[Intel-gfx] [PATCH v2 1/2] drm: Make HW_LOCK access functions optional.

[Peter Antoine]

As these functions are only used by one driver and there are security holes
in these functions. Make the functions optional.

Issue: VIZ-5485
Signed-off-by: Peter Antoine <peter.antoine at intel.com>
---
 drivers/gpu/drm/drm_lock.c            |  6 ++++++
 drivers/gpu/drm/nouveau/nouveau_drm.c |  3 ++-
 include/drm/drmP.h                    | 23 ++++++++++++-----------
 3 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/drm_lock.c b/drivers/gpu/drm/drm_lock.c
index f861361..21eb180 100644
--- a/drivers/gpu/drm/drm_lock.c
+++ b/drivers/gpu/drm/drm_lock.c
@@ -61,6 +61,9 @@ int drm_legacy_lock(struct drm_device *dev, void *data,
 	struct drm_master *master = file_priv->master;
 	int ret = 0;
 
+	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+		return -EINVAL;
+
 	++file_priv->lock_count;
 
 	if (lock->context == DRM_KERNEL_CONTEXT) {
@@ -153,6 +156,9 @@ int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_
 	struct drm_lock *lock = data;
 	struct drm_master *master = file_priv->master;
 
+	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+		return -EINVAL;
+
 	if (lock->context == DRM_KERNEL_CONTEXT) {
 		DRM_ERROR("Process %d using kernel context %d\n",
 			  task_pid_nr(current), lock->context);
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 8904933..9624b38 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -941,7 +941,8 @@ static struct drm_driver
 driver_stub = {
 	.driver_features =
 		DRIVER_USE_AGP |
-		DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME | DRIVER_RENDER,
+		DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME | DRIVER_RENDER |
+		DRIVER_KMS_LEGACY_CONTEXT,
 
 	.load = nouveau_drm_load,
 	.unload = nouveau_drm_unload,
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index df6d997..3874942 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -137,17 +137,18 @@ void drm_err(const char *format, ...);
 /*@{*/
 
 /* driver capabilities and requirements mask */
-#define DRIVER_USE_AGP     0x1
-#define DRIVER_PCI_DMA     0x8
-#define DRIVER_SG          0x10
-#define DRIVER_HAVE_DMA    0x20
-#define DRIVER_HAVE_IRQ    0x40
-#define DRIVER_IRQ_SHARED  0x80
-#define DRIVER_GEM         0x1000
-#define DRIVER_MODESET     0x2000
-#define DRIVER_PRIME       0x4000
-#define DRIVER_RENDER      0x8000
-#define DRIVER_ATOMIC      0x10000
+#define DRIVER_USE_AGP			0x1
+#define DRIVER_PCI_DMA			0x8
+#define DRIVER_SG			0x10
+#define DRIVER_HAVE_DMA			0x20
+#define DRIVER_HAVE_IRQ			0x40
+#define DRIVER_IRQ_SHARED		0x80
+#define DRIVER_GEM			0x1000
+#define DRIVER_MODESET			0x2000
+#define DRIVER_PRIME			0x4000
+#define DRIVER_RENDER			0x8000
+#define DRIVER_ATOMIC			0x10000
+#define DRIVER_KMS_LEGACY_CONTEXT	0x20000
 
 /***********************************************************************/
 /** \name Macros to make printk easier */
-- 
1.9.1