misc: tegra-profiler: add start/stop locks

Locks for ability to use loadable module
to override the built-in driver on rooted devices

Bug 1447640

Change-Id: If20605597d77a0cf76206fbe2f474c8853696a9b
Signed-off-by: Igor Nabirushkin <inabirushkin@nvidia.com>
Reviewed-on: http://git-master/r/365854
Reviewed-by: Automatic_Commit_Validation_User
Tested-by: Daniel Horowitz <dhorowitz@nvidia.com>
Reviewed-by: Gabby Lee <galee@nvidia.com>

4 files changed, 35 insertions, 5 deletions

diff --git a/drivers/misc/tegra-profiler/main.c b/drivers/misc/tegra-profiler/main.c
index 7186e3529602..ef692473d76a 100644
--- a/drivers/misc/tegra-profiler/main.c
+++ b/drivers/misc/tegra-profiler/main.c
@@ -54,16 +54,33 @@ static int get_default_properties(void)
 	return 0;
 }
 
+int tegra_profiler_try_lock(void)
+{
+	return atomic_cmpxchg(&ctx.tegra_profiler_lock, 0, 1);
+}
+EXPORT_SYMBOL_GPL(tegra_profiler_try_lock);
+
+void tegra_profiler_unlock(void)
+{
+	atomic_set(&ctx.tegra_profiler_lock, 0);
+}
+EXPORT_SYMBOL_GPL(tegra_profiler_unlock);
+
 static int start(void)
 {
 	int err;
 
+	if (tegra_profiler_try_lock()) {
+		pr_err("Error: tegra_profiler lock\n");
+		return -EBUSY;
+	}
+
 	if (!atomic_cmpxchg(&ctx.started, 0, 1)) {
 		if (ctx.pmu) {
 			err = ctx.pmu->enable();
 			if (err) {
 				pr_err("error: pmu enable\n");
-				return err;
+				goto errout;
 			}
 		}
 
@@ -71,7 +88,7 @@ static int start(void)
 			err = ctx.pl310->enable();
 			if (err) {
 				pr_err("error: pl310 enable\n");
-				return err;
+				goto errout;
 			}
 		}
 
@@ -81,17 +98,22 @@ static int start(void)
 		err = quadd_power_clk_start();
 		if (err < 0) {
 			pr_err("error: power_clk start\n");
-			return err;
+			goto errout;
 		}
 
 		err = quadd_hrt_start();
 		if (err) {
 			pr_err("error: hrt start\n");
-			return err;
+			goto errout;
 		}
 	}
 
 	return 0;
+
+errout:
+	atomic_set(&ctx.started, 0);
+	tegra_profiler_unlock();
+	return err;
 }
 
 static void stop(void)
@@ -109,6 +131,8 @@ static void stop(void)
 
 		if (ctx.pl310)
 			ctx.pl310->disable();
+
+		tegra_profiler_unlock();
 	}
 }
 
@@ -407,7 +431,9 @@ static int __init quadd_module_init(void)
 #ifdef QM_DEBUG_SAMPLES_ENABLE
 	pr_info("############## DEBUG VERSION! ##############\n");
 #endif
+
 	atomic_set(&ctx.started, 0);
+	atomic_set(&ctx.tegra_profiler_lock, 0);
 
 	get_default_properties();
 
diff --git a/drivers/misc/tegra-profiler/quadd.h b/drivers/misc/tegra-profiler/quadd.h
index 3815f616eaec..8e4d591f8cac 100644
--- a/drivers/misc/tegra-profiler/quadd.h
+++ b/drivers/misc/tegra-profiler/quadd.h
@@ -60,6 +60,7 @@ struct quadd_ctx {
 	struct quadd_mmap_ctx *mmap;
 
 	atomic_t started;
+	atomic_t tegra_profiler_lock;
 
 	int collect_kernel_ips;
 };
diff --git a/drivers/misc/tegra-profiler/version.h b/drivers/misc/tegra-profiler/version.h
index b6b9a9c9a57f..090ff1bf3d6f 100644
--- a/drivers/misc/tegra-profiler/version.h
+++ b/drivers/misc/tegra-profiler/version.h
@@ -18,7 +18,7 @@
 #ifndef __QUADD_VERSION_H
 #define __QUADD_VERSION_H
 
-#define QUADD_MODULE_VERSION		"1.41"
+#define QUADD_MODULE_VERSION		"1.42"
 #define QUADD_MODULE_BRANCH		"Dev"
 
 #endif	/* __QUADD_VERSION_H */
diff --git a/include/linux/tegra_profiler.h b/include/linux/tegra_profiler.h
index e3f90a2688c4..277fc93241e4 100644
--- a/include/linux/tegra_profiler.h
+++ b/include/linux/tegra_profiler.h
@@ -37,6 +37,9 @@
 #define QUADD_DEVICE_NAME	"quadd"
 #define QUADD_AUTH_DEVICE_NAME	"quadd_auth"
 
+#define QUADD_MOD_DEVICE_NAME		"quadd_mod"
+#define QUADD_MOD_AUTH_DEVICE_NAME	"quadd_mod_auth"
+
 #define QUADD_IOCTL	100
 
 /*