Consistent with the kernel.perf_event_paranoid sysctl option that can
allow non-root users to access system wide cpu metrics, this can
optionally allow non-root users to access system wide OA counter metrics
from Gen graphics hardware.
Signed-off-by: Robert Bragg <robert@xxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_perf.c | 46 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 46 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index b1c60bb..6776e18 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2087,6 +2087,7 @@ struct drm_i915_private {
bool initialized;
struct kobject *metrics_kobj;
+ struct ctl_table_header *sysctl_header;
struct mutex lock;
struct list_head streams;
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 5c08a16..7c27d93 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -37,6 +37,8 @@
#define POLL_FREQUENCY 200
#define POLL_PERIOD max_t(u64, 10000, NSEC_PER_SEC / POLL_FREQUENCY)
+static u32 i915_perf_stream_paranoid = true;
+
#define OA_EXPONENT_MAX 0x3f
static struct i915_oa_format hsw_oa_formats[I915_OA_FORMAT_MAX] = {
@@ -956,7 +958,13 @@ int i915_perf_open_ioctl_locked(struct drm_device *dev,
}
}
- if (!specific_ctx && !capable(CAP_SYS_ADMIN)) {
+ /* Similar to perf's kernel.perf_paranoid_cpu sysctl option
+ * we check a dev.i915.perf_stream_paranoid sysctl option
+ * to determine if it's ok to access system wide OA counters
+ * without CAP_SYS_ADMIN privileges.
+ */
+ if (!specific_ctx &&
+ i915_perf_stream_paranoid && !capable(CAP_SYS_ADMIN)) {
DRM_ERROR("Insufficient privileges to open system-wide i915 perf stream\n");
ret = -EACCES;
goto err_ctx;
@@ -1157,6 +1165,38 @@ int i915_perf_open_ioctl(struct drm_device *dev, void *data,
return ret;
}
+
+static struct ctl_table oa_table[] = {
+ {
+ .procname = "perf_stream_paranoid",
+ .data = &i915_perf_stream_paranoid,
+ .maxlen = sizeof(i915_perf_stream_paranoid),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+ {}
+};
+
+static struct ctl_table i915_root[] = {
+ {
+ .procname = "i915",
+ .maxlen = 0,
+ .mode = 0555,
+ .child = oa_table,
+ },
+ {}
+};
+
+static struct ctl_table dev_root[] = {
+ {
+ .procname = "dev",
+ .maxlen = 0,
+ .mode = 0555,
+ .child = i915_root,
+ },
+ {}
+};
+
void i915_perf_init(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = to_i915(dev);
@@ -1198,6 +1238,8 @@ void i915_perf_init(struct drm_device *dev)
return;
}
+ dev_priv->perf.sysctl_header = register_sysctl_table(dev_root);
+
dev_priv->perf.initialized = true;
return;
@@ -1210,6 +1252,8 @@ void i915_perf_fini(struct drm_device *dev)
if (!dev_priv->perf.initialized)
return;
+ unregister_sysctl_table(dev_priv->perf.sysctl_header);
+
i915_perf_deinit_sysfs_hsw(dev_priv);
kobject_put(dev_priv->perf.metrics_kobj);
--
2.7.0
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