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--- b/kernel/cpu.c
+++ a/kernel/cpu.c
@@ -54,7 +54,6 @@
bool rollback;
bool single;
bool bringup;
- bool booted_once;
struct hlist_node *node;
enum cpuhp_state cb_state;
int result;
@@ -356,40 +355,6 @@
EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
#endif /* CONFIG_HOTPLUG_CPU */
-#ifdef CONFIG_HOTPLUG_SMT
-enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED;
-
-static int __init smt_cmdline_disable(char *str)
-{
- cpu_smt_control = CPU_SMT_DISABLED;
- if (str && !strcmp(str, "force")) {
- pr_info("SMT: Force disabled\n");
- cpu_smt_control = CPU_SMT_FORCE_DISABLED;
- }
- return 0;
-}
-early_param("nosmt", smt_cmdline_disable);
-
-static inline bool cpu_smt_allowed(unsigned int cpu)
-{
- if (cpu_smt_control == CPU_SMT_ENABLED)
- return true;
-
- if (topology_is_primary_thread(cpu))
- return true;
-
- /*
- * On x86 it's required to boot all logical CPUs at least once so
- * that the init code can get a chance to set CR4.MCE on each
- * CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any
- * core will shutdown the machine.
- */
- return !per_cpu(cpuhp_state, cpu).booted_once;
-}
-#else
-static inline bool cpu_smt_allowed(unsigned int cpu) { return true; }
-#endif
-
/* Need to know about CPUs going up/down? */
int register_cpu_notifier(struct notifier_block *nb)
{
@@ -466,16 +431,6 @@
stop_machine_unpark(cpu);
kthread_unpark(st->thread);
- /*
- * SMT soft disabling on X86 requires to bring the CPU out of the
- * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The
- * CPU marked itself as booted_once in cpu_notify_starting() so the
- * cpu_smt_allowed() check will now return false if this is not the
- * primary sibling.
- */
- if (!cpu_smt_allowed(cpu))
- return -ECANCELED;
-
/* Should we go further up ? */
if (st->target > CPUHP_AP_ONLINE_IDLE) {
__cpuhp_kick_ap_work(st);
@@ -1023,6 +978,29 @@
EXPORT_SYMBOL(cpu_down);
#endif /*CONFIG_HOTPLUG_CPU*/
+#ifdef CONFIG_HOTPLUG_SMT
+enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED;
+
+static int __init smt_cmdline_disable(char *str)
+{
+ cpu_smt_control = CPU_SMT_DISABLED;
+ if (str && !strcmp(str, "force")) {
+ pr_info("SMT: Force disabled\n");
+ cpu_smt_control = CPU_SMT_FORCE_DISABLED;
+ }
+ return 0;
+}
+early_param("nosmt", smt_cmdline_disable);
+
+static inline bool cpu_smt_allowed(unsigned int cpu)
+{
+ return cpu_smt_control == CPU_SMT_ENABLED ||
+ topology_is_primary_thread(cpu);
+}
+#else
+static inline bool cpu_smt_allowed(unsigned int cpu) { return true; }
+#endif
+
/**
* notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU
* @cpu: cpu that just started
@@ -1036,7 +1014,6 @@
enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE);
rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */
- st->booted_once = true;
while (st->state < target) {
st->state++;
cpuhp_invoke_callback(cpu, st->state, true, NULL);
@@ -2137,6 +2114,5 @@
*/
void __init boot_cpu_hotplug_init(void)
{
+ per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE;
- this_cpu_write(cpuhp_state.booted_once, true);
- this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
}
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