From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Perches Subject: Re: [PATCH] net: hix5hd2_gmac: avoid integer overload warning Date: Fri, 16 Oct 2015 14:22:15 -0700 Message-ID: <1445030535.22921.73.camel@perches.com> References: <1444967657-107994-1-git-send-email-huangdaode@hisilicon.com> <4752736.dePgPCNd9q@wuerfel> <063D6719AE5E284EB5DD2968C1650D6D1CBB97A6@AcuExch.aculab.com> <9667302.4m5v3ViVSt@wuerfel> <1445018654.22921.41.camel@perches.com> <562146ED.1030308@cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: Arnd Bergmann , David Laight , huangdaode , "davem@davemloft.net" , "liguozhu@hisilicon.com" , "Yisen.Zhuang@huawei.com" , "netdev@vger.kernel.org" , "linuxarm@huawei.com" , "salil.mehta@huawei.com" , "kenneth-lee-2012@foxmail.com" , "xuwei5@hisilicon.com" , "lisheng011@huawei.com" , "linux-kernel@vger.kernel.org" , "lipeng321@huawei.com" To: Sergei Shtylyov Return-path: In-Reply-To: <562146ED.1030308@cogentembedded.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Fri, 2015-10-16 at 21:50 +0300, Sergei Shtylyov wrote: > On 10/16/2015 09:04 PM, Joe Perches wrote: > > >>>> BITS_RX_EN is an 'unsigned long' constant, so the ones complement of that > >>>> has bits set that do not fit into a 32-bit variable on 64-bit architectures, > >>>> which causes a harmless gcc warning: > >>> ... > >>>> static void hix5hd2_port_disable(struct hix5hd2_priv *priv) > >>>> { > >>>> - writel_relaxed(~(BITS_RX_EN | BITS_TX_EN), priv->base + PORT_EN); > >>>> + writel_relaxed(~(u32)(BITS_RX_EN | BITS_TX_EN), priv->base + PORT_EN); > >>>> writel_relaxed(0, priv->base + DESC_WR_RD_ENA); > >>> > >>> ISTM that just means that the constants shouldn't be 'long'. > >> > >> Right, but that would probably mean changing the BIT() macro or not using it > >> here. In the past I've argued against using that macro, but I've given > >> up that fight. > > > > Fight on... (Somebody must have gone to USC here) > > > > There might be value in aefin BIT_U32 macro. > > Maybe BIT_U64 too. > > There's BIT_ULL() already. I know, but symmetry is good. I think there'd be no harm in adding it. Perhaps adding all the sized variants would be useful. Something like: #define BIT_OF_TYPE(type, nr) \ ({ \ typeof(type) rtn; \ BUILD_BUG_ON(__builtin_constant_p(nr) && \ ((nr) < 0 || \ (nr) >= sizeof(type) * BITS_PER_BYTE)); \ rtn = ((type)1) << (nr); \ rtn; \ }) #define BIT_U8(nr) BIT_OF_TYPE(u8, nr) #define BIT_U16(nr) BIT_OF_TYPE(u16, nr) #define BIT_U32(nr) BIT_OF_TYPE(u32, nr) #define BIT_U64(nr) BIT_OF_TYPE(u64, nr)