Messages in this thread |  | | | Date | Tue, 29 Apr 2008 21:28:33 -0700 (PDT) | | Subject | Re: [PATCH] /dev/mem gcc weak function workaround | | From | David Miller <> | |
From: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Tue, 29 Apr 2008 18:31:09 -0700
> Some flavors of gcc 4.1.0 and 4.1.1 seems to have trouble understanding
> weak function definitions. Calls to function from the same file where it is
> defined as weak _may_ get inlined, even when there is a non-weak definition of
> the function elsewhere. I tried using attribute 'noinline' which does not
> seem to help either.
>
> One workaround for this is to have weak functions defined in different
> file as below. Other possible way is to not use weak functions and go back
> to ifdef logic.
>
> There are few other usages in kernel that seem to depend on weak (and noinline)
> working correctly, which can also potentially break and needs such workarounds.
> Example -
> mach_reboot_fixups() in arch/x86/kernel/reboot.c is one such call which
> is getting inlined with a flavor of gcc 4.1.1.
>
> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
This sounds like a bug. And if gcc does multi-file compilation it
can in theory do the same mistake even if you move it to another
file.
We need something more bulletproof here.
Also, we have a macro for marking things weak "__weak" which should
be used here.
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