[PATCH v7 00/11] riscv: hwprobe: Expose RVA23U64 base behavior

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.

v7 fixes a v6 bug found while testing against glibc: the vDSO copy of
RISCV_HWPROBE_KEY_BASE_BEHAVIOR was 0, see [3].

Series outline (v7):

  Per-extension cpufeature parsing + hwprobe export:
   1.  B (the Zba/Zbb/Zbs set).

  Zic64b (new first-class extension):
   2.  dt-bindings: require a cbom/cbop/cboz block-size property whenever
       the matching Zicbom/Zicbop/Zicboz is present.
   3.  Zic64b dt-binding, with a schema check.
   4.  Zic64b cpufeature parsing + hwprobe export.
   5-7. dts: declare zic64b in the SpacemiT K3, SpacemiT K1, and Sophgo
        SG2044 device trees.

  RVA23U64 base detection and exposure:
   8.  riscv_have_user_pmlen(): accessor for user pointer-masking PMLEN
       support.
   9.  cpufeature: per-hart and host-wide isa_bases bitmaps; IMA and
       RVA23U64 detection lives here.
  10.  /proc/cpuinfo: print "isa bases:" and "hart isa bases:", e.g.
       rva23u64.
  11.  hwprobe: expose RVA23U64.

A follow-up series exposing these extensions to KVM guests (extending
the KVM ISA extension ONE_REG interface) will be prepared on top of
this one and will be posted separately.

Cc'ing the hwprobe, glibc and Debian side (Andy, Florian, Peter, Zihong,
Mark, Aurelien): the RVA23U64 base behavior bit is what a glibc-hwcaps
"rva23u64" subdirectory would key on. Comments welcome.

Tested on QEMU with '-cpu rva23s64,sv39=on':
1) /proc/cpuinfo reports
     "isa bases : rv64ima rva23u64"
   on both the aggregated and per-hart lines.
2) hwprobe RISCV_HWPROBE_KEY_BASE_BEHAVIOR returns
     BASE_BEHAVIOR_IMA | BASE_BEHAVIOR_RVA23U64
   through both the vDSO and the raw syscall (v6 returned 0 through the
   vDSO, see [3]).
3) With '-cpu rva22s64', /proc/cpuinfo reports "isa bases : rv64ima"
   and both hwprobe paths return BASE_BEHAVIOR_IMA only, as expected.

A branch is available for all patches in the series: [2].

Link: https://lore.kernel.org/linux-riscv/20260206002349.96740-1-andrew.jones@oss.qualcomm.com/ (local) [1]
Link: https://github.com/docularxu/linux/commits/b4/rva23u64-hwprobe-v7/ [2]
Link: https://lore.kernel.org/all/c24e720e279fed0296f1f78630b6a471.guodong.xu@oss.qualcomm.com/ (local) [3]

Changes in v7:
- Patch 09: register riscv_init_isa_bases() at arch_initcall so the vDSO
  hwprobe snapshot (arch_initcall_sync) sees the ISA bases; v6 returned 0
  for RISCV_HWPROBE_KEY_BASE_BEHAVIOR through the vDSO, IMA bit included,
  while the syscall path was correct [3].
- Patch 09: keep riscv_isa_bases static and add riscv_isa_base_available(),
  mirroring the extension accessor; patches 10 and 11 use it.
- Collected Acked-by from Conor Dooley on patches 02 and 03.
- Rebased onto riscv/for-next at 77ae27fd98f3 (post 7.3 merge window);
  no code adaptation needed.
- Link to v6: https://patch.msgid.link/20260812-rva23u64-hwprobe-v2-v6-0-c985af3256b8@oss.qualcomm.com

Changes in v6:
- Rebased onto riscv/for-next; dropped patches 1-6 of v5, which have been
  applied by Paul.
- dt-bindings block-size: only match nodes that have
  riscv,isa-extensions (fix suggested by Conor, breakage reported by
  Rob's bot).
- Zic64b dt-binding: guard the zic64b rule the same way (same defect
  class, found while fixing the above).
- Follow the _BITULL() style of commit 8da45c93dfa9 ("RISC-V: hwprobe:
  Use BIT macro to avoid warnings") for the new hwprobe bits (EXT_B,
  EXT_ZIC64B, BASE_BEHAVIOR_RVA23U64).
- Zic64b: RISCV_ISA_EXT_ZIC64B renumbered 110 to 116 after upstream
  additions took 106-111.
- Link to v5: https://patch.msgid.link/20260701-rva23u64-hwprobe-v2-v5-0-2c61f94a695a@gmail.com

Changes in v5:
- Rebased onto v7.2-rc1.
- New patch: make riscv,cbom/cbop/cboz-block-size required whenever the
  matching Zicbom/Zicbop/Zicboz extension is present (Conor).
- Ziccamoa/Za64rs: drop the Zaamo/Zalrsc validate callbacks (Conor).
- Zic64b dt-binding: fix a double space in the commit message (Conor).
- Collected Reviewed-by and Acked-by tags in v4.
- Link to v4: https://patch.msgid.link/20260611-rva23u64-hwprobe-v2-v4-0-3f01a2449488@gmail.com

Changes in v4:
- New patch: sort the multi-letter Z extensions alphanumerically in the
  dt-binding (Conor), and place zic64b at its sorted position.
- Zic64b cpufeature: validate only the CBO block sizes that are present;
  overlaps Qingwei Hu's earlier patch, so it is now authored by Qingwei.
- Document EXT_ZICFISS / EXT_ZICFILP: cite the riscv-cfi v1.0 tag commit.
- Picked up Inochi Amaoto's Acked-by (SG2044 dts) and Andrew Jones's
  Reviewed-by (documentation patch).
- Link to v3: https://patch.msgid.link/20260603-rva23u64-hwprobe-v2-v3-0-5529a7b28384@gmail.com

Changes in v3:
- Add Zic64b as a first-class ISA extension: dt-binding, cpufeature
  parsing with a validate check, hwprobe export, and device-tree
  declarations for K3/K1/SG2044.
- Patch 1 is now a clean up of hwprobe.rst indentation.
- Document RISCV_HWPROBE_EXT_ZICFILP alongside ZICFISS.
- Move the Zicclsm hwprobe.rst entry to the IMA_EXT_1 section to match
  its bit allocation.
- Collect Anup Patel's Acked-by/Reviewed-by on Patch 3, the capitalization.
- In cpufeature.c, set the local ext_mask with __set_bit().
- Update Guodong Xu's email to docular.xu@gmail.com.
- Link to v2: https://patch.msgid.link/20260511-rva23u64-hwprobe-v2-v2-0-21c5a544f1dc@riscstar.com

Changes in v2 (since Andrew's RFC v1):
- Rebased onto v7.1-rc2.
- Reworked rva23u64 detection into per-hart and host isa_bases bitmaps,
  shared by /proc/cpuinfo and hwprobe.
- Scoped to IMA and RVA23U64 (RVA23S64, RVA20/RVA22 cpuinfo output deferred).
- Link to v1:  https://lore.kernel.org/linux-riscv/20260206002349.96740-1-andrew.jones@oss.qualcomm.com (local)

Signed-off-by: Guodong Xu <redacted>
---
Andrew Jones (2):
      riscv: Add B to hwcap and hwprobe
      riscv: Add a getter for user PMLEN support

Guodong Xu (8):
      dt-bindings: riscv: Require block-size for Zicbom, Zicbop, and Zicboz
      dt-bindings: riscv: Add Zic64b extension description
      riscv: dts: spacemit: k3: Add Zic64b ISA extension
      riscv: dts: spacemit: k1: Add Zic64b ISA extension
      riscv: dts: sophgo: sg2044: Add Zic64b ISA extension
      riscv: cpufeature: Introduce ISA bases bitmap and rva23u64 detection
      riscv: cpu: Output isa bases lines in cpuinfo
      riscv: hwprobe: Introduce rva23u64 base behavior

Qingwei Hu (1):
      riscv: Add Zic64b to cpufeature and hwprobe

 Documentation/arch/riscv/hwprobe.rst               |  16 +++
 .../devicetree/bindings/riscv/extensions.yaml      |  54 ++++++++
 arch/riscv/boot/dts/sophgo/sg2044-cpus.dtsi        | 128 +++++++++----------
 arch/riscv/boot/dts/spacemit/k1.dtsi               |  80 ++++++------
 arch/riscv/boot/dts/spacemit/k3.dtsi               |  48 +++----
 arch/riscv/include/asm/cpufeature.h                |  13 ++
 arch/riscv/include/asm/hwcap.h                     |   2 +
 arch/riscv/include/asm/processor.h                 |   4 +
 arch/riscv/include/uapi/asm/hwcap.h                |   1 +
 arch/riscv/include/uapi/asm/hwprobe.h              |   5 +-
 arch/riscv/kernel/cpu.c                            |  26 ++++
 arch/riscv/kernel/cpufeature.c                     | 140 +++++++++++++++++++++
 arch/riscv/kernel/process.c                        |  12 ++
 arch/riscv/kernel/sys_hwprobe.c                    |  25 ++--
 tools/testing/selftests/riscv/hwprobe/which-cpus.c |   2 +-
 15 files changed, 419 insertions(+), 137 deletions(-)
---
base-commit: 77ae27fd98f3b548797c9f22c10ab5cf1c4ada53
change-id: 20260508-rva23u64-hwprobe-v2-1d20739cbb8e

Best regards,
--  
Guodong Xu [off-list ref]