Multiprocessor Support

LAPIC: Logic Advanced Programmable Interrupt Controller

Exercise 1. Implement mmio_map_region in kern/pmap.c. To see how this is used, look at the beginning of lapic_init in kern/lapic.c. You'll have to do the next exercise, too, before the tests for mmio_map_region will run.

void *
mmio_map_region(physaddr_t pa, size_t size)
{
    static uintptr_t base = MMIOBASE;
    size = ROUNDUP(pa+size, PGSIZE);
    pa = ROUNDDOWN(pa, PGSIZE);
    size -= pa;
    if (base+size >= MMIOLIM) panic("not enough memory");
    boot_map_region(kern_pgdir, base, size, pa, PTE_PCD|PTE_PWT|PTE_W);
    base += size;
    return (void*) (base - size);
}