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drm/i915: Add dev.i915.perf_stream_paranoid sysctl option 

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@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Sourab Gupta <sourab.gupta@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161107194957.3385-9-robert@sixbynine.org
hifive-unleashed-5.1
Robert Bragg 2016-11-07 19:49:54 +00:00 committed by Daniel Vetter
parent 442b8c06fc
commit ccdf6341ed
2 changed files with 50 additions and 1 deletions
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1
drivers/gpu/drm/i915/i915_drv.h
View File

@ -2194,6 +2194,7 @@ struct drm_i915_private {
bool initialized;
struct kobject *metrics_kobj;
struct ctl_table_header *sysctl_header;
struct mutex lock;
struct list_head streams;

50
drivers/gpu/drm/i915/i915_perf.c
View File

@ -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;
@ -1460,6 +1471,39 @@ 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))
@ -1490,6 +1534,8 @@ 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;
}
@ -1498,6 +1544,8 @@ 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;
}