Commit dd355379 authored by Björn Töpel's avatar Björn Töpel Committed by Jonathan Corbet
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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: default avatarBjörn Töpel <bjorn@rivosinc.com>
Reviewed-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20221118171556.1612190-1-bjorn@kernel.org


Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent f13039ce

Documentation/riscv/vm-layout.rst

+36 −0
Original line number Diff line number Diff line
@@ -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

  __________________|____________|__________________|_________|____________________________________________________________