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riscv: don't probe unaligned access speed if already done

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If misaligned_access_speed percpu var isn't so called "HWPROBE
MISALIGNED UNKNOWN", it means the probe has happened(this is possible
for example, hotplug off then hotplug on one cpu), and the percpu var
has been set, don't probe again in this case.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Fixes: 584ea6564b ("RISC-V: Probe for unaligned access speed")
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230912154040.3306-1-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Jisheng Zhang 2023-09-12 23:40:40 +08:00 committed by Palmer Dabbelt
parent 07863871df
commit c20d36cc2a
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1 changed files with 4 additions and 0 deletions
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4
arch/riscv/kernel/cpufeature.c
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@ -572,6 +572,10 @@ void check_unaligned_access(int cpu)
if (check_unaligned_access_emulated(cpu))
return;
/* We are already set since the last check */
if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_UNKNOWN)
return;
page = alloc_pages(GFP_NOWAIT, get_order(MISALIGNED_BUFFER_SIZE));
if (!page) {
pr_warn("Can't alloc pages to measure memcpy performance");