linux/arch/csky/include/asm/bitops.h
Matthew Wilcox 3fc2579e6f 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 <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>
2019-01-04 13:13:46 -08:00

83 lines
1.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
#ifndef __ASM_CSKY_BITOPS_H
#define __ASM_CSKY_BITOPS_H
#include <linux/compiler.h>
#include <asm/barrier.h>
/*
* asm-generic/bitops/ffs.h
*/
static inline int ffs(int x)
{
if (!x)
return 0;
asm volatile (
"brev %0\n"
"ff1 %0\n"
"addi %0, 1\n"
: "=&r"(x)
: "0"(x));
return x;
}
/*
* asm-generic/bitops/__ffs.h
*/
static __always_inline unsigned long __ffs(unsigned long x)
{
asm volatile (
"brev %0\n"
"ff1 %0\n"
: "=&r"(x)
: "0"(x));
return x;
}
/*
* asm-generic/bitops/fls.h
*/
static __always_inline int fls(unsigned int x)
{
asm volatile(
"ff1 %0\n"
: "=&r"(x)
: "0"(x));
return (32 - x);
}
/*
* asm-generic/bitops/__fls.h
*/
static __always_inline unsigned long __fls(unsigned long x)
{
return fls(x) - 1;
}
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/fls64.h>
#include <asm-generic/bitops/find.h>
#ifndef _LINUX_BITOPS_H
#error only <linux/bitops.h> can be included directly
#endif
#include <asm-generic/bitops/sched.h>
#include <asm-generic/bitops/hweight.h>
#include <asm-generic/bitops/lock.h>
#include <asm-generic/bitops/atomic.h>
/*
* bug fix, why only could use atomic!!!!
*/
#include <asm-generic/bitops/non-atomic.h>
#define __clear_bit(nr, vaddr) clear_bit(nr, vaddr)
#include <asm-generic/bitops/le.h>
#include <asm-generic/bitops/ext2-atomic.h>
#endif /* __ASM_CSKY_BITOPS_H */