Commit 8ec2e243 authored Nov 20, 2008 by David Daney Committed by Ralf Baechle Nov 24, 2008

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 <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

parent ed313489

arch/mips/include/asm/bug.h

+20 −9

Original line number	Diff line number	Diff line
		@@ -7,20 +7,31 @@

		#include <asm/break.h>

		#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

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