perf: arm: enable pmuserenr [1/1]

PD#SWPL-4673

Problem:
userspace can't access perf monitor cnt with "mrc ... c9,c13,0"

Solution:
actually userspace should check perf monitor cnt access permissions first
before use, so this is a workround.
enable pmuserenr with "mcr ... c9,c14,0" in several places:
1, perf probe
2, cpu idle (state>0) exit
3, cpu online
4, system resume after suspend

Verify:
u212

Change-Id: Ib09682d1d47545dfef8b088283ddbbf390630d3e
Signed-off-by: Hanjie Lin <hanjie.lin@amlogic.com>

arch/arm/include/asm/perf_event.h

@@ -29,4 +29,9 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs);
 	(regs)->ARM_sp = current_stack_pointer; \
 	(regs)->ARM_cpsr = SVC_MODE; \
 }
+
+#ifdef CONFIG_AMLOGIC_MODIFY
+void enable_pmuserenr(void);
+#endif
+
 #endif /* __ARM_PERF_EVENT_H__ */

arch/arm/kernel/cpuidle.c

@@ -13,6 +13,9 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <asm/cpuidle.h>
+#ifdef CONFIG_AMLOGIC_MODIFY
+#include <asm/perf_event.h>
+#endif
 
 extern struct of_cpuidle_method __cpuidle_method_of_table[];
 
@@ -51,9 +54,22 @@ int arm_cpuidle_simple_enter(struct cpuidle_device *dev,
  */
 int arm_cpuidle_suspend(int index)
 {
+#ifdef CONFIG_AMLOGIC_MODIFY
+	int ret;
+	int cpu = smp_processor_id();
+
+	ret = cpuidle_ops[cpu].suspend(index);
+
+	if (index > 0) {
+		pr_debug("arm_cpuidle_suspend(%d) exit\n", index);
+		enable_pmuserenr();
+	}
+	return ret;
+#else
 	int cpu = smp_processor_id();
 
 	return cpuidle_ops[cpu].suspend(index);
+#endif
 }
 
 /**
@@ -135,7 +151,7 @@ static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu)
  *  this cpu,
  *  -ENOENT if it fails to find an 'enable-method' property,
  *  -ENXIO if the HW reports a failure or a misconfiguration,
- *  -ENOMEM if the HW report an memory allocation failure 
+ *  -ENOMEM if the HW report an memory allocation failure
  */
 int __init arm_cpuidle_init(int cpu)
 {

arch/arm/kernel/perf_event_v7.c

@@ -28,6 +28,10 @@
 #include <linux/perf/arm_pmu.h>
 #include <linux/platform_device.h>
 
+#ifdef CONFIG_AMLOGIC_MODIFY
+#include <asm/perf_event.h>
+#endif
+
 /*
  * Common ARMv7 event types
  *
@@ -2038,8 +2042,86 @@ static const struct pmu_probe_info armv7_pmu_probe_table[] = {
 	{ /* sentinel value */ }
 };
 
+#ifdef CONFIG_AMLOGIC_MODIFY
+#if 0
+static int read_pmuserenr(void)
+{
+	int val = -1;
+
+	asm volatile("mrc p15, 0, %0, c9, c14, 0" : "=r" (val):: "memory");
+	return val;
+}
+#endif
+
+void enable_pmuserenr(void)
+{
+	//pr_emerg("enable_pmuserenr() start, val = %d\n", read_pmuserenr());
+	asm volatile("mcr p15, 0, %0, c9, c14, 0" : : "r" (1) : "memory");
+	//pr_emerg("enable_pmuserenr() end, val = %d\n", read_pmuserenr());
+}
+
+static void enable_pmuserenr_single(void *info)
+{
+	enable_pmuserenr();
+}
+
+static void enable_pmuserenr_all(void)
+{
+	pr_info("enable_pmuserenr_all() start\n");
+
+	enable_pmuserenr_single(NULL);
+	smp_call_function_many(cpu_possible_mask,
+				enable_pmuserenr_single,
+				NULL,
+				1);
+
+	pr_info("enable_pmuserenr_all() end\n");
+}
+
+static int pmu_user_callback(struct notifier_block *nfb,
+			     unsigned long action,
+			     void *hcpu)
+{
+	switch (action) {
+	case CPU_ONLINE:
+	case CPU_ONLINE_FROZEN:
+		pr_debug("cpu online callback\n");
+		enable_pmuserenr();
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block pmu_user_notify = {
+	&pmu_user_callback,
+	NULL,
+	0
+};
+
+static int armv7_pmu_resume(struct platform_device *pdev)
+{
+	pr_debug("armv7_pmu_resume()\n");
+	enable_pmuserenr();
+	return 0;
+}
+
+static int armv7_pmu_suspend(struct platform_device *pdev,
+	pm_message_t state)
+{
+	pr_debug("armv7_pmu_suspend()\n");
+	return 0;
+}
+#endif
+
 static int armv7_pmu_device_probe(struct platform_device *pdev)
 {
+#ifdef CONFIG_AMLOGIC_MODIFY
+		enable_pmuserenr_all();
+		__register_cpu_notifier(&pmu_user_notify);
+#endif
+
 	return arm_pmu_device_probe(pdev, armv7_pmu_of_device_ids,
 				    armv7_pmu_probe_table);
 }
@@ -2050,6 +2132,10 @@ static struct platform_driver armv7_pmu_driver = {
 		.of_match_table = armv7_pmu_of_device_ids,
 	},
 	.probe		= armv7_pmu_device_probe,
+#ifdef CONFIG_AMLOGIC_MODIFY
+	.suspend	= armv7_pmu_suspend,
+	.resume		= armv7_pmu_resume,
+#endif
 };
 
 static int __init register_armv7_pmu_driver(void)