Andrew Jones <ajones@ventanamicro.com> says:
The first six patches of this series are fixes and cleanups of the
unaligned access speed probing code. The next patch introduces a
kernel command line option that allows the probing to be skipped.
This command line option is a different approach than Jesse's [1].
[1] takes a cpu-list for a particular speed, supporting heterogeneous
platforms. With this approach, the kernel command line should only
be used for homogeneous platforms. [1] also only allowed 'fast' and
'slow' to be selected. This parameter also supports 'unsupported',
which could be useful for testing code paths gated on that. The final
patch adds the documentation.
[1] https://lore.kernel.org/linux-riscv/20240805173816.3722002-1-jesse@rivosinc.com/
* patches from https://lore.kernel.org/r/20250304120014.143628-10-ajones@ventanamicro.com:
Documentation/kernel-parameters: Add riscv unaligned speed parameters
riscv: Add parameter for skipping access speed tests
riscv: Fix set up of vector cpu hotplug callback
riscv: Fix set up of cpu hotplug callbacks
riscv: Change check_unaligned_access_speed_all_cpus to void
riscv: Fix check_unaligned_access_all_cpus
riscv: Fix riscv_online_cpu_vec
riscv: Annotate unaligned access init functions
Link: https://lore.kernel.org/r/20250304120014.143628-10-ajones@ventanamicro.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Allow skipping scalar and vector unaligned access speed tests. This
is useful for testing alternative code paths and to skip the tests in
environments where they run too slowly. All CPUs must have the same
unaligned access speed.
The code movement is because we now need the scalar cpu hotplug
callback to always run, so we need to bring it and its supporting
functions out of CONFIG_RISCV_PROBE_UNALIGNED_ACCESS.
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20250304120014.143628-17-ajones@ventanamicro.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
check_vector_unaligned_access_emulated_all_cpus(), like its name
suggests, will return true when all cpus emulate unaligned vector
accesses. If the function returned false it may have been because
vector isn't supported at all (!has_vector()) or because at least
one cpu doesn't emulate unaligned vector accesses. Since false may
be returned for two cases, checking for it isn't sufficient when
attempting to determine if we should proceed with the vector speed
check. Move the !has_vector() functionality to
check_unaligned_access_all_cpus() in order for
check_vector_unaligned_access_emulated_all_cpus() to return false
for a single case.
Fixes: e7c9d66e31 ("RISC-V: Report vector unaligned access speed hwprobe")
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20250304120014.143628-13-ajones@ventanamicro.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
In preparation for misaligned vector performance hwprobe keys, rename
the hwprobe key values associated with misaligned scalar accesses to
include the term SCALAR. Leave the old defines in place to maintain
source compatibility.
This change is intended to be a functional no-op.
Signed-off-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240809214444.3257596-3-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
