Function pmap_asid_alloc

freebsd/mips/mips/pmap.c:3450–3470

* Allocate TLB address space tag (called ASID or TLBPID) and return it. * It takes almost as much or more time to search the TLB for a * specific ASID and flush those entries as it does to flush the entire TLB. * Therefore, when we allocate a new ASID, we just take the next number. When * we run out of numbers, we flush the TLB, increment the generation count * and start over. ASID zero is re

(pmap)

 * and start over. ASID zero is reserved for kernel use.
 */
static void
pmap_asid_alloc(pmap)
	pmap_t pmap;
{
	if (pmap->pm_asid[PCPU_GET(cpuid)].asid != PMAP_ASID_RESERVED &&
	    pmap->pm_asid[PCPU_GET(cpuid)].gen == PCPU_GET(asid_generation));
	else {
		if (PCPU_GET(next_asid) == pmap_max_asid) {
			tlb_invalidate_all_user(NULL);
			PCPU_SET(asid_generation,
			    (PCPU_GET(asid_generation) + 1) & ASIDGEN_MASK);
			if (PCPU_GET(asid_generation) == 0) {
				PCPU_SET(asid_generation, 1);
			}
			PCPU_SET(next_asid, 1);	/* 0 means invalid */
		}
		pmap->pm_asid[PCPU_GET(cpuid)].asid = PCPU_GET(next_asid);
		pmap->pm_asid[PCPU_GET(cpuid)].gen = PCPU_GET(asid_generation);
		PCPU_SET(next_asid, PCPU_GET(next_asid) + 1);
	}
}

static pt_entry_t
init_pte_prot(vm_page_t m, vm_prot_t access, vm_prot_t prot)