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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright © 2017 Keith Packard <keithp@keithp.com>4 */5#include <linux/file.h>6#include <linux/uaccess.h>7 8#include <drm/drm_auth.h>9#include <drm/drm_crtc.h>10#include <drm/drm_drv.h>11#include <drm/drm_file.h>12#include <drm/drm_lease.h>13#include <drm/drm_print.h>14 15#include "drm_crtc_internal.h"16#include "drm_internal.h"17 18/**19 * DOC: drm leasing20 *21 * DRM leases provide information about whether a DRM master may control a DRM22 * mode setting object. This enables the creation of multiple DRM masters that23 * manage subsets of display resources.24 *25 * The original DRM master of a device 'owns' the available drm resources. It26 * may create additional DRM masters and 'lease' resources which it controls27 * to the new DRM master. This gives the new DRM master control over the28 * leased resources until the owner revokes the lease, or the new DRM master29 * is closed. Some helpful terminology:30 *31 * - An 'owner' is a &struct drm_master that is not leasing objects from32 * another &struct drm_master, and hence 'owns' the objects. The owner can be33 * identified as the &struct drm_master for which &drm_master.lessor is NULL.34 *35 * - A 'lessor' is a &struct drm_master which is leasing objects to one or more36 * other &struct drm_master. Currently, lessees are not allowed to37 * create sub-leases, hence the lessor is the same as the owner.38 *39 * - A 'lessee' is a &struct drm_master which is leasing objects from some40 * other &struct drm_master. Each lessee only leases resources from a single41 * lessor recorded in &drm_master.lessor, and holds the set of objects that42 * it is leasing in &drm_master.leases.43 *44 * - A 'lease' is a contract between the lessor and lessee that identifies45 * which resources may be controlled by the lessee. All of the resources46 * that are leased must be owned by or leased to the lessor, and lessors are47 * not permitted to lease the same object to multiple lessees.48 *49 * The set of objects any &struct drm_master 'controls' is limited to the set50 * of objects it leases (for lessees) or all objects (for owners).51 *52 * Objects not controlled by a &struct drm_master cannot be modified through53 * the various state manipulating ioctls, and any state reported back to user54 * space will be edited to make them appear idle and/or unusable. For55 * instance, connectors always report 'disconnected', while encoders56 * report no possible crtcs or clones.57 *58 * Since each lessee may lease objects from a single lessor, display resource59 * leases form a tree of &struct drm_master. As lessees are currently not60 * allowed to create sub-leases, the tree depth is limited to 1. All of61 * these get activated simultaneously when the top level device owner changes62 * through the SETMASTER or DROPMASTER IOCTL, so &drm_device.master points to63 * the owner at the top of the lease tree (i.e. the &struct drm_master for which64 * &drm_master.lessor is NULL). The full list of lessees that are leasing65 * objects from the owner can be searched via the owner's66 * &drm_master.lessee_idr.67 */68 69#define drm_for_each_lessee(lessee, lessor) \70 list_for_each_entry((lessee), &(lessor)->lessees, lessee_list)71 72static uint64_t drm_lease_idr_object;73 74struct drm_master *drm_lease_owner(struct drm_master *master)75{76 while (master->lessor != NULL)77 master = master->lessor;78 return master;79}80 81static struct drm_master*82_drm_find_lessee(struct drm_master *master, int lessee_id)83{84 lockdep_assert_held(&master->dev->mode_config.idr_mutex);85 return idr_find(&drm_lease_owner(master)->lessee_idr, lessee_id);86}87 88static int _drm_lease_held_master(struct drm_master *master, int id)89{90 lockdep_assert_held(&master->dev->mode_config.idr_mutex);91 if (master->lessor)92 return idr_find(&master->leases, id) != NULL;93 return true;94}95 96/* Checks if the given object has been leased to some lessee of drm_master */97static bool _drm_has_leased(struct drm_master *master, int id)98{99 struct drm_master *lessee;100 101 lockdep_assert_held(&master->dev->mode_config.idr_mutex);102 drm_for_each_lessee(lessee, master)103 if (_drm_lease_held_master(lessee, id))104 return true;105 return false;106}107 108/* Called with idr_mutex held */109bool _drm_lease_held(struct drm_file *file_priv, int id)110{111 bool ret;112 struct drm_master *master;113 114 if (!file_priv)115 return true;116 117 master = drm_file_get_master(file_priv);118 if (!master)119 return true;120 ret = _drm_lease_held_master(master, id);121 drm_master_put(&master);122 123 return ret;124}125 126bool drm_lease_held(struct drm_file *file_priv, int id)127{128 struct drm_master *master;129 bool ret;130 131 if (!file_priv)132 return true;133 134 master = drm_file_get_master(file_priv);135 if (!master)136 return true;137 if (!master->lessor) {138 ret = true;139 goto out;140 }141 mutex_lock(&master->dev->mode_config.idr_mutex);142 ret = _drm_lease_held_master(master, id);143 mutex_unlock(&master->dev->mode_config.idr_mutex);144 145out:146 drm_master_put(&master);147 return ret;148}149 150/*151 * Given a bitmask of crtcs to check, reconstructs a crtc mask based on the152 * crtcs which are visible through the specified file.153 */154uint32_t drm_lease_filter_crtcs(struct drm_file *file_priv, uint32_t crtcs_in)155{156 struct drm_master *master;157 struct drm_device *dev;158 struct drm_crtc *crtc;159 int count_in, count_out;160 uint32_t crtcs_out = 0;161 162 if (!file_priv)163 return crtcs_in;164 165 master = drm_file_get_master(file_priv);166 if (!master)167 return crtcs_in;168 if (!master->lessor) {169 crtcs_out = crtcs_in;170 goto out;171 }172 dev = master->dev;173 174 count_in = count_out = 0;175 mutex_lock(&master->dev->mode_config.idr_mutex);176 list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {177 if (_drm_lease_held_master(master, crtc->base.id)) {178 uint32_t mask_in = 1ul << count_in;179 180 if ((crtcs_in & mask_in) != 0) {181 uint32_t mask_out = 1ul << count_out;182 183 crtcs_out |= mask_out;184 }185 count_out++;186 }187 count_in++;188 }189 mutex_unlock(&master->dev->mode_config.idr_mutex);190 191out:192 drm_master_put(&master);193 return crtcs_out;194}195 196/*197 * Uses drm_master_create to allocate a new drm_master, then checks to198 * make sure all of the desired objects can be leased, atomically199 * leasing them to the new drmmaster.200 *201 * ERR_PTR(-EACCES) some other master holds the title to any object202 * ERR_PTR(-ENOENT) some object is not a valid DRM object for this device203 * ERR_PTR(-EBUSY) some other lessee holds title to this object204 * ERR_PTR(-EEXIST) same object specified more than once in the provided list205 * ERR_PTR(-ENOMEM) allocation failed206 */207static struct drm_master *drm_lease_create(struct drm_master *lessor, struct idr *leases)208{209 struct drm_device *dev = lessor->dev;210 int error;211 struct drm_master *lessee;212 int object;213 int id;214 void *entry;215 216 drm_dbg_lease(dev, "lessor %d\n", lessor->lessee_id);217 218 lessee = drm_master_create(lessor->dev);219 if (!lessee) {220 drm_dbg_lease(dev, "drm_master_create failed\n");221 return ERR_PTR(-ENOMEM);222 }223 224 mutex_lock(&dev->mode_config.idr_mutex);225 226 idr_for_each_entry(leases, entry, object) {227 error = 0;228 if (!idr_find(&dev->mode_config.object_idr, object))229 error = -ENOENT;230 else if (_drm_has_leased(lessor, object))231 error = -EBUSY;232 233 if (error != 0) {234 drm_dbg_lease(dev, "object %d failed %d\n", object, error);235 goto out_lessee;236 }237 }238 239 /* Insert the new lessee into the tree */240 id = idr_alloc(&(drm_lease_owner(lessor)->lessee_idr), lessee, 1, 0, GFP_KERNEL);241 if (id < 0) {242 error = id;243 goto out_lessee;244 }245 246 lessee->lessee_id = id;247 lessee->lessor = drm_master_get(lessor);248 list_add_tail(&lessee->lessee_list, &lessor->lessees);249 250 /* Move the leases over */251 lessee->leases = *leases;252 drm_dbg_lease(dev, "new lessee %d %p, lessor %d %p\n",253 lessee->lessee_id, lessee, lessor->lessee_id, lessor);254 255 mutex_unlock(&dev->mode_config.idr_mutex);256 return lessee;257 258out_lessee:259 mutex_unlock(&dev->mode_config.idr_mutex);260 261 drm_master_put(&lessee);262 263 return ERR_PTR(error);264}265 266void drm_lease_destroy(struct drm_master *master)267{268 struct drm_device *dev = master->dev;269 270 mutex_lock(&dev->mode_config.idr_mutex);271 272 drm_dbg_lease(dev, "drm_lease_destroy %d\n", master->lessee_id);273 274 /* This master is referenced by all lessees, hence it cannot be destroyed275 * until all of them have been276 */277 WARN_ON(!list_empty(&master->lessees));278 279 /* Remove this master from the lessee idr in the owner */280 if (master->lessee_id != 0) {281 drm_dbg_lease(dev, "remove master %d from device list of lessees\n",282 master->lessee_id);283 idr_remove(&(drm_lease_owner(master)->lessee_idr), master->lessee_id);284 }285 286 /* Remove this master from any lessee list it may be on */287 list_del(&master->lessee_list);288 289 mutex_unlock(&dev->mode_config.idr_mutex);290 291 if (master->lessor) {292 /* Tell the master to check the lessee list */293 drm_sysfs_lease_event(dev);294 drm_master_put(&master->lessor);295 }296 297 drm_dbg_lease(dev, "drm_lease_destroy done %d\n", master->lessee_id);298}299 300static void _drm_lease_revoke(struct drm_master *top)301{302 int object;303 void *entry;304 struct drm_master *master = top;305 306 lockdep_assert_held(&top->dev->mode_config.idr_mutex);307 308 /*309 * Walk the tree starting at 'top' emptying all leases. Because310 * the tree is fully connected, we can do this without recursing311 */312 for (;;) {313 drm_dbg_lease(master->dev, "revoke leases for %p %d\n",314 master, master->lessee_id);315 316 /* Evacuate the lease */317 idr_for_each_entry(&master->leases, entry, object)318 idr_remove(&master->leases, object);319 320 /* Depth-first list walk */321 322 /* Down */323 if (!list_empty(&master->lessees)) {324 master = list_first_entry(&master->lessees, struct drm_master, lessee_list);325 } else {326 /* Up */327 while (master != top && master == list_last_entry(&master->lessor->lessees, struct drm_master, lessee_list))328 master = master->lessor;329 330 if (master == top)331 break;332 333 /* Over */334 master = list_next_entry(master, lessee_list);335 }336 }337}338 339void drm_lease_revoke(struct drm_master *top)340{341 mutex_lock(&top->dev->mode_config.idr_mutex);342 _drm_lease_revoke(top);343 mutex_unlock(&top->dev->mode_config.idr_mutex);344}345 346static int validate_lease(struct drm_device *dev,347 int object_count,348 struct drm_mode_object **objects,349 bool universal_planes)350{351 int o;352 int has_crtc = -1;353 int has_connector = -1;354 int has_plane = -1;355 356 /* we want to confirm that there is at least one crtc, plane357 connector object. */358 359 for (o = 0; o < object_count; o++) {360 if (objects[o]->type == DRM_MODE_OBJECT_CRTC && has_crtc == -1) {361 has_crtc = o;362 }363 if (objects[o]->type == DRM_MODE_OBJECT_CONNECTOR && has_connector == -1)364 has_connector = o;365 366 if (universal_planes) {367 if (objects[o]->type == DRM_MODE_OBJECT_PLANE && has_plane == -1)368 has_plane = o;369 }370 }371 if (has_crtc == -1 || has_connector == -1)372 return -EINVAL;373 if (universal_planes && has_plane == -1)374 return -EINVAL;375 return 0;376}377 378static int fill_object_idr(struct drm_device *dev,379 struct drm_file *lessor_priv,380 struct idr *leases,381 int object_count,382 u32 *object_ids)383{384 struct drm_mode_object **objects;385 u32 o;386 int ret;387 bool universal_planes = READ_ONCE(lessor_priv->universal_planes);388 389 objects = kcalloc(object_count, sizeof(struct drm_mode_object *),390 GFP_KERNEL);391 if (!objects)392 return -ENOMEM;393 394 /* step one - get references to all the mode objects395 and check for validity. */396 for (o = 0; o < object_count; o++) {397 objects[o] = drm_mode_object_find(dev, lessor_priv,398 object_ids[o],399 DRM_MODE_OBJECT_ANY);400 if (!objects[o]) {401 ret = -ENOENT;402 goto out_free_objects;403 }404 405 if (!drm_mode_object_lease_required(objects[o]->type)) {406 DRM_DEBUG_KMS("invalid object for lease\n");407 ret = -EINVAL;408 goto out_free_objects;409 }410 }411 412 ret = validate_lease(dev, object_count, objects, universal_planes);413 if (ret) {414 drm_dbg_lease(dev, "lease validation failed\n");415 goto out_free_objects;416 }417 418 /* add their IDs to the lease request - taking into account419 universal planes */420 for (o = 0; o < object_count; o++) {421 struct drm_mode_object *obj = objects[o];422 u32 object_id = objects[o]->id;423 424 drm_dbg_lease(dev, "Adding object %d to lease\n", object_id);425 426 /*427 * We're using an IDR to hold the set of leased428 * objects, but we don't need to point at the object's429 * data structure from the lease as the main object_idr430 * will be used to actually find that. Instead, all we431 * really want is a 'leased/not-leased' result, for432 * which any non-NULL pointer will work fine.433 */434 ret = idr_alloc(leases, &drm_lease_idr_object , object_id, object_id + 1, GFP_KERNEL);435 if (ret < 0) {436 drm_dbg_lease(dev, "Object %d cannot be inserted into leases (%d)\n",437 object_id, ret);438 goto out_free_objects;439 }440 if (obj->type == DRM_MODE_OBJECT_CRTC && !universal_planes) {441 struct drm_crtc *crtc = obj_to_crtc(obj);442 443 ret = idr_alloc(leases, &drm_lease_idr_object, crtc->primary->base.id, crtc->primary->base.id + 1, GFP_KERNEL);444 if (ret < 0) {445 drm_dbg_lease(dev, "Object primary plane %d cannot be inserted into leases (%d)\n",446 object_id, ret);447 goto out_free_objects;448 }449 if (crtc->cursor) {450 ret = idr_alloc(leases, &drm_lease_idr_object, crtc->cursor->base.id, crtc->cursor->base.id + 1, GFP_KERNEL);451 if (ret < 0) {452 drm_dbg_lease(dev, "Object cursor plane %d cannot be inserted into leases (%d)\n",453 object_id, ret);454 goto out_free_objects;455 }456 }457 }458 }459 460 ret = 0;461out_free_objects:462 for (o = 0; o < object_count; o++) {463 if (objects[o])464 drm_mode_object_put(objects[o]);465 }466 kfree(objects);467 return ret;468}469 470/*471 * The master associated with the specified file will have a lease472 * created containing the objects specified in the ioctl structure.473 * A file descriptor will be allocated for that and returned to the474 * application.475 */476int drm_mode_create_lease_ioctl(struct drm_device *dev,477 void *data, struct drm_file *lessor_priv)478{479 struct drm_mode_create_lease *cl = data;480 size_t object_count;481 int ret = 0;482 struct idr leases;483 struct drm_master *lessor;484 struct drm_master *lessee = NULL;485 struct file *lessee_file = NULL;486 struct file *lessor_file = lessor_priv->filp;487 struct drm_file *lessee_priv;488 int fd = -1;489 uint32_t *object_ids;490 491 /* Can't lease without MODESET */492 if (!drm_core_check_feature(dev, DRIVER_MODESET))493 return -EOPNOTSUPP;494 495 if (cl->flags && (cl->flags & ~(O_CLOEXEC | O_NONBLOCK))) {496 drm_dbg_lease(dev, "invalid flags\n");497 return -EINVAL;498 }499 500 lessor = drm_file_get_master(lessor_priv);501 /* Do not allow sub-leases */502 if (lessor->lessor) {503 drm_dbg_lease(dev, "recursive leasing not allowed\n");504 ret = -EINVAL;505 goto out_lessor;506 }507 508 object_count = cl->object_count;509 510 /* Handle leased objects, if any */511 idr_init(&leases);512 if (object_count != 0) {513 object_ids = memdup_array_user(u64_to_user_ptr(cl->object_ids),514 object_count, sizeof(__u32));515 if (IS_ERR(object_ids)) {516 ret = PTR_ERR(object_ids);517 idr_destroy(&leases);518 goto out_lessor;519 }520 521 /* fill and validate the object idr */522 ret = fill_object_idr(dev, lessor_priv, &leases,523 object_count, object_ids);524 kfree(object_ids);525 if (ret) {526 drm_dbg_lease(dev, "lease object lookup failed: %i\n", ret);527 idr_destroy(&leases);528 goto out_lessor;529 }530 }531 532 /* Allocate a file descriptor for the lease */533 fd = get_unused_fd_flags(cl->flags & (O_CLOEXEC | O_NONBLOCK));534 if (fd < 0) {535 idr_destroy(&leases);536 ret = fd;537 goto out_lessor;538 }539 540 drm_dbg_lease(dev, "Creating lease\n");541 /* lessee will take the ownership of leases */542 lessee = drm_lease_create(lessor, &leases);543 544 if (IS_ERR(lessee)) {545 ret = PTR_ERR(lessee);546 idr_destroy(&leases);547 goto out_leases;548 }549 550 /* Clone the lessor file to create a new file for us */551 drm_dbg_lease(dev, "Allocating lease file\n");552 lessee_file = file_clone_open(lessor_file);553 if (IS_ERR(lessee_file)) {554 ret = PTR_ERR(lessee_file);555 goto out_lessee;556 }557 558 lessee_priv = lessee_file->private_data;559 /* Change the file to a master one */560 drm_master_put(&lessee_priv->master);561 lessee_priv->master = lessee;562 lessee_priv->is_master = 1;563 lessee_priv->authenticated = 1;564 565 /* Pass fd back to userspace */566 drm_dbg_lease(dev, "Returning fd %d id %d\n", fd, lessee->lessee_id);567 cl->fd = fd;568 cl->lessee_id = lessee->lessee_id;569 570 /* Hook up the fd */571 fd_install(fd, lessee_file);572 573 drm_master_put(&lessor);574 drm_dbg_lease(dev, "drm_mode_create_lease_ioctl succeeded\n");575 return 0;576 577out_lessee:578 drm_master_put(&lessee);579 580out_leases:581 put_unused_fd(fd);582 583out_lessor:584 drm_master_put(&lessor);585 drm_dbg_lease(dev, "drm_mode_create_lease_ioctl failed: %d\n", ret);586 return ret;587}588 589int drm_mode_list_lessees_ioctl(struct drm_device *dev,590 void *data, struct drm_file *lessor_priv)591{592 struct drm_mode_list_lessees *arg = data;593 __u32 __user *lessee_ids = (__u32 __user *) (uintptr_t) (arg->lessees_ptr);594 __u32 count_lessees = arg->count_lessees;595 struct drm_master *lessor, *lessee;596 int count;597 int ret = 0;598 599 if (arg->pad)600 return -EINVAL;601 602 /* Can't lease without MODESET */603 if (!drm_core_check_feature(dev, DRIVER_MODESET))604 return -EOPNOTSUPP;605 606 lessor = drm_file_get_master(lessor_priv);607 drm_dbg_lease(dev, "List lessees for %d\n", lessor->lessee_id);608 609 mutex_lock(&dev->mode_config.idr_mutex);610 611 count = 0;612 drm_for_each_lessee(lessee, lessor) {613 /* Only list un-revoked leases */614 if (!idr_is_empty(&lessee->leases)) {615 if (count_lessees > count) {616 drm_dbg_lease(dev, "Add lessee %d\n",617 lessee->lessee_id);618 ret = put_user(lessee->lessee_id, lessee_ids + count);619 if (ret)620 break;621 }622 count++;623 }624 }625 626 drm_dbg_lease(dev, "Lessor leases to %d\n", count);627 if (ret == 0)628 arg->count_lessees = count;629 630 mutex_unlock(&dev->mode_config.idr_mutex);631 drm_master_put(&lessor);632 633 return ret;634}635 636/* Return the list of leased objects for the specified lessee */637int drm_mode_get_lease_ioctl(struct drm_device *dev,638 void *data, struct drm_file *lessee_priv)639{640 struct drm_mode_get_lease *arg = data;641 __u32 __user *object_ids = (__u32 __user *) (uintptr_t) (arg->objects_ptr);642 __u32 count_objects = arg->count_objects;643 struct drm_master *lessee;644 struct idr *object_idr;645 int count;646 void *entry;647 int object;648 int ret = 0;649 650 if (arg->pad)651 return -EINVAL;652 653 /* Can't lease without MODESET */654 if (!drm_core_check_feature(dev, DRIVER_MODESET))655 return -EOPNOTSUPP;656 657 lessee = drm_file_get_master(lessee_priv);658 drm_dbg_lease(dev, "get lease for %d\n", lessee->lessee_id);659 660 mutex_lock(&dev->mode_config.idr_mutex);661 662 if (lessee->lessor == NULL)663 /* owner can use all objects */664 object_idr = &lessee->dev->mode_config.object_idr;665 else666 /* lessee can only use allowed object */667 object_idr = &lessee->leases;668 669 count = 0;670 idr_for_each_entry(object_idr, entry, object) {671 if (count_objects > count) {672 drm_dbg_lease(dev, "adding object %d\n", object);673 ret = put_user(object, object_ids + count);674 if (ret)675 break;676 }677 count++;678 }679 680 DRM_DEBUG("lease holds %d objects\n", count);681 if (ret == 0)682 arg->count_objects = count;683 684 mutex_unlock(&dev->mode_config.idr_mutex);685 drm_master_put(&lessee);686 687 return ret;688}689 690/*691 * This removes all of the objects from the lease without692 * actually getting rid of the lease itself; that way all693 * references to it still work correctly694 */695int drm_mode_revoke_lease_ioctl(struct drm_device *dev,696 void *data, struct drm_file *lessor_priv)697{698 struct drm_mode_revoke_lease *arg = data;699 struct drm_master *lessor;700 struct drm_master *lessee;701 int ret = 0;702 703 drm_dbg_lease(dev, "revoke lease for %d\n", arg->lessee_id);704 705 /* Can't lease without MODESET */706 if (!drm_core_check_feature(dev, DRIVER_MODESET))707 return -EOPNOTSUPP;708 709 lessor = drm_file_get_master(lessor_priv);710 mutex_lock(&dev->mode_config.idr_mutex);711 712 lessee = _drm_find_lessee(lessor, arg->lessee_id);713 714 /* No such lessee */715 if (!lessee) {716 ret = -ENOENT;717 goto fail;718 }719 720 /* Lease is not held by lessor */721 if (lessee->lessor != lessor) {722 ret = -EACCES;723 goto fail;724 }725 726 _drm_lease_revoke(lessee);727 728fail:729 mutex_unlock(&dev->mode_config.idr_mutex);730 drm_master_put(&lessor);731 732 return ret;733}734