor_v2: Fix -Wshift-negative-value To: Nathan Huckleberry Cc: Dan Williams , Vinod Koul , dmaengine@vger.kernel.org, LKML , clang-built-linux Content-Type: text/plain; charset="UTF-8" Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On Tue, Aug 13, 2019 at 10:35 AM 'Nathan Huckleberry' via Clang Built Linux wrote: > > Clang produces the following warning > > drivers/dma/mv_xor_v2.c:264:40: warning: shifting a negative signed value > is undefined [-Wshift-negative-value] > reg &= (~MV_XOR_V2_DMA_IMSG_THRD_MASK << > MV_XOR_V2_DMA_IMSG_THRD_SHIFT); > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ > drivers/dma/mv_xor_v2.c:271:46: warning: shifting a negative signed value > is undefined [-Wshift-negative-value] > reg &= (~MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK << > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ > > Upon further investigation MV_XOR_V2_DMA_IMSG_THRD_SHIFT and > MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT are both 0. Since shifting by 0 does > nothing, these variables can be removed. > > Cc: clang-built-linux@googlegroups.com > Link: https://github.com/ClangBuiltLinux/linux/issues/521 > Signed-off-by: Nathan Huckleberry Thanks for sending a v2: Reviewed-by: Nick Desaulniers > --- > drivers/dma/mv_xor_v2.c | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/drivers/dma/mv_xor_v2.c b/drivers/dma/mv_xor_v2.c > index fa5dab481203..e3850f04f676 100644 > --- a/drivers/dma/mv_xor_v2.c > +++ b/drivers/dma/mv_xor_v2.c > @@ -33,7 +33,6 @@ > #define MV_XOR_V2_DMA_IMSG_CDAT_OFF 0x014 > #define MV_XOR_V2_DMA_IMSG_THRD_OFF 0x018 > #define MV_XOR_V2_DMA_IMSG_THRD_MASK 0x7FFF > -#define MV_XOR_V2_DMA_IMSG_THRD_SHIFT 0x0 > #define MV_XOR_V2_DMA_IMSG_TIMER_EN BIT(18) > #define MV_XOR_V2_DMA_DESQ_AWATTR_OFF 0x01C > /* Same flags as MV_XOR_V2_DMA_DESQ_ARATTR_OFF */ > @@ -50,7 +49,6 @@ > #define MV_XOR_V2_DMA_DESQ_ADD_OFF 0x808 > #define MV_XOR_V2_DMA_IMSG_TMOT 0x810 > #define MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK 0x1FFF > -#define MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT 0 > > /* XOR Global registers */ > #define MV_XOR_V2_GLOB_BW_CTRL 0x4 > @@ -261,16 +259,15 @@ void mv_xor_v2_enable_imsg_thrd(struct mv_xor_v2_device *xor_dev) > > /* Configure threshold of number of descriptors, and enable timer */ > reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF); > - reg &= (~MV_XOR_V2_DMA_IMSG_THRD_MASK << MV_XOR_V2_DMA_IMSG_THRD_SHIFT); > - reg |= (MV_XOR_V2_DONE_IMSG_THRD << MV_XOR_V2_DMA_IMSG_THRD_SHIFT); > + reg &= ~MV_XOR_V2_DMA_IMSG_THRD_MASK; > + reg |= MV_XOR_V2_DONE_IMSG_THRD; > reg |= MV_XOR_V2_DMA_IMSG_TIMER_EN; > writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF); > > /* Configure Timer Threshold */ > reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_TMOT); > - reg &= (~MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK << > - MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT); > - reg |= (MV_XOR_V2_TIMER_THRD << MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT); > + reg &= ~MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK; > + reg |= MV_XOR_V2_TIMER_THRD; > writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_TMOT); > } > > -- > 2.23.0.rc1.153.gdeed80330f-goog > > -- > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20190813173448.109859-1-nhuck%40google.com. -- Thanks, ~Nick Desaulniers