========================================================================================================================
Start addr | Offset | End addr | Size | VM area description
========================================================================================================================
| | | |
0000000000000000 | 0 | 00fffffffffff000 | ~64 PB | user-space virtual memory, different per mm
00fffffffffff000 | ~64 PB | 00ffffffffffffff | 4 kB | ... guard hole
__________________|____________|__________________|_________|___________________________________________________________
| | | |
0100000000000000 | +64 PB | 7fffffffffffffff | ~8 EB | ... huge, almost 63 bits wide hole of non-canonical
| | | | virtual memory addresses up to the -8EB TB
| | | | starting offset of kernel mappings.
| | | |
| | | | LAM relaxes canonicallity check allowing to create aliases
| | | | for userspace memory here.
__________________|____________|__________________|_________|___________________________________________________________
|
| Kernel-space virtual memory, shared between all processes:
____________________________________________________________|___________________________________________________________
8000000000000000 | -8 EB | feffffffffffffff | ~8 EB | ... huge, almost 63 bits wide hole of non-canonical
| | | | virtual memory addresses up to the -64 PB
| | | | starting offset of kernel mappings.
| | | |
| | | | LAM_SUP relaxes canonicallity check allowing to create
| | | | aliases for kernel memory here.
____________________________________________________________|___________________________________________________________
| | | |
ff00000000000000 | -64 PB | ff0fffffffffffff | 4 PB | ... guard hole, also reserved for hypervisor
ff10000000000000 | -60 PB | ff10ffffffffffff | 0.25 PB | LDT remap for PTI
ff11000000000000 | -59.75 PB | ff90ffffffffffff | 32 PB | direct mapping of all physical memory (page_offset_base)
ff91000000000000 | -27.75 PB | ff9fffffffffffff | 3.75 PB | ... unused hole
ffa0000000000000 | -24 PB | ffd1ffffffffffff | 12.5 PB | vmalloc/ioremap space (vmalloc_base)
ffd2000000000000 | -11.5 PB | ffd3ffffffffffff | 0.5 PB | ... unused hole
ffd4000000000000 | -11 PB | ffd5ffffffffffff | 0.5 PB | virtual memory map (vmemmap_base)
ffd6000000000000 | -10.5 PB | ffdeffffffffffff | 2.25 PB | ... unused hole
ffdf000000000000 | -8.25 PB | fffffbffffffffff | ~8 PB | KASAN shadow memory
__________________|____________|__________________|_________|____________________________________________________________
|
| Identical layout to the 47-bit one from here on:
____________________________________________________________|____________________________________________________________
| | | |
fffffc0000000000 | -4 TB | fffffdffffffffff | 2 TB | ... unused hole
| | | | vaddr_end for KASLR
fffffe0000000000 | -2 TB | fffffe7fffffffff | 0.5 TB | cpu_entry_area mapping
fffffe8000000000 | -1.5 TB | fffffeffffffffff | 0.5 TB | ... unused hole
ffffff0000000000 | -1 TB | ffffff7fffffffff | 0.5 TB | %esp fixup stacks
ffffff8000000000 | -512 GB | ffffffeeffffffff | 444 GB | ... unused hole
ffffffef00000000 | -68 GB | fffffffeffffffff | 64 GB | EFI region mapping space
ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | ... unused hole
ffffffff80000000 | -2 GB | ffffffff9fffffff | 512 MB | kernel text mapping, mapped to physical address 0
ffffffff80000000 |-2048 MB | | |
ffffffffa0000000 |-1536 MB | fffffffffeffffff | 1520 MB | module mapping space
ffffffffff000000 | -16 MB | | |
FIXADDR_START | ~-11 MB | ffffffffff5fffff | ~0.5 MB | kernel-internal fixmap range, variable size and offset
ffffffffff600000 | -10 MB | ffffffffff600fff | 4 kB | legacy vsyscall ABI
ffffffffffe00000 | -2 MB | ffffffffffffffff | 2 MB | ... unused hole
__________________|____________|__________________|_________|___________________________________________________________