drm/tegra: Protect IOMMU operations by mutex
IOMMU support is currently not thread-safe, which can cause crashes,
amongst other things, under certain workloads.
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index ef215fe..90041d5 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -142,6 +142,7 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
DRM_DEBUG_DRIVER("IOMMU aperture initialized (%#llx-%#llx)\n",
start, end);
drm_mm_init(&tegra->mm, start, end - start + 1);
+ mutex_init(&tegra->mm_lock);
}
mutex_init(&tegra->clients_lock);
@@ -208,6 +209,7 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
if (tegra->domain) {
iommu_domain_free(tegra->domain);
drm_mm_takedown(&tegra->mm);
+ mutex_destroy(&tegra->mm_lock);
}
free:
kfree(tegra);
@@ -232,6 +234,7 @@ static void tegra_drm_unload(struct drm_device *drm)
if (tegra->domain) {
iommu_domain_free(tegra->domain);
drm_mm_takedown(&tegra->mm);
+ mutex_destroy(&tegra->mm_lock);
}
kfree(tegra);
@@ -878,7 +881,9 @@ static int tegra_debugfs_iova(struct seq_file *s, void *data)
struct tegra_drm *tegra = drm->dev_private;
struct drm_printer p = drm_seq_file_printer(s);
+ mutex_lock(&tegra->mm_lock);
drm_mm_print(&tegra->mm, &p);
+ mutex_unlock(&tegra->mm_lock);
return 0;
}