+void
+mem_sync_pages(ptr_t mnt,
+ struct mm_region* region,
+ ptr_t start,
+ ptr_t length,
+ int options)
+{
+ if (!region->mfile || !(region->attr & REGION_WSHARED)) {
+ return;
+ }
+
+ v_mapping mapping;
+ for (size_t i = 0; i < length; i += PG_SIZE) {
+ if (!vmm_lookupat(mnt, start + i, &mapping)) {
+ continue;
+ }
+
+ if (PG_IS_DIRTY(*mapping.pte)) {
+ size_t offset = mapping.va - region->start + region->foff;
+ struct v_inode* inode = region->mfile->inode;
+
+ region->mfile->ops->write_page(inode, (void*)mapping.va, offset);
+
+ *mapping.pte &= ~PG_DIRTY;
+
+ cpu_flush_page((ptr_t)mapping.pte);
+ } else if ((options & MS_INVALIDATE)) {
+ goto invalidate;
+ }
+
+ if (options & MS_INVALIDATE_ALL) {
+ goto invalidate;
+ }
+
+ continue;
+
+ invalidate:
+ *mapping.pte &= ~PG_PRESENT;
+ pmm_free_page(KERNEL_PID, mapping.pa);
+ cpu_flush_page((ptr_t)mapping.pte);
+ }
+}
+
+int
+mem_msync(ptr_t mnt,
+ vm_regions_t* regions,
+ ptr_t addr,
+ size_t length,
+ int options)
+{
+ struct mm_region* pos = list_entry(regions->next, struct mm_region, head);
+ while (length && (ptr_t)&pos->head != (ptr_t)regions) {
+ if (pos->end >= addr && pos->start <= addr) {
+ size_t l = MIN(length, pos->end - addr);
+ mem_sync_pages(mnt, pos, addr, l, options);
+
+ addr += l;
+ length -= l;
+ }
+ pos = list_entry(pos->head.next, struct mm_region, head);
+ }
+
+ if (length) {
+ return ENOMEM;
+ }
+
+ return 0;
+}
+
+void
+mem_unmap_region(ptr_t mnt, struct mm_region* region)
+{
+ size_t len = ROUNDUP(region->end - region->start, PG_SIZE);
+ mem_sync_pages(mnt, region, region->start, len, 0);
+
+ for (size_t i = region->start; i <= region->end; i += PG_SIZE) {
+ ptr_t pa = vmm_del_mapping(mnt, i);
+ if (pa) {
+ pmm_free_page(__current->pid, pa);
+ }
+ }
+ llist_delete(®ion->head);
+ region_release(region);
+}
+
+// Case: head inseted, tail inseted
+#define CASE_HITI(vmr, addr, len) \
+ ((vmr)->start <= (addr) && ((addr) + (len)) <= (vmr)->end)
+
+// Case: head inseted, tail extruded
+#define CASE_HITE(vmr, addr, len) \
+ ((vmr)->start <= (addr) && ((addr) + (len)) > (vmr)->end)
+
+// Case: head extruded, tail inseted
+#define CASE_HETI(vmr, addr, len) \
+ ((vmr)->start > (addr) && ((addr) + (len)) <= (vmr)->end)
+
+// Case: head extruded, tail extruded
+#define CASE_HETE(vmr, addr, len) \
+ ((vmr)->start > (addr) && ((addr) + (len)) > (vmr)->end)
+
+static void
+__unmap_overlapped_cases(ptr_t mnt,
+ struct mm_region* vmr,
+ ptr_t* addr,
+ size_t* length)
+{
+ // seg start, umapped segement start
+ ptr_t seg_start = *addr, umps_start = 0;
+
+ // seg len, umapped segement len
+ size_t seg_len = *length, umps_len = 0;
+
+ size_t displ = 0, shrink = 0;
+
+ if (CASE_HITI(vmr, seg_start, seg_len)) {
+ size_t new_start = seg_start + seg_len;
+
+ // Require a split
+ if (new_start < vmr->end) {
+ struct mm_region* region = region_dup(vmr);
+ if (region->mfile) {
+ size_t f_shifted = new_start - region->start;
+ region->foff += f_shifted;
+ }
+ region->start = new_start;
+ llist_insert_after(&vmr->head, ®ion->head);
+ }
+
+ shrink = vmr->end - seg_start;
+ umps_len = shrink;
+ umps_start = seg_start;
+ } else if (CASE_HITE(vmr, seg_start, seg_len)) {
+ shrink = vmr->end - seg_start;
+ umps_len = shrink;
+ umps_start = seg_start;
+ } else if (CASE_HETI(vmr, seg_start, seg_len)) {
+ displ = seg_len - (vmr->start - seg_start);
+ umps_len = displ;
+ umps_start = vmr->start;
+ } else if (CASE_HETE(vmr, seg_start, seg_len)) {
+ shrink = vmr->end - vmr->start;
+ umps_len = shrink;
+ umps_start = vmr->start;
+ }
+
+ mem_sync_pages(mnt, vmr, vmr->start, umps_len, 0);
+ for (size_t i = 0; i < umps_len; i += PG_SIZE) {
+ ptr_t pa = vmm_del_mapping(mnt, vmr->start + i);
+ if (pa) {
+ pmm_free_page(vmr->proc_vms->pid, pa);
+ }
+ }
+
+ vmr->start += displ;
+ vmr->end -= shrink;
+
+ if (vmr->start >= vmr->end) {
+ llist_delete(&vmr->head);
+ region_release(vmr);
+ } else if (vmr->mfile) {
+ vmr->foff += displ;
+ }
+
+ *addr = umps_start + umps_len;
+
+ size_t ump_len = *addr - seg_start;
+ *length = MAX(seg_len, ump_len) - ump_len;
+}
+
+int
+mem_unmap(ptr_t mnt, vm_regions_t* regions, ptr_t addr, size_t length)