Commit | Line | Data |
---|---|---|
1da177e4 | 1 | |
1da177e4 LT |
2 | Virtual memory map with 4 level page tables: |
3 | ||
57d30772 | 4 | 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm |
4c7c4483 | 5 | hole caused by [47:63] sign extension |
beb9147e | 6 | ffff800000000000 - ffff87ffffffffff (=43 bits) guard hole, reserved for hypervisor |
2feceeff | 7 | ffff880000000000 - ffffc7ffffffffff (=64 TB) direct mapping of all phys. memory |
c898faf9 RR |
8 | ffffc80000000000 - ffffc8ffffffffff (=40 bits) hole |
9 | ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space | |
10 | ffffe90000000000 - ffffe9ffffffffff (=40 bits) hole | |
11 | ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB) | |
ef7f0d6a | 12 | ... unused hole ... |
9d9cce7f | 13 | ffffec0000000000 - fffffbffffffffff (=44 bits) kasan shadow memory (16TB) |
1da177e4 | 14 | ... unused hole ... |
1dddd251 | 15 | vaddr_end for KASLR |
f2078904 TG |
16 | fffffe0000000000 - fffffe7fffffffff (=39 bits) cpu_entry_area mapping |
17 | fffffe8000000000 - fffffeffffffffff (=39 bits) LDT remap for PTI | |
3891a04a PA |
18 | ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks |
19 | ... unused hole ... | |
9d9cce7f | 20 | ffffffef00000000 - fffffffeffffffff (=64 GB) EFI region mapping space |
ff3d0a12 | 21 | ... unused hole ... |
9d9cce7f | 22 | ffffffff80000000 - ffffffff9fffffff (=512 MB) kernel text mapping, from phys 0 |
5a7ccf47 AL |
23 | ffffffffa0000000 - [fixmap start] (~1526 MB) module mapping space (variable) |
24 | [fixmap start] - ffffffffff5fffff kernel-internal fixmap range | |
25 | ffffffffff600000 - ffffffffff600fff (=4 kB) legacy vsyscall ABI | |
aca91bfc | 26 | ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole |
1da177e4 | 27 | |
4c7c4483 KS |
28 | Virtual memory map with 5 level page tables: |
29 | ||
30 | 0000000000000000 - 00ffffffffffffff (=56 bits) user space, different per mm | |
31 | hole caused by [56:63] sign extension | |
32 | ff00000000000000 - ff0fffffffffffff (=52 bits) guard hole, reserved for hypervisor | |
33 | ff10000000000000 - ff8fffffffffffff (=55 bits) direct mapping of all phys. memory | |
f55f0501 | 34 | ff90000000000000 - ff9fffffffffffff (=52 bits) LDT remap for PTI |
9f449772 | 35 | ffa0000000000000 - ffd1ffffffffffff (=54 bits) vmalloc/ioremap space (12800 TB) |
4c7c4483 KS |
36 | ffd2000000000000 - ffd3ffffffffffff (=49 bits) hole |
37 | ffd4000000000000 - ffd5ffffffffffff (=49 bits) virtual memory map (512TB) | |
38 | ... unused hole ... | |
12a8cc7f | 39 | ffdf000000000000 - fffffc0000000000 (=53 bits) kasan shadow memory (8PB) |
4c7c4483 | 40 | ... unused hole ... |
1dddd251 | 41 | vaddr_end for KASLR |
f2078904 TG |
42 | fffffe0000000000 - fffffe7fffffffff (=39 bits) cpu_entry_area mapping |
43 | ... unused hole ... | |
4c7c4483 KS |
44 | ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks |
45 | ... unused hole ... | |
46 | ffffffef00000000 - fffffffeffffffff (=64 GB) EFI region mapping space | |
47 | ... unused hole ... | |
48 | ffffffff80000000 - ffffffff9fffffff (=512 MB) kernel text mapping, from phys 0 | |
f5a40711 | 49 | ffffffffa0000000 - fffffffffeffffff (1520 MB) module mapping space |
5a7ccf47 AL |
50 | [fixmap start] - ffffffffff5fffff kernel-internal fixmap range |
51 | ffffffffff600000 - ffffffffff600fff (=4 kB) legacy vsyscall ABI | |
4c7c4483 KS |
52 | ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole |
53 | ||
54 | Architecture defines a 64-bit virtual address. Implementations can support | |
55 | less. Currently supported are 48- and 57-bit virtual addresses. Bits 63 | |
e8ffe96e PZ |
56 | through to the most-significant implemented bit are sign extended. |
57 | This causes hole between user space and kernel addresses if you interpret them | |
58 | as unsigned. | |
4c7c4483 | 59 | |
57d30772 | 60 | The direct mapping covers all memory in the system up to the highest |
8315eca2 | 61 | memory address (this means in some cases it can also include PCI memory |
57d30772 | 62 | holes). |
8315eca2 | 63 | |
4c7c4483 KS |
64 | vmalloc space is lazily synchronized into the different PML4/PML5 pages of |
65 | the processes using the page fault handler, with init_top_pgt as | |
1da177e4 LT |
66 | reference. |
67 | ||
ff3d0a12 MF |
68 | We map EFI runtime services in the 'efi_pgd' PGD in a 64Gb large virtual |
69 | memory window (this size is arbitrary, it can be raised later if needed). | |
70 | The mappings are not part of any other kernel PGD and are only available | |
71 | during EFI runtime calls. | |
d2f7cbe7 | 72 | |
0483e1fa TG |
73 | Note that if CONFIG_RANDOMIZE_MEMORY is enabled, the direct mapping of all |
74 | physical memory, vmalloc/ioremap space and virtual memory map are randomized. | |
75 | Their order is preserved but their base will be offset early at boot time. | |
1dddd251 TG |
76 | |
77 | Be very careful vs. KASLR when changing anything here. The KASLR address | |
78 | range must not overlap with anything except the KASAN shadow area, which is | |
79 | correct as KASAN disables KASLR. |