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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 7C96BC11D13 for ; Thu, 20 Feb 2020 17:37:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 573192467D for ; Thu, 20 Feb 2020 17:37:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728685AbgBTRhb (ORCPT ); Thu, 20 Feb 2020 12:37:31 -0500 Received: from mga01.intel.com ([192.55.52.88]:6474 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728295AbgBTRha (ORCPT ); Thu, 20 Feb 2020 12:37:30 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Feb 2020 09:37:30 -0800 X-IronPort-AV: E=Sophos;i="5.70,465,1574150400"; d="scan'208";a="254546045" Received: from jbrandeb-desk.jf.intel.com ([10.166.244.152]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Feb 2020 09:37:29 -0800 From: Jesse Brandeburg To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de Cc: Jesse Brandeburg , x86@kernel.org, linux-kernel@vger.kernel.org, linux@rasmusvillemoes.dk, andriy.shevchenko@intel.com, dan.j.williams@intel.com Subject: [PATCH v2 1/2] x86: fix bitops.h warning with a moved cast Date: Thu, 20 Feb 2020 09:37:21 -0800 Message-Id: <20200220173722.2034546-1-jesse.brandeburg@intel.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Fix many sparse warnings when building with C=1. When the kernel is compiled with C=1, there are lots of messages like: arch/x86/include/asm/bitops.h:77:37: warning: cast truncates bits from constant value (ffffff7f becomes 7f) CONST_MASK() is using a signed integer "1" to create the mask which is later cast to (u8) when used. Move the cast to the definition so and use local variables so sparse and the compiler can see the correct type. Verified with a test module (see next patch) and assembly inspection that the patch doesn't introduce any change in generated code. Signed-off-by: Jesse Brandeburg --- v2: use correct CC: list --- arch/x86/include/asm/bitops.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h index 062cdecb2f24..2922b352b6ed 100644 --- a/arch/x86/include/asm/bitops.h +++ b/arch/x86/include/asm/bitops.h @@ -46,15 +46,17 @@ * a mask operation on a byte. */ #define CONST_MASK_ADDR(nr, addr) WBYTE_ADDR((void *)(addr) + ((nr)>>3)) -#define CONST_MASK(nr) (1 << ((nr) & 7)) +#define CONST_MASK(nr) ((u8)1 << ((nr) & 7)) static __always_inline void arch_set_bit(long nr, volatile unsigned long *addr) { if (__builtin_constant_p(nr)) { + u8 cmask = CONST_MASK(nr); + asm volatile(LOCK_PREFIX "orb %1,%0" : CONST_MASK_ADDR(nr, addr) - : "iq" ((u8)CONST_MASK(nr)) + : "iq" (cmask) : "memory"); } else { asm volatile(LOCK_PREFIX __ASM_SIZE(bts) " %1,%0" @@ -72,9 +74,11 @@ static __always_inline void arch_clear_bit(long nr, volatile unsigned long *addr) { if (__builtin_constant_p(nr)) { + u8 cmaski = ~CONST_MASK(nr); + asm volatile(LOCK_PREFIX "andb %1,%0" : CONST_MASK_ADDR(nr, addr) - : "iq" ((u8)~CONST_MASK(nr))); + : "iq" (cmaski)); } else { asm volatile(LOCK_PREFIX __ASM_SIZE(btr) " %1,%0" : : RLONG_ADDR(addr), "Ir" (nr) : "memory"); -- 2.24.1