diff options
Diffstat (limited to 'drivers/of/overlay.c')
| -rw-r--r-- | drivers/of/overlay.c | 253 |
1 files changed, 213 insertions, 40 deletions
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c index 905916e17eec..78c50fd57750 100644 --- a/drivers/of/overlay.c +++ b/drivers/of/overlay.c @@ -50,6 +50,22 @@ struct overlay_changeset { struct of_changeset cset; }; +/* flags are sticky - once set, do not reset */ +static int devicetree_state_flags; +#define DTSF_APPLY_FAIL 0x01 +#define DTSF_REVERT_FAIL 0x02 + +/* + * If a changeset apply or revert encounters an error, an attempt will + * be made to undo partial changes, but may fail. If the undo fails + * we do not know the state of the devicetree. + */ +static int devicetree_corrupt(void) +{ + return devicetree_state_flags & + (DTSF_APPLY_FAIL | DTSF_REVERT_FAIL); +} + static int build_changeset_next_level(struct overlay_changeset *ovcs, struct device_node *target_node, const struct device_node *overlay_node, @@ -72,6 +88,13 @@ int of_overlay_notifier_unregister(struct notifier_block *nb) } EXPORT_SYMBOL_GPL(of_overlay_notifier_unregister); +static char *of_overlay_action_name[] = { + "pre-apply", + "post-apply", + "pre-remove", + "post-remove", +}; + static int overlay_notify(struct overlay_changeset *ovcs, enum of_overlay_notify_action action) { @@ -86,8 +109,14 @@ static int overlay_notify(struct overlay_changeset *ovcs, ret = blocking_notifier_call_chain(&overlay_notify_chain, action, &nd); - if (ret) - return notifier_to_errno(ret); + if (ret == NOTIFY_STOP) + return 0; + if (ret) { + ret = notifier_to_errno(ret); + pr_err("overlay changeset %s notifier error %d, target: %pOF\n", + of_overlay_action_name[action], ret, nd.target); + return ret; + } } return 0; @@ -240,6 +269,14 @@ static int add_changeset_property(struct overlay_changeset *ovcs, * build_changeset_next_level(). * * NOTE: Multiple mods of created nodes not supported. + * If more than one fragment contains a node that does not already exist + * in the live tree, then for each fragment of_changeset_attach_node() + * will add a changeset entry to add the node. When the changeset is + * applied, __of_attach_node() will attach the node twice (once for + * each fragment). At this point the device tree will be corrupted. + * + * TODO: add integrity check to ensure that multiple fragments do not + * create the same node. * * Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if * invalid @overlay. @@ -312,8 +349,8 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs, ret = add_changeset_property(ovcs, target_node, prop, is_symbols_node); if (ret) { - pr_err("Failed to apply prop @%pOF/%s\n", - target_node, prop->name); + pr_debug("Failed to apply prop @%pOF/%s, err=%d\n", + target_node, prop->name, ret); return ret; } } @@ -324,8 +361,8 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs, for_each_child_of_node(overlay_node, child) { ret = add_changeset_node(ovcs, target_node, child); if (ret) { - pr_err("Failed to apply node @%pOF/%s\n", - target_node, child->name); + pr_debug("Failed to apply node @%pOF/%s, err=%d\n", + target_node, child->name, ret); of_node_put(child); return ret; } @@ -357,7 +394,7 @@ static int build_changeset(struct overlay_changeset *ovcs) fragment->overlay, fragment->is_symbols_node); if (ret) { - pr_err("apply failed '%pOF'\n", fragment->target); + pr_debug("apply failed '%pOF'\n", fragment->target); return ret; } } @@ -412,6 +449,19 @@ static int init_overlay_changeset(struct overlay_changeset *ovcs, struct fragment *fragments; int cnt, ret; + /* + * Warn for some issues. Can not return -EINVAL for these until + * of_unittest_apply_overlay() is fixed to pass these checks. + */ + if (!of_node_check_flag(tree, OF_DYNAMIC)) + pr_debug("%s() tree is not dynamic\n", __func__); + + if (!of_node_check_flag(tree, OF_DETACHED)) + pr_debug("%s() tree is not detached\n", __func__); + + if (!of_node_is_root(tree)) + pr_debug("%s() tree is not root\n", __func__); + INIT_LIST_HEAD(&ovcs->ovcs_list); of_changeset_init(&ovcs->cset); @@ -485,12 +535,13 @@ static int init_overlay_changeset(struct overlay_changeset *ovcs, return 0; - err_free_fragments: kfree(fragments); err_free_idr: idr_remove(&ovcs_idr, ovcs->id); + pr_err("%s() failed, ret = %d\n", __func__, ret); + return ret; } @@ -517,33 +568,71 @@ static void free_overlay_changeset(struct overlay_changeset *ovcs) /** * of_overlay_apply() - Create and apply an overlay changeset * @tree: Expanded overlay device tree + * @ovcs_id: Pointer to overlay changeset id + * + * Creates and applies an overlay changeset. * - * Creates and applies an overlay changeset. If successful, the overlay - * changeset is added to the overlay changeset list. + * If an error occurs in a pre-apply notifier, then no changes are made + * to the device tree. * - * Returns the id of the created overlay changeset, or a negative error number + + * A non-zero return value will not have created the changeset if error is from: + * - parameter checks + * - building the changeset + * - overlay changset pre-apply notifier + * + * If an error is returned by an overlay changeset pre-apply notifier + * then no further overlay changeset pre-apply notifier will be called. + * + * A non-zero return value will have created the changeset if error is from: + * - overlay changeset entry notifier + * - overlay changset post-apply notifier + * + * If an error is returned by an overlay changeset post-apply notifier + * then no further overlay changeset post-apply notifier will be called. + * + * If more than one notifier returns an error, then the last notifier + * error to occur is returned. + * + * If an error occurred while applying the overlay changeset, then an + * attempt is made to revert any changes that were made to the + * device tree. If there were any errors during the revert attempt + * then the state of the device tree can not be determined, and any + * following attempt to apply or remove an overlay changeset will be + * refused. + * + * Returns 0 on success, or a negative error number. Overlay changeset + * id is returned to *ovcs_id. */ -int of_overlay_apply(struct device_node *tree) + +int of_overlay_apply(struct device_node *tree, int *ovcs_id) { struct overlay_changeset *ovcs; - int ret; + int ret = 0, ret_revert, ret_tmp; + + *ovcs_id = 0; + + if (devicetree_corrupt()) { + pr_err("devicetree state suspect, refuse to apply overlay\n"); + ret = -EBUSY; + goto out; + } ovcs = kzalloc(sizeof(*ovcs), GFP_KERNEL); - if (!ovcs) - return -ENOMEM; + if (!ovcs) { + ret = -ENOMEM; + goto out; + } mutex_lock(&of_mutex); ret = init_overlay_changeset(ovcs, tree); - if (ret) { - pr_err("init_overlay_changeset() failed, ret = %d\n", ret); + if (ret) goto err_free_overlay_changeset; - } ret = overlay_notify(ovcs, OF_OVERLAY_PRE_APPLY); - if (ret < 0) { - pr_err("%s: Pre-apply notifier failed (ret=%d)\n", - __func__, ret); + if (ret) { + pr_err("overlay changeset pre-apply notify error %d\n", ret); goto err_free_overlay_changeset; } @@ -551,23 +640,46 @@ int of_overlay_apply(struct device_node *tree) if (ret) goto err_free_overlay_changeset; - ret = __of_changeset_apply(&ovcs->cset); - if (ret) + ret_revert = 0; + ret = __of_changeset_apply_entries(&ovcs->cset, &ret_revert); + if (ret) { + if (ret_revert) { + pr_debug("overlay changeset revert error %d\n", + ret_revert); + devicetree_state_flags |= DTSF_APPLY_FAIL; + } goto err_free_overlay_changeset; + } else { + ret = __of_changeset_apply_notify(&ovcs->cset); + if (ret) + pr_err("overlay changeset entry notify error %d\n", + ret); + /* fall through */ + } list_add_tail(&ovcs->ovcs_list, &ovcs_list); - - overlay_notify(ovcs, OF_OVERLAY_POST_APPLY); + *ovcs_id = ovcs->id; + + ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_APPLY); + if (ret_tmp) { + pr_err("overlay changeset post-apply notify error %d\n", + ret_tmp); + if (!ret) + ret = ret_tmp; + } mutex_unlock(&of_mutex); - return ovcs->id; + goto out; err_free_overlay_changeset: free_overlay_changeset(ovcs); mutex_unlock(&of_mutex); +out: + pr_debug("%s() err=%d\n", __func__, ret); + return ret; } EXPORT_SYMBOL_GPL(of_overlay_apply); @@ -649,45 +761,106 @@ static int overlay_removal_is_ok(struct overlay_changeset *remove_ovcs) /** * of_overlay_remove() - Revert and free an overlay changeset - * @ovcs_id: Overlay changeset id number + * @ovcs_id: Pointer to overlay changeset id * - * Removes an overlay if it is permissible. ovcs_id was previously returned + * Removes an overlay if it is permissible. @ovcs_id was previously returned * by of_overlay_apply(). * - * Returns 0 on success, or a negative error number + * If an error occurred while attempting to revert the overlay changeset, + * then an attempt is made to re-apply any changeset entry that was + * reverted. If an error occurs on re-apply then the state of the device + * tree can not be determined, and any following attempt to apply or remove + * an overlay changeset will be refused. + * + * A non-zero return value will not revert the changeset if error is from: + * - parameter checks + * - overlay changset pre-remove notifier + * - overlay changeset entry revert + * + * If an error is returned by an overlay changeset pre-remove notifier + * then no further overlay changeset pre-remove notifier will be called. + * + * If more than one notifier returns an error, then the last notifier + * error to occur is returned. + * + * A non-zero return value will revert the changeset if error is from: + * - overlay changeset entry notifier + * - overlay changset post-remove notifier + * + * If an error is returned by an overlay changeset post-remove notifier + * then no further overlay changeset post-remove notifier will be called. + * + * Returns 0 on success, or a negative error number. *ovcs_id is set to + * zero after reverting the changeset, even if a subsequent error occurs. */ -int of_overlay_remove(int ovcs_id) +int of_overlay_remove(int *ovcs_id) { struct overlay_changeset *ovcs; - int ret = 0; + int ret, ret_apply, ret_tmp; + + ret = 0; + + if (devicetree_corrupt()) { + pr_err("suspect devicetree state, refuse to remove overlay\n"); + ret = -EBUSY; + goto out; + } mutex_lock(&of_mutex); - ovcs = idr_find(&ovcs_idr, ovcs_id); + ovcs = idr_find(&ovcs_idr, *ovcs_id); if (!ovcs) { ret = -ENODEV; - pr_err("remove: Could not find overlay #%d\n", ovcs_id); - goto out; + pr_err("remove: Could not find overlay #%d\n", *ovcs_id); + goto out_unlock; } if (!overlay_removal_is_ok(ovcs)) { ret = -EBUSY; - goto out; + goto out_unlock; } - overlay_notify(ovcs, OF_OVERLAY_PRE_REMOVE); + ret = overlay_notify(ovcs, OF_OVERLAY_PRE_REMOVE); + if (ret) { + pr_err("overlay changeset pre-remove notify error %d\n", ret); + goto out_unlock; + } list_del(&ovcs->ovcs_list); - __of_changeset_revert(&ovcs->cset); + ret_apply = 0; + ret = __of_changeset_revert_entries(&ovcs->cset, &ret_apply); + if (ret) { + if (ret_apply) + devicetree_state_flags |= DTSF_REVERT_FAIL; + goto out_unlock; + } else { + ret = __of_changeset_revert_notify(&ovcs->cset); + if (ret) { + pr_err("overlay changeset entry notify error %d\n", + ret); + /* fall through - changeset was reverted */ + } + } - overlay_notify(ovcs, OF_OVERLAY_POST_REMOVE); + *ovcs_id = 0; + + ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_REMOVE); + if (ret_tmp) { + pr_err("overlay changeset post-remove notify error %d\n", + ret_tmp); + if (!ret) + ret = ret_tmp; + } free_overlay_changeset(ovcs); -out: +out_unlock: mutex_unlock(&of_mutex); +out: + pr_debug("%s() err=%d\n", __func__, ret); + return ret; } EXPORT_SYMBOL_GPL(of_overlay_remove); @@ -706,7 +879,7 @@ int of_overlay_remove_all(void) /* the tail of list is guaranteed to be safe to remove */ list_for_each_entry_safe_reverse(ovcs, ovcs_n, &ovcs_list, ovcs_list) { - ret = of_overlay_remove(ovcs->id); + ret = of_overlay_remove(&ovcs->id); if (ret) return ret; } |