• David Gibson's avatar
    [PATCH] powerpc: Merge bitops.h · a0e60b20
    David Gibson authored
    Here's a revised version.  This re-introduces the set_bits() function
    from ppc64, which I removed because I thought it was unused (it exists
    on no other arch).  In fact it is used in the powermac interrupt code
    (but not on pSeries).
    
    - We use LARXL/STCXL macros to generate the right (32 or 64 bit)
      instructions, similar to LDL/STL from ppc_asm.h, used in fpu.S
    
    - ppc32 previously used a full "sync" barrier at the end of
      test_and_*_bit(), whereas ppc64 used an "isync".  The merged version
      uses "isync", since I believe that's sufficient.
    
    - The ppc64 versions of then minix_*() bitmap functions have changed
      semantics.  Previously on ppc64, these functions were big-endian
      (that is bit 0 was the LSB in the first 64-bit, big-endian word).
      On ppc32 (and x86, for that matter, they were little-endian.  As far
      as I can tell, the big-endian usage was simply wrong - I guess
      no-one ever tried to use minixfs on ppc64.
    
    - On ppc32 find_next_bit() and find_next_zero_bit() are no longer
      inline (they were already out-of-line on ppc64).
    
    - For ppc64, sched_find_first_bit() has moved from mmu_context.h to
      the merged bitops.  What it was doing in mmu_context.h in the first
      place, I have no idea.
    
    - The fls() function is now implemented using the cntlzw instruction
      on ppc64, instead of generic_fls(), as it already was on ppc32.
    
    - For ARCH=ppc, this patch requires adding arch/powerpc/lib to the
      arch/ppc/Makefile.  This in turn requires some changes to
      arch/powerpc/lib/Makefile which didn't correctly handle ARCH=ppc.
    
    Built and running on G5.
    Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
    Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    a0e60b20
bitops.h 11.7 KB