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 at sixbynine.org>
---
drivers/gpu/drm/i915/i915_perf.c | 46 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 45 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index bc1c4d1..ab82857 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -38,6 +38,8 @@
#define POLL_FREQUENCY 200
#define POLL_PERIOD max_t(u64, 10000, NSEC_PER_SEC / POLL_FREQUENCY)
+static u32 i915_perf_event_paranoid = true;
+
#define OA_EXPONENT_MAX 0x3f
static struct i915_oa_format hsw_oa_formats[I915_OA_FORMAT_MAX] = {
@@ -1016,7 +1018,13 @@ int i915_perf_open_ioctl_locked(struct drm_device *dev,
void *data,
}
}
- if (!specific_ctx && !capable(CAP_SYS_ADMIN)) {
+ /* Similar to perf's kernel.perf_paranoid_cpu sysctl option
+ * we check a dev.i915.perf_event_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_event_paranoid && !capable(CAP_SYS_ADMIN)) {
DRM_ERROR("Insufficient privileges to open perf event\n");
ret = -EACCES;
goto err_ctx;
@@ -1096,6 +1104,38 @@ int i915_perf_open_ioctl(struct drm_device *dev, void
*data,
return ret;
}
+
+static struct ctl_table oa_table[] = {
+ {
+ .procname = "perf_event_paranoid",
+ .data = &i915_perf_event_paranoid,
+ .maxlen = sizeof(i915_perf_event_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);
@@ -1103,6 +1143,8 @@ void i915_perf_init(struct drm_device *dev)
if (!IS_HASWELL(dev))
return;
+ dev_priv->perf.sysctl_header = register_sysctl_table(dev_root);
+
hrtimer_init(&dev_priv->perf.oa.poll_check_timer,
CLOCK_MONOTONIC, HRTIMER_MODE_REL);
dev_priv->perf.oa.poll_check_timer.function = poll_check_timer_cb;
@@ -1132,6 +1174,8 @@ void i915_perf_fini(struct drm_device *dev)
if (!dev_priv->perf.initialized)
return;
+ unregister_sysctl_table(dev_priv->perf.sysctl_header);
+
dev_priv->perf.oa.ops.init_oa_buffer = NULL;
dev_priv->perf.initialized = false;
--
2.5.2
