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From: David Howells <dhowells@redhat.com>
To: torvalds@osdl.org, akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, David Howells <dhowells@redhat.com>
Subject: [PATCH 3/5] MN10300: Stop gcc from generating uninitialised variable warnings after BUG()
Date: Wed, 15 Apr 2009 19:34:51 +0100	[thread overview]
Message-ID: <20090415183451.11029.87805.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <20090415183441.11029.30619.stgit@warthog.procyon.org.uk>

Stop gcc from generating uninitialised variable warnings after BUG().  The
problem is that MN10300's implementation of BUG() invokes system call 15 which
doesn't return - but there's no way to tell the compiler that and also emit the
bug table element with the correct file and line data.

So instead, we make the do...while wrapper in _debug_bug_trap() an endless loop
from which there's no escape.

Also, while we're at it, (1) get rid of _debug_bug_trap() and just implement
directly as BUG(), and (2) make the implementation of BUG() contingent on
CONFIG_BUG=y.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 arch/mn10300/include/asm/bug.h |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)


diff --git a/arch/mn10300/include/asm/bug.h b/arch/mn10300/include/asm/bug.h
index 4fcf338..aa6a388 100644
--- a/arch/mn10300/include/asm/bug.h
+++ b/arch/mn10300/include/asm/bug.h
@@ -11,10 +11,12 @@
 #ifndef _ASM_BUG_H
 #define _ASM_BUG_H
 
+#ifdef CONFIG_BUG
+
 /*
  * Tell the user there is some problem.
  */
-#define _debug_bug_trap()					\
+#define BUG()							\
 do {								\
 	asm volatile(						\
 		"	syscall 15			\n"	\
@@ -25,11 +27,11 @@ do {								\
 		:						\
 		: "i"(__FILE__), "i"(__LINE__)			\
 		);						\
-} while (0)
-
-#define BUG() _debug_bug_trap()
+} while (1)
 
 #define HAVE_ARCH_BUG
+#endif /* CONFIG_BUG */
+
 #include <asm-generic/bug.h>
 
 #endif /* _ASM_BUG_H */


  parent reply	other threads:[~2009-04-15 18:36 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-15 18:34 [PATCH 1/5] MN10300: Discard duplicate PFN_xxx() macros David Howells
2009-04-15 18:34 ` [PATCH 2/5] MN10300: Wire up missing system calls David Howells
2009-04-15 18:34 ` David Howells [this message]
2009-04-15 18:34 ` [PATCH 4/5] The default CONFIG_BUG=n version of BUG() should have an empty do...while David Howells
2009-04-15 18:35 ` [PATCH 5/5] RCU: Don't try and predeclare inline funcs as it upsets some versions of gcc David Howells
2009-04-17 23:41   ` Paul E. McKenney

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