// SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright © 2017 Keith Packard */ #include #include #include #include #include #include #include #include #include "drm_crtc_internal.h" #include "drm_internal.h" /** * DOC: drm leasing * * DRM leases provide information about whether a DRM master may control a DRM * mode setting object. This enables the creation of multiple DRM masters that * manage subsets of display resources. * * The original DRM master of a device 'owns' the available drm resources. It * may create additional DRM masters and 'lease' resources which it controls * to the new DRM master. This gives the new DRM master control over the * leased resources until the owner revokes the lease, or the new DRM master * is closed. Some helpful terminology: * * - An 'owner' is a &struct drm_master that is not leasing objects from * another &struct drm_master, and hence 'owns' the objects. The owner can be * identified as the &struct drm_master for which &drm_master.lessor is NULL. * * - A 'lessor' is a &struct drm_master which is leasing objects to one or more * other &struct drm_master. Currently, lessees are not allowed to * create sub-leases, hence the lessor is the same as the owner. * * - A 'lessee' is a &struct drm_master which is leasing objects from some * other &struct drm_master. Each lessee only leases resources from a single * lessor recorded in &drm_master.lessor, and holds the set of objects that * it is leasing in &drm_master.leases. * * - A 'lease' is a contract between the lessor and lessee that identifies * which resources may be controlled by the lessee. All of the resources * that are leased must be owned by or leased to the lessor, and lessors are * not permitted to lease the same object to multiple lessees. * * The set of objects any &struct drm_master 'controls' is limited to the set * of objects it leases (for lessees) or all objects (for owners). * * Objects not controlled by a &struct drm_master cannot be modified through * the various state manipulating ioctls, and any state reported back to user * space will be edited to make them appear idle and/or unusable. For * instance, connectors always report 'disconnected', while encoders * report no possible crtcs or clones. * * Since each lessee may lease objects from a single lessor, display resource * leases form a tree of &struct drm_master. As lessees are currently not * allowed to create sub-leases, the tree depth is limited to 1. All of * these get activated simultaneously when the top level device owner changes * through the SETMASTER or DROPMASTER IOCTL, so &drm_device.master points to * the owner at the top of the lease tree (i.e. the &struct drm_master for which * &drm_master.lessor is NULL). The full list of lessees that are leasing * objects from the owner can be searched via the owner's * &drm_master.lessee_idr. */ #define drm_for_each_lessee(lessee, lessor) \ list_for_each_entry((lessee), &(lessor)->lessees, lessee_list) static uint64_t drm_lease_idr_object; struct drm_master *drm_lease_owner(struct drm_master *master) { while (master->lessor != NULL) master = master->lessor; return master; } static struct drm_master* _drm_find_lessee(struct drm_master *master, int lessee_id) { lockdep_assert_held(&master->dev->mode_config.idr_mutex); return idr_find(&drm_lease_owner(master)->lessee_idr, lessee_id); } static int _drm_lease_held_master(struct drm_master *master, int id) { lockdep_assert_held(&master->dev->mode_config.idr_mutex); if (master->lessor) return idr_find(&master->leases, id) != NULL; return true; } /* Checks if the given object has been leased to some lessee of drm_master */ static bool _drm_has_leased(struct drm_master *master, int id) { struct drm_master *lessee; lockdep_assert_held(&master->dev->mode_config.idr_mutex); drm_for_each_lessee(lessee, master) if (_drm_lease_held_master(lessee, id)) return true; return false; } /* Called with idr_mutex held */ bool _drm_lease_held(struct drm_file *file_priv, int id) { bool ret; struct drm_master *master; if (!file_priv) return true; master = drm_file_get_master(file_priv); if (!master) return true; ret = _drm_lease_held_master(master, id); drm_master_put(&master); return ret; } bool drm_lease_held(struct drm_file *file_priv, int id) { struct drm_master *master; bool ret; if (!file_priv) return true; master = drm_file_get_master(file_priv); if (!master) return true; if (!master->lessor) { ret = true; goto out; } mutex_lock(&master->dev->mode_config.idr_mutex); ret = _drm_lease_held_master(master, id); mutex_unlock(&master->dev->mode_config.idr_mutex); out: drm_master_put(&master); return ret; } /* * Given a bitmask of crtcs to check, reconstructs a crtc mask based on the * crtcs which are visible through the specified file. */ uint32_t drm_lease_filter_crtcs(struct drm_file *file_priv, uint32_t crtcs_in) { struct drm_master *master; struct drm_device *dev; struct drm_crtc *crtc; int count_in, count_out; uint32_t crtcs_out = 0; if (!file_priv) return crtcs_in; master = drm_file_get_master(file_priv); if (!master) return crtcs_in; if (!master->lessor) { crtcs_out = crtcs_in; goto out; } dev = master->dev; count_in = count_out = 0; mutex_lock(&master->dev->mode_config.idr_mutex); list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) { if (_drm_lease_held_master(master, crtc->base.id)) { uint32_t mask_in = 1ul << count_in; if ((crtcs_in & mask_in) != 0) { uint32_t mask_out = 1ul << count_out; crtcs_out |= mask_out; } count_out++; } count_in++; } mutex_unlock(&master->dev->mode_config.idr_mutex); out: drm_master_put(&master); return crtcs_out; } /* * Uses drm_master_create to allocate a new drm_master, then checks to * make sure all of the desired objects can be leased, atomically * leasing them to the new drmmaster. * * ERR_PTR(-EACCES) some other master holds the title to any object * ERR_PTR(-ENOENT) some object is not a valid DRM object for this device * ERR_PTR(-EBUSY) some other lessee holds title to this object * ERR_PTR(-EEXIST) same object specified more than once in the provided list * ERR_PTR(-ENOMEM) allocation failed */ static struct drm_master *drm_lease_create(struct drm_master *lessor, struct idr *leases) { struct drm_device *dev = lessor->dev; int error; struct drm_master *lessee; int object; int id; void *entry; DRM_DEBUG_LEASE("lessor %d\n", lessor->lessee_id); lessee = drm_master_create(lessor->dev); if (!lessee) { DRM_DEBUG_LEASE("drm_master_create failed\n"); return ERR_PTR(-ENOMEM); } mutex_lock(&dev->mode_config.idr_mutex); idr_for_each_entry(leases, entry, object) { error = 0; if (!idr_find(&dev->mode_config.object_idr, object)) error = -ENOENT; else if (_drm_has_leased(lessor, object)) error = -EBUSY; if (error != 0) { DRM_DEBUG_LEASE("object %d failed %d\n", object, error); goto out_lessee; } } /* Insert the new lessee into the tree */ id = idr_alloc(&(drm_lease_owner(lessor)->lessee_idr), lessee, 1, 0, GFP_KERNEL); if (id < 0) { error = id; goto out_lessee; } lessee->lessee_id = id; lessee->lessor = drm_master_get(lessor); list_add_tail(&lessee->lessee_list, &lessor->lessees); /* Move the leases over */ lessee->leases = *leases; DRM_DEBUG_LEASE("new lessee %d %p, lessor %d %p\n", lessee->lessee_id, lessee, lessor->lessee_id, lessor); mutex_unlock(&dev->mode_config.idr_mutex); return lessee; out_lessee: mutex_unlock(&dev->mode_config.idr_mutex); drm_master_put(&lessee); return ERR_PTR(error); } void drm_lease_destroy(struct drm_master *master) { struct drm_device *dev = master->dev; mutex_lock(&dev->mode_config.idr_mutex); DRM_DEBUG_LEASE("drm_lease_destroy %d\n", master->lessee_id); /* This master is referenced by all lessees, hence it cannot be destroyed * until all of them have been */ WARN_ON(!list_empty(&master->lessees)); /* Remove this master from the lessee idr in the owner */ if (master->lessee_id != 0) { DRM_DEBUG_LEASE("remove master %d from device list of lessees\n", master->lessee_id); idr_remove(&(drm_lease_owner(master)->lessee_idr), master->lessee_id); } /* Remove this master from any lessee list it may be on */ list_del(&master->lessee_list); mutex_unlock(&dev->mode_config.idr_mutex); if (master->lessor) { /* Tell the master to check the lessee list */ drm_sysfs_lease_event(dev); drm_master_put(&master->lessor); } DRM_DEBUG_LEASE("drm_lease_destroy done %d\n", master->lessee_id); } static void _drm_lease_revoke(struct drm_master *top) { int object; void *entry; struct drm_master *master = top; lockdep_assert_held(&top->dev->mode_config.idr_mutex); /* * Walk the tree starting at 'top' emptying all leases. Because * the tree is fully connected, we can do this without recursing */ for (;;) { DRM_DEBUG_LEASE("revoke leases for %p %d\n", master, master->lessee_id); /* Evacuate the lease */ idr_for_each_entry(&master->leases, entry, object) idr_remove(&master->leases, object); /* Depth-first list walk */ /* Down */ if (!list_empty(&master->lessees)) { master = list_first_entry(&master->lessees, struct drm_master, lessee_list); } else { /* Up */ while (master != top && master == list_last_entry(&master->lessor->lessees, struct drm_master, lessee_list)) master = master->lessor; if (master == top) break; /* Over */ master = list_next_entry(master, lessee_list); } } } void drm_lease_revoke(struct drm_master *top) { mutex_lock(&top->dev->mode_config.idr_mutex); _drm_lease_revoke(top); mutex_unlock(&top->dev->mode_config.idr_mutex); } static int validate_lease(struct drm_device *dev, int object_count, struct drm_mode_object **objects, bool universal_planes) { int o; int has_crtc = -1; int has_connector = -1; int has_plane = -1; /* we want to confirm that there is at least one crtc, plane connector object. */ for (o = 0; o < object_count; o++) { if (objects[o]->type == DRM_MODE_OBJECT_CRTC && has_crtc == -1) { has_crtc = o; } if (objects[o]->type == DRM_MODE_OBJECT_CONNECTOR && has_connector == -1) has_connector = o; if (universal_planes) { if (objects[o]->type == DRM_MODE_OBJECT_PLANE && has_plane == -1) has_plane = o; } } if (has_crtc == -1 || has_connector == -1) return -EINVAL; if (universal_planes && has_plane == -1) return -EINVAL; return 0; } static int fill_object_idr(struct drm_device *dev, struct drm_file *lessor_priv, struct idr *leases, int object_count, u32 *object_ids) { struct drm_mode_object **objects; u32 o; int ret; bool universal_planes = READ_ONCE(lessor_priv->universal_planes); objects = kcalloc(object_count, sizeof(struct drm_mode_object *), GFP_KERNEL); if (!objects) return -ENOMEM; /* step one - get references to all the mode objects and check for validity. */ for (o = 0; o < object_count; o++) { objects[o] = drm_mode_object_find(dev, lessor_priv, object_ids[o], DRM_MODE_OBJECT_ANY); if (!objects[o]) { ret = -ENOENT; goto out_free_objects; } if (!drm_mode_object_lease_required(objects[o]->type)) { DRM_DEBUG_KMS("invalid object for lease\n"); ret = -EINVAL; goto out_free_objects; } } ret = validate_lease(dev, object_count, objects, universal_planes); if (ret) { DRM_DEBUG_LEASE("lease validation failed\n"); goto out_free_objects; } /* add their IDs to the lease request - taking into account universal planes */ for (o = 0; o < object_count; o++) { struct drm_mode_object *obj = objects[o]; u32 object_id = objects[o]->id; DRM_DEBUG_LEASE("Adding object %d to lease\n", object_id); /* * We're using an IDR to hold the set of leased * objects, but we don't need to point at the object's * data structure from the lease as the main object_idr * will be used to actually find that. Instead, all we * really want is a 'leased/not-leased' result, for * which any non-NULL pointer will work fine. */ ret = idr_alloc(leases, &drm_lease_idr_object , object_id, object_id + 1, GFP_KERNEL); if (ret < 0) { DRM_DEBUG_LEASE("Object %d cannot be inserted into leases (%d)\n", object_id, ret); goto out_free_objects; } if (obj->type == DRM_MODE_OBJECT_CRTC && !universal_planes) { struct drm_crtc *crtc = obj_to_crtc(obj); ret = idr_alloc(leases, &drm_lease_idr_object, crtc->primary->base.id, crtc->primary->base.id + 1, GFP_KERNEL); if (ret < 0) { DRM_DEBUG_LEASE("Object primary plane %d cannot be inserted into leases (%d)\n", object_id, ret); goto out_free_objects; } if (crtc->cursor) { ret = idr_alloc(leases, &drm_lease_idr_object, crtc->cursor->base.id, crtc->cursor->base.id + 1, GFP_KERNEL); if (ret < 0) { DRM_DEBUG_LEASE("Object cursor plane %d cannot be inserted into leases (%d)\n", object_id, ret); goto out_free_objects; } } } } ret = 0; out_free_objects: for (o = 0; o < object_count; o++) { if (objects[o]) drm_mode_object_put(objects[o]); } kfree(objects); return ret; } /* * The master associated with the specified file will have a lease * created containing the objects specified in the ioctl structure. * A file descriptor will be allocated for that and returned to the * application. */ int drm_mode_create_lease_ioctl(struct drm_device *dev, void *data, struct drm_file *lessor_priv) { struct drm_mode_create_lease *cl = data; size_t object_count; int ret = 0; struct idr leases; struct drm_master *lessor; struct drm_master *lessee = NULL; struct file *lessee_file = NULL; struct file *lessor_file = lessor_priv->filp; struct drm_file *lessee_priv; int fd = -1; uint32_t *object_ids; /* Can't lease without MODESET */ if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; if (cl->flags && (cl->flags & ~(O_CLOEXEC | O_NONBLOCK))) { DRM_DEBUG_LEASE("invalid flags\n"); return -EINVAL; } lessor = drm_file_get_master(lessor_priv); /* Do not allow sub-leases */ if (lessor->lessor) { DRM_DEBUG_LEASE("recursive leasing not allowed\n"); ret = -EINVAL; goto out_lessor; } object_count = cl->object_count; /* Handle leased objects, if any */ idr_init(&leases); if (object_count != 0) { object_ids = memdup_user(u64_to_user_ptr(cl->object_ids), array_size(object_count, sizeof(__u32))); if (IS_ERR(object_ids)) { ret = PTR_ERR(object_ids); idr_destroy(&leases); goto out_lessor; } /* fill and validate the object idr */ ret = fill_object_idr(dev, lessor_priv, &leases, object_count, object_ids); kfree(object_ids); if (ret) { DRM_DEBUG_LEASE("lease object lookup failed: %i\n", ret); idr_destroy(&leases); goto out_lessor; } } /* Allocate a file descriptor for the lease */ fd = get_unused_fd_flags(cl->flags & (O_CLOEXEC | O_NONBLOCK)); if (fd < 0) { idr_destroy(&leases); ret = fd; goto out_lessor; } DRM_DEBUG_LEASE("Creating lease\n"); /* lessee will take the ownership of leases */ lessee = drm_lease_create(lessor, &leases); if (IS_ERR(lessee)) { ret = PTR_ERR(lessee); idr_destroy(&leases); goto out_leases; } /* Clone the lessor file to create a new file for us */ DRM_DEBUG_LEASE("Allocating lease file\n"); lessee_file = file_clone_open(lessor_file); if (IS_ERR(lessee_file)) { ret = PTR_ERR(lessee_file); goto out_lessee; } lessee_priv = lessee_file->private_data; /* Change the file to a master one */ drm_master_put(&lessee_priv->master); lessee_priv->master = lessee; lessee_priv->is_master = 1; lessee_priv->authenticated = 1; /* Pass fd back to userspace */ DRM_DEBUG_LEASE("Returning fd %d id %d\n", fd, lessee->lessee_id); cl->fd = fd; cl->lessee_id = lessee->lessee_id; /* Hook up the fd */ fd_install(fd, lessee_file); drm_master_put(&lessor); DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl succeeded\n"); return 0; out_lessee: drm_master_put(&lessee); out_leases: put_unused_fd(fd); out_lessor: drm_master_put(&lessor); DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret); return ret; } int drm_mode_list_lessees_ioctl(struct drm_device *dev, void *data, struct drm_file *lessor_priv) { struct drm_mode_list_lessees *arg = data; __u32 __user *lessee_ids = (__u32 __user *) (uintptr_t) (arg->lessees_ptr); __u32 count_lessees = arg->count_lessees; struct drm_master *lessor, *lessee; int count; int ret = 0; if (arg->pad) return -EINVAL; /* Can't lease without MODESET */ if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; lessor = drm_file_get_master(lessor_priv); DRM_DEBUG_LEASE("List lessees for %d\n", lessor->lessee_id); mutex_lock(&dev->mode_config.idr_mutex); count = 0; drm_for_each_lessee(lessee, lessor) { /* Only list un-revoked leases */ if (!idr_is_empty(&lessee->leases)) { if (count_lessees > count) { DRM_DEBUG_LEASE("Add lessee %d\n", lessee->lessee_id); ret = put_user(lessee->lessee_id, lessee_ids + count); if (ret) break; } count++; } } DRM_DEBUG_LEASE("Lessor leases to %d\n", count); if (ret == 0) arg->count_lessees = count; mutex_unlock(&dev->mode_config.idr_mutex); drm_master_put(&lessor); return ret; } /* Return the list of leased objects for the specified lessee */ int drm_mode_get_lease_ioctl(struct drm_device *dev, void *data, struct drm_file *lessee_priv) { struct drm_mode_get_lease *arg = data; __u32 __user *object_ids = (__u32 __user *) (uintptr_t) (arg->objects_ptr); __u32 count_objects = arg->count_objects; struct drm_master *lessee; struct idr *object_idr; int count; void *entry; int object; int ret = 0; if (arg->pad) return -EINVAL; /* Can't lease without MODESET */ if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; lessee = drm_file_get_master(lessee_priv); DRM_DEBUG_LEASE("get lease for %d\n", lessee->lessee_id); mutex_lock(&dev->mode_config.idr_mutex); if (lessee->lessor == NULL) /* owner can use all objects */ object_idr = &lessee->dev->mode_config.object_idr; else /* lessee can only use allowed object */ object_idr = &lessee->leases; count = 0; idr_for_each_entry(object_idr, entry, object) { if (count_objects > count) { DRM_DEBUG_LEASE("adding object %d\n", object); ret = put_user(object, object_ids + count); if (ret) break; } count++; } DRM_DEBUG("lease holds %d objects\n", count); if (ret == 0) arg->count_objects = count; mutex_unlock(&dev->mode_config.idr_mutex); drm_master_put(&lessee); return ret; } /* * This removes all of the objects from the lease without * actually getting rid of the lease itself; that way all * references to it still work correctly */ int drm_mode_revoke_lease_ioctl(struct drm_device *dev, void *data, struct drm_file *lessor_priv) { struct drm_mode_revoke_lease *arg = data; struct drm_master *lessor; struct drm_master *lessee; int ret = 0; DRM_DEBUG_LEASE("revoke lease for %d\n", arg->lessee_id); /* Can't lease without MODESET */ if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; lessor = drm_file_get_master(lessor_priv); mutex_lock(&dev->mode_config.idr_mutex); lessee = _drm_find_lessee(lessor, arg->lessee_id); /* No such lessee */ if (!lessee) { ret = -ENOENT; goto fail; } /* Lease is not held by lessor */ if (lessee->lessor != lessor) { ret = -EACCES; goto fail; } _drm_lease_revoke(lessee); fail: mutex_unlock(&dev->mode_config.idr_mutex); drm_master_put(&lessor); return ret; }