[Xen-devel] Re: [patch 13/26] Xen-paravirt_ops: Consistently wrap paravirt ops callsites to make them patchable

[Andi Kleen <ak@xxxxxx>]

> The bigger problem is that you don't know what registers you can
> clobber.  For the pv_ops in hand-written asm, that a big pain.  The code
> either has to assume the worst, or the "relocator" has to do something
> more sophisticated (like look for push/pop pairs surrounding the call,
> perhaps?).

You could use the dwarf2 unwind tables. They have exact information
what register has what. But it would likely get complicated.

-Andi

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