From 7a635df5ef26e7aaf3232bf454ebdce873433b3e Mon Sep 17 00:00:00 2001 From: Danil Skrebenkov Date: Fri, 19 Sep 2025 16:28:46 +0300 Subject: [PATCH] RISC-V: clear hot-unplugged cores from all task mm_cpumasks to avoid rfence errors [ Upstream commit ae9e9f3d67dcef7582a4524047b01e33c5185ddb ] 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 Reviewed-by: Andrew Jones 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 Signed-off-by: Sasha Levin --- arch/riscv/kernel/cpu-hotplug.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/riscv/kernel/cpu-hotplug.c b/arch/riscv/kernel/cpu-hotplug.c index 6b710ef9d9ae..2114903ee3ad 100644 --- a/arch/riscv/kernel/cpu-hotplug.c +++ b/arch/riscv/kernel/cpu-hotplug.c @@ -61,6 +61,7 @@ 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]->cpu_is_stopped) ret = cpu_ops[cpu]->cpu_is_stopped(cpu);