[PATCH v2 0/6] RISC-V: Detect and report speed of unaligned vector accesses

Jesse Taube
2024-06-13T19:16:35Z

Adds support for detecting and reporting the speed of unaligned vector
accesses on RISC-V CPUs. Adds vec_misaligned_speed key to the hwprobe
adds Zicclsm to cpufeature and fixes the check for scalar unaligned
emulated all CPUs. The vec_misaligned_speed key keeps the same format
as the scalar unaligned access speed key.

This set does not emulate unaligned vector accesses on CPUs that do not
support them. Only reports if userspace can run them and speed of
unaligned vector accesses if supported.

If Zicclsm is present, the kernel will set both scalar and vector unaligned access speed to FAST.

This patch requires the following patche to be applied first:
RISC-V: fix vector insn load/store width mask
https://lore.kernel.org/all/20240606182800.415831-1-jesse@rivosinc.com/

Jesse Taube (6):
RISC-V: Add Zicclsm to cpufeature and hwprobe
dt-bindings: riscv: Add Zicclsm ISA extension description.
RISC-V: Check scalar unaligned access on all CPUs
RISC-V: Detect unaligned vector accesses supported.
RISC-V: Report vector unaligned access speed hwprobe
RISC-V: hwprobe: Document unaligned vector perf key

Documentation/arch/riscv/hwprobe.rst | 19 +++
.../devicetree/bindings/riscv/extensions.yaml | 7 +
arch/riscv/Kconfig | 59 +++++++
arch/riscv/include/asm/cpufeature.h | 7 +-
arch/riscv/include/asm/entry-common.h | 11 --
arch/riscv/include/asm/hwcap.h | 1 +
arch/riscv/include/asm/hwprobe.h | 2 +-
arch/riscv/include/asm/vector.h | 1 +
arch/riscv/include/uapi/asm/hwprobe.h | 6 +
arch/riscv/kernel/Makefile | 7 +-
arch/riscv/kernel/copy-unaligned.h | 5 +
arch/riscv/kernel/cpufeature.c | 1 +
arch/riscv/kernel/sys_hwprobe.c | 48 ++++++
arch/riscv/kernel/traps_misaligned.c | 142 +++++++++++++---
arch/riscv/kernel/unaligned_access_speed.c | 154 +++++++++++++++++-
arch/riscv/kernel/vec-copy-unaligned.S | 58 +++++++
arch/riscv/kernel/vector.c | 2 +-
17 files changed, 484 insertions(+), 46 deletions(-)
create mode 100644 arch/riscv/kernel/vec-copy-unaligned.S

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2.43.0