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s390/bitops: Switch to generic fls(), fls64(), etc.

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Switch to generic fls(), fls64(), etc. which are implemented with
__builtin_ctzl(), __builtin_clzl().
Those builtins are available for all supported compilers.

Kernel image size is reduced by ~10kb (gcc 15.1.0 + defconfig).

Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2025-09-22 13:40:19 +02:00 committed by Alexander Gordeev
parent 5671ce2a1f
commit 7b80a23c0e
1 changed files with 5 additions and 51 deletions
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56
arch/s390/include/asm/bitops.h
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@ -180,17 +180,6 @@ static __always_inline __attribute_const__ unsigned long __flogr(unsigned long w
}
}
/**
* __ffs - find first bit in word.
* @word: The word to search
*
* Undefined if no bit exists, so code should check against 0 first.
*/
static __always_inline __flatten unsigned long __ffs(unsigned long word)
{
return __flogr(-word & word) ^ (BITS_PER_LONG - 1);
}
/**
* ffs - find first bit set
* @word: the word to search
@ -205,48 +194,13 @@ static __always_inline __flatten int ffs(int word)
return BITS_PER_LONG - __flogr(-val & val);
}
/**
* __fls - find last (most-significant) set bit in a long word
* @word: the word to search
*
* Undefined if no set bit exists, so code should check against 0 first.
*/
static __always_inline __flatten unsigned long __fls(unsigned long word)
{
return __flogr(word) ^ (BITS_PER_LONG - 1);
}
/**
* fls64 - find last set bit in a 64-bit word
* @word: 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.
*/
static __always_inline __flatten int fls64(unsigned long word)
{
return BITS_PER_LONG - __flogr(word);
}
/**
* fls - find last (most-significant) bit set
* @word: the word to search
*
* This is defined the same way as ffs.
* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
*/
static __always_inline __flatten int fls(unsigned int word)
{
return fls64(word);
}
#include <asm-generic/bitops/builtin-__ffs.h>
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/builtin-__fls.h>
#include <asm-generic/bitops/builtin-fls.h>
#include <asm-generic/bitops/fls64.h>
#include <asm/arch_hweight.h>
#include <asm-generic/bitops/const_hweight.h>
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/sched.h>
#include <asm-generic/bitops/le.h>
#include <asm-generic/bitops/ext2-atomic-setbit.h>