MM_PROT_WRITE
MM_PROT_READ|MM_PROT_WRITE);
randva + i * PAGE_SIZE, MM_PROT_READ|MM_PROT_WRITE);
randva + i * PAGE_SIZE, MM_PROT_READ|MM_PROT_WRITE);
randva + i * PAGE_SIZE, MM_PROT_READ|MM_PROT_WRITE);
iom_base + i * PAGE_SIZE, MM_PROT_READ|MM_PROT_WRITE);
[MM_PROT_WRITE] = PTE_W | PTE_NX,