pmap of amd64

Matthew Dillon dillon at
Mon Oct 15 10:32:07 PDT 2007

:You can check the stack frame for the RIP and if it is alreday in the
:kernel, you can skip the swapgs. Given that you have to do more work for
:traps from userland anyway, that's a relatively cheap change.

    You can't, because not all traps to the system disable interrupts.
    This means that another interrupt can occur after the stack frame has
    been pushed, but before swapgs has been run the first time.

    It really is a lot easier to just load a pointer from a fixed address.

					Matthew Dillon 
					<dillon at>

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