Implement proc_unmap ()

kernel/.gitignore

@@ -1 +1,2 @@
 *.json
+.cache

kernel/proc/proc.c

@@ -38,9 +38,13 @@ static bool proc_check_elf (uint8_t* elf) {
   return true;
 }
 
-void proc_map (struct proc* proc, uintptr_t start_paddr, uintptr_t start_vaddr, size_t pages,
+bool proc_map (struct proc* proc, uintptr_t start_paddr, uintptr_t start_vaddr, size_t pages,
                uint32_t flags) {
   struct proc_mapping* mapping = malloc (sizeof (*mapping));
+
+  if (mapping == NULL)
+    return false;
+
   mapping->paddr = start_paddr;
   mapping->vaddr = start_vaddr;
   mapping->size = pages * PAGE_SIZE;
@@ -57,6 +61,68 @@ void proc_map (struct proc* proc, uintptr_t start_paddr, uintptr_t start_vaddr,
   }
 
   spin_unlock (&proc->pd.lock);
+
+  return true;
+}
+
+bool proc_unmap (struct proc* proc, uintptr_t start_vaddr, size_t pages) {
+  size_t unmap_size = pages * PAGE_SIZE;
+  uintptr_t end_vaddr = start_vaddr + unmap_size;
+  struct list_node_link *mapping_link, *mapping_link_tmp;
+  bool used_tail_mapping = false;
+
+  struct proc_mapping* tail_mapping = malloc (sizeof (*tail_mapping));
+  if (tail_mapping == NULL)
+    return false;
+
+  spin_lock (&proc->pd.lock);
+
+  list_foreach (proc->mappings, mapping_link, mapping_link_tmp) {
+    struct proc_mapping* mapping =
+        list_entry (mapping_link, struct proc_mapping, proc_mappings_link);
+
+    uintptr_t m_end = mapping->vaddr + mapping->size;
+
+    /* check overlap */
+    if ((start_vaddr < m_end) && (end_vaddr > mapping->vaddr)) {
+      /* split in the middle */
+      if ((start_vaddr > mapping->vaddr) && (end_vaddr < m_end)) {
+        tail_mapping->vaddr = end_vaddr;
+        tail_mapping->paddr = mapping->paddr + (end_vaddr - mapping->vaddr);
+        tail_mapping->size = m_end - end_vaddr;
+
+        mapping->size = start_vaddr - mapping->vaddr;
+
+        list_insert_after (proc->mappings, &mapping->proc_mappings_link,
+                           &tail_mapping->proc_mappings_link);
+
+        used_tail_mapping = true;
+
+        break;
+      } else if ((start_vaddr <= mapping->vaddr) && (end_vaddr < m_end)) { /* shrink left */
+        size_t diff = end_vaddr - mapping->vaddr;
+        mapping->vaddr += diff;
+        mapping->paddr += diff;
+        mapping->size -= diff;
+      } else if ((start_vaddr > mapping->vaddr) && (end_vaddr >= m_end)) { /* shrink right */
+        mapping->size = start_vaddr - mapping->vaddr;
+      } else { /* full overlap */
+        list_remove (proc->mappings, &mapping->proc_mappings_link);
+        free (mapping);
+      }
+    }
+  }
+
+  if (!used_tail_mapping)
+    free (tail_mapping);
+
+  for (uintptr_t vpage = start_vaddr; vpage < end_vaddr; vpage += PAGE_SIZE) {
+    mm_unmap_page (&proc->pd, vpage, 0);
+  }
+
+  spin_unlock (&proc->pd.lock);
+
+  return true;
 }
 
 struct elf_aux proc_load_segments (struct proc* proc, uint8_t* elf) {

kernel/proc/proc.h

@@ -44,7 +44,7 @@ struct proc {
 
 void proc_sched (void);
 void proc_kill (struct proc* proc);
-void proc_map (struct proc* proc, uintptr_t start_paddr, uintptr_t start_vaddr, size_t pages,
+bool proc_map (struct proc* proc, uintptr_t start_paddr, uintptr_t start_vaddr, size_t pages,
                uint32_t flags);
 struct elf_aux proc_load_segments (struct proc* proc, uint8_t* elf);
 void proc_init (void);