1 files changed, 113 insertions, 74 deletions

diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index 9f001d904599..b28d2f1253bb 100644
--- a/arch/x86/oprofile/nmi_int.c
+++ b/arch/x86/oprofile/nmi_int.c
@@ -31,8 +31,9 @@ static struct op_x86_model_spec *model;
 static DEFINE_PER_CPU(struct op_msrs, cpu_msrs);
 static DEFINE_PER_CPU(unsigned long, saved_lvtpc);
 
-/* 0 == registered but off, 1 == registered and on */
-static int nmi_enabled = 0;
+/* must be protected with get_online_cpus()/put_online_cpus(): */
+static int nmi_enabled;
+static int ctr_running;
 
 struct op_counter_config counter_config[OP_MAX_COUNTER];
 
@@ -61,12 +62,16 @@ static int profile_exceptions_notify(struct notifier_block *self,
 {
         struct die_args *args = (struct die_args *)data;
         int ret = NOTIFY_DONE;
-        int cpu = smp_processor_id();
 
         switch (val) {
         case DIE_NMI:
         case DIE_NMI_IPI:
-                model->check_ctrs(args->regs, &per_cpu(cpu_msrs, cpu));
+                if (ctr_running)
+                        model->check_ctrs(args->regs, &__get_cpu_var(cpu_msrs));
+                else if (!nmi_enabled)
+                        break;
+                else
+                        model->stop(&__get_cpu_var(cpu_msrs));
                 ret = NOTIFY_STOP;
                 break;
         default:
@@ -95,24 +100,36 @@ static void nmi_cpu_save_registers(struct op_msrs *msrs)
 static void nmi_cpu_start(void *dummy)
 {
         struct op_msrs const *msrs = &__get_cpu_var(cpu_msrs);
-        model->start(msrs);
+        if (!msrs->controls)
+                WARN_ON_ONCE(1);
+        else
+                model->start(msrs);
 }
 
 static int nmi_start(void)
 {
+        get_online_cpus();
         on_each_cpu(nmi_cpu_start, NULL, 1);
+        ctr_running = 1;
+        put_online_cpus();
         return 0;
 }
 
 static void nmi_cpu_stop(void *dummy)
 {
         struct op_msrs const *msrs = &__get_cpu_var(cpu_msrs);
-        model->stop(msrs);
+        if (!msrs->controls)
+                WARN_ON_ONCE(1);
+        else
+                model->stop(msrs);
 }
 
 static void nmi_stop(void)
 {
+        get_online_cpus();
         on_each_cpu(nmi_cpu_stop, NULL, 1);
+        ctr_running = 0;
+        put_online_cpus();
 }
 
 #ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
@@ -252,7 +269,10 @@ static int nmi_switch_event(void)
         if (nmi_multiplex_on() < 0)
                 return -EINVAL;         /* not necessary */
 
-        on_each_cpu(nmi_cpu_switch, NULL, 1);
+        get_online_cpus();
+        if (ctr_running)
+                on_each_cpu(nmi_cpu_switch, NULL, 1);
+        put_online_cpus();
 
         return 0;
 }
@@ -344,50 +364,6 @@ static struct notifier_block profile_exceptions_nb = {
         .priority = 2
 };
 
-static int nmi_setup(void)
-{
-        int err = 0;
-        int cpu;
-
-        if (!allocate_msrs())
-                return -ENOMEM;
-
-        /* We need to serialize save and setup for HT because the subset
-         * of msrs are distinct for save and setup operations
-         */
-
-        /* Assume saved/restored counters are the same on all CPUs */
-        err = model->fill_in_addresses(&per_cpu(cpu_msrs, 0));
-        if (err)
-                goto fail;
-
-        for_each_possible_cpu(cpu) {
-                if (!cpu)
-                        continue;
-
-                memcpy(per_cpu(cpu_msrs, cpu).counters,
-                       per_cpu(cpu_msrs, 0).counters,
-                       sizeof(struct op_msr) * model->num_counters);
-
-                memcpy(per_cpu(cpu_msrs, cpu).controls,
-                       per_cpu(cpu_msrs, 0).controls,
-                       sizeof(struct op_msr) * model->num_controls);
-
-                mux_clone(cpu);
-        }
-
-        err = register_die_notifier(&profile_exceptions_nb);
-        if (err)
-                goto fail;
-
-        on_each_cpu(nmi_cpu_setup, NULL, 1);
-        nmi_enabled = 1;
-        return 0;
-fail:
-        free_msrs();
-        return err;
-}
-
 static void nmi_cpu_restore_registers(struct op_msrs *msrs)
 {
         struct op_msr *counters = msrs->counters;
@@ -421,19 +397,24 @@ static void nmi_cpu_shutdown(void *dummy)
         apic_write(APIC_LVTPC, per_cpu(saved_lvtpc, cpu));
         apic_write(APIC_LVTERR, v);
         nmi_cpu_restore_registers(msrs);
+        if (model->cpu_down)
+                model->cpu_down();
 }
 
-static void nmi_shutdown(void)
+static void nmi_cpu_up(void *dummy)
 {
-        struct op_msrs *msrs;
+        if (nmi_enabled)
+                nmi_cpu_setup(dummy);
+        if (ctr_running)
+                nmi_cpu_start(dummy);
+}
 
-        nmi_enabled = 0;
-        on_each_cpu(nmi_cpu_shutdown, NULL, 1);
-        unregister_die_notifier(&profile_exceptions_nb);
-        msrs = &get_cpu_var(cpu_msrs);
-        model->shutdown(msrs);
-        free_msrs();
-        put_cpu_var(cpu_msrs);
+static void nmi_cpu_down(void *dummy)
+{
+        if (ctr_running)
+                nmi_cpu_stop(dummy);
+        if (nmi_enabled)
+                nmi_cpu_shutdown(dummy);
 }
 
 static int nmi_create_files(struct super_block *sb, struct dentry *root)
@@ -465,7 +446,6 @@ static int nmi_create_files(struct super_block *sb, struct dentry *root)
         return 0;
 }
 
-#ifdef CONFIG_SMP
 static int oprofile_cpu_notifier(struct notifier_block *b, unsigned long action,
                                  void *data)
 {
@@ -473,10 +453,10 @@ static int oprofile_cpu_notifier(struct notifier_block *b, unsigned long action,
         switch (action) {
         case CPU_DOWN_FAILED:
         case CPU_ONLINE:
-                smp_call_function_single(cpu, nmi_cpu_start, NULL, 0);
+                smp_call_function_single(cpu, nmi_cpu_up, NULL, 0);
                 break;
         case CPU_DOWN_PREPARE:
-                smp_call_function_single(cpu, nmi_cpu_stop, NULL, 1);
+                smp_call_function_single(cpu, nmi_cpu_down, NULL, 1);
                 break;
         }
         return NOTIFY_DONE;
@@ -485,7 +465,75 @@ static int oprofile_cpu_notifier(struct notifier_block *b, unsigned long action,
 static struct notifier_block oprofile_cpu_nb = {
         .notifier_call = oprofile_cpu_notifier
 };
-#endif
+
+static int nmi_setup(void)
+{
+        int err = 0;
+        int cpu;
+
+        if (!allocate_msrs())
+                return -ENOMEM;
+
+        /* We need to serialize save and setup for HT because the subset
+         * of msrs are distinct for save and setup operations
+         */
+
+        /* Assume saved/restored counters are the same on all CPUs */
+        err = model->fill_in_addresses(&per_cpu(cpu_msrs, 0));
+        if (err)
+                goto fail;
+
+        for_each_possible_cpu(cpu) {
+                if (!cpu)
+                        continue;
+
+                memcpy(per_cpu(cpu_msrs, cpu).counters,
+                       per_cpu(cpu_msrs, 0).counters,
+                       sizeof(struct op_msr) * model->num_counters);
+
+                memcpy(per_cpu(cpu_msrs, cpu).controls,
+                       per_cpu(cpu_msrs, 0).controls,
+                       sizeof(struct op_msr) * model->num_controls);
+
+                mux_clone(cpu);
+        }
+
+        nmi_enabled = 0;
+        ctr_running = 0;
+        barrier();
+        err = register_die_notifier(&profile_exceptions_nb);
+        if (err)
+                goto fail;
+
+        get_online_cpus();
+        register_cpu_notifier(&oprofile_cpu_nb);
+        on_each_cpu(nmi_cpu_setup, NULL, 1);
+        nmi_enabled = 1;
+        put_online_cpus();
+
+        return 0;
+fail:
+        free_msrs();
+        return err;
+}
+
+static void nmi_shutdown(void)
+{
+        struct op_msrs *msrs;
+
+        get_online_cpus();
+        unregister_cpu_notifier(&oprofile_cpu_nb);
+        on_each_cpu(nmi_cpu_shutdown, NULL, 1);
+        nmi_enabled = 0;
+        ctr_running = 0;
+        put_online_cpus();
+        barrier();
+        unregister_die_notifier(&profile_exceptions_nb);
+        msrs = &get_cpu_var(cpu_msrs);
+        model->shutdown(msrs);
+        free_msrs();
+        put_cpu_var(cpu_msrs);
+}
 
 #ifdef CONFIG_PM
 
@@ -695,9 +743,6 @@ int __init op_nmi_init(struct oprofile_operations *ops)
                 return -ENODEV;
         }
 
-#ifdef CONFIG_SMP
-        register_cpu_notifier(&oprofile_cpu_nb);
-#endif
         /* default values, can be overwritten by model */
         ops->create_files       = nmi_create_files;
         ops->setup              = nmi_setup;
@@ -724,12 +769,6 @@ int __init op_nmi_init(struct oprofile_operations *ops)
 
 void op_nmi_exit(void)
 {
-        if (using_nmi) {
+        if (using_nmi)
                 exit_sysfs();
-#ifdef CONFIG_SMP
-                unregister_cpu_notifier(&oprofile_cpu_nb);
-#endif
-        }
-        if (model->exit)
-                model->exit();
 }