1 .. SPDX-License-Identifier: GPL-2.0
2
3 =====================================
4 Virtual Memory Layout on RISC-V Linux
5 =====================================
6
7 :Author: Alexandre Ghiti <alex@ghiti.fr>
8 :Date: 12 February 2021
9
10 This document describes the virtual memory lay
11 Kernel.
12
13 RISC-V Linux Kernel 32bit
14 =========================
15
16 RISC-V Linux Kernel SV32
17 ------------------------
18
19 TODO
20
21 RISC-V Linux Kernel 64bit
22 =========================
23
24 The RISC-V privileged architecture document st
25 "must have bits 63–48 all equal to bit 47, o
26 occur.": that splits the virtual address space
27 big hole, the lower half is where the userspac
28 the RISC-V Linux Kernel resides.
29
30 RISC-V Linux Kernel SV39
31 ------------------------
32
33 ::
34
35 ============================================
36 Start addr | Offset | End add
37 ============================================
38 | |
39 0000000000000000 | 0 | 0000003ffff
40 __________________|____________|____________
41 | |
42 0000004000000000 | +256 GB | ffffffbffff
43 | |
44 | |
45 __________________|____________|____________
46
47
48 ____________________________________________
49 | |
50 ffffffc4fea00000 | -236 GB | ffffffc4fef
51 ffffffc4ff000000 | -236 GB | ffffffc4fff
52 ffffffc500000000 | -236 GB | ffffffc5fff
53 ffffffc600000000 | -232 GB | ffffffd5fff
54 ffffffd600000000 | -168 GB | fffffff5fff
55 | |
56 fffffff700000000 | -36 GB | fffffffefff
57 __________________|____________|____________
58
59
60 ____________________________________________
61 | |
62 ffffffff00000000 | -4 GB | ffffffff7ff
63 ffffffff80000000 | -2 GB | fffffffffff
64 __________________|____________|____________
65
66
67 RISC-V Linux Kernel SV48
68 ------------------------
69
70 ::
71
72 =============================================
73 Start addr | Offset | End add
74 =============================================
75 | |
76 0000000000000000 | 0 | 00007ffffff
77 __________________|____________|____________
78 | |
79 0000800000000000 | +128 TB | ffff7ffffff
80 | |
81 | |
82 __________________|____________|____________
83
84
85 ____________________________________________
86 | |
87 ffff8d7ffea00000 | -114.5 TB | ffff8d7ffef
88 ffff8d7fff000000 | -114.5 TB | ffff8d7ffff
89 ffff8d8000000000 | -114.5 TB | ffff8f7ffff
90 ffff8f8000000000 | -112.5 TB | ffffaf7ffff
91 ffffaf8000000000 | -80.5 TB | ffffef7ffff
92 ffffef8000000000 | -16.5 TB | fffffffefff
93 __________________|____________|____________
94
95
96 ____________________________________________
97 | |
98 ffffffff00000000 | -4 GB | ffffffff7ff
99 ffffffff80000000 | -2 GB | fffffffffff
100 __________________|____________|____________
101
102
103 RISC-V Linux Kernel SV57
104 ------------------------
105
106 ::
107
108 =============================================
109 Start addr | Offset | End add
110 =============================================
111 | |
112 0000000000000000 | 0 | 00fffffffff
113 __________________|____________|____________
114 | |
115 0100000000000000 | +64 PB | fefffffffff
116 | |
117 | |
118 __________________|____________|____________
119
120
121 ____________________________________________
122 | |
123 ff1bfffffea00000 | -57 PB | ff1bfffffef
124 ff1bffffff000000 | -57 PB | ff1bfffffff
125 ff1c000000000000 | -57 PB | ff1ffffffff
126 ff20000000000000 | -56 PB | ff5ffffffff
127 ff60000000000000 | -40 PB | ffdefffffff
128 ffdf000000000000 | -8 PB | fffffffefff
129 __________________|____________|____________
130
131
132 ____________________________________________
133 | |
134 ffffffff00000000 | -4 GB | ffffffff7ff
135 ffffffff80000000 | -2 GB | fffffffffff
136 __________________|____________|____________
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.