void arm_mmu_init(void)
{
/* unmap the initial mapings that are marked temporary */
struct mmu_initial_mapping *map = mmu_initial_mappings;
while (map->size > 0) {
if (map->flags & MMU_INITIAL_MAPPING_TEMPORARY) {
vaddr_t va = map->virt;
size_t size = map->size;
DEBUG_ASSERT(IS_SECTION_ALIGNED(size));
while (size > 0) {
arm_mmu_unmap_section(va);
va += MB;
size -= MB;
}
}
map++;
}
arm_after_invalidate_tlb_barrier();
}
int arch_mmu_unmap(arch_aspace_t *aspace, vaddr_t vaddr, uint count)
{
DEBUG_ASSERT(aspace);
DEBUG_ASSERT(aspace->tt_virt);
DEBUG_ASSERT(is_valid_vaddr(aspace, vaddr));
if (!is_valid_vaddr(aspace, vaddr))
return ERR_OUT_OF_RANGE;
DEBUG_ASSERT(IS_PAGE_ALIGNED(vaddr));
if (!IS_PAGE_ALIGNED(vaddr))
return ERR_INVALID_ARGS;
LTRACEF("vaddr 0x%lx count %u\n", vaddr, count);
int unmapped = 0;
while (count > 0) {
uint l1_index = vaddr / SECTION_SIZE;
uint32_t tt_entry = aspace->tt_virt[l1_index];
switch (tt_entry & MMU_MEMORY_L1_DESCRIPTOR_MASK) {
case MMU_MEMORY_L1_DESCRIPTOR_INVALID: {
/* this top level page is not mapped, move on to the next one */
uint page_cnt = MIN((SECTION_SIZE - (vaddr % SECTION_SIZE)) / PAGE_SIZE, count);
vaddr += page_cnt * PAGE_SIZE;
count -= page_cnt;
break;
}
case MMU_MEMORY_L1_DESCRIPTOR_SECTION:
if (IS_SECTION_ALIGNED(vaddr) && count >= SECTION_SIZE / PAGE_SIZE) {
/* we're asked to remove at least all of this section, so just zero it out */
// XXX test for supersection
arm_mmu_unmap_section(aspace, vaddr);
vaddr += SECTION_SIZE;
count -= SECTION_SIZE / PAGE_SIZE;
unmapped += SECTION_SIZE / PAGE_SIZE;
} else {
// XXX handle unmapping just part of a section
// will need to convert to a L2 table and then unmap the parts we are asked to
PANIC_UNIMPLEMENTED;
}
break;
case MMU_MEMORY_L1_DESCRIPTOR_PAGE_TABLE: {
uint32_t *l2_table = paddr_to_kvaddr(MMU_MEMORY_L1_PAGE_TABLE_ADDR(tt_entry));
uint page_idx = (vaddr % SECTION_SIZE) / PAGE_SIZE;
uint page_cnt = MIN((SECTION_SIZE / PAGE_SIZE) - page_idx, count);
/* unmap page run */
for (uint i = 0; i < page_cnt; i++) {
l2_table[page_idx++] = 0;
}
DSB;
/* invalidate tlb */
for (uint i = 0; i < page_cnt; i++) {
arm_invalidate_tlb_mva_no_barrier(vaddr);
vaddr += PAGE_SIZE;
}
count -= page_cnt;
unmapped += page_cnt;
/*
* Check if all pages related to this l1 entry are deallocated.
* We only need to check pages that we did not clear above starting
* from page_idx and wrapped around SECTION.
*/
page_cnt = (SECTION_SIZE / PAGE_SIZE) - page_cnt;
while (page_cnt) {
if (page_idx == (SECTION_SIZE / PAGE_SIZE))
page_idx = 0;
if (l2_table[page_idx++])
break;
page_cnt--;
}
if (!page_cnt) {
/* we can kill l1 entry */
arm_mmu_unmap_l1_entry(aspace->tt_virt, l1_index);
/* try to free l2 page itself */
put_l2_table(aspace, l1_index, MMU_MEMORY_L1_PAGE_TABLE_ADDR(tt_entry));
}
break;
}
default:
// XXX not implemented supersections or L2 tables
PANIC_UNIMPLEMENTED;
}
}
arm_after_invalidate_tlb_barrier();
return unmapped;
}