Commit 0c65f459 authored by Andrew Morton's avatar Andrew Morton Committed by Russell King
Browse files

[ARM] fix fls() for 64-bit arguments 



arm's fls() is implemented as a macro, causing it to misbehave when passed
64-bit arguments.  Fix.

Cc: Nickolay Vinogradov <nickolay@protei.ru>
Tested-by: default avatarKrzysztof Halasa <khc@pm.waw.pl>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 9d9fa83b

include/asm-arm/bitops.h

+8 −1
Original line number Original line Diff line number Diff line
@@ -277,9 +277,16 @@ static inline int constant_fls(int x) 
 * the clz instruction for much better code efficiency.

 * the clz instruction for much better code efficiency.

 */

 */





#define fls(x) \

#define __fls(x) \

	( __builtin_constant_p(x) ? constant_fls(x) : \

	( __builtin_constant_p(x) ? constant_fls(x) : \

	  ({ int __r; asm("clz\t%0, %1" : "=r"(__r) : "r"(x) : "cc"); 32-__r; }) )

	  ({ int __r; asm("clz\t%0, %1" : "=r"(__r) : "r"(x) : "cc"); 32-__r; }) )



/* Implement fls() in C so that 64-bit args are suitably truncated */

static inline int fls(int x)

{

	return __fls(x);

}



#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })

#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })

#define __ffs(x) (ffs(x) - 1)

#define __ffs(x) (ffs(x) - 1)

#define ffz(x) __ffs( ~(x) )

#define ffz(x) __ffs( ~(x) )

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