coresight-etm3x: Support context-ID tracing when PID namespace is enabled

The Coresight ETM drivers already support context-ID tracing, but it won't
work when PID namespace is enabled. This is because when using PID
namespace a process id (ie. VPID) seen from the current namespace differs
from the id (ie. PID) seen by kernel.

So when users write the process id seen by themselves to ETM, there needs
to be a translation from VPID to PID, as such ETM drivers will write the
PID into the Context ID register correctly.

Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h
index 52af5f0adbed2ca8bae5ae063d2d072c45f9c6d0..b4481eb29304a1ddf4a2b5a86d9244daa3c05f14 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm.h
+++ b/drivers/hwtracing/coresight/coresight-etm.h
@@ -184,6 +184,8 @@
  * @seq_curr_state: current value of the sequencer register.
  * @ctxid_idx: index for the context ID registers.
  * @ctxid_pid: value for the context ID to trigger on.
+ * @ctxid_vpid:        Virtual PID seen by users if PID namespace is enabled, otherwise
+ *             the same value of ctxid_pid.
  * @ctxid_mask: mask applicable to all the context IDs.
  * @sync_freq: Synchronisation frequency.
  * @timestamp_event: Defines an event that requests the insertion
@@ -236,6 +238,7 @@ struct etm_drvdata {
        u32                             seq_curr_state;
        u8                              ctxid_idx;
        u32                             ctxid_pid[ETM_MAX_CTXID_CMP];
+       u32                             ctxid_vpid[ETM_MAX_CTXID_CMP];
        u32                             ctxid_mask;
        u32                             sync_freq;
        u32                             timestamp_event;

diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index 361b82068dda9b979cdfa9ec41b8ae19b64c1507..bf2476ed9356a7a2ec0b31a4a36e08a427aa121e 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -237,8 +237,11 @@ static void etm_set_default(struct etm_drvdata *drvdata)
 
        drvdata->seq_curr_state = 0x0;
        drvdata->ctxid_idx = 0x0;
-       for (i = 0; i < drvdata->nr_ctxid_cmp; i++)
+       for (i = 0; i < drvdata->nr_ctxid_cmp; i++) {
                drvdata->ctxid_pid[i] = 0x0;
+               drvdata->ctxid_vpid[i] = 0x0;
+       }
+
        drvdata->ctxid_mask = 0x0;
 }
 
@@ -1393,7 +1396,7 @@ static ssize_t ctxid_pid_show(struct device *dev,
        struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
        spin_lock(&drvdata->spinlock);
-       val = drvdata->ctxid_pid[drvdata->ctxid_idx];
+       val = drvdata->ctxid_vpid[drvdata->ctxid_idx];
        spin_unlock(&drvdata->spinlock);
 
        return sprintf(buf, "%#lx\n", val);
@@ -1404,15 +1407,18 @@ static ssize_t ctxid_pid_store(struct device *dev,
                               const char *buf, size_t size)
 {
        int ret;
-       unsigned long val;
+       unsigned long vpid, pid;
        struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
-       ret = kstrtoul(buf, 16, &val);
+       ret = kstrtoul(buf, 16, &vpid);
        if (ret)
                return ret;
 
+       pid = coresight_vpid_to_pid(vpid);
+
        spin_lock(&drvdata->spinlock);
-       drvdata->ctxid_pid[drvdata->ctxid_idx] = val;
+       drvdata->ctxid_pid[drvdata->ctxid_idx] = pid;
+       drvdata->ctxid_vpid[drvdata->ctxid_idx] = vpid;
        spin_unlock(&drvdata->spinlock);
 
        return size;