[patch 13/29] ARM: fix fls() for 64-bit arguments

[Greg KH <gregkh@suse.de>]

[-- Attachment #1: arm-fix-fls-for-64-bit-arguments.patch --]
[-- Type: text/plain, Size: 1269 bytes --]

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) )

--