(2013/07/11 6:36), H. Peter Anvin wrote: > On 07/10/2013 02:31 PM, Jiri Kosina wrote: >> >> If any CPU instruction execution would collide with the patching, >> it'd be trapped by the int3 breakpoint and redirected to the provided >> "handler" (which would typically mean just skipping over the patched >> region, acting as "nop" has been there, in case we are doing nop -> jump >> and jump -> nop transitions). >> > > I'm wondering if it would be easier/more general to just return to the > instruction. The "more general" bit would allow this to be used for > other things, like alternatives, and perhaps eventually dynamic call > patching. > > Returning to the instruction will, in effect, be a busy-wait for the > faulted CPU until the patch is complete; more or less what stop_machine > would do, but only for a CPU which actually strays into the affected region.
Sounds a good idea :) It may minimize the interface and the implementation will be self-contained. Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu...@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
