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=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, USER_AGENT_SANE_1 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 B4C10C43460 for ; Tue, 6 Apr 2021 10:58:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 941AC613CA for ; Tue, 6 Apr 2021 10:58:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245255AbhDFK6R (ORCPT ); Tue, 6 Apr 2021 06:58:17 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:35500 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245257AbhDFK6P (ORCPT ); Tue, 6 Apr 2021 06:58:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1617706687; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=aoo4T5OcYVMmIH5rVBArOHDK8SbcOJSOJ1qUYgR/5T8=; b=AvnKlSPrT2rbxeIr7hzHPgE1FIFEaIEmuwVwtjzpFDSS7c89SEXHhCcM585T6XgLiWkA93 MmgNkWfTtvkJispz9eMSEDyNIh47YNDIPqCTeTWfYl3YP0hIGUH8S7xlwgn6Dbn5T+ykvh 0oqFpWqa9s2D1y17v8/Tv0wqSwWiJnQ= Received: from mail-pg1-f200.google.com (mail-pg1-f200.google.com [209.85.215.200]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-10-oGGRjvfYN_yas4iF57RVdA-1; Tue, 06 Apr 2021 06:58:05 -0400 X-MC-Unique: oGGRjvfYN_yas4iF57RVdA-1 Received: by mail-pg1-f200.google.com with SMTP id n23so4473052pgl.2 for ; Tue, 06 Apr 2021 03:58:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=aoo4T5OcYVMmIH5rVBArOHDK8SbcOJSOJ1qUYgR/5T8=; b=eDd43bMzIsiEW/e6yTbYWc4F7ETnCfWQ7OZ8YFdnQltQiTcGymxioUanFJKvcNT8dW Ege414bXAElf/rAs9E+XBYBfvBehUfp2//dWRMr2VhlrS+XRp/a3aPHNilXlr2c3tgih QQxUYfGXVLzs8nno6faHO5zW6KTOky5oiQehC1VzFXD6YdLdhcCgWiiT3zS30DMhBzYd V60twO1WULeHgJ6OXHg+3kJqGkt1Dm0SxTTP182GHoDz+k0PCr0Gj9sFQJCxDmCCPc9v e2c+A2znrMo+upWBhbDvU1pqV1r4UnTeL0h6Otm2TJHxSXJFMFnouJjtKOxpH9RZJjJw i6Hw== X-Gm-Message-State: AOAM532BhB/VcwgwPPTGA8TTDcpreNu3TwY2zFgm2alq1QGKGzFNbtL1 ZnigWf+C6OM4EUhmht2GcyF5q+fG8zE7c4W02UqYDQ1uy+Ymn9Kz9DObmucmcis2we6LaO4DuVL ry7yrm/H64fG/fA6ZdkdO7IPK X-Received: by 2002:a65:6643:: with SMTP id z3mr1474564pgv.387.1617706684307; Tue, 06 Apr 2021 03:58:04 -0700 (PDT) X-Google-Smtp-Source: ABdhPJya/JAeXp9rFtQDgDn8HW+qGdQS73sx5LoNGY80ZZXhkPwr1QTS3aX8lbQdzfQ4srYGA95yMQ== X-Received: by 2002:a65:6643:: with SMTP id z3mr1474553pgv.387.1617706684057; Tue, 06 Apr 2021 03:58:04 -0700 (PDT) Received: from xiangao.remote.csb ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id c6sm19868861pfj.99.2021.04.06.03.58.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Apr 2021 03:58:03 -0700 (PDT) Date: Tue, 6 Apr 2021 18:57:53 +0800 From: Gao Xiang To: Helge Deller Cc: Gao Xiang , linux-parisc@vger.kernel.org, Liam Beguin , linux-kernel@vger.kernel.org Subject: Re: [PATCH] parisc: avoid a warning on u8 cast for cmpxchg on u8 pointers Message-ID: <20210406105753.GA550515@xiangao.remote.csb> References: <20210406045929.30331-1-xiang@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org On Tue, Apr 06, 2021 at 12:08:55PM +0200, Helge Deller wrote: > On 4/6/21 6:59 AM, Gao Xiang wrote: > > From: Gao Xiang > > > > commit b344d6a83d01 ("parisc: add support for cmpxchg on u8 pointers") > > can generate a sparse warningi ("cast truncates bits from constant > > value"), which has been reported several times [1] [2] [3]. > > > > The original code worked as expected, but anyway, let silence such > > sparse warning as what others did [4]. > > > > [1] https://lore.kernel.org/r/202104061220.nRMBwCXw-lkp@intel.com > > [2] https://lore.kernel.org/r/202012291914.T5Agcn99-lkp@intel.com > > [3] https://lore.kernel.org/r/202008210829.KVwn7Xeh%25lkp@intel.com > > [4] https://lore.kernel.org/r/20210315131512.133720-2-jacopo+renesas@jmondi.org > > Cc: Liam Beguin > > Cc: Helge Deller > > Signed-off-by: Gao Xiang > > applied to the parisc for-next git tree. > (I fixed up the typo above too) Thanks all! :) Thanks, Gao Xiang > > Thanks! > Helge > > > --- > > arch/parisc/include/asm/cmpxchg.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/parisc/include/asm/cmpxchg.h b/arch/parisc/include/asm/cmpxchg.h > > index cf5ee9b0b393..84ee232278a6 100644 > > --- a/arch/parisc/include/asm/cmpxchg.h > > +++ b/arch/parisc/include/asm/cmpxchg.h > > @@ -72,7 +72,7 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size) > > #endif > > case 4: return __cmpxchg_u32((unsigned int *)ptr, > > (unsigned int)old, (unsigned int)new_); > > - case 1: return __cmpxchg_u8((u8 *)ptr, (u8)old, (u8)new_); > > + case 1: return __cmpxchg_u8((u8 *)ptr, old & 0xff, new_ & 0xff); > > } > > __cmpxchg_called_with_bad_pointer(); > > return old; > > >