diff options
Diffstat (limited to 'Documentation/x86/x86_64/mm.txt')
| -rw-r--r-- | Documentation/x86/x86_64/mm.txt | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt index 05712ac83..5aa738346 100644 --- a/Documentation/x86/x86_64/mm.txt +++ b/Documentation/x86/x86_64/mm.txt @@ -16,8 +16,10 @@ ffffec0000000000 - fffffc0000000000 (=44 bits) kasan shadow memory (16TB) ... unused hole ... ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks ... unused hole ... +ffffffef00000000 - ffffffff00000000 (=64 GB) EFI region mapping space +... unused hole ... ffffffff80000000 - ffffffffa0000000 (=512 MB) kernel text mapping, from phys 0 -ffffffffa0000000 - ffffffffff5fffff (=1525 MB) module mapping space +ffffffffa0000000 - ffffffffff5fffff (=1526 MB) module mapping space ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole @@ -29,14 +31,12 @@ 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) +Current X86-64 implementations support up to 46 bits of address space (64 TB), +which is our current limit. This expands into MBZ space in the page tables. -0xffffffef00000000 - 0xffffffff00000000 +We map EFI runtime services in the 'efi_pgd' PGD in a 64Gb large virtual +memory window (this size is arbitrary, it can be raised later if needed). +The mappings are not part of any other kernel PGD and are only available +during EFI runtime calls. -Andi Kleen, Jul 2004 |