| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Functions for working with device tree overlays |
| * |
| * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com> |
| * Copyright (C) 2012 Texas Instruments Inc. |
| */ |
| |
| #define pr_fmt(fmt) "OF: overlay: " fmt |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/of.h> |
| #include <linux/of_device.h> |
| #include <linux/of_fdt.h> |
| #include <linux/string.h> |
| #include <linux/ctype.h> |
| #include <linux/errno.h> |
| #include <linux/slab.h> |
| #include <linux/libfdt.h> |
| #include <linux/err.h> |
| #include <linux/idr.h> |
| |
| #include "of_private.h" |
| |
| /** |
| * struct fragment - info about fragment nodes in overlay expanded device tree |
| * @target: target of the overlay operation |
| * @overlay: pointer to the __overlay__ node |
| */ |
| struct fragment { |
| struct device_node *target; |
| struct device_node *overlay; |
| }; |
| |
| /** |
| * struct overlay_changeset |
| * @id: changeset identifier |
| * @ovcs_list: list on which we are located |
| * @fdt: FDT that was unflattened to create @overlay_tree |
| * @overlay_tree: expanded device tree that contains the fragment nodes |
| * @count: count of fragment structures |
| * @fragments: fragment nodes in the overlay expanded device tree |
| * @symbols_fragment: last element of @fragments[] is the __symbols__ node |
| * @cset: changeset to apply fragments to live device tree |
| */ |
| struct overlay_changeset { |
| int id; |
| struct list_head ovcs_list; |
| const void *fdt; |
| struct device_node *overlay_tree; |
| int count; |
| struct fragment *fragments; |
| bool symbols_fragment; |
| 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); |
| |
| /* |
| * of_resolve_phandles() finds the largest phandle in the live tree. |
| * of_overlay_apply() may add a larger phandle to the live tree. |
| * Do not allow race between two overlays being applied simultaneously: |
| * mutex_lock(&of_overlay_phandle_mutex) |
| * of_resolve_phandles() |
| * of_overlay_apply() |
| * mutex_unlock(&of_overlay_phandle_mutex) |
| */ |
| static DEFINE_MUTEX(of_overlay_phandle_mutex); |
| |
| void of_overlay_mutex_lock(void) |
| { |
| mutex_lock(&of_overlay_phandle_mutex); |
| } |
| |
| void of_overlay_mutex_unlock(void) |
| { |
| mutex_unlock(&of_overlay_phandle_mutex); |
| } |
| |
| |
| static LIST_HEAD(ovcs_list); |
| static DEFINE_IDR(ovcs_idr); |
| |
| static BLOCKING_NOTIFIER_HEAD(overlay_notify_chain); |
| |
| /** |
| * of_overlay_notifier_register() - Register notifier for overlay operations |
| * @nb: Notifier block to register |
| * |
| * Register for notification on overlay operations on device tree nodes. The |
| * reported actions definied by @of_reconfig_change. The notifier callback |
| * furthermore receives a pointer to the affected device tree node. |
| * |
| * Note that a notifier callback is not supposed to store pointers to a device |
| * tree node or its content beyond @OF_OVERLAY_POST_REMOVE corresponding to the |
| * respective node it received. |
| */ |
| int of_overlay_notifier_register(struct notifier_block *nb) |
| { |
| return blocking_notifier_chain_register(&overlay_notify_chain, nb); |
| } |
| EXPORT_SYMBOL_GPL(of_overlay_notifier_register); |
| |
| /** |
| * of_overlay_notifier_register() - Unregister notifier for overlay operations |
| * @nb: Notifier block to unregister |
| */ |
| int of_overlay_notifier_unregister(struct notifier_block *nb) |
| { |
| return blocking_notifier_chain_unregister(&overlay_notify_chain, 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) |
| { |
| struct of_overlay_notify_data nd; |
| int i, ret; |
| |
| for (i = 0; i < ovcs->count; i++) { |
| struct fragment *fragment = &ovcs->fragments[i]; |
| |
| nd.target = fragment->target; |
| nd.overlay = fragment->overlay; |
| |
| ret = blocking_notifier_call_chain(&overlay_notify_chain, |
| action, &nd); |
| if (ret == NOTIFY_OK || 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; |
| } |
| |
| /* |
| * The values of properties in the "/__symbols__" node are paths in |
| * the ovcs->overlay_tree. When duplicating the properties, the paths |
| * need to be adjusted to be the correct path for the live device tree. |
| * |
| * The paths refer to a node in the subtree of a fragment node's "__overlay__" |
| * node, for example "/fragment@0/__overlay__/symbol_path_tail", |
| * where symbol_path_tail can be a single node or it may be a multi-node path. |
| * |
| * The duplicated property value will be modified by replacing the |
| * "/fragment_name/__overlay/" portion of the value with the target |
| * path from the fragment node. |
| */ |
| static struct property *dup_and_fixup_symbol_prop( |
| struct overlay_changeset *ovcs, const struct property *prop) |
| { |
| struct fragment *fragment; |
| struct property *new_prop; |
| struct device_node *fragment_node; |
| struct device_node *overlay_node; |
| const char *path; |
| const char *path_tail; |
| const char *target_path; |
| int k; |
| int overlay_name_len; |
| int path_len; |
| int path_tail_len; |
| int target_path_len; |
| |
| if (!prop->value) |
| return NULL; |
| if (strnlen(prop->value, prop->length) >= prop->length) |
| return NULL; |
| path = prop->value; |
| path_len = strlen(path); |
| |
| if (path_len < 1) |
| return NULL; |
| fragment_node = __of_find_node_by_path(ovcs->overlay_tree, path + 1); |
| overlay_node = __of_find_node_by_path(fragment_node, "__overlay__/"); |
| of_node_put(fragment_node); |
| of_node_put(overlay_node); |
| |
| for (k = 0; k < ovcs->count; k++) { |
| fragment = &ovcs->fragments[k]; |
| if (fragment->overlay == overlay_node) |
| break; |
| } |
| if (k >= ovcs->count) |
| return NULL; |
| |
| overlay_name_len = snprintf(NULL, 0, "%pOF", fragment->overlay); |
| |
| if (overlay_name_len > path_len) |
| return NULL; |
| path_tail = path + overlay_name_len; |
| path_tail_len = strlen(path_tail); |
| |
| target_path = kasprintf(GFP_KERNEL, "%pOF", fragment->target); |
| if (!target_path) |
| return NULL; |
| target_path_len = strlen(target_path); |
| |
| new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL); |
| if (!new_prop) |
| goto err_free_target_path; |
| |
| new_prop->name = kstrdup(prop->name, GFP_KERNEL); |
| new_prop->length = target_path_len + path_tail_len + 1; |
| new_prop->value = kzalloc(new_prop->length, GFP_KERNEL); |
| if (!new_prop->name || !new_prop->value) |
| goto err_free_new_prop; |
| |
| strcpy(new_prop->value, target_path); |
| strcpy(new_prop->value + target_path_len, path_tail); |
| |
| of_property_set_flag(new_prop, OF_DYNAMIC); |
| |
| return new_prop; |
| |
| err_free_new_prop: |
| kfree(new_prop->name); |
| kfree(new_prop->value); |
| kfree(new_prop); |
| err_free_target_path: |
| kfree(target_path); |
| |
| return NULL; |
| } |
| |
| /** |
| * add_changeset_property() - add @overlay_prop to overlay changeset |
| * @ovcs: overlay changeset |
| * @target_node: where to place @overlay_prop in live tree |
| * @overlay_prop: property to add or update, from overlay tree |
| * @is_symbols_prop: 1 if @overlay_prop is from node "/__symbols__" |
| * |
| * If @overlay_prop does not already exist in @target_node, add changeset entry |
| * to add @overlay_prop in @target_node, else add changeset entry to update |
| * value of @overlay_prop. |
| * |
| * Some special properties are not updated (no error returned). |
| * |
| * Update of property in symbols node is not allowed. |
| * |
| * Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if |
| * invalid @overlay. |
| */ |
| static int add_changeset_property(struct overlay_changeset *ovcs, |
| struct device_node *target_node, |
| struct property *overlay_prop, |
| bool is_symbols_prop) |
| { |
| struct property *new_prop = NULL, *prop; |
| int ret = 0; |
| |
| prop = of_find_property(target_node, overlay_prop->name, NULL); |
| |
| if (!of_prop_cmp(overlay_prop->name, "name") || |
| !of_prop_cmp(overlay_prop->name, "phandle") || |
| !of_prop_cmp(overlay_prop->name, "linux,phandle")) |
| return 0; |
| |
| if (is_symbols_prop) { |
| if (prop) |
| return -EINVAL; |
| new_prop = dup_and_fixup_symbol_prop(ovcs, overlay_prop); |
| } else { |
| new_prop = __of_prop_dup(overlay_prop, GFP_KERNEL); |
| } |
| |
| if (!new_prop) |
| return -ENOMEM; |
| |
| if (!prop) |
| ret = of_changeset_add_property(&ovcs->cset, target_node, |
| new_prop); |
| else |
| ret = of_changeset_update_property(&ovcs->cset, target_node, |
| new_prop); |
| |
| if (ret) { |
| kfree(new_prop->name); |
| kfree(new_prop->value); |
| kfree(new_prop); |
| } |
| return ret; |
| } |
| |
| /** |
| * add_changeset_node() - add @node (and children) to overlay changeset |
| * @ovcs: overlay changeset |
| * @target_node: where to place @node in live tree |
| * @node: node from within overlay device tree fragment |
| * |
| * If @node does not already exist in @target_node, add changeset entry |
| * to add @node in @target_node. |
| * |
| * If @node already exists in @target_node, and the existing node has |
| * a phandle, the overlay node is not allowed to have a phandle. |
| * |
| * If @node has child nodes, add the children recursively via |
| * build_changeset_next_level(). |
| * |
| * NOTE_1: A live devicetree created from a flattened device tree (FDT) will |
| * not contain the full path in node->full_name. Thus an overlay |
| * created from an FDT also will not contain the full path in |
| * node->full_name. However, a live devicetree created from Open |
| * Firmware may have the full path in node->full_name. |
| * |
| * add_changeset_node() follows the FDT convention and does not include |
| * the full path in node->full_name. Even though it expects the overlay |
| * to not contain the full path, it uses kbasename() to remove the |
| * full path should it exist. It also uses kbasename() in comparisons |
| * to nodes in the live devicetree so that it can apply an overlay to |
| * a live devicetree created from Open Firmware. |
| * |
| * NOTE_2: 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. |
| */ |
| static int add_changeset_node(struct overlay_changeset *ovcs, |
| struct device_node *target_node, struct device_node *node) |
| { |
| const char *node_kbasename; |
| struct device_node *tchild; |
| int ret = 0; |
| |
| node_kbasename = kbasename(node->full_name); |
| |
| for_each_child_of_node(target_node, tchild) |
| if (!of_node_cmp(node_kbasename, kbasename(tchild->full_name))) |
| break; |
| |
| if (!tchild) { |
| tchild = __of_node_dup(node, node_kbasename); |
| if (!tchild) |
| return -ENOMEM; |
| |
| tchild->parent = target_node; |
| |
| ret = of_changeset_attach_node(&ovcs->cset, tchild); |
| if (ret) |
| return ret; |
| |
| return build_changeset_next_level(ovcs, tchild, node); |
| } |
| |
| if (node->phandle && tchild->phandle) |
| ret = -EINVAL; |
| else |
| ret = build_changeset_next_level(ovcs, tchild, node); |
| of_node_put(tchild); |
| |
| return ret; |
| } |
| |
| /** |
| * build_changeset_next_level() - add level of overlay changeset |
| * @ovcs: overlay changeset |
| * @target_node: where to place @overlay_node in live tree |
| * @overlay_node: node from within an overlay device tree fragment |
| * |
| * Add the properties (if any) and nodes (if any) from @overlay_node to the |
| * @ovcs->cset changeset. If an added node has child nodes, they will |
| * be added recursively. |
| * |
| * Do not allow symbols node to have any children. |
| * |
| * Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if |
| * invalid @overlay_node. |
| */ |
| static int build_changeset_next_level(struct overlay_changeset *ovcs, |
| struct device_node *target_node, |
| const struct device_node *overlay_node) |
| { |
| struct device_node *child; |
| struct property *prop; |
| int ret; |
| |
| for_each_property_of_node(overlay_node, prop) { |
| ret = add_changeset_property(ovcs, target_node, prop, 0); |
| if (ret) { |
| pr_debug("Failed to apply prop @%pOF/%s, err=%d\n", |
| target_node, prop->name, ret); |
| return ret; |
| } |
| } |
| |
| for_each_child_of_node(overlay_node, child) { |
| ret = add_changeset_node(ovcs, target_node, child); |
| if (ret) { |
| pr_debug("Failed to apply node @%pOF/%s, err=%d\n", |
| target_node, child->name, ret); |
| of_node_put(child); |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Add the properties from __overlay__ node to the @ovcs->cset changeset. |
| */ |
| static int build_changeset_symbols_node(struct overlay_changeset *ovcs, |
| struct device_node *target_node, |
| const struct device_node *overlay_symbols_node) |
| { |
| struct property *prop; |
| int ret; |
| |
| for_each_property_of_node(overlay_symbols_node, prop) { |
| ret = add_changeset_property(ovcs, target_node, prop, 1); |
| if (ret) { |
| pr_debug("Failed to apply prop @%pOF/%s, err=%d\n", |
| target_node, prop->name, ret); |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * build_changeset() - populate overlay changeset in @ovcs from @ovcs->fragments |
| * @ovcs: Overlay changeset |
| * |
| * Create changeset @ovcs->cset to contain the nodes and properties of the |
| * overlay device tree fragments in @ovcs->fragments[]. If an error occurs, |
| * any portions of the changeset that were successfully created will remain |
| * in @ovcs->cset. |
| * |
| * Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if |
| * invalid overlay in @ovcs->fragments[]. |
| */ |
| static int build_changeset(struct overlay_changeset *ovcs) |
| { |
| struct fragment *fragment; |
| int fragments_count, i, ret; |
| |
| /* |
| * if there is a symbols fragment in ovcs->fragments[i] it is |
| * the final element in the array |
| */ |
| if (ovcs->symbols_fragment) |
| fragments_count = ovcs->count - 1; |
| else |
| fragments_count = ovcs->count; |
| |
| for (i = 0; i < fragments_count; i++) { |
| fragment = &ovcs->fragments[i]; |
| |
| ret = build_changeset_next_level(ovcs, fragment->target, |
| fragment->overlay); |
| if (ret) { |
| pr_debug("apply failed '%pOF'\n", fragment->target); |
| return ret; |
| } |
| } |
| |
| if (ovcs->symbols_fragment) { |
| fragment = &ovcs->fragments[ovcs->count - 1]; |
| ret = build_changeset_symbols_node(ovcs, fragment->target, |
| fragment->overlay); |
| if (ret) { |
| pr_debug("apply failed '%pOF'\n", fragment->target); |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Find the target node using a number of different strategies |
| * in order of preference: |
| * |
| * 1) "target" property containing the phandle of the target |
| * 2) "target-path" property containing the path of the target |
| */ |
| static struct device_node *find_target_node(struct device_node *info_node) |
| { |
| struct device_node *node; |
| const char *path; |
| u32 val; |
| int ret; |
| |
| ret = of_property_read_u32(info_node, "target", &val); |
| if (!ret) { |
| node = of_find_node_by_phandle(val); |
| if (!node) |
| pr_err("find target, node: %pOF, phandle 0x%x not found\n", |
| info_node, val); |
| return node; |
| } |
| |
| ret = of_property_read_string(info_node, "target-path", &path); |
| if (!ret) { |
| node = of_find_node_by_path(path); |
| if (!node) |
| pr_err("find target, node: %pOF, path '%s' not found\n", |
| info_node, path); |
| return node; |
| } |
| |
| pr_err("find target, node: %pOF, no target property\n", info_node); |
| |
| return NULL; |
| } |
| |
| /** |
| * init_overlay_changeset() - initialize overlay changeset from overlay tree |
| * @ovcs: Overlay changeset to build |
| * @fdt: the FDT that was unflattened to create @tree |
| * @tree: Contains all the overlay fragments and overlay fixup nodes |
| * |
| * Initialize @ovcs. Populate @ovcs->fragments with node information from |
| * the top level of @tree. The relevant top level nodes are the fragment |
| * nodes and the __symbols__ node. Any other top level node will be ignored. |
| * |
| * Returns 0 on success, -ENOMEM if memory allocation failure, -EINVAL if error |
| * detected in @tree, or -ENOSPC if idr_alloc() error. |
| */ |
| static int init_overlay_changeset(struct overlay_changeset *ovcs, |
| const void *fdt, struct device_node *tree) |
| { |
| struct device_node *node, *overlay_node; |
| struct fragment *fragment; |
| struct fragment *fragments; |
| int cnt, id, 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__); |
| |
| ovcs->overlay_tree = tree; |
| ovcs->fdt = fdt; |
| |
| INIT_LIST_HEAD(&ovcs->ovcs_list); |
| |
| of_changeset_init(&ovcs->cset); |
| |
| id = idr_alloc(&ovcs_idr, ovcs, 1, 0, GFP_KERNEL); |
| if (id <= 0) |
| return id; |
| |
| cnt = 0; |
| |
| /* fragment nodes */ |
| for_each_child_of_node(tree, node) { |
| overlay_node = of_get_child_by_name(node, "__overlay__"); |
| if (overlay_node) { |
| cnt++; |
| of_node_put(overlay_node); |
| } |
| } |
| |
| node = of_get_child_by_name(tree, "__symbols__"); |
| if (node) { |
| cnt++; |
| of_node_put(node); |
| } |
| |
| fragments = kcalloc(cnt, sizeof(*fragments), GFP_KERNEL); |
| if (!fragments) { |
| ret = -ENOMEM; |
| goto err_free_idr; |
| } |
| |
| cnt = 0; |
| for_each_child_of_node(tree, node) { |
| overlay_node = of_get_child_by_name(node, "__overlay__"); |
| if (!overlay_node) |
| continue; |
| |
| fragment = &fragments[cnt]; |
| fragment->overlay = overlay_node; |
| fragment->target = find_target_node(node); |
| if (!fragment->target) { |
| of_node_put(fragment->overlay); |
| ret = -EINVAL; |
| goto err_free_fragments; |
| } |
| |
| cnt++; |
| } |
| |
| /* |
| * if there is a symbols fragment in ovcs->fragments[i] it is |
| * the final element in the array |
| */ |
| node = of_get_child_by_name(tree, "__symbols__"); |
| if (node) { |
| ovcs->symbols_fragment = 1; |
| fragment = &fragments[cnt]; |
| fragment->overlay = node; |
| fragment->target = of_find_node_by_path("/__symbols__"); |
| |
| if (!fragment->target) { |
| pr_err("symbols in overlay, but not in live tree\n"); |
| ret = -EINVAL; |
| goto err_free_fragments; |
| } |
| |
| cnt++; |
| } |
| |
| if (!cnt) { |
| pr_err("no fragments or symbols in overlay\n"); |
| ret = -EINVAL; |
| goto err_free_fragments; |
| } |
| |
| ovcs->id = id; |
| ovcs->count = cnt; |
| ovcs->fragments = fragments; |
| |
| return 0; |
| |
| err_free_fragments: |
| kfree(fragments); |
| err_free_idr: |
| idr_remove(&ovcs_idr, id); |
| |
| pr_err("%s() failed, ret = %d\n", __func__, ret); |
| |
| return ret; |
| } |
| |
| static void free_overlay_changeset(struct overlay_changeset *ovcs) |
| { |
| int i; |
| |
| if (ovcs->cset.entries.next) |
| of_changeset_destroy(&ovcs->cset); |
| |
| if (ovcs->id) |
| idr_remove(&ovcs_idr, ovcs->id); |
| |
| for (i = 0; i < ovcs->count; i++) { |
| of_node_put(ovcs->fragments[i].target); |
| of_node_put(ovcs->fragments[i].overlay); |
| } |
| kfree(ovcs->fragments); |
| /* |
| * There should be no live pointers into ovcs->overlay_tree and |
| * ovcs->fdt due to the policy that overlay notifiers are not allowed |
| * to retain pointers into the overlay devicetree. |
| */ |
| kfree(ovcs->overlay_tree); |
| kfree(ovcs->fdt); |
| kfree(ovcs); |
| } |
| |
| /* |
| * internal documentation |
| * |
| * of_overlay_apply() - Create and apply an overlay changeset |
| * @fdt: the FDT that was unflattened to create @tree |
| * @tree: Expanded overlay device tree |
| * @ovcs_id: Pointer to overlay changeset id |
| * |
| * Creates and applies an overlay changeset. |
| * |
| * If an error occurs in a pre-apply notifier, then no changes are made |
| * to the device tree. |
| * |
| |
| * A non-zero return value will not have created the changeset if error is from: |
| * - parameter checks |
| * - building the changeset |
| * - overlay changeset 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 changeset 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. |
| */ |
| |
| static int of_overlay_apply(const void *fdt, struct device_node *tree, |
| int *ovcs_id) |
| { |
| struct overlay_changeset *ovcs; |
| int ret = 0, ret_revert, ret_tmp; |
| |
| /* |
| * As of this point, fdt and tree belong to the overlay changeset. |
| * overlay changeset code is responsible for freeing them. |
| */ |
| |
| if (devicetree_corrupt()) { |
| pr_err("devicetree state suspect, refuse to apply overlay\n"); |
| kfree(fdt); |
| kfree(tree); |
| ret = -EBUSY; |
| goto out; |
| } |
| |
| ovcs = kzalloc(sizeof(*ovcs), GFP_KERNEL); |
| if (!ovcs) { |
| kfree(fdt); |
| kfree(tree); |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| of_overlay_mutex_lock(); |
| mutex_lock(&of_mutex); |
| |
| ret = of_resolve_phandles(tree); |
| if (ret) |
| goto err_free_tree; |
| |
| ret = init_overlay_changeset(ovcs, fdt, tree); |
| if (ret) |
| goto err_free_tree; |
| |
| /* |
| * after overlay_notify(), ovcs->overlay_tree related pointers may have |
| * leaked to drivers, so can not kfree() tree, aka ovcs->overlay_tree; |
| * and can not free fdt, aka ovcs->fdt |
| */ |
| ret = overlay_notify(ovcs, OF_OVERLAY_PRE_APPLY); |
| if (ret) { |
| pr_err("overlay changeset pre-apply notify error %d\n", ret); |
| goto err_free_overlay_changeset; |
| } |
| |
| ret = build_changeset(ovcs); |
| if (ret) |
| goto err_free_overlay_changeset; |
| |
| 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; |
| } |
| |
| ret = __of_changeset_apply_notify(&ovcs->cset); |
| if (ret) |
| pr_err("overlay changeset entry notify error %d\n", ret); |
| /* notify failure is not fatal, continue */ |
| |
| list_add_tail(&ovcs->ovcs_list, &ovcs_list); |
| *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; |
| } |
| |
| goto out_unlock; |
| |
| err_free_tree: |
| kfree(fdt); |
| kfree(tree); |
| |
| err_free_overlay_changeset: |
| free_overlay_changeset(ovcs); |
| |
| out_unlock: |
| mutex_unlock(&of_mutex); |
| of_overlay_mutex_unlock(); |
| |
| out: |
| pr_debug("%s() err=%d\n", __func__, ret); |
| |
| return ret; |
| } |
| |
| int of_overlay_fdt_apply(const void *overlay_fdt, u32 overlay_fdt_size, |
| int *ovcs_id) |
| { |
| const void *new_fdt; |
| int ret; |
| u32 size; |
| struct device_node *overlay_root; |
| |
| *ovcs_id = 0; |
| ret = 0; |
| |
| if (overlay_fdt_size < sizeof(struct fdt_header) || |
| fdt_check_header(overlay_fdt)) { |
| pr_err("Invalid overlay_fdt header\n"); |
| return -EINVAL; |
| } |
| |
| size = fdt_totalsize(overlay_fdt); |
| if (overlay_fdt_size < size) |
| return -EINVAL; |
| |
| /* |
| * Must create permanent copy of FDT because of_fdt_unflatten_tree() |
| * will create pointers to the passed in FDT in the unflattened tree. |
| */ |
| new_fdt = kmemdup(overlay_fdt, size, GFP_KERNEL); |
| if (!new_fdt) |
| return -ENOMEM; |
| |
| of_fdt_unflatten_tree(new_fdt, NULL, &overlay_root); |
| if (!overlay_root) { |
| pr_err("unable to unflatten overlay_fdt\n"); |
| ret = -EINVAL; |
| goto out_free_new_fdt; |
| } |
| |
| ret = of_overlay_apply(new_fdt, overlay_root, ovcs_id); |
| if (ret < 0) { |
| /* |
| * new_fdt and overlay_root now belong to the overlay |
| * changeset. |
| * overlay changeset code is responsible for freeing them. |
| */ |
| goto out; |
| } |
| |
| return 0; |
| |
| |
| out_free_new_fdt: |
| kfree(new_fdt); |
| |
| out: |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(of_overlay_fdt_apply); |
| |
| /* |
| * Find @np in @tree. |
| * |
| * Returns 1 if @np is @tree or is contained in @tree, else 0 |
| */ |
| static int find_node(struct device_node *tree, struct device_node *np) |
| { |
| struct device_node *child; |
| |
| if (tree == np) |
| return 1; |
| |
| for_each_child_of_node(tree, child) { |
| if (find_node(child, np)) { |
| of_node_put(child); |
| return 1; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Is @remove_ce_node a child of, a parent of, or the same as any |
| * node in an overlay changeset more topmost than @remove_ovcs? |
| * |
| * Returns 1 if found, else 0 |
| */ |
| static int node_overlaps_later_cs(struct overlay_changeset *remove_ovcs, |
| struct device_node *remove_ce_node) |
| { |
| struct overlay_changeset *ovcs; |
| struct of_changeset_entry *ce; |
| |
| list_for_each_entry_reverse(ovcs, &ovcs_list, ovcs_list) { |
| if (ovcs == remove_ovcs) |
| break; |
| |
| list_for_each_entry(ce, &ovcs->cset.entries, node) { |
| if (find_node(ce->np, remove_ce_node)) { |
| pr_err("%s: #%d overlaps with #%d @%pOF\n", |
| __func__, remove_ovcs->id, ovcs->id, |
| remove_ce_node); |
| return 1; |
| } |
| if (find_node(remove_ce_node, ce->np)) { |
| pr_err("%s: #%d overlaps with #%d @%pOF\n", |
| __func__, remove_ovcs->id, ovcs->id, |
| remove_ce_node); |
| return 1; |
| } |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * We can safely remove the overlay only if it's the top-most one. |
| * Newly applied overlays are inserted at the tail of the overlay list, |
| * so a top most overlay is the one that is closest to the tail. |
| * |
| * The topmost check is done by exploiting this property. For each |
| * affected device node in the log list we check if this overlay is |
| * the one closest to the tail. If another overlay has affected this |
| * device node and is closest to the tail, then removal is not permited. |
| */ |
| static int overlay_removal_is_ok(struct overlay_changeset *remove_ovcs) |
| { |
| struct of_changeset_entry *remove_ce; |
| |
| list_for_each_entry(remove_ce, &remove_ovcs->cset.entries, node) { |
| if (node_overlaps_later_cs(remove_ovcs, remove_ce->np)) { |
| pr_err("overlay #%d is not topmost\n", remove_ovcs->id); |
| return 0; |
| } |
| } |
| |
| return 1; |
| } |
| |
| /** |
| * of_overlay_remove() - Revert and free an overlay changeset |
| * @ovcs_id: Pointer to overlay changeset id |
| * |
| * Removes an overlay if it is permissible. @ovcs_id was previously returned |
| * by of_overlay_fdt_apply(). |
| * |
| * 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 changeset 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 changeset 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) |
| { |
| struct overlay_changeset *ovcs; |
| 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); |
| if (!ovcs) { |
| ret = -ENODEV; |
| pr_err("remove: Could not find overlay #%d\n", *ovcs_id); |
| goto out_unlock; |
| } |
| |
| if (!overlay_removal_is_ok(ovcs)) { |
| ret = -EBUSY; |
| goto out_unlock; |
| } |
| |
| 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); |
| |
| 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; |
| } |
| |
| ret = __of_changeset_revert_notify(&ovcs->cset); |
| if (ret) |
| pr_err("overlay changeset entry notify error %d\n", ret); |
| /* notify failure is not fatal, continue */ |
| |
| *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_unlock: |
| mutex_unlock(&of_mutex); |
| |
| out: |
| pr_debug("%s() err=%d\n", __func__, ret); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(of_overlay_remove); |
| |
| /** |
| * of_overlay_remove_all() - Reverts and frees all overlay changesets |
| * |
| * Removes all overlays from the system in the correct order. |
| * |
| * Returns 0 on success, or a negative error number |
| */ |
| int of_overlay_remove_all(void) |
| { |
| struct overlay_changeset *ovcs, *ovcs_n; |
| int ret; |
| |
| /* 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); |
| if (ret) |
| return ret; |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(of_overlay_remove_all); |