lkml.org 
[lkml]   [2004]   [Nov]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [RFC] Splitting kernel headers and deprecating __KERNEL__
    From
    Date
    On Mon, 2004-11-29 at 20:53 +1100, Paul Mackerras wrote:
    > Linus Torvalds writes:
    >
    > > In particular, any re-organization that breaks _existing_ uses is totally
    > > pointless. If you break existing uses, you might as well _not_ re-
    > > organize, since if you consider kernel headers to be purely kernel-
    > > internal (like they should be, but hey, reality trumps any wishes we might
    > > have), then the current organization is perfectly fine.
    >
    > Recently I had some users complaining because their userspace program
    > that includes <asm/atomic.h> compiles OK as a ppc64 program but not as
    > a ppc32 program. The reason for that is that asm-ppc/atomic.h has
    > #ifdef __KERNEL__ around the inline definitions of atomic_inc et al.,
    > but asm-ppc64/atomic.h doesn't.
    >
    > My response was that they shouldn't be using <asm/atomic.h> because
    > (a) it's an internal kernel header, not part of the kernel ABI, (b)
    > it's not portable (it happens to work on some popular architectures,
    > but won't work on all) and (c) they're really only entitled to use
    > those particular inline function definitions in GPL'd programs anyway.

    and (d) on x86 at least the "atomic" part of the atomic ops are #ifdef
    CONFIG_SMP, which might well not be set in userland... so you get a
    false sense of atomicity.

    > I'd be interested to hear your take on this. Should we try to make
    > our atomics easy and safe for userspace to use (including putting them
    > under the LGPL)? Or can you see a better solution?

    it's not the kernel's job to provide this functionality imo.
    glibc could. glib does. apr does. there's several options already.
    apr is BSD licensed for exanpmle, glib LGPL.


    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 14:08    [W:0.022 / U:29.740 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site