diff options
Diffstat (limited to 'Documentation/x86/x86_64/mm.txt')
| -rw-r--r-- | Documentation/x86/x86_64/mm.txt | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt index ee3f9c30957c..b0798e281aa6 100644 --- a/Documentation/x86/x86_64/mm.txt +++ b/Documentation/x86/x86_64/mm.txt @@ -4,7 +4,7 @@ Virtual memory map with 4 level page tables: 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm -hole caused by [48:63] sign extension +hole caused by [47:63] sign extension ffff800000000000 - ffff87ffffffffff (=43 bits) guard hole, reserved for hypervisor ffff880000000000 - ffffc7ffffffffff (=64 TB) direct mapping of all phys. memory ffffc80000000000 - ffffc8ffffffffff (=40 bits) hole @@ -23,12 +23,39 @@ ffffffffa0000000 - ffffffffff5fffff (=1526 MB) module mapping space (variable) ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole +Virtual memory map with 5 level page tables: + +0000000000000000 - 00ffffffffffffff (=56 bits) user space, different per mm +hole caused by [56:63] sign extension +ff00000000000000 - ff0fffffffffffff (=52 bits) guard hole, reserved for hypervisor +ff10000000000000 - ff8fffffffffffff (=55 bits) direct mapping of all phys. memory +ff90000000000000 - ff91ffffffffffff (=49 bits) hole +ff92000000000000 - ffd1ffffffffffff (=54 bits) vmalloc/ioremap space +ffd2000000000000 - ffd3ffffffffffff (=49 bits) hole +ffd4000000000000 - ffd5ffffffffffff (=49 bits) virtual memory map (512TB) +... unused hole ... +ffd8000000000000 - fff7ffffffffffff (=53 bits) kasan shadow memory (8PB) +... unused hole ... +ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks +... unused hole ... +ffffffef00000000 - fffffffeffffffff (=64 GB) EFI region mapping space +... unused hole ... +ffffffff80000000 - ffffffff9fffffff (=512 MB) kernel text mapping, from phys 0 +ffffffffa0000000 - ffffffffff5fffff (=1526 MB) module mapping space +ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls +ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole + +Architecture defines a 64-bit virtual address. Implementations can support +less. Currently supported are 48- and 57-bit virtual addresses. Bits 63 +through to the most-significant implemented bit are set to either all ones +or all zero. This causes hole between user space and kernel addresses. + 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 +vmalloc space is lazily synchronized into the different PML4/PML5 pages of +the processes using the page fault handler, with init_top_pgt as reference. Current X86-64 implementations support up to 46 bits of address space (64 TB), |