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From: David Daney <ddaney@caviumnetworks.com>
To: torvalds@linux-foundation.org, akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	David Daney <ddaney@caviumnetworks.com>,
	Ingo Molnar <mingo@elte.hu>
Subject: [PATCH 11/11] Use unreachable() in asm-generic/bug.h for !CONFIG_BUG case.
Date: Mon, 14 Sep 2009 14:55:40 -0700	[thread overview]
Message-ID: <1252965340-31735-11-git-send-email-ddaney@caviumnetworks.com> (raw)
In-Reply-To: <4AAEBAC2.1050905@caviumnetworks.com>

The subject says it all (most).  The only drawback here is that for a
pre-GCC-5.4 compiler, instead of expanding to nothing we now expand
BUG() to an endless loop.  Before the patch when configured with
!CONFIG_BUG() you might get some warnings, but the code would be
small.  After the patch there are no warnings, but there is an endless
loop at each BUG() site.

Of course for the GCC-4.5 case we get the best of both worlds.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Suggested-by: Ingo Molnar <mingo@elte.hu>
CC: Ingo Molnar <mingo@elte.hu>
---
 include/asm-generic/bug.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 4b67559..e952242 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -89,11 +89,11 @@ extern void warn_slowpath_null(const char *file, const int line);
 
 #else /* !CONFIG_BUG */
 #ifndef HAVE_ARCH_BUG
-#define BUG() do {} while(0)
+#define BUG() unreachable()
 #endif
 
 #ifndef HAVE_ARCH_BUG_ON
-#define BUG_ON(condition) do { if (condition) ; } while(0)
+#define BUG_ON(condition) do { if (condition) unreachable(); } while (0)
 #endif
 
 #ifndef HAVE_ARCH_WARN_ON
-- 
1.6.2.5


  parent reply	other threads:[~2009-09-14 21:57 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-14 21:50 [PATCH 00/11] Add support for GCC's __builtin_unreachable() and use it in BUG (v2) David Daney
2009-09-14 21:50 ` David Daney
2009-09-14 21:50 ` David Daney
2009-09-14 21:50 ` David Daney
2009-09-14 21:55 ` [PATCH 01/11] Add support for GCC-4.5's __builtin_unreachable() to compiler.h (v2) David Daney
2009-09-14 21:55 ` [PATCH 02/11] x86: Convert BUG() to use unreachable() David Daney
2009-09-14 21:55 ` [PATCH 03/11] MIPS: " David Daney
2009-09-15  8:39   ` [PATCH] MIPS: Make more use of unreachable() Ralf Baechle
2009-09-14 21:55 ` [PATCH 04/11] s390: Convert BUG() to use unreachable() David Daney
2009-09-14 21:55 ` [PATCH 05/11] mn10300: " David Daney
2009-09-14 21:55 ` [PATCH 06/11] parisc: " David Daney
2009-09-14 21:55 ` [PATCH 07/11] powerpc: " David Daney
2009-09-14 21:55   ` David Daney
2009-09-14 21:55 ` [PATCH 08/11] alpha: " David Daney
2009-09-14 21:55 ` [PATCH 09/11] avr32: " David Daney
2009-09-14 21:55 ` [PATCH 10/11] blackfin: " David Daney
2009-09-14 21:55   ` David Daney
2009-09-14 21:55 ` David Daney [this message]
2009-09-14 23:12   ` [PATCH 11/11] Use unreachable() in asm-generic/bug.h for !CONFIG_BUG case Brian Gerst
2009-09-14 23:12     ` Brian Gerst
2009-09-14 23:28     ` David Daney
2009-09-14 23:39       ` Linus Torvalds
2009-09-14 23:39         ` Linus Torvalds
2009-09-15 15:35         ` David Daney
2009-09-14 23:54       ` Brian Gerst
2009-09-14 23:54         ` Brian Gerst
2009-09-15 16:02         ` David Daney

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