MM_PROT_READ
MM_PROT_READ|MM_PROT_WRITE);
prot = MM_PROT_READ|MM_PROT_EXECUTE;
prot = MM_PROT_READ;
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_READ] = PTE_NX,