.. SPDX-License-Identifier: GPL-2.0
.. include:: ../disclaimer-zh_CN.rst
:Original: Documentation/riscv/vm-layout.rst
:翻译:
司延腾 Yanteng Si <siyanteng@loongson.cn>
Binbin Zhou <zhoubinbin@loongson.cn>
============================
RISC-V Linux上的虚拟内存布局
============================
:作者: Alexandre Ghiti <alex@ghiti.fr>
:日期: 12 February 2021
这份文件描述了RISC-V Linux内核使用的虚拟内存布局。
32位 RISC-V Linux 内核
======================
RISC-V Linux Kernel SV32
------------------------
TODO
64位 RISC-V Linux 内核
======================
RISC-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
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
内核所在的地方。
RISC-V Linux Kernel SV39
------------------------
::
========================================================================================================================
开始地址 | 偏移 | 结束地址 | 大小 | 虚拟内存区域描述
========================================================================================================================
| | | |
0000000000000000 | 0 | 0000003fffffffff | 256 GB | 用户空间虚拟内存，每个内存管理器不同
__________________|____________|__________________|_________|___________________________________________________________
| | | |
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
| | | | 开始偏移的非经典虚拟内存地址空洞。
| | | |
__________________|____________|__________________|_________|___________________________________________________________
|
| 内核空间的虚拟内存，在所有进程之间共享:
____________________________________________________________|___________________________________________________________
| | | |
ffffffc6fee00000 | -228 GB | ffffffc6feffffff | 2 MB | fixmap
ffffffc6ff000000 | -228 GB | ffffffc6ffffffff | 16 MB | PCI io
ffffffc700000000 | -228 GB | ffffffc7ffffffff | 4 GB | vmemmap
ffffffc800000000 | -224 GB | ffffffd7ffffffff | 64 GB | vmalloc/ioremap space
ffffffd800000000 | -160 GB | fffffff6ffffffff | 124 GB | 直接映射所有物理内存
fffffff700000000 | -36 GB | fffffffeffffffff | 32 GB | kasan
__________________|____________|__________________|_________|____________________________________________________________
|
|
____________________________________________________________|____________________________________________________________
| | | |
ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | modules, BPF
ffffffff80000000 | -2 GB | ffffffffffffffff | 2 GB | kernel
__________________|____________|__________________|_________|____________________________________________________________
RISC-V Linux Kernel SV48
------------------------
::
========================================================================================================================
开始地址 | 偏移 | 结束地址 | 大小 | 虚拟内存区域描述
========================================================================================================================
| | | |
0000000000000000 | 0 | 00007fffffffffff | 128 TB | 用户空间虚拟内存，每个内存管理器不同
__________________|____________|__________________|_________|___________________________________________________________
| | | |
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
| | | | 开始偏移的非经典虚拟内存地址空洞。
| | | |
__________________|____________|__________________|_________|___________________________________________________________
|
| 内核空间的虚拟内存，在所有进程之间共享:
____________________________________________________________|___________________________________________________________
| | | |
ffff8d7ffee00000 | -114.5 TB | ffff8d7ffeffffff | 2 MB | fixmap
ffff8d7fff000000 | -114.5 TB | ffff8d7fffffffff | 16 MB | PCI io
ffff8d8000000000 | -114.5 TB | ffff8f7fffffffff | 2 TB | vmemmap
ffff8f8000000000 | -112.5 TB | ffffaf7fffffffff | 32 TB | vmalloc/ioremap space
ffffaf8000000000 | -80.5 TB | ffffef7fffffffff | 64 TB | 直接映射所有物理内存
ffffef8000000000 | -16.5 TB | fffffffeffffffff | 16.5 TB | kasan
__________________|____________|__________________|_________|____________________________________________________________
|
| 从此处开始，与39-bit布局相同：
____________________________________________________________|____________________________________________________________
| | | |
ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | modules, BPF
ffffffff80000000 | -2 GB | ffffffffffffffff | 2 GB | kernel
__________________|____________|__________________|_________|____________________________________________________________