1.. SPDX-License-Identifier: GPL-2.0
2.. include:: ../disclaimer-zh_CN.rst
3
4:Original: Documentation/riscv/vm-layout.rst
5
6:翻译:
7
8 司延腾 Yanteng Si <siyanteng@loongson.cn>
9        Binbin Zhou <zhoubinbin@loongson.cn>
10
11============================
12RISC-V Linux上的虚拟内存布局
13============================
14
15:作者: Alexandre Ghiti <alex@ghiti.fr>
16:日期: 12 February 2021
17
18这份文件描述了RISC-V Linux内核使用的虚拟内存布局。
19
2032位 RISC-V Linux 内核
21======================
22
23RISC-V Linux Kernel SV32
24------------------------
25
26TODO
27
2864位 RISC-V Linux 内核
29======================
30
31RISC-V特权架构文档指出，64位地址 "必须使第63-48位值都等于第47位，否则将发生缺页异常。"：这将虚
32拟地址空间分成两半，中间有一个非常大的洞，下半部分是用户空间所在的地方，上半部分是RISC-V Linux
33内核所在的地方。
34
35RISC-V Linux Kernel SV39
36------------------------
37
38::
39
40  ========================================================================================================================
41      开始地址       |   偏移      |     结束地址      |  大小    | 虚拟内存区域描述
42  ========================================================================================================================
43                    |            |                  |         |
44   0000000000000000 |    0       | 0000003fffffffff |  256 GB | 用户空间虚拟内存，每个内存管理器不同
45  __________________|____________|__________________|_________|___________________________________________________________
46                    |            |                  |         |
47   0000004000000000 | +256    GB | ffffffbfffffffff | ~16M TB | ... 巨大的、几乎64位宽的直到内核映射的-256GB地方
48                    |            |                  |         |     开始偏移的非经典虚拟内存地址空洞。
49                    |            |                  |         |
50  __________________|____________|__________________|_________|___________________________________________________________
51                                                              |
52                                                              | 内核空间的虚拟内存，在所有进程之间共享:
53  ____________________________________________________________|___________________________________________________________
54                    |            |                  |         |
55   ffffffc6fee00000 | -228    GB | ffffffc6feffffff |    2 MB | fixmap
56   ffffffc6ff000000 | -228    GB | ffffffc6ffffffff |   16 MB | PCI io
57   ffffffc700000000 | -228    GB | ffffffc7ffffffff |    4 GB | vmemmap
58   ffffffc800000000 | -224    GB | ffffffd7ffffffff |   64 GB | vmalloc/ioremap space
59   ffffffd800000000 | -160    GB | fffffff6ffffffff |  124 GB | 直接映射所有物理内存
60   fffffff700000000 |  -36    GB | fffffffeffffffff |   32 GB | kasan
61  __________________|____________|__________________|_________|____________________________________________________________
62                                                              |
63                                                              |
64  ____________________________________________________________|____________________________________________________________
65                    |            |                  |         |
66   ffffffff00000000 |   -4    GB | ffffffff7fffffff |    2 GB | modules, BPF
67   ffffffff80000000 |   -2    GB | ffffffffffffffff |    2 GB | kernel
68  __________________|____________|__________________|_________|____________________________________________________________
69
70
71RISC-V Linux Kernel SV48
72------------------------
73
74::
75
76 ========================================================================================================================
77      开始地址       |   偏移      |     结束地址      |  大小    | 虚拟内存区域描述
78 ========================================================================================================================
79                    |            |                  |         |
80   0000000000000000 |    0       | 00007fffffffffff |  128 TB | 用户空间虚拟内存，每个内存管理器不同
81  __________________|____________|__________________|_________|___________________________________________________________
82                    |            |                  |         |
83   0000800000000000 | +128    TB | ffff7fffffffffff | ~16M TB | ... 巨大的、几乎64位宽的直到内核映射的-128TB地方
84                    |            |                  |         |     开始偏移的非经典虚拟内存地址空洞。
85                    |            |                  |         |
86  __________________|____________|__________________|_________|___________________________________________________________
87                                                              |
88                                                              | 内核空间的虚拟内存，在所有进程之间共享:
89  ____________________________________________________________|___________________________________________________________
90                    |            |                  |         |
91   ffff8d7ffee00000 |  -114.5 TB | ffff8d7ffeffffff |    2 MB | fixmap
92   ffff8d7fff000000 |  -114.5 TB | ffff8d7fffffffff |   16 MB | PCI io
93   ffff8d8000000000 |  -114.5 TB | ffff8f7fffffffff |    2 TB | vmemmap
94   ffff8f8000000000 |  -112.5 TB | ffffaf7fffffffff |   32 TB | vmalloc/ioremap space
95   ffffaf8000000000 |  -80.5  TB | ffffef7fffffffff |   64 TB | 直接映射所有物理内存
96   ffffef8000000000 |  -16.5  TB | fffffffeffffffff | 16.5 TB | kasan
97  __________________|____________|__________________|_________|____________________________________________________________
98                                                              |
99                                                              | 从此处开始，与39-bit布局相同：
100  ____________________________________________________________|____________________________________________________________
101                    |            |                  |         |
102   ffffffff00000000 |   -4    GB | ffffffff7fffffff |    2 GB | modules, BPF
103   ffffffff80000000 |   -2    GB | ffffffffffffffff |    2 GB | kernel
104  __________________|____________|__________________|_________|____________________________________________________________
105