[PATCH] doc: correct Documentation/x86/x86_64/mm.txt

From: Juergen Gross
Date: Fri Apr 22 2016 - 03:35:17 EST

Correct the size of the module mapping space and the maximum available
physical memory size of current processors.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Documentation/x86/x86_64/mm.txt | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
index c518dce..5aa7383 100644
--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -19,7 +19,7 @@ ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
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

@@ -31,8 +31,8 @@ vmalloc space is lazily synchronized into the different PML4 pages of
the processes using the page fault handler, with init_level4_pgt as

-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.
+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.

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).