On 14 September 2016 at 15:19, Robert Bragg <robert@xxxxxxxxxxxxx> 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>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 1 +
> drivers/gpu/drm/i915/i915_perf.c | 45 +++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 45 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index f5ddf70..eaba7a9 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2142,6 +2142,7 @@ 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 e890c38..38b13fa 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -62,6 +62,8 @@
> #define POLL_FREQUENCY 200
> #define POLL_PERIOD (NSEC_PER_SEC / POLL_FREQUENCY)
>
> +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.
> @@ -1170,7 +1172,13 @@ 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;
> @@ -1417,6 +1425,37 @@ 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,
If this really is just a bool, why not:
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &one
Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx>
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