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    SubjectRe: [patch] SMP alternatives
    Alan Cox wrote:
    > On Mer, 2005-11-23 at 12:17 -0700, Andi Kleen wrote:
    >>> + /* Paranoia */
    >>> + asm volatile ("jmp 1f\n1:");
    >>> + mb();
    >> That would be totally obsolete 386 era paranoia. If anything then use
    >> a CLFLUSH (but not available on all x86s)
    >
    > If you are patching code another x86 CPU is running you must halt the
    > other processors and ensure it executes a serialzing instruction before
    > it enters any patched code.

    Patching in/out SMP-locking with more than one active CPU would be a
    pretty silly idea in the first place ;)

    > How many kilobytes of tables do you add to the kernel to do this
    > pointless stunt btw ?

    16 .smp_altinstructions 0000ae0b c03b4000 003b4000 002b4000 2**2
    CONTENTS, ALLOC, LOAD, READONLY, DATA
    17 .smp_altinstr_replacement 00000f6e c03bee0b 003bee0b 002bee0b 2**0
    CONTENTS, ALLOC, LOAD, CODE

    cheers,

    Gerd

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