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RISC-V: clear hot-unplugged cores from all task mm_cpumasks to avoid rfence errors

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openSBI v1.7 adds harts checks for ipi operations. Especially it
adds comparison between hmask passed as an argument from linux
and mask of online harts (from openSBI side). If they don't
fit each other the error occurs.

When cpu is offline, cpu_online_mask is explicitly cleared in
__cpu_disable. However, there is no explicit clearing of
mm_cpumask. mm_cpumask is used for rfence operations that
call openSBI RFENCE extension which uses ipi to remote harts.
If hart is offline there may be error if mask of linux is not
as mask of online harts in openSBI.

this patch adds explicit clearing of mm_cpumask for offline hart.

Signed-off-by: Danil Skrebenkov <danil.skrebenkov@cloudbear.ru>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20250919132849.31676-1-danil.skrebenkov@cloudbear.ru
[pjw@kernel.org: rewrote subject line for clarity]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
This commit is contained in:
Danil Skrebenkov 2025-09-19 16:28:46 +03:00 • committed by Paul Walmsley
parent 781380d2cd
commit ae9e9f3d67
1 changed files with 1 additions and 0 deletions
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1
arch/riscv/kernel/cpu-hotplug.c
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@ -54,6 +54,7 @@ void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu)
pr_notice("CPU%u: off\n", cpu);
clear_tasks_mm_cpumask(cpu);
/* Verify from the firmware if the cpu is really stopped*/
if (cpu_ops->cpu_is_stopped)
ret = cpu_ops->cpu_is_stopped(cpu);