lkml.org 
[lkml]   [2008]   [Jul]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[patch 13/29] ARM: fix fls() for 64-bit arguments
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) )
--


\
 
 \ /
  Last update: 2008-07-31 01:39    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site