From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 569941A2C62 for ; Tue, 15 Sep 2015 15:50:02 +1000 (AEST) Received: from e23smtp08.au.ibm.com (e23smtp08.au.ibm.com [202.81.31.141]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 0E6841401B5 for ; Tue, 15 Sep 2015 15:50:02 +1000 (AEST) Received: from /spool/local by e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 15 Sep 2015 15:50:01 +1000 Received: from d23relay10.au.ibm.com (d23relay10.au.ibm.com [9.190.26.77]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id A8619357804F for ; Tue, 15 Sep 2015 15:49:57 +1000 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay10.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t8F5nnaH22806774 for ; Tue, 15 Sep 2015 15:49:57 +1000 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t8F5nO7l017973 for ; Tue, 15 Sep 2015 15:49:25 +1000 From: "Ian Munsie" To: Michael Ellerman Cc: Anton Blanchard , Michael Neuling , linuxppc-dev , Ian Munsie Subject: [PATCH] cxl: Fix build failure due to -Wunused-variable behaviour change Date: Tue, 15 Sep 2015 15:48:34 +1000 Message-Id: <1442296114-16796-1-git-send-email-imunsie@au.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Ian Munsie A recent change in gcc caused this build failure: /var/lib/jenkins/workspace/gcc_kernel_build/linux/drivers/misc/cxl/cxl.h:72:27: error: ‘CXL_PSL_DLCNTL’ defined but not used [-Werror=unused-const-variable] static const cxl_p1_reg_t CXL_PSL_DLCNTL = {0x0060}; Because of this gcc commit: Commit 1bca8cbd0c68366f07277f98ce6963e10c2aa617 by mark PR28901 -Wunused-variable ignores unused const initialised variables in C 12 years ago it was decided that -Wunused-variable shouldn't warn about static const variables because some code used const static char rcsid[] strings which were never used but wanted in the code anyway. But as the bug points out this hides some real bugs. These days the usage of rcsids is not very popular anymore. So this patch changes the default to warn about unused static const variables in C with -Wunused-variable. And it adds a new option -Wno-unused-const-variable to turn this warning off. For C++ this new warning is off by default, since const variables can be used as #defines in C++. New testcases for the new defaults in C and C++ are included testing the new warning and suppressing it with an unused attribute or using -Wno-unused-const-variable. gcc/ChangeLog The cxl driver uses static consts in place of #defines in some cases for type safety, so this change causes the driver to fail to build on new copilers as these constants are not all used in every file that imports the header. Suppress the warning for this driver to return to the old behaviour of -Wunused-variable. Reported-by: Anton Blanchard Signed-off-by: Ian Munsie --- drivers/misc/cxl/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/misc/cxl/Makefile b/drivers/misc/cxl/Makefile index 6f484df..6982f60 100644 --- a/drivers/misc/cxl/Makefile +++ b/drivers/misc/cxl/Makefile @@ -1,4 +1,4 @@ -ccflags-y := -Werror +ccflags-y := -Werror -Wno-unused-const-variable cxl-y += main.o file.o irq.o fault.o native.o cxl-y += context.o sysfs.o debugfs.o pci.o trace.o -- 2.1.4