x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation

[linux-block.git] / kernel / cpu.c

diff --git a/kernel/cpu.c b/kernel/cpu.c
index aa7fe85ad62e86de2060d2b89e525b93506cbf0d..2fb49916ea560735d7f51f8a7610892303ec243a 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2025,6 +2025,12 @@ static void cpuhp_online_cpu_device(unsigned int cpu)
        kobject_uevent(&dev->kobj, KOBJ_ONLINE);
 }
 
+/*
+ * Architectures that need SMT-specific errata handling during SMT hotplug
+ * should override this.
+ */
+void __weak arch_smt_update(void) { };
+
 static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
 {
        int cpu, ret = 0;
@@ -2051,8 +2057,10 @@ static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
                 */
                cpuhp_offline_cpu_device(cpu);
        }
-       if (!ret)
+       if (!ret) {
                cpu_smt_control = ctrlval;
+               arch_smt_update();
+       }
        cpu_maps_update_done();
        return ret;
 }
@@ -2063,6 +2071,7 @@ static int cpuhp_smt_enable(void)
 
        cpu_maps_update_begin();
        cpu_smt_control = CPU_SMT_ENABLED;
+       arch_smt_update();
        for_each_present_cpu(cpu) {
                /* Skip online CPUs and CPUs on offline nodes */
                if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))