From: Danil Skrebenkov Date: Fri, 19 Sep 2025 13:28:46 +0000 (+0300) Subject: RISC-V: clear hot-unplugged cores from all task mm_cpumasks to avoid rfence errors X-Git-Tag: v6.18-rc2~17^2~5 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ae9e9f3d67dcef7582a4524047b01e33c5185ddb;p=thirdparty%2Flinux.git RISC-V: clear hot-unplugged cores from all task mm_cpumasks to avoid rfence errors 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 --- diff --git a/arch/riscv/kernel/cpu-hotplug.c b/arch/riscv/kernel/cpu-hotplug.c index a1e38ecfc8be2..3f50d3dd76c6f 100644 --- a/arch/riscv/kernel/cpu-hotplug.c +++ b/arch/riscv/kernel/cpu-hotplug.c @@ -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);