1 #include "mmio.h"
2 #include "mmio-buddy.h"
3 #include <common/math.h>
4
mmio_init()5 void mmio_init()
6 {
7 mmio_buddy_init();
8 }
9
10 /**
11 * @brief 创建一块mmio区域，并将vma绑定到initial_mm
12 *
13 * @param size mmio区域的大小（字节）
14 * @param vm_flags 要把vma设置成的标志
15 * @param res_vaddr 返回值-分配得到的虚拟地址
16 * @param res_length 返回值-分配的虚拟地址空间长度
17 * @return int 错误码
18 */
mmio_create(uint32_t size,vm_flags_t vm_flags,uint64_t * res_vaddr,uint64_t * res_size)19 int mmio_create(uint32_t size, vm_flags_t vm_flags, uint64_t *res_vaddr, uint64_t *res_size)
20 {
21 int retval = 0;
22 // 申请的内存超过允许的最大大小
23 if (unlikely(size > PAGE_1G_SIZE || size == 0))
24 return -EPERM;
25
26 // 计算要从buddy中申请地址空间大小(按照2的n次幂来对齐)
27 int size_exp = 31 - __clz(size);
28 if (size_exp < PAGE_4K_SHIFT)
29 {
30 size_exp = PAGE_4K_SHIFT;
31 size = PAGE_4K_SIZE;
32 }
33 else if (size & (~(1 << size_exp)))
34 {
35 ++size_exp;
36 size = 1 << size_exp;
37 }
38 // 申请内存
39 struct __mmio_buddy_addr_region *buddy_region = mmio_buddy_query_addr_region(size_exp);
40 if (buddy_region == NULL) // 没有空闲的mmio空间了
41 return -ENOMEM;
42
43 *res_vaddr = buddy_region->vaddr;
44 *res_size = size;
45 // 释放region
46 __mmio_buddy_release_addr_region(buddy_region);
47
48 // ====创建vma===
49 // 设置vma flags
50 vm_flags |= (VM_IO | VM_DONTCOPY);
51 uint64_t len_4k = size % PAGE_2M_SIZE;
52 uint64_t len_2m = size - len_4k;
53 // 先创建2M的vma，然后创建4k的
54 for (uint32_t i = 0; i < len_2m; i += PAGE_2M_SIZE)
55 {
56
57 retval = mm_create_vma(&initial_mm, buddy_region->vaddr + i, PAGE_2M_SIZE, vm_flags, NULL, NULL);
58 if (unlikely(retval != 0))
59 goto failed;
60 }
61
62 for (uint32_t i = len_2m; i < size; i += PAGE_4K_SIZE)
63 {
64 retval = mm_create_vma(&initial_mm, buddy_region->vaddr + i, PAGE_4K_SIZE, vm_flags, NULL, NULL);
65 if (unlikely(retval != 0))
66 goto failed;
67 }
68 return 0;
69 failed:;
70 kerror("failed to create mmio vma. pid=%d", current_pcb->pid);
71 // todo: 当失败时，将已创建的vma删除
72 return retval;
73 }
74
75 /**
76 * @brief 取消mmio的映射并将地址空间归还到buddy中
77 *
78 * @param vaddr 起始的虚拟地址
79 * @param length 要归还的地址空间的长度
80 * @return int 错误码
81 */
mmio_release(uint64_t vaddr,uint64_t length)82 int mmio_release(uint64_t vaddr, uint64_t length)
83 {
84 int retval = 0;
85 // 先将这些区域都unmap了
86 mm_unmap(&initial_mm, vaddr, length, false);
87
88 // 将这些区域加入buddy
89 for (uint64_t i = 0; i < length;)
90 {
91 struct vm_area_struct *vma = vma_find(&initial_mm, vaddr + i);
92 if (unlikely(vma == NULL))
93 {
94 kerror("mmio_release failed: vma not found. At address: %#018lx, pid=%ld", vaddr + i, current_pcb->pid);
95 return -EINVAL;
96 }
97
98 if (unlikely(vma->vm_start != (vaddr + i)))
99 {
100 kerror("mmio_release failed: addr_start is not equal to current: %#018lx.", vaddr + i);
101 return -EINVAL;
102 }
103 // 往buddy中插入内存块
104 retval = __mmio_buddy_give_back(vma->vm_start, 31 - __clz(vma->vm_end - vma->vm_start));
105 i += vma->vm_end - vma->vm_start;
106
107 // 释放vma结构体
108 vm_area_del(vma);
109 vm_area_free(vma);
110
111 if (unlikely(retval != 0))
112 goto give_back_failed;
113 }
114 return 0;
115 give_back_failed:;
116 kerror("mmio_release give_back failed: ");
117 return retval;
118 }
119