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    Subject[PATCH 4/4] LOG2: Provide ilog2() fallbacks for powerpc [try #4]
    Date
    From: David Howells <dhowells@redhat.com>

    Provide ilog2() fallbacks for powerpc for 32-bit numbers and 64-bit numbers on
    ppc64.

    Signed-Off-By: David Howells <dhowells@redhat.com>
    ---

    arch/powerpc/Kconfig | 4 ++--
    include/asm-powerpc/bitops.h | 21 ++++++++++++++++++++-
    include/asm-powerpc/page_32.h | 10 +---------
    3 files changed, 23 insertions(+), 12 deletions(-)

    diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
    index 1cf67b7..9515489 100644
    --- a/arch/powerpc/Kconfig
    +++ b/arch/powerpc/Kconfig
    @@ -43,11 +43,11 @@ config RWSEM_XCHGADD_ALGORITHM

    config ARCH_HAS_ILOG2_U32
    bool
    - default n
    + default y

    config ARCH_HAS_ILOG2_U64
    bool
    - default n
    + default y if 64BIT

    config GENERIC_HWEIGHT
    bool
    diff --git a/include/asm-powerpc/bitops.h b/include/asm-powerpc/bitops.h
    index c341063..0288144 100644
    --- a/include/asm-powerpc/bitops.h
    +++ b/include/asm-powerpc/bitops.h
    @@ -190,7 +190,8 @@ #include <asm-generic/bitops/non-atomic.
    * Return the zero-based bit position (LE, not IBM bit numbering) of
    * the most significant 1-bit in a double word.
    */
    -static __inline__ int __ilog2(unsigned long x)
    +static __inline__ __attribute__((const))
    +int __ilog2(unsigned long x)
    {
    int lz;

    @@ -198,6 +199,24 @@ static __inline__ int __ilog2(unsigned l
    return BITS_PER_LONG - 1 - lz;
    }

    +static inline __attribute__((const))
    +int __ilog2_u32(u32 n)
    +{
    + int bit;
    + asm ("cntlzw %0,%1" : "=r" (bit) : "r" (n));
    + return 31 - bit;
    +}
    +
    +#ifdef __powerpc64__
    +static inline __attribute__((const))
    +int __ilog2_u64(u32 n)
    +{
    + int bit;
    + asm ("cntlzd %0,%1" : "=r" (bit) : "r" (n));
    + return 63 - bit;
    +}
    +#endif
    +
    /*
    * Determines the bit position of the least significant 0 bit in the
    * specified double word. The returned bit position will be
    diff --git a/include/asm-powerpc/page_32.h b/include/asm-powerpc/page_32.h
    index 2677bad..07f6d3c 100644
    --- a/include/asm-powerpc/page_32.h
    +++ b/include/asm-powerpc/page_32.h
    @@ -26,15 +26,7 @@ extern void clear_pages(void *page, int
    static inline void clear_page(void *page) { clear_pages(page, 0); }
    extern void copy_page(void *to, void *from);

    -/* Pure 2^n version of get_order */
    -extern __inline__ int get_order(unsigned long size)
    -{
    - int lz;
    -
    - size = (size-1) >> PAGE_SHIFT;
    - asm ("cntlzw %0,%1" : "=r" (lz) : "r" (size));
    - return 32 - lz;
    -}
    +#include <asm-generic/page.h>

    #endif /* __ASSEMBLY__ */

    -
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