From 871480933a1c28f8a9fed4c4d34d06c439a7a422 Mon Sep 17 00:00:00 2001
From: Srikant Patnaik
Date: Sun, 11 Jan 2015 12:28:04 +0530
Subject: Moved, renamed, and deleted files

The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.
---
 Documentation/x86/x86_64/mm.txt | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 Documentation/x86/x86_64/mm.txt

(limited to 'Documentation/x86/x86_64/mm.txt')

diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
new file mode 100644
index 00000000..d6498e3c
--- /dev/null
+++ b/Documentation/x86/x86_64/mm.txt
@@ -0,0 +1,29 @@
+
+<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 - ffff80ffffffffff (=40 bits) guard hole
+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 ...
+ffffffff80000000 - ffffffffa0000000 (=512 MB)  kernel text mapping, from phys 0
+ffffffffa0000000 - fffffffffff00000 (=1536 MB) module mapping space
+
+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.
+
+-Andi Kleen, Jul 2004
-- 
cgit