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author | Ingo Molnar <mingo@elte.hu> | 2008-07-31 18:43:41 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-07-31 18:43:41 +0200 |
commit | 85e9ca333d03fbd56b9e123c8456f0d98e20faad (patch) | |
tree | 7bb15ada5f536950efa23ad60ea9eea60380ca1c /Documentation/x86/x86_64/mm.txt | |
parent | a300bec952127d9a15e666b391bb35c9aecb3002 (diff) | |
parent | 6e86841d05f371b5b9b86ce76c02aaee83352298 (diff) | |
download | op-kernel-dev-85e9ca333d03fbd56b9e123c8456f0d98e20faad.zip op-kernel-dev-85e9ca333d03fbd56b9e123c8456f0d98e20faad.tar.gz |
Merge branch 'linus' into timers/hpet
Diffstat (limited to 'Documentation/x86/x86_64/mm.txt')
-rw-r--r-- | Documentation/x86/x86_64/mm.txt | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt new file mode 100644 index 0000000..efce750 --- /dev/null +++ b/Documentation/x86/x86_64/mm.txt @@ -0,0 +1,28 @@ + +<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 +ffff810000000000 - ffffc0ffffffffff (=46 bits) 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) +... 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 |