linux-kernel - linux-next: manual merge of the kspp tree with the s390 tree

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Message-ID: <aNVUMLnpNVGWz7Pb@sirena.org.uk>
Date: Thu, 25 Sep 2025 15:39:44 +0100
From: Mark Brown <broonie@...nel.org>
To: Kees Cook <kees@...nel.org>
Cc: Alexander Gordeev <agordeev@...ux.ibm.com>,
	Heiko Carstens <hca@...ux.ibm.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linux Next Mailing List <linux-next@...r.kernel.org>
Subject: linux-next: manual merge of the kspp tree with the s390 tree

Hi all,

Today's linux-next merge of the kspp tree got a conflict in:

  arch/s390/include/asm/bitops.h

between commits:

  de88e74889a30 ("s390/bitops: Slightly optimize ffs() and fls64()")
  7b80a23c0e33a ("s390/bitops: Switch to generic fls(), fls64(), etc.")
  6c4e0cb3d87ad ("s390/bitops: Switch to generic ffs() if supported by compiler")

from the s390 tree and commit:

  b77fee88bfdfc ("s390: Add __attribute_const__ to ffs()-family implementations")

from the kspp tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

diff --cc arch/s390/include/asm/bitops.h
index 1564dd3a5a826,fbcc3e1cc7769..0000000000000
--- a/arch/s390/include/asm/bitops.h
+++ b/arch/s390/include/asm/bitops.h
@@@ -189,26 -191,58 +189,26 @@@ static __always_inline __attribute_cons
   * This is defined the same way as the libc and
   * compiler builtin ffs routines (man ffs).
   */
- static __always_inline __flatten int ffs(int word)
 -static inline __attribute_const__ int ffs(int word)
++static __always_inline __flatten __attribute_const__ int ffs(int word)
  {
 -	unsigned long mask = 2 * BITS_PER_LONG - 1;
  	unsigned int val = (unsigned int)word;
  
 -	return (1 + (__flogr(-val & val) ^ (BITS_PER_LONG - 1))) & mask;
 +	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 inline __attribute_const__ unsigned long __fls(unsigned long word)
 -{
 -	return __flogr(word) ^ (BITS_PER_LONG - 1);
 -}
 +#else /* CONFIG_CC_HAS_BUILTIN_FFS */
  
 -/**
 - * 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 inline __attribute_const__ int fls64(unsigned long word)
 -{
 -	unsigned long mask = 2 * BITS_PER_LONG - 1;
 +#include <asm-generic/bitops/builtin-ffs.h>
  
 -	return (1 + (__flogr(word) ^ (BITS_PER_LONG - 1))) & mask;
 -}
 -
 -/**
 - * 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 inline __attribute_const__ int fls(unsigned int word)
 -{
 -	return fls64(word);
 -}
 +#endif /* CONFIG_CC_HAS_BUILTIN_FFS */
  
 +#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>

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