This ensures that BUG() always has a definition that causes a trap (via an undefined instruction), and that the compiler still recognizes the code following BUG() as unreachable, avoiding warnings that would otherwise appear (such as on non-void functions that don't return a value after BUG()). In addition to saving a few bytes over the generic infinite-loop implementation, this implementation traps rather than looping, which potentially allows for better error-recovery behavior (such as by rebooting). Signed-off-by: Josh Triplett <josh@joshtriplett.org> Reported-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
		
			
				
	
	
		
			37 lines
		
	
	
	
		
			743 B
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			37 lines
		
	
	
	
		
			743 B
			
		
	
	
	
		
			C
		
	
	
	
	
	
#ifndef _ASM_X86_BUG_H
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#define _ASM_X86_BUG_H
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#define HAVE_ARCH_BUG
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#ifdef CONFIG_DEBUG_BUGVERBOSE
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#ifdef CONFIG_X86_32
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# define __BUG_C0	"2:\t.long 1b, %c0\n"
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#else
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# define __BUG_C0	"2:\t.long 1b - 2b, %c0 - 2b\n"
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#endif
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#define BUG()							\
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do {								\
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	asm volatile("1:\tud2\n"				\
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		     ".pushsection __bug_table,\"a\"\n"		\
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		     __BUG_C0					\
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		     "\t.word %c1, 0\n"				\
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		     "\t.org 2b+%c2\n"				\
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		     ".popsection"				\
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		     : : "i" (__FILE__), "i" (__LINE__),	\
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		     "i" (sizeof(struct bug_entry)));		\
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	unreachable();						\
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} while (0)
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#else
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#define BUG()							\
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do {								\
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	asm volatile("ud2");					\
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	unreachable();						\
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} while (0)
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#endif
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#include <asm-generic/bug.h>
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#endif /* _ASM_X86_BUG_H */
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