1 .. SPDX-License-Identifier: GPL-2.0
2 .. include:: ../disclaimer-zh_CN.rst
4 :Original: Documentation/riscv/vm-layout.rst
8 司延腾 Yanteng Si <siyanteng@loongson.cn>
10 ============================
12 ============================
14 :作者: Alexandre Ghiti <alex@ghiti.fr>
17 这份文件描述了RISC-V Linux内核使用的虚拟内存布局。
20 ======================
22 RISC-V Linux Kernel SV32
23 ------------------------
28 ======================
30 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
31 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
34 RISC-V Linux Kernel SV39
35 ------------------------
39 ========================================================================================================================
40 开始地址 | 偏移 | 结束地址 | 大小 | 虚拟内存区域描述
41 ========================================================================================================================
43 0000000000000000 | 0 | 0000003fffffffff | 256 GB | 用户空间虚拟内存,每个内存管理器不同
44 __________________|____________|__________________|_________|___________________________________________________________
46 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
47 | | | | 开始偏移的非经典虚拟内存地址空洞。
49 __________________|____________|__________________|_________|___________________________________________________________
51 | 内核空间的虚拟内存,在所有进程之间共享:
52 ____________________________________________________________|___________________________________________________________
54 ffffffc6fee00000 | -228 GB | ffffffc6feffffff | 2 MB | fixmap
55 ffffffc6ff000000 | -228 GB | ffffffc6ffffffff | 16 MB | PCI io
56 ffffffc700000000 | -228 GB | ffffffc7ffffffff | 4 GB | vmemmap
57 ffffffc800000000 | -224 GB | ffffffd7ffffffff | 64 GB | vmalloc/ioremap space
58 ffffffd800000000 | -160 GB | fffffff6ffffffff | 124 GB | 直接映射所有物理内存
59 fffffff700000000 | -36 GB | fffffffeffffffff | 32 GB | kasan
60 __________________|____________|__________________|_________|____________________________________________________________
63 ____________________________________________________________|____________________________________________________________
65 ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | modules, BPF
66 ffffffff80000000 | -2 GB | ffffffffffffffff | 2 GB | kernel
67 __________________|____________|__________________|_________|____________________________________________________________