[PATCH v2 00/10] riscv: hwprobe: Expose RVA23U64 base behavior

[Guodong Xu]

This series builds on Andrew Jones's earlier RFC [1]. It lets
userspace check for RVA23U64 conformance in one call, instead of
walking hwprobe + prctl across every mandatory extension.

The series adds a small framework that resolves profile-class
bases (IMA and RVA23U64) from the kernel's ISA extension bitmap at
init time, and surfaces the result through both /proc/cpuinfo and
hwprobe. Later patches can add RVA23S64, and backward RVA22 / RVA20
detection, to riscv_set_isa_bases() without changes to the
surrounding code.

To detect RVA23U64 the kernel first has to recognise every extension
it mandates, so patches 4-6 bring Zicclsm; Ziccamoa, Ziccif,
Ziccrse, Za64rs; and B into the cpufeature parser. The framework
then reads the resulting bitmap, and the final patch exposes the
RVA23U64 bit through RISCV_HWPROBE_BASE_BEHAVIOR_RVA23U64.

Series outline:

  1-3. hwprobe.rst clean-ups: document EXT_ZICFISS, normalize
       indentation, and standardize extension capitalization.

   4.  Zicclsm: cpufeature parsing + hwprobe export.
   5.  Ziccamoa, Ziccif, Ziccrse, Za64rs: cpufeature parsing + hwprobe
       export, with cpufeature dependency validation for
       Ziccamoa->Zaamo and Za64rs->Zalrsc.
   6.  B (hwcap + hwprobe), as the Zba/Zbb/Zbs set.

   7.  riscv_have_user_pmlen(): arch-level accessor for user
       pointer-masking PMLEN support, used by RVA23U64 detection.

   8.  cpufeature: per-hart and host-wide isa_bases bitmaps,
       populated at init time. IMA and RVA23U64 detection lives
       here; /proc/cpuinfo and hwprobe both read from these bitmaps.

   9.  /proc/cpuinfo: print "isa bases" / "hart isa bases" lines
       sourced from the cached bitmaps.

  10.  hwprobe: expose RVA23U64 via
       RISCV_HWPROBE_BASE_BEHAVIOR_RVA23U64.

Tested on qemu booted with -cpu rva23s64,sv39=on,pmp=on:
  - /proc/cpuinfo reports "isa bases : rv64ima rva23u64" on both the
    aggregated and per-hart lines.
  - hwprobe RISCV_HWPROBE_KEY_BASE_BEHAVIOR returns
    BASE_BEHAVIOR_IMA | BASE_BEHAVIOR_RVA23U64.

Based on v7.2-rc2; happy to rebase onto another tree if needed.

Link: https://lore.kernel.org/linux-riscv/20260206002349.96740-1-andrew.jones@oss.qualcomm.com/ [1]

BR,
Guodong Xu

Signed-off-by: Guodong Xu <guodong at riscstar.com>
---
Andrew Jones (4):
      riscv: hwprobe.rst: Replace tabs with spaces
      riscv: Add Ziccamoa, Ziccif, Ziccrse, and Za64rs to cpufeature and hwprobe
      riscv: Add B to hwcap and hwprobe
      riscv: Add a getter for user PMLEN support

Charlie Jenkins (1):
      riscv: Standardize extension capitalization

Guodong Xu (4):
      riscv: hwprobe.rst: Document EXT_ZICFISS
      riscv: cpufeature: Introduce ISA bases bitmap and rva23u64 detection
      riscv: cpu: Output isa bases lines in cpuinfo
      riscv: hwprobe: Introduce rva23u64 base behavior

Jesse Taube (1):
      riscv: Add Zicclsm to cpufeature and hwprobe

 Documentation/arch/riscv/hwprobe.rst               |  46 +++++-
 arch/riscv/include/asm/cpufeature.h                |  14 ++
 arch/riscv/include/asm/hwcap.h                     |  23 +--
 arch/riscv/include/asm/processor.h                 |   4 +
 arch/riscv/include/asm/switch_to.h                 |   4 +-
 arch/riscv/include/uapi/asm/hwcap.h                |   1 +
 arch/riscv/include/uapi/asm/hwprobe.h              |   9 +-
 arch/riscv/kernel/cpu.c                            |  26 ++++
 arch/riscv/kernel/cpufeature.c                     | 154 ++++++++++++++++++---
 arch/riscv/kernel/process.c                        |  12 ++
 arch/riscv/kernel/sys_hwprobe.c                    |  33 +++--
 arch/riscv/kvm/isa.c                               |  16 +--
 arch/riscv/kvm/main.c                              |   2 +-
 arch/riscv/kvm/vcpu_fp.c                           |  20 +--
 arch/riscv/kvm/vcpu_onereg.c                       |   6 +-
 arch/riscv/kvm/vcpu_vector.c                       |  10 +-
 tools/testing/selftests/riscv/hwprobe/which-cpus.c |   2 +-
 17 files changed, 312 insertions(+), 70 deletions(-)
---
base-commit: 7fd2df204f342fc17d1a0bfcd474b24232fb0f32
change-id: 20260508-rva23u64-hwprobe-v2-1d20739cbb8e

Best regards,
--  
Guodong Xu <guodong at riscstar.com>