diff options
Diffstat (limited to 'Documentation/x86_64/mm.txt')
| -rw-r--r-- | Documentation/x86_64/mm.txt | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/Documentation/x86_64/mm.txt b/Documentation/x86_64/mm.txt index 133561b9cb0..f42798ed1c5 100644 --- a/Documentation/x86_64/mm.txt +++ b/Documentation/x86_64/mm.txt @@ -3,26 +3,26 @@ Virtual memory map with 4 level page tables: -0000000000000000 - 00007fffffffffff (=47bits) user space, different per mm +0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension -ffff800000000000 - ffff80ffffffffff (=40bits) guard hole -ffff810000000000 - ffffc0ffffffffff (=46bits) direct mapping of all phys. memory -ffffc10000000000 - ffffc1ffffffffff (=40bits) hole -ffffc20000000000 - ffffe1ffffffffff (=45bits) vmalloc/ioremap space +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 ... unused hole ... -ffffffff80000000 - ffffffff82800000 (=40MB) kernel text mapping, from phys 0 +ffffffff80000000 - ffffffff82800000 (=40 MB) kernel text mapping, from phys 0 ... unused hole ... -ffffffff88000000 - fffffffffff00000 (=1919MB) module mapping space +ffffffff88000000 - fffffffffff00000 (=1919 MB) module mapping space -The direct mapping covers all memory in the system upto the highest +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) +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 bit of address space, -but we support upto 46bits. This expands into MBZ space in the page tables. +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 |