[PATCH 7/8] coresight: etm4x: implementing user/kernel mode tracing

From: Mathieu Poirier
Date: Mon Feb 29 2016 - 13:55:37 EST


Adding new mode to limit tracing to kernel or user space.

Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
---
.../hwtracing/coresight/coresight-etm4x-sysfs.c | 3 ++
drivers/hwtracing/coresight/coresight-etm4x.c | 35 ++++++++++++++++++++++
drivers/hwtracing/coresight/coresight-etm4x.h | 5 +++-
3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index a996db7ef2fc..0e80ec668402 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -440,6 +440,9 @@ static ssize_t mode_store(struct device *dev,
else
config->vinst_ctrl &= ~BIT(11);

+ if (config->mode & (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER))
+ etm4_config_trace_mode(config);
+
spin_unlock(&drvdata->spinlock);

return size;
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 738acee18967..743c34b92a80 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -567,6 +567,41 @@ static void etm4_set_default(struct etmv4_config *config)
config->vissctlr = 0x0;
}

+void etm4_config_trace_mode(struct etmv4_config *config)
+{
+ u32 addr_acc, mode;
+
+ mode = config->mode;
+ mode &= (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER);
+
+ /* excluding kernel AND user space doesn't make sense */
+ WARN_ON_ONCE(mode == (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER));
+
+ /* nothing to do if neither flags are set */
+ if (!(mode & ETM_MODE_EXCL_KERN) && !(mode & ETM_MODE_EXCL_USER))
+ return;
+
+ addr_acc = config->addr_acc[ETM_DEFAULT_ADDR_COMP];
+ /* clear default config */
+ addr_acc &= ~(ETM_EXLEVEL_NS_APP | ETM_EXLEVEL_NS_OS);
+
+ /*
+ * EXLEVEL_NS, bits[15:12]
+ * The Exception levels are:
+ * Bit[12] Exception level 0 - Application
+ * Bit[13] Exception level 1 - OS
+ * Bit[14] Exception level 2 - Hypervisor
+ * Bit[15] Never implemented
+ */
+ if (mode & ETM_MODE_EXCL_KERN)
+ addr_acc |= ETM_EXLEVEL_NS_OS;
+ else
+ addr_acc |= ETM_EXLEVEL_NS_APP;
+
+ config->addr_acc[ETM_DEFAULT_ADDR_COMP] = addr_acc;
+ config->addr_acc[ETM_DEFAULT_ADDR_COMP + 1] = addr_acc;
+}
+
static int etm4_cpu_callback(struct notifier_block *nfb, unsigned long action,
void *hcpu)
{
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index f7748ae63451..a291d4cc8bd8 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -176,7 +176,9 @@
#define ETM_MODE_TRACE_RESET BIT(25)
#define ETM_MODE_TRACE_ERR BIT(26)
#define ETM_MODE_VIEWINST_STARTSTOP BIT(27)
-#define ETMv4_MODE_ALL 0xFFFFFFF
+#define ETMv4_MODE_ALL (GENMASK(27, 0) | \
+ ETM_MODE_EXCL_KERN | \
+ ETM_MODE_EXCL_USER)

#define TRCSTATR_IDLE_BIT 0
#define ETM_DEFAULT_ADDR_COMP 0
@@ -414,4 +416,5 @@ enum etm_addr_type {
};

extern const struct attribute_group *coresight_etmv4_groups[];
+void etm4_config_trace_mode(struct etmv4_config *config);
#endif
--
2.1.4