Function pmap_update_pte1_kernel

freebsd/arm/arm/pmap-v6.c:3279–3329

* Update kernel pte1 on all pmaps. * * The following function is called only on one cpu with disabled interrupts. * In SMP case, smp_rendezvous_cpus() is used to stop other cpus. This way * nobody can invoke explicit hardware table walk during the update of pte1. * Unsolicited hardware table walk can still happen, invoked by speculative * data or instruction prefetch or even by specula

 *  itself unexpectedly but voluntarily.
 */
static void
pmap_update_pte1_kernel(vm_offset_t va, pt1_entry_t npte1)
{
	pmap_t pmap;
	pt1_entry_t *pte1p;

	/*
	 * Get current pmap. Interrupts should be disabled here
	 * so PCPU_GET() is done atomically.
	 */
	pmap = PCPU_GET(curpmap);
	if (pmap == NULL)
		pmap = kernel_pmap;

	/*
	 * (1) Change pte1 on current pmap.
	 * (2) Flush all obsolete TLB entries on current CPU.
	 * (3) Change pte1 on all pmaps.
	 * (4) Flush all obsolete TLB entries on all CPUs in SMP case.
	 */

	pte1p = pmap_pte1(pmap, va);
	pte1_store(pte1p, npte1);

	/* Kill all the small mappings or the big one only. */
	if (pte1_is_section(npte1)) {
		pmap_pte1_kern_promotions++;
		tlb_flush_range_local(pte1_trunc(va), PTE1_SIZE);
	} else {
		pmap_pte1_kern_demotions++;
		tlb_flush_local(pte1_trunc(va));
	}

	/*
	 * In SMP case, this function is called when all cpus are at smp
	 * rendezvous, so there is no need to use 'allpmaps_lock' lock here.
	 * In UP case, the function is called with this lock locked.
	 */
	LIST_FOREACH(pmap, &allpmaps, pm_list) {
		pte1p = pmap_pte1(pmap, va);
		pte1_store(pte1p, npte1);
	}

#ifdef SMP
	/* Kill all the small mappings or the big one only. */
	if (pte1_is_section(npte1))
		tlb_flush_range(pte1_trunc(va), PTE1_SIZE);
	else
		tlb_flush(pte1_trunc(va));
#endif
}

#ifdef SMP
struct pte1_action {