[PATCH 3/5] Coresight: Add an interface for supporting ETM3/4 Context ID tracing
From: Chunyan Zhang <hidden>
Date: 2015-07-07 08:44:22
Also in:
linux-arm-kernel, lkml
Subsystem:
arm/coresight framework and drivers, the rest · Maintainers:
Suzuki K Poulose, Linus Torvalds
If PID namespace is enabled, everytime users configure the Context ID register to trace the specific process, there needs to be a translation between the real PID seen from the kernel and VPID seen from the namespace in which the user's process resides . This patch just adds the translation interface for ETMs. Signed-off-by: Chunyan Zhang <redacted> --- include/linux/coresight.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 3486b90..626da69 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h@@ -248,4 +248,24 @@ static inline struct coresight_platform_data *of_get_coresight_platform_data( struct device *dev, struct device_node *node) { return NULL; } #endif +#ifdef CONFIG_PID_NS +static inline unsigned long +coresight_vpid_to_pid(unsigned long vpid) +{ + struct task_struct *task = NULL; + unsigned long pid = 0; + + rcu_read_lock(); + task = find_task_by_vpid(vpid); + if (task) + pid = task_pid_nr(task); + rcu_read_unlock(); + + return pid; +} +#else +static inline unsigned long +coresight_vpid_to_pid(unsigned long vpid) { return vpid; } +#endif + #endif
--
1.9.1