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    SubjectRe: [tip:perf/core] perf/x86: Fix USER/KERNEL tagging of samples
    On 07/10/2012 02:48 AM, Ingo Molnar wrote:
    >
    > We could read out the current GDT [the SGDT instruction] instead
    > of looking at gdt_page.
    >
    > Then we'd have to decode that descriptor, the limit. Decide
    > whether the selector points to the GDT or LDT. All the fun x86
    > legacies that we mostly forgot already after two decades of
    > running the kernel in flat linear mode...
    >

    In 32-bit mode there are actually instructions that do that work for you.

    -hpa

    --
    H. Peter Anvin, Intel Open Source Technology Center
    I work for Intel. I don't speak on their behalf.



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