43 lines
1.7 KiB
Plaintext
43 lines
1.7 KiB
Plaintext
|
|
<previous description obsolete, deleted>
|
|
|
|
Virtual memory map with 4 level page tables:
|
|
|
|
0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm
|
|
hole caused by [48:63] sign extension
|
|
ffff800000000000 - ffff87ffffffffff (=43 bits) guard hole, reserved for hypervisor
|
|
ffff880000000000 - ffffc7ffffffffff (=64 TB) direct mapping of all phys. memory
|
|
ffffc80000000000 - ffffc8ffffffffff (=40 bits) hole
|
|
ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space
|
|
ffffe90000000000 - ffffe9ffffffffff (=40 bits) hole
|
|
ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
|
|
... unused hole ...
|
|
ffffec0000000000 - fffffc0000000000 (=44 bits) kasan shadow memory (16TB)
|
|
... unused hole ...
|
|
ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
|
|
... unused hole ...
|
|
ffffffff80000000 - ffffffffa0000000 (=512 MB) kernel text mapping, from phys 0
|
|
ffffffffa0000000 - ffffffffff5fffff (=1525 MB) module mapping space
|
|
ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls
|
|
ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
|
|
|
|
The direct mapping covers all memory in the system up to the highest
|
|
memory address (this means in some cases it can also include PCI memory
|
|
holes).
|
|
|
|
vmalloc space is lazily synchronized into the different PML4 pages of
|
|
the processes using the page fault handler, with init_level4_pgt as
|
|
reference.
|
|
|
|
Current X86-64 implementations only support 40 bits of address space,
|
|
but we support up to 46 bits. This expands into MBZ space in the page tables.
|
|
|
|
->trampoline_pgd:
|
|
|
|
We map EFI runtime services in the aforementioned PGD in the virtual
|
|
range of 64Gb (arbitrarily set, can be raised if needed)
|
|
|
|
0xffffffef00000000 - 0xffffffff00000000
|
|
|
|
-Andi Kleen, Jul 2004
|