On Thu, Jan 02, 2025 at 03:52:37PM +0900, Sangmoon Kim wrote:
> Commit 031e011d8b22 ("arm64: mm: Move PCI I/O emulation region above
> the vmemmap region") and commit b730b0f2b1fc ("arm64: mm: Move fixmap
> region above vmemmap region") have placed PCI I/O and fixmap region
> above vmemmap region.
>
> And commit 32697ff38287 ("arm64: vmemmap: Avoid base2 order of struct
> page size to dimension region") has moved vmemmap region to higher
> address.
>
> Update document as the memory layout modified by the previous patches.
>
> Signed-off-by: Sangmoon Kim <sangmoon.kim@xxxxxxxxxxx>
> ---
> Documentation/arch/arm64/memory.rst | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
To be honest with you, this document is pretty stale (it doesn't even
mention 16k pages) and almost impossible to keep in-sync with the code.
I'd be inclined to remove these tables; we have ptdump support if people
really want to see where things are.
Will
--->8
diff --git a/Documentation/arch/arm64/memory.rst b/Documentation/arch/arm64/memory.rst
index 8a658984b8bb..678fbb418c3a 100644
--- a/Documentation/arch/arm64/memory.rst
+++ b/Documentation/arch/arm64/memory.rst
@@ -23,71 +23,6 @@ swapper_pg_dir contains only kernel (global) mappings while the user pgd
contains only user (non-global) mappings. The swapper_pg_dir address is
written to TTBR1 and never written to TTBR0.
-
-AArch64 Linux memory layout with 4KB pages + 4 levels (48-bit)::
-
- Start End Size Use
- -----------------------------------------------------------------------
- 0000000000000000 0000ffffffffffff 256TB user
- ffff000000000000 ffff7fffffffffff 128TB kernel logical memory map
- [ffff600000000000 ffff7fffffffffff] 32TB [kasan shadow region]
- ffff800000000000 ffff80007fffffff 2GB modules
- ffff800080000000 fffffbffefffffff 124TB vmalloc
- fffffbfff0000000 fffffbfffdffffff 224MB fixed mappings (top down)
- fffffbfffe000000 fffffbfffe7fffff 8MB [guard region]
- fffffbfffe800000 fffffbffff7fffff 16MB PCI I/O space
- fffffbffff800000 fffffbffffffffff 8MB [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)::
-
- Start End Size Use
- -----------------------------------------------------------------------
- 0000000000000000 000fffffffffffff 4PB user
- fff0000000000000 ffff7fffffffffff ~4PB kernel logical memory map
- [fffd800000000000 ffff7fffffffffff] 512TB [kasan shadow region]
- ffff800000000000 ffff80007fffffff 2GB modules
- ffff800080000000 fffffbffefffffff 124TB vmalloc
- fffffbfff0000000 fffffbfffdffffff 224MB fixed mappings (top down)
- fffffbfffe000000 fffffbfffe7fffff 8MB [guard region]
- fffffbfffe800000 fffffbffff7fffff 16MB PCI I/O space
- fffffbffff800000 fffffbffffffffff 8MB [guard region]
- fffffc0000000000 ffffffdfffffffff ~4TB vmemmap
- ffffffe000000000 ffffffffffffffff 128GB [guard region]
-
-
-Translation table lookup with 4KB pages::
-
- +--------+--------+--------+--------+--------+--------+--------+--------+
- |63 56|55 48|47 40|39 32|31 24|23 16|15 8|7 0|
- +--------+--------+--------+--------+--------+--------+--------+--------+
- | | | | | |
- | | | | | v
- | | | | | [11:0] in-page offset
- | | | | +-> [20:12] L3 index
- | | | +-----------> [29:21] L2 index
- | | +---------------------> [38:30] L1 index
- | +-------------------------------> [47:39] L0 index
- +----------------------------------------> [55] TTBR0/1
-
-
-Translation table lookup with 64KB pages::
-
- +--------+--------+--------+--------+--------+--------+--------+--------+
- |63 56|55 48|47 40|39 32|31 24|23 16|15 8|7 0|
- +--------+--------+--------+--------+--------+--------+--------+--------+
- | | | | |
- | | | | v
- | | | | [15:0] in-page offset
- | | | +----------> [28:16] L3 index
- | | +--------------------------> [41:29] L2 index
- | +-------------------------------> [47:42] L1 index (48-bit)
- | [51:42] L1 index (52-bit)
- +----------------------------------------> [55] TTBR0/1
-
-
When using KVM without the Virtualization Host Extensions, the
hypervisor maps kernel pages in EL2 at a fixed (and potentially
random) offset from the linear mapping. See the kern_hyp_va macro and
