[RFC PATCH v2 0/4] riscv: Add hwcaps-subdir support for profiles

[Yao Zihong]

Changes since v1
----------------
- Fixed comment wording issues in header files.
- Corrected a bug in resolver example.
- Minor cleanups (identifiers, commit message clarity).

Hi all,
This series synchronizes the RISC-V hwprobe UAPI header, and adds support
for glibc hwcaps-subdirectories keyed on RISC-V profile levels (starting
with RVA20U64, RVA22U64, and RVA23U64).  It also includes a small test
suite to validate selection of profile-specific optimized objects.

The motivation is to enable distribution maintainers and users to ship
optimized libraries (e.g. memcpy variants) only for the relevant RISC-V
profiles, reducing binary size while still allowing generic fallbacks.
The design follows the x86 hwcaps-subdir mechanism.

Request for comments
--------------------
Feedback on any aspect of the design is welcome. In particular, I would
like confirmation on:
- Whether the profile-based subdirectory scheme aligns with glibc’s
  intended multiarch design and direction.
- Whether the current probing coverage for each profile level is
  sufficient and appropriate.

Yao Zihong (4):
  riscv: Sync hwprobe.h for compatibility
  riscv: Add hwcaps-subdir support for RVA20U64
  riscv: Add hwcaps-subdir support for RVA22U64 and RVA23U64
  riscv: Add test for hwcaps-subdir

 elf/Makefile                                  |   2 +-
 elf/tst-glibc-hwcaps-cache.script             |  10 +
 sysdeps/riscv/Makefile                        |  39 ++++
 sysdeps/riscv/get-profile-level.h             |  82 +++++++
 sysdeps/riscv/multiarch/memcpy-generic.c      |   5 +
 sysdeps/riscv/multiarch/memcpy_noalignment.S  |   5 +
 sysdeps/riscv/multiarch/memcpy_vector.S       |  54 +++++
 sysdeps/riscv/profile-ifunc-macros.h          |  69 ++++++
 sysdeps/riscv/profile-level.h                 | 121 ++++++++++
 sysdeps/riscv/rv64/dl-hwcaps-subdirs.c        |  48 ++++
 sysdeps/riscv/tst-glibc-hwcaps.c              |  64 ++++++
 .../unix/sysv/linux/riscv/multiarch/Makefile  |   1 +
 .../linux/riscv/multiarch/ifunc-impl-list.c   |  19 +-
 .../unix/sysv/linux/riscv/multiarch/memcpy.c  |  18 +-
 sysdeps/unix/sysv/linux/riscv/sys/hwprobe.h   | 212 ++++++++++++++++++
 15 files changed, 741 insertions(+), 8 deletions(-)
 create mode 100644 sysdeps/riscv/get-profile-level.h
 create mode 100644 sysdeps/riscv/multiarch/memcpy_vector.S
 create mode 100644 sysdeps/riscv/profile-ifunc-macros.h
 create mode 100644 sysdeps/riscv/profile-level.h
 create mode 100644 sysdeps/riscv/rv64/dl-hwcaps-subdirs.c
 create mode 100644 sysdeps/riscv/tst-glibc-hwcaps.c

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2.47.2