1f2bf84678
struct fpstate *. add a new entry point ipi_savefpstate() that is used for this IPI instead of the plain ipi_savefpstate(). check for %o0 being NULL, and if so, just return. add event counters for the savefpstate IPI, and another one for when it detects the NULL problem. make the cpu_info struct xmpsg be aligned to a single cache line. with this change applied (and another minor change in testing) my SS20 with dual SM75's has survived for 17 hours on build.sh -j5, and has reported 7 NULL savefps. (the minor change seems to have a significant effect at reducing this number, but more testing is needed for it.) XXX: this is horrible and we really need to find the real problem XXX: but this should let people use sparc smp again, and fixes XXX: for the real problem can be tested by seeing if any of the XXX: savefp IPI null counter becomes non-zero.