From 3fc2579e6f162fcff964f5aa01c8a29438ca5c05 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Thu, 3 Jan 2019 15:26:41 -0800 Subject: fls: change parameter to unsigned int When testing in userspace, UBSAN pointed out that shifting into the sign bit is undefined behaviour. It doesn't really make sense to ask for the highest set bit of a negative value, so just turn the argument type into an unsigned int. Some architectures (eg ppc) already had it declared as an unsigned int, so I don't expect too many problems. Link: http://lkml.kernel.org/r/20181105221117.31828-1-willy@infradead.org Signed-off-by: Matthew Wilcox Acked-by: Thomas Gleixner Acked-by: Geert Uytterhoeven Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/arc/include/asm/bitops.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arc') diff --git a/arch/arc/include/asm/bitops.h b/arch/arc/include/asm/bitops.h index 8da87feec59a..ee9246184033 100644 --- a/arch/arc/include/asm/bitops.h +++ b/arch/arc/include/asm/bitops.h @@ -278,7 +278,7 @@ static inline __attribute__ ((const)) int clz(unsigned int x) return res; } -static inline int constant_fls(int x) +static inline int constant_fls(unsigned int x) { int r = 32; @@ -312,7 +312,7 @@ static inline int constant_fls(int x) * @result: [1-32] * fls(1) = 1, fls(0x80000000) = 32, fls(0) = 0 */ -static inline __attribute__ ((const)) int fls(unsigned long x) +static inline __attribute__ ((const)) int fls(unsigned int x) { if (__builtin_constant_p(x)) return constant_fls(x); -- cgit v1.2.3