[PATCH v6 00/14] riscv: support for Svpbmt and D1 memory types

[Heiko Stuebner]

Svpbmt is an extension defining "Supervisor-mode: page-based memory types"
for things like non-cacheable pages or I/O memory pages.


So this is my 2nd try at implementing Svpbmt (and the diverging D1 memory
types) using the alternatives framework.

This includes a number of changes to the alternatives mechanism itself.
The biggest one being the move to a more central location, as I expect
in the future, nearly every chip needing some sort of patching, be it
either for erratas or for optional features (svpbmt or others).

The dt-binding for svpbmt itself is of course not finished and is still
using the binding introduced in previous versions, as where to put
a svpbmt-property in the devicetree is still under dicussion.
Atish seems to be working on a framework for extensions [0],

The series also introduces support for the memory types of the D1
which are implemented differently to svpbmt. But when patching anyway
it's pretty clean to add the D1 variant via ALTERNATIVE_2 to the same
location.

The only slightly bigger difference is that the "normal" type is not 0
as with svpbmt, so kernel patches for this PMA type need to be applied
even before the MMU is brought up, so the series introduces a separate
stage for that.


In theory this series is 3 parts:
- sbi cache-flush / null-ptr
- alternatives improvements
- svpbmt+d1

So expecially patches from the first 2 areas could be applied when
deemed ready, I just thought to keep it together to show-case where
the end-goal is and not requiring jumping between different series.


The sbi cache-flush patch is based on Atish's sparse-hartid patch [1],
as it touches a similar area in mm/cacheflush.c


I picked the recipient list from the previous version, hopefully
I didn't forget anybody.

changes in v6:
- rebase onto 5.17-rc1
- handle sbi null-ptr differently
- improve commit messages
- use riscv,mmu as property name

changes in v5:
- move to use alternatives for runtime-patching
- add D1 variant


[0] https://lore.kernel.org/r/20211224211632.1698523-1-atishp@rivosinc.com
[1] https://lore.kernel.org/r/20220120090918.2646626-1-atishp@rivosinc.com


Heiko Stuebner (12):
  riscv: prevent null-pointer dereference with sbi_remote_fence_i
  riscv: integrate alternatives better into the main architecture
  riscv: allow different stages with alternatives
  riscv: implement module alternatives
  riscv: implement ALTERNATIVE_2 macro
  riscv: extend concatenated alternatives-lines to the same length
  riscv: prevent compressed instructions in alternatives
  riscv: move boot alternatives to a slightly earlier position
  riscv: Fix accessing pfn bits in PTEs for non-32bit variants
  riscv: add cpufeature handling via alternatives
  riscv: remove FIXMAP_PAGE_IO and fall back to its default value
  riscv: add memory-type errata for T-Head

Wei Fu (2):
  dt-bindings: riscv: add MMU Standard Extensions support for Svpbmt
  riscv: add RISC-V Svpbmt extension support

 .../devicetree/bindings/riscv/cpus.yaml       |  10 ++
 arch/riscv/Kconfig.erratas                    |  29 ++--
 arch/riscv/Kconfig.socs                       |   1 -
 arch/riscv/Makefile                           |   2 +-
 arch/riscv/errata/Makefile                    |   2 +-
 arch/riscv/errata/sifive/errata.c             |  10 +-
 arch/riscv/errata/thead/Makefile              |   1 +
 arch/riscv/errata/thead/errata.c              |  85 +++++++++++
 arch/riscv/include/asm/alternative-macros.h   | 114 ++++++++-------
 arch/riscv/include/asm/alternative.h          |  16 ++-
 arch/riscv/include/asm/errata_list.h          |  52 +++++++
 arch/riscv/include/asm/fixmap.h               |   2 -
 arch/riscv/include/asm/pgtable-32.h           |  17 +++
 arch/riscv/include/asm/pgtable-64.h           |  79 +++++++++-
 arch/riscv/include/asm/pgtable-bits.h         |  10 --
 arch/riscv/include/asm/pgtable.h              |  53 +++++--
 arch/riscv/include/asm/vendorid_list.h        |   1 +
 arch/riscv/kernel/Makefile                    |   1 +
 arch/riscv/{errata => kernel}/alternative.c   |  48 ++++++-
 arch/riscv/kernel/cpufeature.c                | 136 +++++++++++++++++-
 arch/riscv/kernel/head.S                      |   2 +
 arch/riscv/kernel/module.c                    |  29 ++++
 arch/riscv/kernel/sbi.c                       |  10 +-
 arch/riscv/kernel/smpboot.c                   |   4 -
 arch/riscv/kernel/traps.c                     |   2 +-
 arch/riscv/mm/init.c                          |   1 +
 26 files changed, 606 insertions(+), 111 deletions(-)
 create mode 100644 arch/riscv/errata/thead/Makefile
 create mode 100644 arch/riscv/errata/thead/errata.c
 rename arch/riscv/{errata => kernel}/alternative.c (59%)

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2.30.2