lkml.org 
[lkml]   [2008]   [Jun]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] x86: set PAE PHYSICAL_MASK_SHIFT to match 64-bit
    Jeremy Fitzhardinge wrote:
    >
    > We could have an auction:
    >
    > Do I hear 46? 47? 48? 50? 52! Going once, twice, 52 bits!
    >
    > Anyway, we can fix it later in a separate patch. This is a
    > change-as-little-as-possible bugfix patch.
    >

    It should either be 52 bits or dynamic based on CPUID information. The
    latter is very expensive.

    If there end up being additional control bits assigned in this space we
    won't use them since we know the size of the address space (which won't
    include the control bits) and thus will leave them at zero.

    It's largely theoretical, since I believe Linux on x86-64 relies on
    virtual >= physical+N, where I believe N is about 3 bits, and the page
    table format or page size need to change to support more than 48 bits of
    virtual address space.

    -hpa


    \
     
     \ /
      Last update: 2008-06-05 19:05    [W:0.028 / U:0.516 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site