Re: Patch to fix race between the NMI code and the CMOS clock

[Andrew Morton <akpm@osdl.org>]

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?