On 23/05/2025 20:30, Charlie Jenkins wrote:
On Fri, May 23, 2025 at 12:19:26PM +0200, Clément Léger wrote:
Split the code that check for the uniformity of misaligned accesses performance on all cpus from check_unaligned_access_emulated_all_cpus() to its own function which will be used for delegation check. No functional changes intended.
Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com
arch/riscv/kernel/traps_misaligned.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c index f1b2af515592..7ecaa8103fe7 100644 --- a/arch/riscv/kernel/traps_misaligned.c +++ b/arch/riscv/kernel/traps_misaligned.c @@ -645,6 +645,18 @@ bool __init check_vector_unaligned_access_emulated_all_cpus(void) } #endif +static bool all_cpus_unaligned_scalar_access_emulated(void) +{
- int cpu;
- for_each_online_cpu(cpu)
if (per_cpu(misaligned_access_speed, cpu) !=RISCV_HWPROBE_MISALIGNED_SCALAR_EMULATED)return false;- return true;
+}
This ends up wasting time when !CONFIG_RISCV_SCALAR_MISALIGNED since it will always return false in that case. Maybe there is a way to simplify the ifdefs and still have performant code, but I don't think this is a big enough problem to prevent this patch from merging.
Yeah I though of that as well but the amount of call to this function is probably well below 10 times so I guess it does not really matters in that case to justify yet another ifdef ?
Reviewed-by: Charlie Jenkins charlie@rivosinc.com Tested-by: Charlie Jenkins charlie@rivosinc.com
Thanks,
Clément
#ifdef CONFIG_RISCV_SCALAR_MISALIGNED static bool unaligned_ctl __read_mostly; @@ -683,8 +695,6 @@ static int cpu_online_check_unaligned_access_emulated(unsigned int cpu) bool __init check_unaligned_access_emulated_all_cpus(void) {
- int cpu;
- /*
- We can only support PR_UNALIGN controls if all CPUs have misaligned
- accesses emulated since tasks requesting such control can run on any
@@ -692,10 +702,8 @@ bool __init check_unaligned_access_emulated_all_cpus(void) */ on_each_cpu(check_unaligned_access_emulated, NULL, 1);
- for_each_online_cpu(cpu)
if (per_cpu(misaligned_access_speed, cpu)!= RISCV_HWPROBE_MISALIGNED_SCALAR_EMULATED)return false;
- if (!all_cpus_unaligned_scalar_access_emulated())
return false;unaligned_ctl = true; return true; -- 2.49.0