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 | 2 ++
drivers/gpu/drm/i915/i915_oa_perf.c | 40 ++++++++++++++++++++++++++++++++++++-
2 files changed, 41 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1e65dc2..7bc7243 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1831,6 +1831,8 @@ struct drm_i915_private {
struct hrtimer timer;
struct pt_regs dummy_regs;
+ struct ctl_table_header *sysctl_header;
+
struct perf_event *exclusive_event;
struct intel_context *specific_ctx;
bool event_active;
diff --git a/drivers/gpu/drm/i915/i915_oa_perf.c b/drivers/gpu/drm/i915/i915_oa_perf.c
index d0e144c..c3e5059 100644
--- a/drivers/gpu/drm/i915/i915_oa_perf.c
+++ b/drivers/gpu/drm/i915/i915_oa_perf.c
@@ -11,6 +11,8 @@
#define FREQUENCY 200
#define PERIOD max_t(u64, 10000, NSEC_PER_SEC / FREQUENCY)
+static u32 i915_oa_event_paranoid = true;
+
static int hsw_perf_format_sizes[] = {
64, /* A13_HSW */
128, /* A29_HSW */
@@ -548,7 +550,8 @@ static int i915_oa_event_init(struct perf_event *event)
}
}
- if (!dev_priv->oa_pmu.specific_ctx && !capable(CAP_SYS_ADMIN))
+ if (!dev_priv->oa_pmu.specific_ctx &&
+ i915_oa_event_paranoid && !capable(CAP_SYS_ADMIN))
return -EACCES;
mutex_lock(&dev_priv->dev->struct_mutex);
@@ -795,6 +798,37 @@ void i915_oa_context_unpin_notify(struct drm_i915_private *dev_priv,
spin_unlock_irqrestore(&dev_priv->oa_pmu.lock, flags);
}
+static struct ctl_table oa_table[] = {
+ {
+ .procname = "oa_event_paranoid",
+ .data = &i915_oa_event_paranoid,
+ .maxlen = sizeof(i915_oa_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_oa_pmu_register(struct drm_device *dev)
{
struct drm_i915_private *i915 = to_i915(dev);
@@ -802,6 +836,8 @@ void i915_oa_pmu_register(struct drm_device *dev)
if (!IS_HASWELL(dev))
return;
+ i915->oa_pmu.sysctl_header = register_sysctl_table(dev_root);
+
/* We need to be careful about forwarding cpu metrics to
* userspace considering that PERF_PMU_CAP_IS_DEVICE bypasses
* the events/core security check that stops an unprivileged
@@ -841,6 +877,8 @@ void i915_oa_pmu_unregister(struct drm_device *dev)
if (i915->oa_pmu.pmu.event_init == NULL)
return;
+ unregister_sysctl_table(i915->oa_pmu.sysctl_header);
+
perf_pmu_unregister(&i915->oa_pmu.pmu);
i915->oa_pmu.pmu.event_init = NULL;
}
--
2.3.2
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