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as multi-processor kernels. The old way made it difficult for kernel modules to be portable between uni-processor and multi-processor kernels. It is no longer necessary to jump through hoops. - always load %fs with the private segment on entry to the kernel - change the type of the self referntial pointer from struct privatespace to struct globaldata - make the globaldata symbol have value 0 in all cases, so the symbols in globals.s are always offsets, not aliases for fields in globaldata - define the globaldata space used for uniprocessor kernels in C, rather than assembler - change the assmebly language accessors to use %fs, add a macro PCPU_ADDR(member, reg), which loads the register reg with the address of the per-cpu variable member