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linux-stable-mirror/tools/include/asm-generic/bitops/fls64.h
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Arnaldo Carvalho de Melo 549042f167 tools headers asm: Sync fls headers header with the kernel sources
To pick the changes in:

  6606c8c7e8 ("bitops: Add __attribute_const__ to generic ffs()-family implementations")

This addresses these tools build warnings:

  Warning: Kernel ABI header differences:
    diff -u tools/include/asm-generic/bitops/__fls.h include/asm-generic/bitops/__fls.h
    diff -u tools/include/asm-generic/bitops/fls.h include/asm-generic/bitops/fls.h
    diff -u tools/include/asm-generic/bitops/fls64.h include/asm-generic/bitops/fls64.h

Please see tools/include/uapi/README for further details.

Cc: Kees Cook <kees@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2025-11-03 13:35:06 -03:00

38 lines
900 B
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_GENERIC_BITOPS_FLS64_H_
#define _ASM_GENERIC_BITOPS_FLS64_H_
#include <asm/types.h>
/**
* fls64 - find last set bit in a 64-bit word
* @x: the word to search
*
* This is defined in a similar way as the libc and compiler builtin
* ffsll, but returns the position of the most significant set bit.
*
* fls64(value) returns 0 if value is 0 or the position of the last
* set bit if value is nonzero. The last (most significant) bit is
* at position 64.
*/
#if BITS_PER_LONG == 32
static __always_inline __attribute_const__ int fls64(__u64 x)
{
__u32 h = x >> 32;
if (h)
return fls(h) + 32;
return fls(x);
}
#elif BITS_PER_LONG == 64
static __always_inline __attribute_const__ int fls64(__u64 x)
{
if (x == 0)
return 0;
return __fls(x) + 1;
}
#else
#error BITS_PER_LONG not 32 or 64
#endif
#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */