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author | Ingo Molnar <mingo@elte.hu> | 2008-07-08 09:43:01 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-07-08 09:43:01 +0200 |
commit | 3c1ca43fafea41e38cb2d0c1684119af4c1de547 (patch) | |
tree | 122e41a7b9fca26ea25ea9864180f5016274a8c8 /Documentation/x86/x86_64/mm.txt | |
parent | 6924d1ab8b7bbe5ab416713f5701b3316b2df85b (diff) | |
parent | 6bcb13b35a2ea39be6c7cc0292b8ad1191b1a748 (diff) | |
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Merge branch 'x86/setup' into x86/devel
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 |