Re: 2.4.9-ac12 ppc ftr_fixup

From: Tom Rini (trini@kernel.crashing.org)
Date: Sun Aug 26 2001 - 21:54:58 EST


On Mon, Aug 27, 2001 at 12:47:57PM +1000, Keith Owens wrote:
>
> On Sun, 26 Aug 2001 19:15:36 -0700,
> Tom Rini <trini@kernel.crashing.org> wrote:
> >On Mon, Aug 27, 2001 at 10:27:22AM +1000, Keith Owens wrote:
> >
> >> 2.4.9-ac12 has new ppc code for CPU feature fixups. The ftr_fixup code
> >> only handles entries that are built into the kernel. timex.h defines
> >> get_cycles() using ftr_fixup and get_cycles() is used all over the
> >> place, including in modules. AFAICT we need to add modutils support
> >> for ftr_fixup.
> >
> >Er, eh? Excuse me if I'm being obtuse, but where is the problem? The fixup
> >stuff is closely tied to bootup and what processor we happen to be on
> >at the time. So we won't be trying to fixup any code in a module...
>
> do_cpu_ftr_fixups() replaces unsupported code with NOP, based on the
> table from __start___ftr_fixup to __stop___ftr_fixup which contains all
> the data marked as section(__ftr_fixup). Fine, but it only handles
> section __ftr_fixup data in the kernel, it does not write NOP over
> __ftr_fixup data in modules. So any code marked as section __ftr_fixup
> in a module executes unchanged. Unless I am missing something, that is
> a problem.

Hmm.. I'm guessing no one's tried get_cycles from a module on a 601 in
ages...

-- 
Tom Rini (TR1265)
http://gate.crashing.org/~trini/
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