On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
> 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>
> Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 1 +
> drivers/gpu/drm/i915/i915_perf.c | 50 +++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 50 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 01438fb..a138f86 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2171,6 +2171,7 @@ 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 8d07c41..4e42073 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -64,6 +64,11 @@
> #define POLL_FREQUENCY 200
> #define POLL_PERIOD (NSEC_PER_SEC / POLL_FREQUENCY)
>
> +/* for sysctl proc_dointvec_minmax of dev.i915.perf_stream_paranoid */
> +static int zero;
> +static int one = 1;
> +static u32 i915_perf_stream_paranoid = true;
> +
> /* The maximum exponent the hardware accepts is 63 (essentially it selects one
> * of the 64bit timestamp bits to trigger reports from) but there's currently
> * no known use case for sampling as infrequently as once per 47 thousand years.
> @@ -1207,7 +1212,13 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
> }
> }
>
> - 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;
> @@ -1454,6 +1465,39 @@ void i915_perf_unregister(struct drm_i915_private *dev_priv)
> dev_priv->perf.metrics_kobj = NULL;
> }
>
> +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_minmax,
> + .extra1 = &zero,
> + .extra2 = &one,
> + },
> + {}
> +};
> +
> +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_i915_private *dev_priv)
> {
> if (!IS_HASWELL(dev_priv))
> @@ -1484,6 +1528,8 @@ void i915_perf_init(struct drm_i915_private *dev_priv)
> dev_priv->perf.oa.n_builtin_sets =
> i915_oa_n_builtin_metric_sets_hsw;
>
> + dev_priv->perf.sysctl_header = register_sysctl_table(dev_root);
> +
> dev_priv->perf.initialized = true;
> }
>
> @@ -1492,6 +1538,8 @@ void i915_perf_fini(struct drm_i915_private *dev_priv)
> if (!dev_priv->perf.initialized)
> return;
>
> + unregister_sysctl_table(dev_priv->perf.sysctl_header);
> +
> memset(&dev_priv->perf.oa.ops, 0, sizeof(dev_priv->perf.oa.ops));
> dev_priv->perf.initialized = false;
> }
Looks fine.
Reviewed-by: Sourab Gupta <sourab.gupta@xxxxxxxxx>
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