[PATCH 4/5] 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/i915/i915_dma.c       |  3 +++
 drivers/gpu/drm/nouveau/nouveau_drm.c |  3 ++-
 include/drm/drmP.h                    | 23 ++++++++++++-----------
 include/uapi/drm/i915_drm.h           |  1 +
 5 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/drm_lock.c b/drivers/gpu/drm/drm_lock.c
index 94500930..b61d4c7 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 (_DRM_LOCKING_CONTEXT(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 (_DRM_LOCKING_CONTEXT(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/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index e44116f..c771ef0 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -163,6 +163,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
 		if (!value)
 			return -ENODEV;
 		break;
+	case I915_PARAM_HAS_LEGACY_CONTEXT:
+		value = drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT);
+		break;
 	default:
 		DRM_DEBUG("Unknown parameter %d\n", param->param);
 		return -EINVAL;
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 8763deb..936b423 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -940,7 +940,8 @@ 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 62c40777..367e42f 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 */
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 4851d66..0ad611a2 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -350,6 +350,7 @@ typedef struct drm_i915_irq_wait {
 #define I915_PARAM_REVISION              32
 #define I915_PARAM_SUBSLICE_TOTAL	 33
 #define I915_PARAM_EU_TOTAL		 34
+#define I915_PARAM_HAS_LEGACY_CONTEXT	 35
 
 typedef struct drm_i915_getparam {
 	int param;
-- 
1.9.1