[PATCH v2 08/10] Documentation: riscv: Add sv48 description to VM layout
From: Alexandre Ghiti <hidden>
Date: 2021-09-29 14:59:53
Also in:
linux-doc, linux-efi, linux-riscv, lkml
Subsystem:
documentation, the rest · Maintainers:
Jonathan Corbet, Linus Torvalds
sv48 was just introduced, so add its virtual memory layout to the documentation. Signed-off-by: Alexandre Ghiti <redacted> --- Documentation/riscv/vm-layout.rst | 36 +++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+)
diff --git a/Documentation/riscv/vm-layout.rst b/Documentation/riscv/vm-layout.rst
index b7f98930d38d..f10128e0a95f 100644
--- a/Documentation/riscv/vm-layout.rst
+++ b/Documentation/riscv/vm-layout.rst@@ -61,3 +61,39 @@ RISC-V Linux Kernel SV39 ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | modules, BPF ffffffff80000000 | -2 GB | ffffffffffffffff | 2 GB | kernel __________________|____________|__________________|_________|____________________________________________________________ + + +RISC-V Linux Kernel SV48 +------------------------ + +:: + + ======================================================================================================================== + 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 | ffff8fffffffffff | 16 TB | kasan + ffff9dfffee00000 | -94 TB | ffff9dfffeffffff | 2 MB | fixmap + ffff9dffff000000 | -94 TB | ffff9dffffffffff | 16 MB | PCI io + ffff9e0000000000 | -94 TB | ffff9fffffffffff | 2 TB | vmemmap + ffffa00000000000 | -92 TB | ffffbfffffffffff | 32 TB | vmalloc/ioremap space + ffffc00000000000 | -64 TB | fffffffeffffffff | 64 TB | direct mapping of all physical memory + __________________|____________|__________________|_________|____________________________________________________________ + | + | Identical layout to the 39-bit one from here on: + ____________________________________________________________|____________________________________________________________ + | | | | + ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | modules, BPF + ffffffff80000000 | -2 GB | ffffffffffffffff | 2 GB | kernel + __________________|____________|__________________|_________|____________________________________________________________
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2.30.2