| From: |
| Charlie Jenkins <charlie-AT-rivosinc.com> |
| To: |
| Paul Walmsley <paul.walmsley-AT-sifive.com>, Palmer Dabbelt <palmer-AT-dabbelt.com>, Albert Ou <aou-AT-eecs.berkeley.edu>, Jisheng Zhang <jszhang-AT-kernel.org>, Evan Green <evan-AT-rivosinc.com>, Clément Léger <cleger-AT-rivosinc.com>, Eric Biggers <ebiggers-AT-kernel.org>, Elliot Berman <quic_eberman-AT-quicinc.com>, Charles Lohr <lohr85-AT-gmail.com>, Conor Dooley <conor.dooley-AT-microchip.com> |
| Subject: |
| [PATCH v7 0/4] riscv: Use Kconfig to set unaligned access speed |
| Date: |
| Wed, 06 Mar 2024 12:00:00 -0800 |
| Message-ID: |
| <20240306-disable_misaligned_probe_config-v7-0-6c90419e7a96@rivosinc.com> |
| Cc: |
| linux-riscv-AT-lists.infradead.org, linux-kernel-AT-vger.kernel.org, Charlie Jenkins <charlie-AT-rivosinc.com> |
| Archive-link: |
| Article |
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@rivosinc.com>
---
Changes in v7:
- Fix check_unaligned_access_emulated_all_cpus to return false when any
cpu has emulated accesses
- Fix wording in Kconfig (Conor)
- Link to v6: https://lore.kernel.org/r/20240301-disable_misaligned_pro...
Changes in v6:
- Consolidate Kconfig into 4 options (probe, emulated, slow,
efficient)
- Change the behavior of "emulated" to allow hwprobe to return "slow" if
unaligned accesses are not emulated by the kernel
- With this consolidation, check_unaligned_access_emulated is able to be
moved back into the original file (traps_misaligned.c)
- Link to v5: https://lore.kernel.org/r/20240227-disable_misaligned_pro...
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_pro...
Changes in v4:
- Add additional Kconfig options for the other unaligned access speeds
- Link to v3: https://lore.kernel.org/r/20240202-disable_misaligned_pro...
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_pro...
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_pro...
---
Charlie Jenkins (4):
riscv: lib: Introduce has_fast_unaligned_access function
riscv: Only check online cpus for emulated accesses
riscv: Decouple emulated unaligned accesses from access speed
riscv: Set unaligned access speed at compile time
arch/riscv/Kconfig | 60 ++++--
arch/riscv/include/asm/cpufeature.h | 31 ++--
arch/riscv/kernel/Makefile | 4 +-
arch/riscv/kernel/cpufeature.c | 255 --------------------------
arch/riscv/kernel/sys_hwprobe.c | 15 ++
arch/riscv/kernel/traps_misaligned.c | 17 +-
arch/riscv/kernel/unaligned_access_speed.c | 282 +++++++++++++++++++++++++++++
arch/riscv/lib/csum.c | 7 +-
8 files changed, 378 insertions(+), 293 deletions(-)
---
base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d
change-id: 20240131-disable_misaligned_probe_config-043aea375f93
--
- Charlie
