From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 21 Nov 2008 01:27:32 +0000 (GMT) Received: from mail3.caviumnetworks.com ([12.108.191.235]:30610 "EHLO mail3.caviumnetworks.com") by ftp.linux-mips.org with ESMTP id S23802213AbYKUB12 (ORCPT ); Fri, 21 Nov 2008 01:27:28 +0000 Received: from exch4.caveonetworks.com (Not Verified[192.168.16.23]) by mail3.caviumnetworks.com with MailMarshal (v6,2,2,3503) id ; Thu, 20 Nov 2008 20:26:59 -0500 Received: from exch4.caveonetworks.com ([192.168.16.23]) by exch4.caveonetworks.com with Microsoft SMTPSVC(6.0.3790.3959); Thu, 20 Nov 2008 17:26:37 -0800 Received: from dd1.caveonetworks.com ([64.169.86.201]) by exch4.caveonetworks.com with Microsoft SMTPSVC(6.0.3790.3959); Thu, 20 Nov 2008 17:26:36 -0800 Message-ID: <49260E4C.8080500@caviumnetworks.com> Date: Thu, 20 Nov 2008 17:26:36 -0800 From: David Daney User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: linux-mips CC: linux-kernel@vger.kernel.org Subject: [PATCH] MIPS: Make BUG() __noreturn. Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 21 Nov 2008 01:26:36.0849 (UTC) FILETIME=[3247BA10:01C94B78] Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 21350 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ddaney@caviumnetworks.com Precedence: bulk X-list: linux-mips MIPS: Make BUG() __noreturn. Often we do things like put BUG() in the default clause of a case statement. Since it was not declared __noreturn, this could sometimes lead to bogus compiler warnings that variables were used uninitialized. There is a small problem in that we have to put a magic while(1); loop to fool GCC into really thinking it is noreturn. This makes the new BUG() function 3 instructions long instead of just 1, but I think it is worth it as it is now unnecessary to do extra work to silence the 'used uninitialized' warnings. I also re-wrote BUG_ON so that if it is given a constant condition, it just does BUG() instead of loading a constant value in to a register and testing it. Signed-off-by: David Daney --- arch/mips/include/asm/bug.h | 29 ++++++++++++++++++++--------- 1 files changed, 20 insertions(+), 9 deletions(-) diff --git a/arch/mips/include/asm/bug.h b/arch/mips/include/asm/bug.h index 7eb63de..08ea468 100644 --- a/arch/mips/include/asm/bug.h +++ b/arch/mips/include/asm/bug.h @@ -7,20 +7,31 @@ #include -#define BUG() \ -do { \ - __asm__ __volatile__("break %0" : : "i" (BRK_BUG)); \ -} while (0) +static inline void __noreturn BUG(void) +{ + __asm__ __volatile__("break %0" : : "i" (BRK_BUG)); + /* Fool GCC into thinking the function doesn't return. */ + while (1) + ; +} #define HAVE_ARCH_BUG #if (_MIPS_ISA > _MIPS_ISA_MIPS1) -#define BUG_ON(condition) \ -do { \ - __asm__ __volatile__("tne $0, %0, %1" \ - : : "r" (condition), "i" (BRK_BUG)); \ -} while (0) +static inline void __BUG_ON(unsigned long condition) +{ + if (__builtin_constant_p(condition)) { + if (condition) + BUG(); + else + return; + } + __asm__ __volatile__("tne $0, %0, %1" + : : "r" (condition), "i" (BRK_BUG)); +} + +#define BUG_ON(C) __BUG_ON((unsigned long)(C)) #define HAVE_ARCH_BUG_ON