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    SubjectRe: [patch 13/26] Xen-paravirt_ops: Consistently wrap paravirt ops callsites to make them patchable
    On Sun, Mar 18, 2007 at 10:29:10AM -0700, Jeremy Fitzhardinge wrote:
    > Andi Kleen wrote:
    > > You could use the dwarf2 unwind tables. They have exact information
    > > what register has what. But it would likely get complicated.
    >
    > Yes. And would they be accurate for hand-written asm, which is where we
    > have this problem?

    Yes. All inline assembly tells gcc what registers are clobbered
    and it fills in the tables. Hand clobbering in inline assembly cannot
    be expressed with the current toolchain, so we moved all those
    out of line.

    But again I'm not sure it will work anyways. For once you would
    need large padding around the calls anyways for inline replacement --
    how would you generate that? I expect you would need to put the calls
    into asm() again and with that a custom annotiation format looks reasonable.

    -Andi
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