[PATCH v5 0/2] riscv: Use Kconfig to set unaligned access speed

[Charlie Jenkins]

If the hardware unaligned access speed is known at compile time, it is
possible to avoid running the unaligned access speed probe to speedup
boot-time.

Signed-off-by: Charlie Jenkins <charlie at rivosinc.com>
---
Changes in v5:
- Clarify Kconfig options from Conor's feedback
- Use "unaligned" instead of "misaligned" in introduced file/function.
  This is a bit hard to standardize because the riscv manual says
  "misaligned" but the existing Linux configs say "unaligned".
- Link to v4: https://lore.kernel.org/r/20240216-disable_misaligned_probe_config-v4-0-dc01e581c0ac@rivosinc.com

Changes in v4:
- Add additional Kconfig options for the other unaligned access speeds
- Link to v3: https://lore.kernel.org/r/20240202-disable_misaligned_probe_config-v3-0-c44f91f03bb6@rivosinc.com

Changes in v3:
- Revert change to csum (Eric)
- Change ifndefs for ifdefs (Eric)
- Change config in Makefile (Elliot/Eric)
- Link to v2: https://lore.kernel.org/r/20240201-disable_misaligned_probe_config-v2-0-77c368bed7b2@rivosinc.com

Changes in v2:
- Move around definitions to reduce ifdefs (Clément)
- Make RISCV_MISALIGNED depend on !HAVE_EFFICIENT_UNALIGNED_ACCESS
  (Clément)
- Link to v1: https://lore.kernel.org/r/20240131-disable_misaligned_probe_config-v1-0-98d155e9cda8@rivosinc.com

---
Charlie Jenkins (2):
      riscv: lib: Introduce has_fast_unaligned_access function
      riscv: Set unaligned access speed at compile time

 arch/riscv/Kconfig                        |  47 +++++-
 arch/riscv/include/asm/cpufeature.h       |  43 ++++-
 arch/riscv/kernel/Makefile                |   6 +-
 arch/riscv/kernel/cpufeature.c            | 255 ------------------------------
 arch/riscv/kernel/probe_emulated_access.c |  64 ++++++++
 arch/riscv/kernel/sys_hwprobe.c           |  23 +++
 arch/riscv/kernel/traps_misaligned.c      |  54 +------
 arch/riscv/lib/csum.c                     |   7 +-
 8 files changed, 173 insertions(+), 326 deletions(-)
---
base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d
change-id: 20240131-disable_misaligned_probe_config-043aea375f93
-- 
- Charlie