Messages in this thread Patch in this message | | | Date | Wed, 16 Apr 2008 15:55:08 +0200 | From | Alexander van Heukelum <> | Subject | [PATCH] x86: fix find_next_bit breakage on ppc and powerpc |
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Powerpc (and ppc) have their have some code in their bitops.h which used to be exacly the same as asm-generic/bitops/find.h. Include this header instead.
This should also fix the compile problems due to the generic find_next_bit changes. Those were fixed by Thomas Gleixner in asm-generic/bitops/find.h earlier.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
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On Wed, Apr 16, 2008 at 02:57:24PM +0200, Ingo Molnar wrote: > * Alexander van Heukelum <heukelum@fastmail.fm> wrote: > > Hello Thomas, > > > > I see Ingo has applied three fixes to the x86-tree: > > find_first_bit() ppc fix > > powerpc: fix powerpc build > > find_next_bit() fix > > > > Could you please give some insight in what went wrong with > > ppc and powerpc? > > > > "find_first_bit() ppc fix" disables the use of find_first_bit > > for every user of GENERIC_FIND_NEXT_BIT=y. It replaces it by a > > macro to call find_next_bit with offset=0. It should be possible > > for an arch to use GENERIC_FIND_NEXT_BIT=y and implement > > find_first_bit by itself. > > > > "powerpc: fix powerpc build" removes the private 'implementation' > > of asm-generic/bitops/find.h. It seems correct code to me. What > > was the problem here? If it is duplicate declarations, then > > I would suggest putting #ifndef GENERIC_FIND_NEXT_BIT around > > them. > > > > "find_next_bit() fix" changes asm-generic/bitops/find.h to > > declare find_next_bit only if CONFIG_GENERIC_FIND_NEXT_BIT=n. > > That is indeed a good change. It would be better if this > > file disappeared completely, though. > > we had trouble making ppc64 defconfig build fine with your bitops > changes applied (Thomas might still have the build failure logs). The > fixes are ad-hoc band-aids to get it to build. We used crosscompilers to > build on ppc64.
Hello,
Yeah, I reproduced the breakage on x86 by putting an #include <asm-generic/bitops/find.h> in asm-x86/bitops.h. It's complaining a lot, then. Sorry about that breakage. I should have put more thought in the possibility of breakage due to that header file (I did look at it, but I thought it was harmless).
Thomas' "find_next_bit() fix" is certainly needed and correct. Acked-by: Alexander van Heukelum <heukelum@fastmail.fm>.
Could you/Thomas try the following on top of that fix? (i.e., with "find_next_bit() fix" and "find_first_bit() ppc fix" removed?) I think it should work then.
Architectures that use CONFIG_GENERIC_FIND_NEXT_BIT=y and include asm-generic/bitops/find.h should be able to switch to the generic find_first_bit implementation by setting GENERIC_FIND_FIRST_BIT=y in asm-$ARCH/Kconfig and removing the #include <asm-generic/bitops/find.h> from their asm-$ARCH/bitops.h.
Greetings, Alexander
include/asm-powerpc/bitops.h | 17 +---------------- 1 files changed, 1 insertions(+), 16 deletions(-)
diff --git a/include/asm-powerpc/bitops.h b/include/asm-powerpc/bitops.h index 2fc0c45..e2dbb53 100644 --- a/include/asm-powerpc/bitops.h +++ b/include/asm-powerpc/bitops.h @@ -318,23 +318,8 @@ static __inline__ unsigned long __fls(unsigned long x) return __ilog2(x); } #include <asm-generic/bitops/fls64.h> - #include <asm-generic/bitops/hweight.h> - -#define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0) -unsigned long find_next_zero_bit(const unsigned long *addr, - unsigned long size, unsigned long offset); -/** - * find_first_bit - find the first set bit in a memory region - * @addr: The address to start the search at - * @size: The maximum size to search - * - * Returns the bit-number of the first set bit, not the number of the byte - * containing a bit. - */ -#define find_first_bit(addr, size) find_next_bit((addr), (size), 0) -unsigned long find_next_bit(const unsigned long *addr, - unsigned long size, unsigned long offset); +#include <asm-generic/bitops/find.h> /* Little-endian versions */
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