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    SubjectRe: 2.4.19pre3aa2
    On Thu, Mar 14, 2002 at 10:53:01AM -0500, Bill Davidsen wrote:
    > On Thu, 14 Mar 2002, Dave Jones wrote:
    >
    > > On Thu, Mar 14, 2002 at 03:28:01AM +0100, Andrea Arcangeli wrote:
    > > > Only in 2.4.19pre3aa2: 21_pte-highmem-f00f-1
    > > >
    > > > vmalloc called before smp_init was an hack, right way
    > > > is to use fixmap. CONFIG_M686 doesn't mean much these
    > > > days, but it's ok and probably most vendors will use it
    > > > for the smp kernels, so it will save 4096 of the vmalloc space.
    > > > I just didn't wanted to clobber the code with || CONFIG_K7 ||
    > > > CONFIG_... | ... given all the other f00f stuff is also
    > > > conditional only to M686 and probably nobody bothered to compile
    > > > it out for my same reason
    > >
    > > Brian Gerst had a patch a few months back to introduce a CONFIG_F00F
    > > if a relevant CONFIG_Mxxx was chosen[1]. It never got applied anywhere, but makes
    > > more sense than the CONFIG_M686 we currently use.
    > >
    > > [1] 386/486/586. With addition of my Vendor choice menu, we could even further
    > > narrow it down to Intel only.
    >
    > Since vendors (and consultants) like to build a single kernel for use on
    > multiple machines, it would be nice if this could be done by some init
    > code (released) and a module. I don't know what the overhead would be,
    > perhaps the runtime code is so small it's not worth doing. Does that mean

    Correct. I think the CONFIG option isn't worthwhile in the first place
    and this is why I only left the CONFIG_M686 knowing most smp kernels are
    compiled that way. 4096bytes of virtual vmallc space and some houndred
    bytes of bytecode doesn't worth the config option. If something the
    CONFIG_F00F would be more a documentation effort 8). But nevertheless if
    somebody really cares, that still make sense and it doesn't hurt. At the
    very least it is better than the current halfway broken CONFIG_M686.
    But personally I'm not going to implement it and if I would really be
    bothered by the halfway broken CONFIG_M686 I would drop it instead.

    > it's not worth doing the option either? It certainly would seen desirable
    > to check for the F00F bug and if the code to handle it was not present
    > refuse to boot right away.
    >
    > The code actually looks so small as to be unworthy of an option, given
    > that many people would set it off not knowing was it was much less whether
    > they needed it. This is not like a missing FPU where you can do a graceful
    > reject of the instructions, if you have the bug and not the fix you are
    > vulnerable to sudden total failures, correct?
    >
    > --
    > bill davidsen <davidsen@tmr.com>
    > CTO, TMR Associates, Inc
    > Doing interesting things with little computers since 1979.


    Andrea
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