From 8dbe1b4a15977f31f6b3b79e577ad96a795c9827 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Thu, 20 Feb 2020 17:16:28 +0200 Subject: drm: Move legacy device list out of drm_driver The drm_driver structure contains a single field (legacy_dev_list) that is modified by the DRM core, used to store a linked list of legacy DRM devices associated with the driver. In order to make the structure const, move the field out to a global variable. This requires locking access to the global where the local field didn't require serialization, but this only affects legacy drivers, and isn't in any hot path. While at it, compile-out the legacy_dev_list field when DRM_LEGACY isn't defined. Signed-off-by: Laurent Pinchart Reviewed-by: Daniel Vetter Reviewed-by: Emil Velikov --- drivers/gpu/drm/drm_pci.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) (limited to 'drivers/gpu/drm/drm_pci.c') diff --git a/drivers/gpu/drm/drm_pci.c b/drivers/gpu/drm/drm_pci.c index 6dba4b8ce4fe..dfb138aaccba 100644 --- a/drivers/gpu/drm/drm_pci.c +++ b/drivers/gpu/drm/drm_pci.c @@ -24,6 +24,8 @@ #include #include +#include +#include #include #include @@ -36,6 +38,9 @@ #include "drm_legacy.h" #ifdef CONFIG_DRM_LEGACY +/* List of devices hanging off drivers with stealth attach. */ +static LIST_HEAD(legacy_dev_list); +static DEFINE_MUTEX(legacy_dev_list_lock); /** * drm_pci_alloc - Allocate a PCI consistent memory block, for DMA. @@ -225,10 +230,11 @@ static int drm_get_pci_dev(struct pci_dev *pdev, if (ret) goto err_agp; - /* No locking needed since shadow-attach is single-threaded since it may - * only be called from the per-driver module init hook. */ - if (drm_core_check_feature(dev, DRIVER_LEGACY)) - list_add_tail(&dev->legacy_dev_list, &driver->legacy_dev_list); + if (drm_core_check_feature(dev, DRIVER_LEGACY)) { + mutex_lock(&legacy_dev_list_lock); + list_add_tail(&dev->legacy_dev_list, &legacy_dev_list); + mutex_unlock(&legacy_dev_list_lock); + } return 0; @@ -261,7 +267,6 @@ int drm_legacy_pci_init(struct drm_driver *driver, struct pci_driver *pdriver) return -EINVAL; /* If not using KMS, fall back to stealth mode manual scanning. */ - INIT_LIST_HEAD(&driver->legacy_dev_list); for (i = 0; pdriver->id_table[i].vendor != 0; i++) { pid = &pdriver->id_table[i]; @@ -304,11 +309,15 @@ void drm_legacy_pci_exit(struct drm_driver *driver, struct pci_driver *pdriver) if (!(driver->driver_features & DRIVER_LEGACY)) { WARN_ON(1); } else { - list_for_each_entry_safe(dev, tmp, &driver->legacy_dev_list, + mutex_lock(&legacy_dev_list_lock); + list_for_each_entry_safe(dev, tmp, &legacy_dev_list, legacy_dev_list) { - list_del(&dev->legacy_dev_list); - drm_put_dev(dev); + if (dev->driver == driver) { + list_del(&dev->legacy_dev_list); + drm_put_dev(dev); + } } + mutex_unlock(&legacy_dev_list_lock); } DRM_INFO("Module unloaded\n"); } -- cgit v1.2.3 From b1dda997a8a98fcb98189e5f4ee3108bc3da3d21 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Fri, 21 Feb 2020 00:19:22 +0200 Subject: drm: Use a const drm_driver for legacy PCI devices Now that the legacy PCI support code doesn't need to write to the drm_driver structure, it can be treated as const through the whole DRM core, unconditionally. This allows declaring the structure as const in all drivers, removing one possible attack vector. Signed-off-by: Laurent Pinchart Reviewed-by: Daniel Vetter --- drivers/gpu/drm/drm_drv.c | 4 ---- drivers/gpu/drm/drm_pci.c | 8 +++++--- include/drm/drm_device.h | 4 ---- include/drm/drm_legacy.h | 10 ++++++---- 4 files changed, 11 insertions(+), 15 deletions(-) (limited to 'drivers/gpu/drm/drm_pci.c') diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 734303802bc3..3f57e880685e 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -589,11 +589,7 @@ static int drm_dev_init(struct drm_device *dev, kref_init(&dev->ref); dev->dev = get_device(parent); -#ifdef CONFIG_DRM_LEGACY - dev->driver = (struct drm_driver *)driver; -#else dev->driver = driver; -#endif INIT_LIST_HEAD(&dev->managed.resources); spin_lock_init(&dev->managed.lock); diff --git a/drivers/gpu/drm/drm_pci.c b/drivers/gpu/drm/drm_pci.c index dfb138aaccba..5370e6b492fd 100644 --- a/drivers/gpu/drm/drm_pci.c +++ b/drivers/gpu/drm/drm_pci.c @@ -201,7 +201,7 @@ static void drm_pci_agp_init(struct drm_device *dev) static int drm_get_pci_dev(struct pci_dev *pdev, const struct pci_device_id *ent, - struct drm_driver *driver) + const struct drm_driver *driver) { struct drm_device *dev; int ret; @@ -255,7 +255,8 @@ err_free: * * Return: 0 on success or a negative error code on failure. */ -int drm_legacy_pci_init(struct drm_driver *driver, struct pci_driver *pdriver) +int drm_legacy_pci_init(const struct drm_driver *driver, + struct pci_driver *pdriver) { struct pci_dev *pdev = NULL; const struct pci_device_id *pid; @@ -300,7 +301,8 @@ EXPORT_SYMBOL(drm_legacy_pci_init); * Unregister a DRM driver shadow-attached through drm_legacy_pci_init(). This * is deprecated and only used by dri1 drivers. */ -void drm_legacy_pci_exit(struct drm_driver *driver, struct pci_driver *pdriver) +void drm_legacy_pci_exit(const struct drm_driver *driver, + struct pci_driver *pdriver) { struct drm_device *dev, *tmp; diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h index bd5abe7cd48f..939904ae88fc 100644 --- a/include/drm/drm_device.h +++ b/include/drm/drm_device.h @@ -76,11 +76,7 @@ struct drm_device { } managed; /** @driver: DRM driver managing the device */ -#ifdef CONFIG_DRM_LEGACY - struct drm_driver *driver; -#else const struct drm_driver *driver; -#endif /** * @dev_private: diff --git a/include/drm/drm_legacy.h b/include/drm/drm_legacy.h index 852d7451eeb1..8ed04e9be997 100644 --- a/include/drm/drm_legacy.h +++ b/include/drm/drm_legacy.h @@ -198,8 +198,10 @@ struct drm_dma_handle *drm_pci_alloc(struct drm_device *dev, size_t size, size_t align); void drm_pci_free(struct drm_device *dev, struct drm_dma_handle *dmah); -int drm_legacy_pci_init(struct drm_driver *driver, struct pci_driver *pdriver); -void drm_legacy_pci_exit(struct drm_driver *driver, struct pci_driver *pdriver); +int drm_legacy_pci_init(const struct drm_driver *driver, + struct pci_driver *pdriver); +void drm_legacy_pci_exit(const struct drm_driver *driver, + struct pci_driver *pdriver); #else @@ -214,13 +216,13 @@ static inline void drm_pci_free(struct drm_device *dev, { } -static inline int drm_legacy_pci_init(struct drm_driver *driver, +static inline int drm_legacy_pci_init(const struct drm_driver *driver, struct pci_driver *pdriver) { return -EINVAL; } -static inline void drm_legacy_pci_exit(struct drm_driver *driver, +static inline void drm_legacy_pci_exit(const struct drm_driver *driver, struct pci_driver *pdriver) { } -- cgit v1.2.3