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authorBjörn Töpel <bjorn@rivosinc.com>2022-11-18 20:15:56 +0300
committerJonathan Corbet <corbet@lwn.net>2022-11-22 00:40:26 +0300
commitdd3553793a759e4f7f21c1aaffd5cb2de7a0068d (patch)
tree313f8a5c8fb5db4d2a7cd21a6571046854d643a9 /Documentation/riscv
parentf13039ceec58a89f1457db5270a38b7ad4a9f07b (diff)
downloadlinux-dd3553793a759e4f7f21c1aaffd5cb2de7a0068d.tar.xz
Documentation: riscv: Document the sv57 VM layout
RISC-V has been supporting the "sv57" address translation mode for a while, but is has not been added to the VM layout documentation. Let us fix that. Signed-off-by: Björn Töpel <bjorn@rivosinc.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20221118171556.1612190-1-bjorn@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/riscv')
-rw-r--r--Documentation/riscv/vm-layout.rst36
1 files changed, 36 insertions, 0 deletions
diff --git a/Documentation/riscv/vm-layout.rst b/Documentation/riscv/vm-layout.rst
index 5b36e45fef60..3be44e74ec5d 100644
--- a/Documentation/riscv/vm-layout.rst
+++ b/Documentation/riscv/vm-layout.rst
@@ -97,3 +97,39 @@ RISC-V Linux Kernel SV48
ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | modules, BPF
ffffffff80000000 | -2 GB | ffffffffffffffff | 2 GB | kernel
__________________|____________|__________________|_________|____________________________________________________________
+
+
+RISC-V Linux Kernel SV57
+------------------------
+
+::
+
+ ========================================================================================================================
+ Start addr | Offset | End addr | Size | VM area description
+ ========================================================================================================================
+ | | | |
+ 0000000000000000 | 0 | 00ffffffffffffff | 64 PB | user-space virtual memory, different per mm
+ __________________|____________|__________________|_________|___________________________________________________________
+ | | | |
+ 0100000000000000 | +64 PB | feffffffffffffff | ~16K PB | ... huge, almost 64 bits wide hole of non-canonical
+ | | | | virtual memory addresses up to the -64 PB
+ | | | | starting offset of kernel mappings.
+ __________________|____________|__________________|_________|___________________________________________________________
+ |
+ | Kernel-space virtual memory, shared between all processes:
+ ____________________________________________________________|___________________________________________________________
+ | | | |
+ ff1bfffffee00000 | -57 PB | ff1bfffffeffffff | 2 MB | fixmap
+ ff1bffffff000000 | -57 PB | ff1bffffffffffff | 16 MB | PCI io
+ ff1c000000000000 | -57 PB | ff1fffffffffffff | 1 PB | vmemmap
+ ff20000000000000 | -56 PB | ff5fffffffffffff | 16 PB | vmalloc/ioremap space
+ ff60000000000000 | -40 PB | ffdeffffffffffff | 32 PB | direct mapping of all physical memory
+ ffdf000000000000 | -8 PB | fffffffeffffffff | 8 PB | kasan
+ __________________|____________|__________________|_________|____________________________________________________________
+ |
+ | 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
+ __________________|____________|__________________|_________|____________________________________________________________