void
as_destroy(struct addrspace *as)
{
pt_destroy(as->as_pgtbl);
#if OPT_ASID
tlb_flush_asid(as->as_id);
#endif
kfree(as);
}
// NIY: think about real int safe
static void
alloc_asid(ADDRESS *adp) {
static int asid_rotor = 1;
int asid, i;
ADDRESS *oldadp;
/*
* Be very, very careful in here. We can be allocating an asid for
* somebody and have an interrupt go off. If the interrupt has a
* handler routine, we will re-enterantly execute this code to set up
* the address space for the routine.
*/
/*
* Do a quick scan through the asid_map and see
* if there are any unallocated entries. The
* reason why we do this is because it is cheaper
* to do this one scan than to steal an asid,
* do a MemPageFlushAsid, and also possibly incur
* tlb refills for the poor guy we stole from.
* If there are no unallocated asids, then go
* back to where we were in the asid_map.
*/
// asid 0 is reserved for system address space
for(i = 1; i <= VM_ASID_BOUNDARY; ++i) {
if(asid_map[i] == NULL) {
asid_map[i] = adp;
adp->cpu.asid = i;
#ifdef VARIANT_smp
/*
* Indicate ASID needs purging on all cpus
*/
atomic_set(&adp->cpu.asid_flush, LEGAL_CPU_BITMASK);
#endif
return;
}
}
/* have to steal one */
asid = asid_rotor;
if(++asid_rotor > VM_ASID_BOUNDARY) {
asid_rotor = 1;
}
adp->cpu.asid = asid;
#ifdef VARIANT_smp
/*
* Indicate ASID needs purging on all cpus
*/
atomic_set(&adp->cpu.asid_flush, LEGAL_CPU_BITMASK);
#endif
oldadp = asid_map[asid];
asid_map[asid] = adp;
if(oldadp != NULL) {
/*
* Mark his asid as invalid so
* that when we switch to him he'll
* pick up another one.
*/
oldadp->cpu.asid = ~0;
#ifdef VARIANT_smp
/*
* We will flush the asid in vmm_aspace
*/
#else
tlb_flush_asid(asid);
#endif
}
}