mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 21:54:06 +08:00
3fc2579e6f
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 <willy@infradead.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
50 lines
1.2 KiB
C
50 lines
1.2 KiB
C
/*
|
|
* linux/arch/unicore32/include/asm/bitops.h
|
|
*
|
|
* Code specific to PKUnity SoC and UniCore ISA
|
|
*
|
|
* Copyright (C) 2001-2010 GUAN Xue-tao
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#ifndef __UNICORE_BITOPS_H__
|
|
#define __UNICORE_BITOPS_H__
|
|
|
|
#define _ASM_GENERIC_BITOPS_FLS_H_
|
|
#define _ASM_GENERIC_BITOPS___FLS_H_
|
|
#define _ASM_GENERIC_BITOPS_FFS_H_
|
|
#define _ASM_GENERIC_BITOPS___FFS_H_
|
|
/*
|
|
* On UNICORE, those functions can be implemented around
|
|
* the cntlz instruction for much better code efficiency.
|
|
*/
|
|
|
|
static inline int fls(unsigned int x)
|
|
{
|
|
int ret;
|
|
|
|
asm("cntlz\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)
|
|
|
|
#include <asm-generic/bitops.h>
|
|
|
|
/* following definitions: to avoid using codes in lib/find_*.c */
|
|
#define find_next_bit find_next_bit
|
|
#define find_next_zero_bit find_next_zero_bit
|
|
#define find_first_bit find_first_bit
|
|
#define find_first_zero_bit find_first_zero_bit
|
|
|
|
#include <asm-generic/bitops/find.h>
|
|
|
|
#endif /* __UNICORE_BITOPS_H__ */
|