From 2a8d3eac3d6e11638893ec3c4ba8bc5884db2ef9 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Thu, 25 Jan 2018 15:30:20 +0200 Subject: [PATCH] drm: Warn if plane/crtc/encoder/connector index exceeds our 32bit bitmasks MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit We use 32bit bitmasks to track planes/crtcs/encoders/connectors. Naturally we can only do that if the index of those objects stays below 32. Issue a warning whenever we exceed that limit, hopefully prompting someone to fix the problem. For connectors the issue is a bit more complicated as they can be created/destroyed at runtime due to MST. So the problem is no longer a purely theoretical programmer error. As the connector indexes are allocated via ida, we can simply limit the maximum value the ida is allowed to hand out. The error handling is already in place. v2: Return an error to the caller (Harry) v3: Print a debug message so that we know what happened (Maarten) Cc: Harry Wentland Cc: Maarten Lankhorst Cc: Daniel Vetter Reviewed-by: Maarten Lankhorst Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20180125133020.23845-1-ville.syrjala@linux.intel.com Reviewed-by: Harry Wentland --- drivers/gpu/drm/drm_connector.c | 9 +++++++-- drivers/gpu/drm/drm_crtc.c | 4 ++++ drivers/gpu/drm/drm_encoder.c | 4 ++++ drivers/gpu/drm/drm_plane.c | 4 ++++ 4 files changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index e6a21e6..d6a7eba 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -205,9 +205,14 @@ int drm_connector_init(struct drm_device *dev, connector->dev = dev; connector->funcs = funcs; - ret = ida_simple_get(&config->connector_ida, 0, 0, GFP_KERNEL); - if (ret < 0) + /* connector index is used with 32bit bitmasks */ + ret = ida_simple_get(&config->connector_ida, 0, 32, GFP_KERNEL); + if (ret < 0) { + DRM_DEBUG_KMS("Failed to allocate %s connector index: %d\n", + drm_connector_enum_list[connector_type].name, + ret); goto out_put; + } connector->index = ret; ret = 0; diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index f0556e6..5b4be38 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -282,6 +282,10 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc, WARN_ON(primary && primary->type != DRM_PLANE_TYPE_PRIMARY); WARN_ON(cursor && cursor->type != DRM_PLANE_TYPE_CURSOR); + /* crtc index is used with 32bit bitmasks */ + if (WARN_ON(config->num_crtc >= 32)) + return -EINVAL; + crtc->dev = dev; crtc->funcs = funcs; diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c index 59e0ebe..273e1c5 100644 --- a/drivers/gpu/drm/drm_encoder.c +++ b/drivers/gpu/drm/drm_encoder.c @@ -110,6 +110,10 @@ int drm_encoder_init(struct drm_device *dev, { int ret; + /* encoder index is used with 32bit bitmasks */ + if (WARN_ON(dev->mode_config.num_encoder >= 32)) + return -EINVAL; + ret = drm_mode_object_add(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER); if (ret) return ret; diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c index 2c90519..22b5466 100644 --- a/drivers/gpu/drm/drm_plane.c +++ b/drivers/gpu/drm/drm_plane.c @@ -173,6 +173,10 @@ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane, unsigned int format_modifier_count = 0; int ret; + /* plane index is used with 32bit bitmasks */ + if (WARN_ON(config->num_total_plane >= 32)) + return -EINVAL; + ret = drm_mode_object_add(dev, &plane->base, DRM_MODE_OBJECT_PLANE); if (ret) return ret; -- 2.7.4