An unexpected modeset or connector detection by a user (user space or FB
console) during the initialization/shutdown sequence is possible either
via a hotplug IRQ handling work or via the connector sysfs
(status/detect) interface. These modesets/detections should be prevented
by disabling/flushing all related hotplug handling work and
unregistering the interfaces that can start them at the beginning of the
shutdown sequence. Some of this - disabling all related intel_hotplug
work - will be done by the next patch, but others - for instance
disabling the MST hotplug works - require a bigger rework.
It makes sense - for diagnostic purpose, even with all the above work and
interface disabled - to detect and reject any such user access. This
patch does that for modeset accesses and a follow-up patch for connector
detection.
After the display is disabled during the shutdown sequence, no modeset
should happen so it's disabled for both users and the shutdown thread.
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_display.c | 3 +
.../gpu/drm/i915/display/intel_display_core.h | 7 ++
.../drm/i915/display/intel_display_driver.c | 74 +++++++++++++++++++
.../drm/i915/display/intel_display_driver.h | 6 ++
drivers/gpu/drm/i915/i915_driver.c | 16 +++-
5 files changed, 104 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 927d124457b61..31a6a82c12616 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -6310,6 +6310,9 @@ int intel_atomic_check(struct drm_device *dev,
int ret, i;
bool any_ms = false;
+ if (!intel_display_driver_check_access(dev_priv))
+ return -ENODEV;
+
for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
new_crtc_state, i) {
/*
diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h b/drivers/gpu/drm/i915/display/intel_display_core.h
index 47297ed858223..0b130ca9e6698 100644
--- a/drivers/gpu/drm/i915/display/intel_display_core.h
+++ b/drivers/gpu/drm/i915/display/intel_display_core.h
@@ -28,6 +28,8 @@
#include "intel_opregion.h"
#include "intel_wm_types.h"
+struct task_struct;
+
struct drm_i915_private;
struct drm_property;
struct drm_property_blob;
@@ -298,6 +300,11 @@ struct intel_display {
const struct intel_audio_funcs *audio;
} funcs;
+ struct {
+ bool any_task_allowed;
+ struct task_struct *allowed_task;
+ } access;
+
struct {
/* backlight registers and fields in struct intel_panel */
struct mutex lock;
diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.c b/drivers/gpu/drm/i915/display/intel_display_driver.c
index 1974f2394a518..b2441ab9822c2 100644
--- a/drivers/gpu/drm/i915/display/intel_display_driver.c
+++ b/drivers/gpu/drm/i915/display/intel_display_driver.c
@@ -45,6 +45,7 @@
#include "intel_hdcp.h"
#include "intel_hotplug.h"
#include "intel_hti.h"
+#include "intel_modeset_lock.h"
#include "intel_modeset_setup.h"
#include "intel_opregion.h"
#include "intel_overlay.h"
@@ -276,6 +277,71 @@ int intel_display_driver_probe_noirq(struct drm_i915_private *i915)
return ret;
}
+static void set_display_access(struct drm_i915_private *i915,
+ bool any_task_allowed,
+ struct task_struct *allowed_task)
+{
+ struct drm_modeset_acquire_ctx ctx;
+ int err;
+
+ intel_modeset_lock_ctx_retry(&ctx, NULL, 0, err) {
+ err = drm_modeset_lock_all_ctx(&i915->drm, &ctx);
+ if (err)
+ continue;
+
+ i915->display.access.any_task_allowed = any_task_allowed;
+ i915->display.access.allowed_task = allowed_task;
+ }
+
+ drm_WARN_ON(&i915->drm, err);
+}
+
+void intel_display_driver_enable_user_access(struct drm_i915_private *i915)
+{
+ set_display_access(i915, true, NULL);
+}
+
+void intel_display_driver_disable_user_access(struct drm_i915_private *i915)
+{
+ set_display_access(i915, false, current);
+}
+
+void intel_display_driver_suspend_access(struct drm_i915_private *i915)
+{
+ set_display_access(i915, false, NULL);
+}
+
+void intel_display_driver_resume_access(struct drm_i915_private *i915)
+{
+ set_display_access(i915, false, current);
+}
+
+bool intel_display_driver_check_access(struct drm_i915_private *i915)
+{
+ char comm[TASK_COMM_LEN];
+ char current_task[TASK_COMM_LEN + 16];
+ char allowed_task[TASK_COMM_LEN + 16] = "none";
+
+ if (i915->display.access.any_task_allowed ||
+ i915->display.access.allowed_task == current)
+ return true;
+
+ snprintf(current_task, sizeof(current_task), "%s[%d]",
+ get_task_comm(comm, current),
+ task_pid_vnr(current));
+
+ if (i915->display.access.allowed_task)
+ snprintf(allowed_task, sizeof(allowed_task), "%s[%d]",
+ get_task_comm(comm, i915->display.access.allowed_task),
+ task_pid_vnr(i915->display.access.allowed_task));
+
+ drm_dbg_kms(&i915->drm,
+ "Reject display access from task %s (allowed to %s)\n",
+ current_task, allowed_task);
+
+ return false;
+}
+
/* part #2: call after irq install, but before gem init */
int intel_display_driver_probe_nogem(struct drm_i915_private *i915)
{
@@ -326,6 +392,8 @@ int intel_display_driver_probe_nogem(struct drm_i915_private *i915)
intel_vga_disable(i915);
intel_setup_outputs(i915);
+ intel_display_driver_disable_user_access(i915);
+
drm_modeset_lock_all(dev);
intel_modeset_setup_hw_state(i915, dev->mode_config.acquire_ctx);
intel_acpi_assign_connector_fwnodes(i915);
@@ -393,6 +461,8 @@ void intel_display_driver_register(struct drm_i915_private *i915)
intel_audio_init(i915);
+ intel_display_driver_enable_user_access(i915);
+
intel_display_debugfs_register(i915);
/*
@@ -440,6 +510,8 @@ void intel_display_driver_remove_noirq(struct drm_i915_private *i915)
if (!HAS_DISPLAY(i915))
return;
+ intel_display_driver_suspend_access(i915);
+
/*
* Due to the hpd irq storm handling the hotplug work can re-arm the
* poll handlers. Hence disable polling after hpd handling is shut down.
@@ -493,6 +565,8 @@ void intel_display_driver_unregister(struct drm_i915_private *i915)
*/
drm_kms_helper_poll_fini(&i915->drm);
+ intel_display_driver_disable_user_access(i915);
+
intel_audio_deinit(i915);
drm_atomic_helper_shutdown(&i915->drm);
diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.h b/drivers/gpu/drm/i915/display/intel_display_driver.h
index c276a58ee3293..42cc4af6d3fd5 100644
--- a/drivers/gpu/drm/i915/display/intel_display_driver.h
+++ b/drivers/gpu/drm/i915/display/intel_display_driver.h
@@ -32,5 +32,11 @@ int __intel_display_driver_resume(struct drm_i915_private *i915,
struct drm_atomic_state *state,
struct drm_modeset_acquire_ctx *ctx);
+void intel_display_driver_enable_user_access(struct drm_i915_private *i915);
+void intel_display_driver_disable_user_access(struct drm_i915_private *i915);
+void intel_display_driver_suspend_access(struct drm_i915_private *i915);
+void intel_display_driver_resume_access(struct drm_i915_private *i915);
+bool intel_display_driver_check_access(struct drm_i915_private *i915);
+
#endif /* __INTEL_DISPLAY_DRIVER_H__ */
diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
index 166476948c896..068ca48e05323 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -1006,6 +1006,7 @@ void i915_driver_shutdown(struct drm_i915_private *i915)
intel_fbdev_set_suspend(&i915->drm, FBINFO_STATE_SUSPENDED, true);
if (HAS_DISPLAY(i915)) {
drm_kms_helper_poll_disable(&i915->drm);
+ intel_display_driver_disable_user_access(i915);
drm_atomic_helper_shutdown(&i915->drm);
}
@@ -1015,6 +1016,8 @@ void i915_driver_shutdown(struct drm_i915_private *i915)
intel_runtime_pm_disable_interrupts(i915);
intel_hpd_cancel_work(i915);
+ intel_display_driver_suspend_access(i915);
+
intel_suspend_encoders(i915);
intel_shutdown_encoders(i915);
@@ -1082,8 +1085,10 @@ static int i915_drm_suspend(struct drm_device *dev)
* properly. */
intel_power_domains_disable(dev_priv);
intel_fbdev_set_suspend(dev, FBINFO_STATE_SUSPENDED, true);
- if (HAS_DISPLAY(dev_priv))
+ if (HAS_DISPLAY(dev_priv)) {
drm_kms_helper_poll_disable(dev);
+ intel_display_driver_disable_user_access(dev_priv);
+ }
pci_save_state(pdev);
@@ -1094,6 +1099,8 @@ static int i915_drm_suspend(struct drm_device *dev)
intel_runtime_pm_disable_interrupts(dev_priv);
intel_hpd_cancel_work(dev_priv);
+ intel_display_driver_suspend_access(dev_priv);
+
intel_suspend_encoders(dev_priv);
/* Must be called before GGTT is suspended. */
@@ -1243,14 +1250,19 @@ static int i915_drm_resume(struct drm_device *dev)
intel_display_driver_init_hw(dev_priv);
intel_clock_gating_init(dev_priv);
+
+ intel_display_driver_resume_access(dev_priv);
+
intel_hpd_init(dev_priv);
/* MST sideband requires HPD interrupts enabled */
intel_dp_mst_resume(dev_priv);
intel_display_driver_resume(dev_priv);
- if (HAS_DISPLAY(dev_priv))
+ if (HAS_DISPLAY(dev_priv)) {
+ intel_display_driver_enable_user_access(dev_priv);
drm_kms_helper_poll_enable(dev);
+ }
intel_hpd_poll_disable(dev_priv);
intel_opregion_resume(dev_priv);
--
2.39.2
