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| author | Rik van Riel <riel@redhat.com> | 2009-05-05 17:28:56 -0400 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2009-05-05 19:10:18 -0700 |
| commit | c898faf91b3ec6b0f6efa35831b3984fa3331db0 (patch) | |
| tree | 5fa6850127cfe510e1e2d45b6c80044e29a137f5 /Documentation/x86 | |
| parent | a454ab3110175d710f4f9a96226a26ce4d5d5de2 (diff) | |
| download | lwn-c898faf91b3ec6b0f6efa35831b3984fa3331db0.tar.gz lwn-c898faf91b3ec6b0f6efa35831b3984fa3331db0.zip | |
x86: 46 bit physical address support on 64 bits
Extend the maximum addressable memory on x86-64 from 2^44 to
2^46 bytes. This requires some shuffling around of the vmalloc
and virtual memmap memory areas, to keep them away from the
direct mapping of up to 64TB of physical memory.
This patch also introduces a guard hole between the vmalloc
area and the virtual memory map space. There's really no
good reason why we wouldn't have a guard hole there.
[ Impact: future hardware enablement ]
Signed-off-by: Rik van Riel <riel@redhat.com>
LKML-Reference: <20090505172856.6820db22@cuia.bos.redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'Documentation/x86')
| -rw-r--r-- | Documentation/x86/x86_64/mm.txt | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt index 29b52b14d0b4..539413235845 100644 --- a/Documentation/x86/x86_64/mm.txt +++ b/Documentation/x86/x86_64/mm.txt @@ -6,10 +6,11 @@ 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 - ffffc0ffffffffff (=57 TB) direct mapping of all phys. memory -ffffc10000000000 - ffffc1ffffffffff (=40 bits) hole -ffffc20000000000 - ffffe1ffffffffff (=45 bits) vmalloc/ioremap space -ffffe20000000000 - ffffe2ffffffffff (=40 bits) virtual memory map (1TB) +ffff880000000000 - ffffc8ffffffffff (=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 |