lkml.org 
[lkml]   [2005]   [Nov]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 1/10] Cr4 is valid on some 486s


    On Fri, 11 Nov 2005, Zachary Amsden wrote:
    >
    > Yes, this is fine, but is it worth writing the feature discovery code? I
    > suppose it doesn't matter, as it gets jettisoned after init. I guess it is
    > just preference.

    Well, you could do the feature discovery by trying to take a fault early
    at boot-time. That's how we verify that write-protect works, and how we
    check that math exceptions come in the right way..

    > Could we consider doing the same with LOCK prefix for SMP kernels booted on
    > UP? Evil grin.

    Not so evil - I think it's been discussed. Not with alternates (not worth
    it), but it wouldn't be hard to do: just add a new section for "lock
    address", and have each inline asm that does a lock prefix do basically

    1:
    lock ; xyzzy

    .section .lock.address
    .long 1b
    .previous

    and then just walk the ".lock.address" thing and turn all locks into 0x90
    (nop).

    Linus
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2009-11-18 23:46    [W:0.021 / U:1.836 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site