diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2020-10-08 17:36:01 +0200 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-11-09 17:15:37 +0000 |
| commit | 8c96400d6a39be763130a5c493647c57726f7013 (patch) | |
| tree | 0794db8f11e674731069015b34a5c593f8a77ac7 /Documentation/arm64 | |
| parent | f4693c2716b35d0846fd45a4ad7db78bfb25efc8 (diff) | |
arm64: mm: make vmemmap region a projection of the linear region
Now that we have reverted the introduction of the vmemmap struct page
pointer and the separate physvirt_offset, we can simplify things further,
and place the vmemmap region in the VA space in such a way that virtual
to page translations and vice versa can be implemented using a single
arithmetic shift.
One happy coincidence resulting from this is that the 48-bit/4k and
52-bit/64k configurations (which are assumed to be the two most
prevalent) end up with the same placement of the vmemmap region. In
a subsequent patch, we will take advantage of this, and unify the
memory maps even more.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Steve Capper <steve.capper@arm.com>
Link: https://lore.kernel.org/r/20201008153602.9467-4-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'Documentation/arm64')
| -rw-r--r-- | Documentation/arm64/memory.rst | 30 |
1 files changed, 15 insertions, 15 deletions
diff --git a/Documentation/arm64/memory.rst b/Documentation/arm64/memory.rst index ee51eb66a578..476edb6015b2 100644 --- a/Documentation/arm64/memory.rst +++ b/Documentation/arm64/memory.rst @@ -35,14 +35,14 @@ AArch64 Linux memory layout with 4KB pages + 4 levels (48-bit):: [ ffff600000000000 ffff7fffffffffff ] 32TB [ kasan shadow region ] ffff800000000000 ffff800007ffffff 128MB bpf jit region ffff800008000000 ffff80000fffffff 128MB modules - ffff800010000000 fffffdffbffeffff 125TB vmalloc - fffffdffbfff0000 fffffdfffe5f8fff ~998MB [guard region] - fffffdfffe5f9000 fffffdfffe9fffff 4124KB fixed mappings - fffffdfffea00000 fffffdfffebfffff 2MB [guard region] - fffffdfffec00000 fffffdffffbfffff 16MB PCI I/O space - fffffdffffc00000 fffffdffffdfffff 2MB [guard region] - fffffdffffe00000 ffffffffffdfffff 2TB vmemmap - ffffffffffe00000 ffffffffffffffff 2MB [guard region] + ffff800010000000 fffffbffbffeffff 123TB vmalloc + fffffbffbfff0000 fffffbfffe7f8fff ~998MB [guard region] + fffffbfffe7f9000 fffffbfffebfffff 4124KB fixed mappings + fffffbfffec00000 fffffbfffedfffff 2MB [guard region] + fffffbfffee00000 fffffbffffdfffff 16MB PCI I/O space + fffffbffffe00000 fffffbffffffffff 2MB [guard region] + fffffc0000000000 fffffdffffffffff 2TB vmemmap + fffffe0000000000 ffffffffffffffff 2TB [guard region] AArch64 Linux memory layout with 64KB pages + 3 levels (52-bit with HW support):: @@ -55,13 +55,13 @@ AArch64 Linux memory layout with 64KB pages + 3 levels (52-bit with HW support): ffff800000000000 ffff800007ffffff 128MB bpf jit region ffff800008000000 ffff80000fffffff 128MB modules ffff800010000000 fffff81ffffeffff 120TB vmalloc - fffff81fffff0000 fffffc1ffe58ffff ~3TB [guard region] - fffffc1ffe590000 fffffc1ffe9fffff 4544KB fixed mappings - fffffc1ffea00000 fffffc1ffebfffff 2MB [guard region] - fffffc1ffec00000 fffffc1fffbfffff 16MB PCI I/O space - fffffc1fffc00000 fffffc1fffdfffff 2MB [guard region] - fffffc1fffe00000 ffffffffffdfffff 3968GB vmemmap - ffffffffffe00000 ffffffffffffffff 2MB [guard region] + fffff81fffff0000 fffffbfffe38ffff ~3TB [guard region] + fffffbfffe390000 fffffbfffebfffff 4544KB fixed mappings + fffffbfffec00000 fffffbfffedfffff 2MB [guard region] + fffffbfffee00000 fffffbffffdfffff 16MB PCI I/O space + fffffbffffe00000 fffffbffffffffff 2MB [guard region] + fffffc0000000000 ffffffdfffffffff ~4TB vmemmap + ffffffe000000000 ffffffffffffffff 128GB [guard region] Translation table lookup with 4KB pages:: |