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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 29ACCC76191 for ; Thu, 18 Jul 2019 08:42:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F17E92173E for ; Thu, 18 Jul 2019 08:42:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389488AbfGRImq (ORCPT ); Thu, 18 Jul 2019 04:42:46 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:58046 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726386AbfGRImq (ORCPT ); Thu, 18 Jul 2019 04:42:46 -0400 Received: from 79.184.255.39.ipv4.supernova.orange.pl (79.184.255.39) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.267) id 52ae64ba30307854; Thu, 18 Jul 2019 10:42:43 +0200 From: "Rafael J. Wysocki" To: Arnd Bergmann Cc: Len Brown , Mika Westerberg , Andy Shevchenko , Hans de Goede , Sakari Ailus , Rasmus Villemoes , Keith Busch , Heikki Krogerus , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH] acpi: fix false-positive -Wuninitialized warning Date: Thu, 18 Jul 2019 10:42:43 +0200 Message-ID: <7785979.oluxICSiVJ@kreacher> In-Reply-To: <20190712090148.36582-1-arnd@arndb.de> References: <20190712090148.36582-1-arnd@arndb.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Friday, July 12, 2019 11:01:21 AM CEST Arnd Bergmann wrote: > clang gets confused by an uninitialized variable in what looks > to it like a never executed code path: > > arch/x86/kernel/acpi/boot.c:618:13: error: variable 'polarity' is uninitialized when used here [-Werror,-Wuninitialized] > polarity = polarity ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH; > ^~~~~~~~ > arch/x86/kernel/acpi/boot.c:606:32: note: initialize the variable 'polarity' to silence this warning > int rc, irq, trigger, polarity; > ^ > = 0 > arch/x86/kernel/acpi/boot.c:617:12: error: variable 'trigger' is uninitialized when used here [-Werror,-Wuninitialized] > trigger = trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE; > ^~~~~~~ > arch/x86/kernel/acpi/boot.c:606:22: note: initialize the variable 'trigger' to silence this warning > int rc, irq, trigger, polarity; > ^ > = 0 > > This is unfortunately a design decision in clang and won't be fixed. > > Changing the acpi_get_override_irq() macro to an inline function > reliably avoids the issue. > > Signed-off-by: Arnd Bergmann > --- > include/linux/acpi.h | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/include/linux/acpi.h b/include/linux/acpi.h > index a95cce5e82e7..9426b9aaed86 100644 > --- a/include/linux/acpi.h > +++ b/include/linux/acpi.h > @@ -324,7 +324,10 @@ struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags, > #ifdef CONFIG_X86_IO_APIC > extern int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity); > #else > -#define acpi_get_override_irq(gsi, trigger, polarity) (-1) > +static inline int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity) > +{ > + return -1; > +} > #endif > /* > * This function undoes the effect of one call to acpi_register_gsi(). > Applied, thanks!