redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity
alistair23-linux/Documentation/x86/x86_64/mm.rst

162 lines
11 KiB
ReStructuredText
Raw Permalink Normal View History

Documentation: x86: convert x86_64/mm.txt to reST This converts the plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-05-08 09:21:37 -06:00
.. SPDX-License-Identifier: GPL-2.0
================
Memory Managment
================
Complete virtual memory map with 4-level page tables
====================================================
.. note::
- Negative addresses such as "-23 TB" are absolute addresses in bytes, counted down
from the top of the 64-bit address space. It's easier to understand the layout
when seen both in absolute addresses and in distance-from-top notation.
For example 0xffffe90000000000 == -23 TB, it's 23 TB lower than the top of the
64-bit address space (ffffffffffffffff).
Note that as we get closer to the top of the address space, the notation changes
from TB to GB and then MB/KB.
- "16M TB" might look weird at first sight, but it's an easier to visualize size
notation than "16 EB", which few will recognize at first sight as 16 exabytes.
It also shows it nicely how incredibly large 64-bit address space is.
::
========================================================================================================================
Start addr | Offset | End addr | Size | VM area description
========================================================================================================================
| | | |
0000000000000000 | 0 | 00007fffffffffff | 128 TB | user-space virtual memory, different per mm
__________________|____________|__________________|_________|___________________________________________________________
| | | |
0000800000000000 | +128 TB | ffff7fffffffffff | ~16M TB | ... huge, almost 64 bits wide hole of non-canonical
| | | | virtual memory addresses up to the -128 TB
| | | | starting offset of kernel mappings.
__________________|____________|__________________|_________|___________________________________________________________
|
| Kernel-space virtual memory, shared between all processes:
____________________________________________________________|___________________________________________________________
| | | |
ffff800000000000 | -128 TB | ffff87ffffffffff | 8 TB | ... guard hole, also reserved for hypervisor
ffff880000000000 | -120 TB | ffff887fffffffff | 0.5 TB | LDT remap for PTI
ffff888000000000 | -119.5 TB | ffffc87fffffffff | 64 TB | direct mapping of all physical memory (page_offset_base)
ffffc88000000000 | -55.5 TB | ffffc8ffffffffff | 0.5 TB | ... unused hole
ffffc90000000000 | -55 TB | ffffe8ffffffffff | 32 TB | vmalloc/ioremap space (vmalloc_base)
ffffe90000000000 | -23 TB | ffffe9ffffffffff | 1 TB | ... unused hole
ffffea0000000000 | -22 TB | ffffeaffffffffff | 1 TB | virtual memory map (vmemmap_base)
ffffeb0000000000 | -21 TB | ffffebffffffffff | 1 TB | ... unused hole
ffffec0000000000 | -20 TB | fffffbffffffffff | 16 TB | KASAN shadow memory
__________________|____________|__________________|_________|____________________________________________________________
|
| Identical layout to the 56-bit one from here on:
____________________________________________________________|____________________________________________________________
| | | |
fffffc0000000000 | -4 TB | fffffdffffffffff | 2 TB | ... unused hole
| | | | vaddr_end for KASLR
fffffe0000000000 | -2 TB | fffffe7fffffffff | 0.5 TB | cpu_entry_area mapping
fffffe8000000000 | -1.5 TB | fffffeffffffffff | 0.5 TB | ... unused hole
ffffff0000000000 | -1 TB | ffffff7fffffffff | 0.5 TB | %esp fixup stacks
ffffff8000000000 | -512 GB | ffffffeeffffffff | 444 GB | ... unused hole
ffffffef00000000 | -68 GB | fffffffeffffffff | 64 GB | EFI region mapping space
ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | ... unused hole
ffffffff80000000 | -2 GB | ffffffff9fffffff | 512 MB | kernel text mapping, mapped to physical address 0
ffffffff80000000 |-2048 MB | | |
ffffffffa0000000 |-1536 MB | fffffffffeffffff | 1520 MB | module mapping space
ffffffffff000000 | -16 MB | | |
FIXADDR_START | ~-11 MB | ffffffffff5fffff | ~0.5 MB | kernel-internal fixmap range, variable size and offset
ffffffffff600000 | -10 MB | ffffffffff600fff | 4 kB | legacy vsyscall ABI
ffffffffffe00000 | -2 MB | ffffffffffffffff | 2 MB | ... unused hole
__________________|____________|__________________|_________|___________________________________________________________
Complete virtual memory map with 5-level page tables
====================================================
.. note::
- With 56-bit addresses, user-space memory gets expanded by a factor of 512x,
Some late arriving documentation changes. In particular, this contains the conversion of the x86 docs to RST, which has been in the works for some time but needed a couple of final tweaks. -----BEGIN PGP SIGNATURE----- iQFDBAABCAAtFiEEIw+MvkEiF49krdp9F0NaE2wMflgFAlzVlVoPHGNvcmJldEBs d24ubmV0AAoJEBdDWhNsDH5YPWgH/1z+HO4QiLZ72kVxLf2U5r6FAo4CtQYLymL/ GiDabC7Jt7hobXdFQmDXhFnLOR/ibMnawJw2JAgWXDo33KenKGbE2OiW8ecsebSb hd1F3pU6P3gVTYItcuM8dZ6/0C/F98/J/O3O3sOhZ0Uup2WPxW5XdNOp7LjFQScc ENkgm2C5trs1wGjVswXWztGxSTcYrF7ehhjpWsFr9MUnUOI6ghvXX1akN3cEo7eo 7D8nvG2/HWOkf9Oq87/1uQxF6lERRqOQE+HN1J80XUsNTV5Hn40RP40FeebVv1rr 1GjUu+mKk/5uV+OlRWFqLbt10cU4+TKKfNTqfEchHyDOMpJD+S0= =hfly -----END PGP SIGNATURE----- Merge tag 'docs-5.2a' of git://git.lwn.net/linux Pull more documentation updates from Jonathan Corbet: "Some late arriving documentation changes. In particular, this contains the conversion of the x86 docs to RST, which has been in the works for some time but needed a couple of final tweaks" * tag 'docs-5.2a' of git://git.lwn.net/linux: (29 commits) Documentation: x86: convert x86_64/machinecheck to reST Documentation: x86: convert x86_64/cpu-hotplug-spec to reST Documentation: x86: convert x86_64/fake-numa-for-cpusets to reST Documentation: x86: convert x86_64/5level-paging.txt to reST Documentation: x86: convert x86_64/mm.txt to reST Documentation: x86: convert x86_64/uefi.txt to reST Documentation: x86: convert x86_64/boot-options.txt to reST Documentation: x86: convert i386/IO-APIC.txt to reST Documentation: x86: convert usb-legacy-support.txt to reST Documentation: x86: convert orc-unwinder.txt to reST Documentation: x86: convert resctrl_ui.txt to reST Documentation: x86: convert microcode.txt to reST Documentation: x86: convert pti.txt to reST Documentation: x86: convert amd-memory-encryption.txt to reST Documentation: x86: convert intel_mpx.txt to reST Documentation: x86: convert protection-keys.txt to reST Documentation: x86: convert pat.txt to reST Documentation: x86: convert mtrr.txt to reST Documentation: x86: convert tlb.txt to reST Documentation: x86: convert zero-page.txt to reST ...
2019-05-10 11:24:53 -06:00
from 0.125 PB to 64 PB. All kernel mappings shift down to the -64 PB starting
Documentation: x86: convert x86_64/mm.txt to reST This converts the plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-05-08 09:21:37 -06:00
offset and many of the regions expand to support the much larger physical
memory supported.
::
========================================================================================================================
Start addr | Offset | End addr | Size | VM area description
========================================================================================================================
| | | |
0000000000000000 | 0 | 00ffffffffffffff | 64 PB | user-space virtual memory, different per mm
__________________|____________|__________________|_________|___________________________________________________________
| | | |
Some late arriving documentation changes. In particular, this contains the conversion of the x86 docs to RST, which has been in the works for some time but needed a couple of final tweaks. -----BEGIN PGP SIGNATURE----- iQFDBAABCAAtFiEEIw+MvkEiF49krdp9F0NaE2wMflgFAlzVlVoPHGNvcmJldEBs d24ubmV0AAoJEBdDWhNsDH5YPWgH/1z+HO4QiLZ72kVxLf2U5r6FAo4CtQYLymL/ GiDabC7Jt7hobXdFQmDXhFnLOR/ibMnawJw2JAgWXDo33KenKGbE2OiW8ecsebSb hd1F3pU6P3gVTYItcuM8dZ6/0C/F98/J/O3O3sOhZ0Uup2WPxW5XdNOp7LjFQScc ENkgm2C5trs1wGjVswXWztGxSTcYrF7ehhjpWsFr9MUnUOI6ghvXX1akN3cEo7eo 7D8nvG2/HWOkf9Oq87/1uQxF6lERRqOQE+HN1J80XUsNTV5Hn40RP40FeebVv1rr 1GjUu+mKk/5uV+OlRWFqLbt10cU4+TKKfNTqfEchHyDOMpJD+S0= =hfly -----END PGP SIGNATURE----- Merge tag 'docs-5.2a' of git://git.lwn.net/linux Pull more documentation updates from Jonathan Corbet: "Some late arriving documentation changes. In particular, this contains the conversion of the x86 docs to RST, which has been in the works for some time but needed a couple of final tweaks" * tag 'docs-5.2a' of git://git.lwn.net/linux: (29 commits) Documentation: x86: convert x86_64/machinecheck to reST Documentation: x86: convert x86_64/cpu-hotplug-spec to reST Documentation: x86: convert x86_64/fake-numa-for-cpusets to reST Documentation: x86: convert x86_64/5level-paging.txt to reST Documentation: x86: convert x86_64/mm.txt to reST Documentation: x86: convert x86_64/uefi.txt to reST Documentation: x86: convert x86_64/boot-options.txt to reST Documentation: x86: convert i386/IO-APIC.txt to reST Documentation: x86: convert usb-legacy-support.txt to reST Documentation: x86: convert orc-unwinder.txt to reST Documentation: x86: convert resctrl_ui.txt to reST Documentation: x86: convert microcode.txt to reST Documentation: x86: convert pti.txt to reST Documentation: x86: convert amd-memory-encryption.txt to reST Documentation: x86: convert intel_mpx.txt to reST Documentation: x86: convert protection-keys.txt to reST Documentation: x86: convert pat.txt to reST Documentation: x86: convert mtrr.txt to reST Documentation: x86: convert tlb.txt to reST Documentation: x86: convert zero-page.txt to reST ...
2019-05-10 11:24:53 -06:00
0100000000000000 | +64 PB | feffffffffffffff | ~16K PB | ... huge, still almost 64 bits wide hole of non-canonical
Documentation: x86: convert x86_64/mm.txt to reST This converts the plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-05-08 09:21:37 -06:00
| | | | virtual memory addresses up to the -64 PB
| | | | starting offset of kernel mappings.
__________________|____________|__________________|_________|___________________________________________________________
|
| Kernel-space virtual memory, shared between all processes:
____________________________________________________________|___________________________________________________________
| | | |
ff00000000000000 | -64 PB | ff0fffffffffffff | 4 PB | ... guard hole, also reserved for hypervisor
ff10000000000000 | -60 PB | ff10ffffffffffff | 0.25 PB | LDT remap for PTI
ff11000000000000 | -59.75 PB | ff90ffffffffffff | 32 PB | direct mapping of all physical memory (page_offset_base)
ff91000000000000 | -27.75 PB | ff9fffffffffffff | 3.75 PB | ... unused hole
ffa0000000000000 | -24 PB | ffd1ffffffffffff | 12.5 PB | vmalloc/ioremap space (vmalloc_base)
ffd2000000000000 | -11.5 PB | ffd3ffffffffffff | 0.5 PB | ... unused hole
ffd4000000000000 | -11 PB | ffd5ffffffffffff | 0.5 PB | virtual memory map (vmemmap_base)
ffd6000000000000 | -10.5 PB | ffdeffffffffffff | 2.25 PB | ... unused hole
Some late arriving documentation changes. In particular, this contains the conversion of the x86 docs to RST, which has been in the works for some time but needed a couple of final tweaks. -----BEGIN PGP SIGNATURE----- iQFDBAABCAAtFiEEIw+MvkEiF49krdp9F0NaE2wMflgFAlzVlVoPHGNvcmJldEBs d24ubmV0AAoJEBdDWhNsDH5YPWgH/1z+HO4QiLZ72kVxLf2U5r6FAo4CtQYLymL/ GiDabC7Jt7hobXdFQmDXhFnLOR/ibMnawJw2JAgWXDo33KenKGbE2OiW8ecsebSb hd1F3pU6P3gVTYItcuM8dZ6/0C/F98/J/O3O3sOhZ0Uup2WPxW5XdNOp7LjFQScc ENkgm2C5trs1wGjVswXWztGxSTcYrF7ehhjpWsFr9MUnUOI6ghvXX1akN3cEo7eo 7D8nvG2/HWOkf9Oq87/1uQxF6lERRqOQE+HN1J80XUsNTV5Hn40RP40FeebVv1rr 1GjUu+mKk/5uV+OlRWFqLbt10cU4+TKKfNTqfEchHyDOMpJD+S0= =hfly -----END PGP SIGNATURE----- Merge tag 'docs-5.2a' of git://git.lwn.net/linux Pull more documentation updates from Jonathan Corbet: "Some late arriving documentation changes. In particular, this contains the conversion of the x86 docs to RST, which has been in the works for some time but needed a couple of final tweaks" * tag 'docs-5.2a' of git://git.lwn.net/linux: (29 commits) Documentation: x86: convert x86_64/machinecheck to reST Documentation: x86: convert x86_64/cpu-hotplug-spec to reST Documentation: x86: convert x86_64/fake-numa-for-cpusets to reST Documentation: x86: convert x86_64/5level-paging.txt to reST Documentation: x86: convert x86_64/mm.txt to reST Documentation: x86: convert x86_64/uefi.txt to reST Documentation: x86: convert x86_64/boot-options.txt to reST Documentation: x86: convert i386/IO-APIC.txt to reST Documentation: x86: convert usb-legacy-support.txt to reST Documentation: x86: convert orc-unwinder.txt to reST Documentation: x86: convert resctrl_ui.txt to reST Documentation: x86: convert microcode.txt to reST Documentation: x86: convert pti.txt to reST Documentation: x86: convert amd-memory-encryption.txt to reST Documentation: x86: convert intel_mpx.txt to reST Documentation: x86: convert protection-keys.txt to reST Documentation: x86: convert pat.txt to reST Documentation: x86: convert mtrr.txt to reST Documentation: x86: convert tlb.txt to reST Documentation: x86: convert zero-page.txt to reST ...
2019-05-10 11:24:53 -06:00
ffdf000000000000 | -8.25 PB | fffffbffffffffff | ~8 PB | KASAN shadow memory
Documentation: x86: convert x86_64/mm.txt to reST This converts the plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-05-08 09:21:37 -06:00
__________________|____________|__________________|_________|____________________________________________________________
|
| Identical layout to the 47-bit one from here on:
____________________________________________________________|____________________________________________________________
| | | |
fffffc0000000000 | -4 TB | fffffdffffffffff | 2 TB | ... unused hole
| | | | vaddr_end for KASLR
fffffe0000000000 | -2 TB | fffffe7fffffffff | 0.5 TB | cpu_entry_area mapping
fffffe8000000000 | -1.5 TB | fffffeffffffffff | 0.5 TB | ... unused hole
ffffff0000000000 | -1 TB | ffffff7fffffffff | 0.5 TB | %esp fixup stacks
ffffff8000000000 | -512 GB | ffffffeeffffffff | 444 GB | ... unused hole
ffffffef00000000 | -68 GB | fffffffeffffffff | 64 GB | EFI region mapping space
ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | ... unused hole
ffffffff80000000 | -2 GB | ffffffff9fffffff | 512 MB | kernel text mapping, mapped to physical address 0
ffffffff80000000 |-2048 MB | | |
ffffffffa0000000 |-1536 MB | fffffffffeffffff | 1520 MB | module mapping space
ffffffffff000000 | -16 MB | | |
FIXADDR_START | ~-11 MB | ffffffffff5fffff | ~0.5 MB | kernel-internal fixmap range, variable size and offset
ffffffffff600000 | -10 MB | ffffffffff600fff | 4 kB | legacy vsyscall ABI
ffffffffffe00000 | -2 MB | 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 sign extended.
This causes hole between user space and kernel addresses if you interpret them
as unsigned.
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/PML5 pages of
the processes using the page fault handler, with init_top_pgt as
reference.
We map EFI runtime services in the 'efi_pgd' PGD in a 64Gb large virtual
memory window (this size is arbitrary, it can be raised later if needed).
The mappings are not part of any other kernel PGD and are only available
during EFI runtime calls.
Note that if CONFIG_RANDOMIZE_MEMORY is enabled, the direct mapping of all
physical memory, vmalloc/ioremap space and virtual memory map are randomized.
Their order is preserved but their base will be offset early at boot time.
Be very careful vs. KASLR when changing anything here. The KASLR address
range must not overlap with anything except the KASAN shadow area, which is
correct as KASAN disables KASLR.
For both 4- and 5-level layouts, the STACKLEAK_POISON value in the last 2MB
hole: ffffffffffff4111