new: 引入vmarea

kernel/mm/vma.c

@@ -16,6 +16,18 @@ struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
     return vma;
 }
 
+/**
+ * @brief 从链表中删除指定的vma结构体
+ *
+ * @param vma
+ */
+void vm_area_del(struct vm_area_struct *vma)
+{
+    if (vma->vm_mm == NULL)
+        return;
+    __vma_unlink_list(vma->vm_mm, vma);
+}
+
 /**
  * @brief 释放vma结构体
  *
@@ -71,7 +83,74 @@ void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma)
         prev->vm_next = next;
     else // 当前vma是链表中的第一个vma
         mm->vmas = next;
-    
+
     if (next)
         next->vm_prev = prev;
+}
+
+/**
+ * @brief 查找第一个符合“addr < vm_end”条件的vma
+ *
+ * @param mm 内存空间分布结构体
+ * @param addr 虚拟地址
+ * @return struct vm_area_struct* 符合条件的vma
+ */
+struct vm_area_struct *vma_find(struct mm_struct *mm, uint64_t addr)
+{
+    struct vm_area_struct *vma = mm->vmas;
+    struct vm_area_struct *result = NULL;
+    while (vma != NULL)
+    {
+        if (vma->vm_end > addr)
+        {
+            result = vma;
+            break;
+        }
+        vma = vma->vm_next;
+    }
+    return result;
+}
+
+/**
+ * @brief 插入vma
+ *
+ * @param mm
+ * @param vma
+ * @return int
+ */
+int vma_insert(struct mm_struct *mm, struct vm_area_struct *vma)
+{
+
+    struct vm_area_struct *prev;
+    prev = vma_find(mm, vma->vm_start);
+    if (prev && prev->vm_start == vma->vm_start && prev->vm_end == vma->vm_end)
+    {
+        // 已经存在了相同的vma
+        return -EEXIST;
+    }
+    else if (prev && (prev->vm_start == vma->vm_start || prev->vm_end == vma->vm_end)) // 暂时不支持扩展vma
+    {
+        kwarn("Not support: expand vma");
+        return -ENOTSUP;
+    }
+
+    prev = vma_find(mm, vma->vm_end);
+    if (prev)
+        prev = prev->vm_prev;
+    if (prev == NULL) // 要将当前vma插入到链表的尾部
+    {
+        struct vm_area_struct * ptr = mm->vmas;
+        while(ptr)
+        {
+            if(ptr->vm_next)
+                ptr = ptr->vm_next;
+            else
+            {
+                prev = ptr;
+                break;
+            }
+        }
+    }
+    __vma_link_list(mm, vma, prev);
+    return 0;
 }