[PATCH v4 0/9] Support Zve32[xf] and Zve64[xfd] Vector subextensions

[Andy Chiu]

The series composes of two parts. The first part provides a quick fix for
the issue on a recent thread[1]. The issue happens when a platform has
ununified vector register length across multiple cores. Specifically,
patch 1 adds a comment at a callsite of riscv_setup_vsize to clarify how
vlenb is observed by the system. Patch 2 fixes the issue by failing the
boot process of a secondary core if vlenb mismatches.

The second part of the series provide a finer grain view of the Vector
extension. Patch 3 give the obsolete ISA parser the ability to expand
ISA extensions for sigle letter extensions. Patch 3, 4 introduces Zve32x,
Zve32f, Zve64x, Zve64f, Zve64d for isa parsing and hwprobe. Patch 5
updates all callsites such that Vector subextensions are maximumly
supported by the kernel.

Two parts of the series are sent together to ease the effort of picking
dependency patches. The first part can be merged independent of the
second one if necessary.

The series is tested on a QEMU and verified that booting, Vector
programs context-switch, signal, ptrace, prctl interfaces works when we
only report partial V from the ISA.

Note that the signal test was performed after applying the commit
c27fa53b858b ("riscv: Fix vector state restore in rt_sigreturn()")

This patch should be able to apply on risc-v for-next branch on top of
the commit ba5ea59f768f ("riscv: Do not save the scratch CSR during suspend")

[1]: https://lore.kernel.org/all/20240228-vicinity-cornstalk-4b8eb5fe5730@spud/T/#u

Changes in v4:
- Add a patch to trigger prctl test on ZVE32X (9)
- Add a patch to fix integer promotion bug in hwprobe (8)
- Fix a build fail on !CONFIG_RISCV_ISA_V (7)
- Add more comment in the assembly code change (2)
- Link to v3: https://lore.kernel.org/r/20240318-zve-detection-v3-0-e12d42107fa8@sifive.com

Changelog v3:
 - Include correct maintainers and mailing list into CC.
 - Cleanup isa string parser code (3)
 - Adjust extensions order and name (4, 5)
 - Refine commit message (6)

Changelog v2:
 - Update comments and commit messages (1, 2, 7)
 - Refine isa_exts[] lists for zve extensions (4)
 - Add a patch for dt-binding (5)
 - Make ZVE* extensions depend on has_vector(ZVE32X) (6, 7)

---
---
Andy Chiu (9):
      riscv: vector: add a comment when calling riscv_setup_vsize()
      riscv: smp: fail booting up smp if inconsistent vlen is detected
      riscv: cpufeature: call match_isa_ext() for single-letter extensions
      riscv: cpufeature: add zve32[xf] and zve64[xfd] isa detection
      dt-bindings: riscv: add Zve32[xf] Zve64[xfd] ISA extension description
      riscv: hwprobe: add zve Vector subextensions into hwprobe interface
      riscv: vector: adjust minimum Vector requirement to ZVE32X
      hwprobe: fix integer promotion in RISCV_HWPROBE_EXT macro
      selftest: run vector prctl test for ZVE32X

 Documentation/arch/riscv/hwprobe.rst               | 15 ++++++
 .../devicetree/bindings/riscv/extensions.yaml      | 30 ++++++++++++
 arch/riscv/include/asm/hwcap.h                     |  5 ++
 arch/riscv/include/asm/switch_to.h                 |  2 +-
 arch/riscv/include/asm/vector.h                    | 25 ++++++----
 arch/riscv/include/asm/xor.h                       |  2 +-
 arch/riscv/include/uapi/asm/hwprobe.h              |  7 ++-
 arch/riscv/kernel/cpufeature.c                     | 56 ++++++++++++++++++----
 arch/riscv/kernel/head.S                           | 19 +++++---
 arch/riscv/kernel/kernel_mode_vector.c             |  4 +-
 arch/riscv/kernel/process.c                        |  4 +-
 arch/riscv/kernel/signal.c                         |  6 +--
 arch/riscv/kernel/smpboot.c                        | 14 ++++--
 arch/riscv/kernel/sys_hwprobe.c                    | 13 ++++-
 arch/riscv/kernel/vector.c                         | 15 +++---
 arch/riscv/lib/uaccess.S                           |  2 +-
 .../testing/selftests/riscv/vector/vstate_prctl.c  |  6 +--
 17 files changed, 174 insertions(+), 51 deletions(-)
---
base-commit: ba5ea59f768f67d127b319b26ba209ff67e0d9a5
change-id: 20240318-zve-detection-50106d2da527

Best regards,
-- 
Andy Chiu <andy.chiu at sifive.com>