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SubjectRe: Patch to fix race between the NMI code and the CMOS clock
Corey Minyard <minyard@acm.org> wrote:
>
> This patch fixes a race between the CMOS clock setting and the NMI
> code. The NMI code indiscriminatly sets index registers and values
> in the same place the CMOS clock is set. If you are setting the
> CMOS clock and an NMI occurs, Bad values could be written to or
> read from the CMOS RAM, or the NMI operation might not occur
> correctly.
>
> Fixing this requires creating a special lock so the NMI code can
> know its CPU owns the lock an "do the right thing" in that case.

hm, tricky patch. I can't see any holes in it. The volatile variable is
awkward but should be OK on x86 and I can see the need for it.

There's a preposterous amount of inlining happening in this code. Hence
your patch took the size of drivers/char/rtc.o from

text data bss dec hex filename
3657 540 8 4205 106d drivers/char/rtc.o
to
5419 540 8 5967 174f drivers/char/rtc.o

Do you think you could take a look at uninlining everything sometime?
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