Messages in this thread Patch in this message | | | Date | Wed, 30 Jul 2008 16:27:10 -0700 | From | Greg KH <> | Subject | [patch 13/29] ARM: fix fls() for 64-bit arguments |
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2.6.25-stable review patch. If anyone has any objections, please let us know.
------------------ From: Andrew Morton <akpm@linux-foundation.org>
commit 0c65f459ce6c8bd873a61b3ae1e57858ab1debf3 upstream
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: Krzysztof Halasa <khc@pm.waw.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- include/asm-arm/bitops.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
--- a/include/asm-arm/bitops.h +++ b/include/asm-arm/bitops.h @@ -277,9 +277,16 @@ static inline int constant_fls(int x) * the clz instruction for much better code efficiency. */ -#define fls(x) \ +#define __fls(x) \ ( __builtin_constant_p(x) ? constant_fls(x) : \ ({ 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) (ffs(x) - 1) #define ffz(x) __ffs( ~(x) ) --
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