Re: [PATCH 1/3] drm: Turn off Legacy Context Functions

Antoine, Peter
2015-06-23T13:14:43Z

> From: Peter Antoine <peter.antoine@intel.com>
>
> The context functions are not used by the i915 driver and should not
> be used by modeset drivers. These driver functions contain several bugs
> and security holes. This change makes these functions optional can be
> turned on by a setting, they are turned off by default for modeset
> driver with the exception of the nouvea driver that may require them with
> an old version of libdrm.
>
> The previous attempt was
>
> commit 7c510133d93dd6f15ca040733ba7b2891ed61fd1
> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> Date: Thu Aug 8 15:41:21 2013 +0200
>
> drm: mark context support as a legacy subsystem
>
> but this had to be reverted
>
> commit c21eb21cb50d58e7cbdcb8b9e7ff68b85cfa5095
> Author: Dave Airlie <airlied@redhat.com>
> Date: Fri Sep 20 08:32:59 2013 +1000
>
> Revert "drm: mark context support as a legacy subsystem"
>
> v2: remove returns from void function, and formatting (Daniel Vetter)
>
> v3:
> - s/Nova/nouveau/ in the commit message, and add references to the
> previous attempts
> - drop the part touching the drm hw lock, that should be a separate
> patch.
>
> Signed-off-by: Peter Antoine <peter.antoine@intel.com> (v2)
> Cc: Peter Antoine <peter.antoine@intel.com> (v2)
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
> drivers/gpu/drm/drm_context.c | 48 +++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/drm_drv.c | 13 ++++++----
> drivers/gpu/drm/nouveau/nouveau_drm.c | 3 ++-
> include/drm/drmP.h | 23 +++++++++--------
> 4 files changed, 70 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_context.c b/drivers/gpu/drm/drm_context.c
> index 9b23525c0ed0..32958dabd7b0 100644
> --- a/drivers/gpu/drm/drm_context.c
> +++ b/drivers/gpu/drm/drm_context.c
> @@ -53,6 +53,10 @@ struct drm_ctx_list {
> */
> void drm_legacy_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
> {
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return;
> +
> mutex_lock(&dev->struct_mutex);
> idr_remove(&dev->ctx_idr, ctx_handle);
> mutex_unlock(&dev->struct_mutex);
> @@ -87,6 +91,10 @@ static int drm_legacy_ctxbitmap_next(struct drm_device * dev)
> */
> int drm_legacy_ctxbitmap_init(struct drm_device * dev)
> {
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return -EINVAL;
> +
> idr_init(&dev->ctx_idr);
> return 0;
> }
> @@ -101,6 +109,10 @@ int drm_legacy_ctxbitmap_init(struct drm_device * dev)
> */
> void drm_legacy_ctxbitmap_cleanup(struct drm_device * dev)
> {
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return;
> +
> mutex_lock(&dev->struct_mutex);
> idr_destroy(&dev->ctx_idr);
> mutex_unlock(&dev->struct_mutex);
> @@ -119,6 +131,10 @@ void drm_legacy_ctxbitmap_flush(struct drm_device *dev, struct drm_file *file)
> {
> struct drm_ctx_list *pos, *tmp;
>
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return;
> +
> mutex_lock(&dev->ctxlist_mutex);
>
> list_for_each_entry_safe(pos, tmp, &dev->ctxlist, head) {
> @@ -161,6 +177,10 @@ int drm_legacy_getsareactx(struct drm_device *dev, void *data,
> struct drm_local_map *map;
> struct drm_map_list *_entry;
>
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return -EINVAL;
> +
> mutex_lock(&dev->struct_mutex);
>
> map = idr_find(&dev->ctx_idr, request->ctx_id);
> @@ -205,6 +225,10 @@ int drm_legacy_setsareactx(struct drm_device *dev, void *data,
> struct drm_local_map *map = NULL;
> struct drm_map_list *r_list = NULL;
>
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return -EINVAL;
> +
> mutex_lock(&dev->struct_mutex);
> list_for_each_entry(r_list, &dev->maplist, head) {
> if (r_list->map
> @@ -305,6 +329,10 @@ int drm_legacy_resctx(struct drm_device *dev, void *data,
> struct drm_ctx ctx;
> int i;
>
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return -EINVAL;
> +
> if (res->count >= DRM_RESERVED_CONTEXTS) {
> memset(&ctx, 0, sizeof(ctx));
> for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
> @@ -335,6 +363,10 @@ int drm_legacy_addctx(struct drm_device *dev, void *data,
> struct drm_ctx_list *ctx_entry;
> struct drm_ctx *ctx = data;
>
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return -EINVAL;
> +
> ctx->handle = drm_legacy_ctxbitmap_next(dev);
> if (ctx->handle == DRM_KERNEL_CONTEXT) {
> /* Skip kernel's context and get a new one. */
> @@ -378,6 +410,10 @@ int drm_legacy_getctx(struct drm_device *dev, void *data,
> {
> struct drm_ctx *ctx = data;
>
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return -EINVAL;
> +
> /* This is 0, because we don't handle any context flags */
> ctx->flags = 0;
>
> @@ -400,6 +436,10 @@ int drm_legacy_switchctx(struct drm_device *dev, void *data,
> {
> struct drm_ctx *ctx = data;
>
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return -EINVAL;
> +
> DRM_DEBUG("%d\n", ctx->handle);
> return drm_context_switch(dev, dev->last_context, ctx->handle);
> }
> @@ -420,6 +460,10 @@ int drm_legacy_newctx(struct drm_device *dev, void *data,
> {
> struct drm_ctx *ctx = data;
>
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return -EINVAL;
> +
> DRM_DEBUG("%d\n", ctx->handle);
> drm_context_switch_complete(dev, file_priv, ctx->handle);
>
> @@ -442,6 +486,10 @@ int drm_legacy_rmctx(struct drm_device *dev, void *data,
> {
> struct drm_ctx *ctx = data;
>
> + if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
> + drm_core_check_feature(dev, DRIVER_MODESET))
> + return -EINVAL;
> +
> DRM_DEBUG("%d\n", ctx->handle);
> if (ctx->handle != DRM_KERNEL_CONTEXT) {
> if (dev->driver->context_dtor)
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 3b3c4f537e95..e5717116346d 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -584,11 +584,14 @@ struct drm_device *drm_dev_alloc(struct drm_driver *driver,
> if (drm_ht_create(&dev->map_hash, 12))
> goto err_minors;
>
> - ret = drm_legacy_ctxbitmap_init(dev);
> - if (ret) {
> - DRM_ERROR("Cannot allocate memory for context bitmap.\n");
> - goto err_ht;
> - }
> + if (drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) ||
> + !drm_core_check_feature(dev, DRIVER_MODESET))
> + ret = drm_legacy_ctxbitmap_init(dev);
> + if (ret) {
> + DRM_ERROR(
> + "Cannot allocate memory for context bitmap.\n");
> + goto err_ht;
> + }
>
> if (drm_core_check_feature(dev, DRIVER_GEM)) {
> ret = drm_gem_init(dev);
> diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
> index 89049335b738..9624b3827c34 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 48db6a56975f..3dc7c16c18f2 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 */