diff options
Diffstat (limited to 'drivers/gpu/drm/drm_lease.c')
| -rw-r--r-- | drivers/gpu/drm/drm_lease.c | 729 |
1 files changed, 729 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c new file mode 100644 index 000000000..b7362356e --- /dev/null +++ b/drivers/gpu/drm/drm_lease.c @@ -0,0 +1,729 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright © 2017 Keith Packard <keithp@keithp.com> + */ +#include <linux/file.h> +#include <linux/uaccess.h> + +#include <drm/drm_auth.h> +#include <drm/drm_crtc_helper.h> +#include <drm/drm_drv.h> +#include <drm/drm_file.h> +#include <drm/drm_lease.h> +#include <drm/drm_print.h> + +#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_array_user(u64_to_user_ptr(cl->object_ids), + 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; +} |