new: 初步完成了mmio地址空间自动分配（未测试）

bugfix: mmio虚拟地址分配的bug

kernel/mm/mmio.c

@@ -1,5 +1,6 @@
 #include "mmio.h"
 #include "mmio-buddy.h"
+#include <common/math.h>
 
 void mmio_init()
 {
@@ -10,25 +11,108 @@ void mmio_init()
  * @brief 创建一块mmio区域，并将vma绑定到initial_mm
  *
  * @param size mmio区域的大小（字节）
- * @param length mmio区域长度
  * @param vm_flags 要把vma设置成的标志
  * @param res_vaddr 返回值-分配得到的虚拟地址
  * @param res_length 返回值-分配的虚拟地址空间长度
  * @return int 错误码
  */
-int mmio_create(uint32_t size, uint64_t length, vm_flags_t vm_flags, uint64_t * res_vaddr, uint64_t *res_length)
+int mmio_create(uint32_t size, vm_flags_t vm_flags, uint64_t *res_vaddr, uint64_t *res_size)
 {
-    
+    int retval = 0;
+    // 申请的内存超过允许的最大大小
+    if (unlikely(size > PAGE_1G_SIZE || size == 0))
+        return -EPERM;
+
+    // 计算要从buddy中申请地址空间大小(按照2的n次幂来对齐)
+    int size_exp = 31 - __clz(size);
+    if (size_exp < PAGE_4K_SHIFT)
+    {
+        size_exp = PAGE_4K_SHIFT;
+        size = PAGE_4K_SIZE;
+    }
+    else if (size & (~(1 << size_exp)))
+    {
+        ++size_exp;
+        size = 1 << size_exp;
+    }
+    // 申请内存
+    struct __mmio_buddy_addr_region *buddy_region = mmio_buddy_query_addr_region(size_exp);
+    if (buddy_region == NULL) // 没有空闲的mmio空间了
+        return -ENOMEM;
+
+    *res_vaddr = buddy_region->vaddr;
+    *res_size = size;
+    // 释放region
+    __mmio_buddy_release_addr_region(buddy_region);
+
+    // ====创建vma===
+    // 设置vma flags
+    vm_flags |= (VM_IO | VM_DONTCOPY);
+    uint64_t len_4k = size % PAGE_2M_SIZE;
+    uint64_t len_2m = size - len_4k;
+    // 先创建2M的vma，然后创建4k的
+    for (uint32_t i = 0; i < len_2m; i += PAGE_2M_SIZE)
+    {
+
+        retval = mm_create_vma(&initial_mm, buddy_region->vaddr + i, PAGE_2M_SIZE, vm_flags, NULL, NULL);
+        if (unlikely(retval != 0))
+            goto failed;
+    }
+
+    for (uint32_t i = len_2m; i < size; i += PAGE_4K_SIZE)
+    {
+        retval = mm_create_vma(&initial_mm, buddy_region->vaddr + i, PAGE_4K_SIZE, vm_flags, NULL, NULL);
+        if (unlikely(retval != 0))
+            goto failed;
+    }
+    return 0;
+failed:;
+    kerror("failed to create mmio vma. pid=%d", current_pcb->pid);
+    // todo: 当失败时，将已创建的vma删除
+    return retval;
 }
 
 /**
  * @brief 取消mmio的映射并将地址空间归还到buddy中
- * 
+ *
  * @param vaddr 起始的虚拟地址
  * @param length 要归还的地址空间的长度
  * @return int 错误码
  */
 int mmio_release(uint64_t vaddr, uint64_t length)
 {
+    int retval = 0;
+    // 先将这些区域都unmap了
+    mm_unmap(&initial_mm, vaddr, length, false);
 
-}
+    // 将这些区域加入buddy
+    for (uint64_t i = 0; i < length;)
+    {
+        struct vm_area_struct *vma = vma_find(&initial_mm, vaddr + i);
+        if (unlikely(vma == NULL))
+        {
+            kerror("mmio_release failed: vma not found. At address: %#018lx, pid=%ld", vaddr + i, current_pcb->pid);
+            return -EINVAL;
+        }
+
+        if (unlikely(vma->vm_start != (vaddr + i)))
+        {
+            kerror("mmio_release failed: addr_start is not equal to current: %#018lx.", vaddr + i);
+            return -EINVAL;
+        }
+        // 往buddy中插入内存块
+        retval = __mmio_buddy_give_back(vma->vm_start, 31 - __clz(vma->vm_end - vma->vm_start));
+        i += vma->vm_end - vma->vm_start;
+
+        // 释放vma结构体
+        vm_area_del(vma);
+        vm_area_free(vma);
+
+        if (unlikely(retval != 0))
+            goto give_back_failed;
+    }
+    return 0;
+give_back_failed:;
+    kerror("mmio_release give_back failed: ");
+    return retval;
+}