oprofile/x86: return -EBUSY if counters are already reserved

In case a counter is already reserved by the watchdog or perf_event
subsystem, oprofile ignored this counters silently. This case is
handled now and oprofile_setup() now reports an error.

Signed-off-by: Robert Richter <robert.richter@amd.com>

arch/x86/oprofile/nmi_int.c

@@ -357,7 +357,10 @@ static int nmi_setup(void)
 	 */
 
 	/* Assume saved/restored counters are the same on all CPUs */
-	model->fill_in_addresses(&per_cpu(cpu_msrs, 0));
+	err = model->fill_in_addresses(&per_cpu(cpu_msrs, 0));
+	if (err)
+		goto fail;
+
 	for_each_possible_cpu(cpu) {
 		if (!cpu)
 			continue;

arch/x86/oprofile/op_model_amd.c

@@ -138,21 +138,30 @@ static void op_amd_shutdown(struct op_msrs const * const msrs)
 	}
 }
 
-static void op_amd_fill_in_addresses(struct op_msrs * const msrs)
+static int op_amd_fill_in_addresses(struct op_msrs * const msrs)
 {
 	int i;
 
 	for (i = 0; i < NUM_COUNTERS; i++) {
 		if (!reserve_perfctr_nmi(MSR_K7_PERFCTR0 + i))
-			continue;
+			goto fail;
 		if (!reserve_evntsel_nmi(MSR_K7_EVNTSEL0 + i)) {
 			release_perfctr_nmi(MSR_K7_PERFCTR0 + i);
-			continue;
+			goto fail;
 		}
 		/* both registers must be reserved */
 		msrs->counters[i].addr = MSR_K7_PERFCTR0 + i;
 		msrs->controls[i].addr = MSR_K7_EVNTSEL0 + i;
+		continue;
+	fail:
+		if (!counter_config[i].enabled)
+			continue;
+		op_x86_warn_reserved(i);
+		op_amd_shutdown(msrs);
+		return -EBUSY;
 	}
+
+	return 0;
 }
 
 static void op_amd_setup_ctrs(struct op_x86_model_spec const *model,
@@ -172,15 +181,8 @@ static void op_amd_setup_ctrs(struct op_x86_model_spec const *model,
 
 	/* clear all counters */
 	for (i = 0; i < NUM_COUNTERS; ++i) {
-		if (unlikely(!msrs->controls[i].addr)) {
+		if (!msrs->controls[i].addr)
-			if (counter_config[i].enabled && !smp_processor_id())
-				/*
-				 * counter is reserved, this is on all
-				 * cpus, so report only for cpu #0
-				 */
-				op_x86_warn_reserved(i);
 			continue;
-		}
 		rdmsrl(msrs->controls[i].addr, val);
 		if (val & ARCH_PERFMON_EVENTSEL_ENABLE)
 			op_x86_warn_in_use(i);

arch/x86/oprofile/op_model_p4.c

@@ -404,7 +404,7 @@ static void p4_shutdown(struct op_msrs const * const msrs)
 	}
 }
 
-static void p4_fill_in_addresses(struct op_msrs * const msrs)
+static int p4_fill_in_addresses(struct op_msrs * const msrs)
 {
 	unsigned int i;
 	unsigned int addr, cccraddr, stag;
@@ -486,6 +486,18 @@ static void p4_fill_in_addresses(struct op_msrs * const msrs)
 			msrs->controls[i++].addr = MSR_P4_CRU_ESCR5;
 		}
 	}
+
+	for (i = 0; i < num_counters; ++i) {
+		if (!counter_config[i].enabled)
+			continue;
+		if (msrs->controls[i].addr)
+			continue;
+		op_x86_warn_reserved(i);
+		p4_shutdown(msrs);
+		return -EBUSY;
+	}
+
+	return 0;
 }
 
 

arch/x86/oprofile/op_model_ppro.c

@@ -46,21 +46,30 @@ static void ppro_shutdown(struct op_msrs const * const msrs)
 	}
 }
 
-static void ppro_fill_in_addresses(struct op_msrs * const msrs)
+static int ppro_fill_in_addresses(struct op_msrs * const msrs)
 {
 	int i;
 
 	for (i = 0; i < num_counters; i++) {
 		if (!reserve_perfctr_nmi(MSR_P6_PERFCTR0 + i))
-			continue;
+			goto fail;
 		if (!reserve_evntsel_nmi(MSR_P6_EVNTSEL0 + i)) {
 			release_perfctr_nmi(MSR_P6_PERFCTR0 + i);
-			continue;
+			goto fail;
 		}
 		/* both registers must be reserved */
 		msrs->counters[i].addr = MSR_P6_PERFCTR0 + i;
 		msrs->controls[i].addr = MSR_P6_EVNTSEL0 + i;
+		continue;
+	fail:
+		if (!counter_config[i].enabled)
+			continue;
+		op_x86_warn_reserved(i);
+		ppro_shutdown(msrs);
+		return -EBUSY;
 	}
+
+	return 0;
 }
 
 
@@ -96,15 +105,8 @@ static void ppro_setup_ctrs(struct op_x86_model_spec const *model,
 
 	/* clear all counters */
 	for (i = 0; i < num_counters; ++i) {
-		if (unlikely(!msrs->controls[i].addr)) {
+		if (!msrs->controls[i].addr)
-			if (counter_config[i].enabled && !smp_processor_id())
-				/*
-				 * counter is reserved, this is on all
-				 * cpus, so report only for cpu #0
-				 */
-				op_x86_warn_reserved(i);
 			continue;
-		}
 		rdmsrl(msrs->controls[i].addr, val);
 		if (val & ARCH_PERFMON_EVENTSEL_ENABLE)
 			op_x86_warn_in_use(i);

arch/x86/oprofile/op_x86_model.h

@@ -41,7 +41,7 @@ struct op_x86_model_spec {
 	u16		event_mask;
 	int		(*init)(struct oprofile_operations *ops);
 	void		(*exit)(void);
-	void		(*fill_in_addresses)(struct op_msrs * const msrs);
+	int		(*fill_in_addresses)(struct op_msrs * const msrs);
 	void		(*setup_ctrs)(struct op_x86_model_spec const *model,
 				      struct op_msrs const * const msrs);
 	int		(*check_ctrs)(struct pt_regs * const regs,