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    SubjectRe: [Patch 1/4] Allow arch-specific cleanup before breakpoint unregistration
    On Wed, 2010-05-26 at 10:54 +0100, David Howells wrote:
    > K.Prasad <> wrote:
    > > > My understanding is weak function definitions must appear in a different C
    > > > file than their call sites to work on some toolchains.
    > > >
    > >
    > > Atleast, there are quite a few precedents inside the Linux kernel for
    > > __weak functions being invoked from the file in which they are defined
    > > (arch_hwblk_init, arch_enable_nonboot_cpus_begin and hw_perf_disable to
    > > name a few).
    > > Moreover the online GCC docs haven't any such constraints mentioned.
    > I've seen problems in this area. gcc sometimes inlines a weak function that's
    > in the same file as the call point.

    See the functions in kernel/softirq.c for example, and commits 43a256322
    and b2e2fe996 - though unhelpfully they don't mention the gcc version. A
    bit of googling suggests it was probably "gcc version 4.1.1 20060525
    (Red Hat 4.1.1-1)" in that case.

    But the example of hw_perf_enable() (which is weak in the same unit),
    suggests maybe this isn't a bug many people are hitting in practice

    Having said that the #define foo foo pattern is reasonably neat and
    avoids the problem altogether, see eg. arch_setup_msi_irqs.

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      Last update: 2010-05-26 17:17    [W:0.029 / U:8.032 seconds]
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