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author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2008-07-15 07:44:51 +0200 |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2008-07-15 07:44:51 +0200 |
commit | 43d2548bb2ef7e6d753f91468a746784041e522d (patch) | |
tree | 77d13fcd48fd998393abb825ec36e2b732684a73 /Documentation/x86/x86_64/mm.txt | |
parent | powerpc: Fix pte_update for CONFIG_PTE_64BIT and !PTE_ATOMIC_UPDATES (diff) | |
parent | Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm (diff) | |
download | linux-43d2548bb2ef7e6d753f91468a746784041e522d.tar.xz linux-43d2548bb2ef7e6d753f91468a746784041e522d.zip |
Merge commit '85082fd7cbe3173198aac0eb5e85ab1edcc6352c' into test-build
Manual fixup of:
arch/powerpc/Kconfig
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 000000000000..efce75097369 --- /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 |