From: Nicolas Pitre Date: Thu, 4 Dec 2008 02:59:41 +0000 (+0100) Subject: [ARM] 5339/1: fix __fls() on ARM X-Git-Tag: v2.6.28-rc8~34^2~2 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=94fc7336646b392234c0fafea5d696d020c3677c;p=linux-2.6-omap-h63xx.git [ARM] 5339/1: fix __fls() on ARM Commit 0c65f459ce6c intended to fix truncation issues with fls() on ARMv5+ by renaming it to __fls() and wrapping it into a C function. However that didn't take into account the fact that __fls() already already had different semantics in the kernel. Let's move the __fls() code into fls() function directly, and redefine __fls() with the appropriate semantics. While at it, bring a generic __fls() definition for pre ARMv5 too. Signed-off-by: Nicolas Pitre Signed-off-by: Russell King --- diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h index 9a1db20e032..63a481fbbed 100644 --- a/arch/arm/include/asm/bitops.h +++ b/arch/arm/include/asm/bitops.h @@ -237,6 +237,7 @@ extern int _find_next_bit_be(const unsigned long *p, int size, int offset); #if __LINUX_ARM_ARCH__ < 5 #include +#include #include #include #include @@ -277,16 +278,19 @@ static inline int constant_fls(int x) * the clz instruction for much better code efficiency. */ -#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); + int ret; + + if (__builtin_constant_p(x)) + return constant_fls(x); + + asm("clz\t%0, %1" : "=r" (ret) : "r" (x) : "cc"); + ret = 32 - ret; + return ret; } +#define __fls(x) (fls(x) - 1) #define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); }) #define __ffs(x) (ffs(x) - 1) #define ffz(x) __ffs( ~(x) )