/** * struct target - info about current target node as recursing through overlay * @np: node where current level of overlay will be applied * @in_livetree: @np is a node in the live devicetree * * Used in the algorithm to create the portion of a changeset that describes * an overlay fragment, which is a devicetree subtree. Initially @np is a node * in the live devicetree where the overlay subtree is targeted to be grafted * into. When recursing to the next level of the overlay subtree, the target * also recurses to the next level of the live devicetree, as long as overlay * subtree node also exists in the live devicetree. When a node in the overlay * subtree does not exist at the same level in the live devicetree, target->np * points to a newly allocated node, and all subsequent targets in the subtree * will be newly allocated nodes.
*/ struct target { struct device_node *np; bool in_livetree;
};
/** * struct fragment - info about fragment nodes in overlay expanded device tree * @overlay: pointer to the __overlay__ node * @target: target of the overlay operation
*/ struct fragment { struct device_node *overlay; struct device_node *target;
};
/** * struct overlay_changeset * @id: changeset identifier * @ovcs_list: list on which we are located * @new_fdt: Memory allocated to hold unflattened aligned FDT * @overlay_mem: the memory chunk that contains @overlay_root * @overlay_root: expanded device tree that contains the fragment nodes * @notify_state: most recent notify action used on overlay * @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; constvoid *new_fdt; constvoid *overlay_mem; struct device_node *overlay_root; enum of_overlay_notify_action notify_state; int count; struct fragment *fragments; bool symbols_fragment; struct of_changeset cset;
};
/* flags are sticky - once set, do not reset */ staticint 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.
*/ staticint devicetree_corrupt(void)
{ return devicetree_state_flags &
(DTSF_APPLY_FAIL | DTSF_REVERT_FAIL);
}
/* * 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);
/** * 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_unregister() - 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);
staticint overlay_notify(struct overlay_changeset *ovcs, enum of_overlay_notify_action action)
{ struct of_overlay_notify_data nd; int i, ret;
ovcs->notify_state = action;
for (i = 0; i < ovcs->count; i++) { struct fragment *fragment = &ovcs->fragments[i];
ret = blocking_notifier_call_chain(&overlay_notify_chain,
action, &nd); if (notifier_to_errno(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_root. 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.
*/ staticstruct property *dup_and_fixup_symbol_prop( struct overlay_changeset *ovcs, conststruct property *prop)
{ struct fragment *fragment; struct property *new_prop; struct device_node *fragment_node; struct device_node *overlay_node; constchar *path; constchar *path_tail; constchar *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);
/** * add_changeset_property() - add @overlay_prop to overlay changeset * @ovcs: overlay changeset * @target: where @overlay_prop will be placed * @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 live devicetree, add changeset * entry to add @overlay_prop in @target, else add changeset entry to update * value of @overlay_prop. * * @target may be either in the live devicetree or in a new subtree that * is contained in the changeset. * * Some special properties are not added or updated (no error returned): * "name", "phandle", "linux,phandle". * * Properties "#address-cells" and "#size-cells" are not updated if they * are already in the live tree, but if present in the live tree, the values * in the overlay must match the values in the live tree. * * Update of property in symbols node is not allowed. * * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if * invalid @overlay.
*/ staticint add_changeset_property(struct overlay_changeset *ovcs, struct target *target, conststruct property *overlay_prop, bool is_symbols_prop)
{ struct property *new_prop = NULL; conststruct property *prop; int ret = 0;
if (target->in_livetree) if (is_pseudo_property(overlay_prop->name)) return 0;
if (prop) { if (!of_prop_cmp(prop->name, "#address-cells")) { if (!of_prop_val_eq(prop, overlay_prop)) {
pr_err("ERROR: changing value of #address-cells is not allowed in %pOF\n",
target->np);
ret = -EINVAL;
} return ret;
} elseif (!of_prop_cmp(prop->name, "#size-cells")) { if (!of_prop_val_eq(prop, overlay_prop)) {
pr_err("ERROR: changing value of #size-cells is not allowed in %pOF\n",
target->np);
ret = -EINVAL;
} return ret;
}
}
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) { if (!target->in_livetree) {
new_prop->next = target->np->deadprops;
target->np->deadprops = new_prop;
}
ret = of_changeset_add_property(&ovcs->cset, target->np,
new_prop);
} else {
ret = of_changeset_update_property(&ovcs->cset, target->np,
new_prop);
}
if (!of_node_check_flag(target->np, OF_OVERLAY))
pr_err("WARNING: memory leak will occur if overlay removed, property: %pOF/%s\n",
target->np, new_prop->name);
if (ret)
__of_prop_free(new_prop); return ret;
}
/** * add_changeset_node() - add @node (and children) to overlay changeset * @ovcs: overlay changeset * @target: where @node will be placed in live tree or changeset * @node: node from within overlay device tree fragment * * If @node does not already exist in @target, add changeset entry * to add @node in @target. * * If @node already exists in @target, 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. * * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if * invalid @overlay.
*/ staticint add_changeset_node(struct overlay_changeset *ovcs, struct target *target, conststruct device_node *node)
{ constchar *node_kbasename; const __be32 *phandle; struct device_node *tchild; struct target target_child; int ret = 0, size;
node_kbasename = kbasename(node->full_name);
for_each_child_of_node(target->np, tchild) if (!of_node_cmp(node_kbasename, kbasename(tchild->full_name))) break;
if (!tchild) {
tchild = __of_node_dup(NULL, node_kbasename); if (!tchild) return -ENOMEM;
ret = build_changeset_next_level(ovcs, &target_child, node);
of_node_put(tchild); return ret;
}
if (node->phandle && tchild->phandle) {
ret = -EINVAL;
} else {
target_child.np = tchild;
target_child.in_livetree = target->in_livetree;
ret = build_changeset_next_level(ovcs, &target_child, node);
}
of_node_put(tchild);
return ret;
}
/** * build_changeset_next_level() - add level of overlay changeset * @ovcs: overlay changeset * @target: 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. * * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if * invalid @overlay_node.
*/ staticint build_changeset_next_level(struct overlay_changeset *ovcs, struct target *target, conststruct device_node *overlay_node)
{ struct property *prop; int ret;
for_each_property_of_node(overlay_node, prop) {
ret = add_changeset_property(ovcs, target, prop, 0); if (ret) {
pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
target->np, prop->name, ret); return ret;
}
}
for_each_child_of_node_scoped(overlay_node, child) {
ret = add_changeset_node(ovcs, target, child); if (ret) {
pr_debug("Failed to apply node @%pOF/%pOFn, err=%d\n",
target->np, child, ret); return ret;
}
}
return 0;
}
/* * Add the properties from __overlay__ node to the @ovcs->cset changeset.
*/ staticint build_changeset_symbols_node(struct overlay_changeset *ovcs, struct target *target, conststruct 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, prop, 1); if (ret) {
pr_debug("Failed to apply symbols prop @%pOF/%s, err=%d\n",
target->np, prop->name, ret); return ret;
}
}
/** * changeset_dup_entry_check() - check for duplicate entries * @ovcs: Overlay changeset * * Check changeset @ovcs->cset for multiple {add or delete} node entries for * the same node or duplicate {add, delete, or update} properties entries * for the same property. * * Return: 0 on success, or -EINVAL if duplicate changeset entry found.
*/ staticint changeset_dup_entry_check(struct overlay_changeset *ovcs)
{ struct of_changeset_entry *ce_1; int dup_entry = 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. * * Return: 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if * invalid overlay in @ovcs->fragments[].
*/ staticint build_changeset(struct overlay_changeset *ovcs)
{ struct fragment *fragment; struct target target; 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];
if (ovcs->symbols_fragment) {
fragment = &ovcs->fragments[ovcs->count - 1];
target.np = fragment->target;
target.in_livetree = true;
ret = build_changeset_symbols_node(ovcs, &target,
fragment->overlay); if (ret) {
pr_debug("symbols fragment apply failed '%pOF'\n",
fragment->target); return ret;
}
}
return changeset_dup_entry_check(ovcs);
}
/* * 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
*/ staticstruct device_node *find_target(conststruct device_node *info_node, conststruct device_node *target_base)
{ struct device_node *node; char *target_path; constchar *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) { if (target_base) {
target_path = kasprintf(GFP_KERNEL, "%pOF%s", target_base, path); if (!target_path) return NULL;
node = of_find_node_by_path(target_path); if (!node) {
pr_err("find target, node: %pOF, path '%s' not found\n",
info_node, target_path);
}
kfree(target_path);
} else {
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 * @target_base: Point to the target node to apply overlay * * Initialize @ovcs. Populate @ovcs->fragments with node information from * the top level of @overlay_root. The relevant top level nodes are the * fragment nodes and the __symbols__ node. Any other top level node will * be ignored. Populate other @ovcs fields. * * Return: 0 on success, -ENOMEM if memory allocation failure, -EINVAL if error * detected in @overlay_root. On error return, the caller of * init_overlay_changeset() must call free_overlay_changeset().
*/ staticint init_overlay_changeset(struct overlay_changeset *ovcs, conststruct device_node *target_base)
{ struct device_node *node, *overlay_node; struct fragment *fragment; struct fragment *fragments; int cnt, ret;
/* * None of the resources allocated by this function will be freed in * the error paths. Instead the caller of this function is required * to call free_overlay_changeset() (which will free the resources) * if error return.
*/
/* * 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(ovcs->overlay_root, OF_DYNAMIC))
pr_debug("%s() ovcs->overlay_root is not dynamic\n", __func__);
if (!of_node_check_flag(ovcs->overlay_root, OF_DETACHED))
pr_debug("%s() ovcs->overlay_root is not detached\n", __func__);
if (!of_node_is_root(ovcs->overlay_root))
pr_debug("%s() ovcs->overlay_root is not root\n", __func__);
cnt = 0;
/* fragment nodes */
for_each_child_of_node(ovcs->overlay_root, 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(ovcs->overlay_root, "__symbols__"); if (node) {
cnt++;
of_node_put(node);
}
fragments = kcalloc(cnt, sizeof(*fragments), GFP_KERNEL); if (!fragments) {
ret = -ENOMEM; goto err_out;
}
ovcs->fragments = fragments;
fragment = &fragments[cnt];
fragment->overlay = overlay_node;
fragment->target = find_target(node, target_base); if (!fragment->target) {
of_node_put(fragment->overlay);
ret = -EINVAL;
of_node_put(node); goto err_out;
}
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(ovcs->overlay_root, "__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;
of_node_put(node); goto err_out;
}
cnt++;
}
if (!cnt) {
pr_err("no fragments or symbols in overlay\n");
ret = -EINVAL; goto err_out;
}
ovcs->count = cnt;
return 0;
err_out:
pr_err("%s() failed, ret = %d\n", __func__, ret);
return ret;
}
staticvoid 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);
list_del(&ovcs->ovcs_list);
ovcs->id = 0;
}
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_mem and * ovcs->new_fdt due to the policy that overlay notifiers are not * allowed to retain pointers into the overlay devicetree other * than during the window from OF_OVERLAY_PRE_APPLY overlay * notifiers until the OF_OVERLAY_POST_REMOVE overlay notifiers. * * A memory leak will occur here if within the window.
*/
/* * internal documentation * * of_overlay_apply() - Create and apply an overlay changeset * @ovcs: overlay changeset * @base: point to the target node to apply overlay * * Creates and applies an overlay changeset. * * If an error is returned by an overlay changeset pre-apply notifier * then no further overlay changeset pre-apply notifier will be called. * * 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. On error return, * the caller of of_overlay_apply() must call free_overlay_changeset().
*/
staticint of_overlay_apply(struct overlay_changeset *ovcs, conststruct device_node *base)
{ int ret = 0, ret_revert, ret_tmp;
ret = of_resolve_phandles(ovcs->overlay_root); if (ret) goto out;
ret = init_overlay_changeset(ovcs, base); if (ret) goto out;
ret = overlay_notify(ovcs, OF_OVERLAY_PRE_APPLY); if (ret) goto out;
ret = build_changeset(ovcs); if (ret) goto out;
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 out;
}
ret = __of_changeset_apply_notify(&ovcs->cset); if (ret)
pr_err("overlay apply changeset entry notify error %d\n", ret); /* notify failure is not fatal, continue */
ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_APPLY); if (ret_tmp) if (!ret)
ret = ret_tmp;
out:
pr_debug("%s() err=%d\n", __func__, ret);
return ret;
}
/** * of_overlay_fdt_apply() - Create and apply an overlay changeset * @overlay_fdt: pointer to overlay FDT * @overlay_fdt_size: number of bytes in @overlay_fdt * @ret_ovcs_id: pointer for returning created changeset id * @base: pointer for the target node to apply overlay * * Creates and applies an overlay changeset. * * See of_overlay_apply() for important behavior information. * * Return: 0 on success, or a negative error number. *@ret_ovcs_id is set to * the value of overlay changeset id, which can be passed to of_overlay_remove() * to remove the overlay. * * On error return, the changeset may be partially applied. This is especially * likely if an OF_OVERLAY_POST_APPLY notifier returns an error. In this case * the caller should call of_overlay_remove() with the value in *@ret_ovcs_id.
*/
int of_overlay_fdt_apply(constvoid *overlay_fdt, u32 overlay_fdt_size, int *ret_ovcs_id, conststruct device_node *base)
{ void *new_fdt; void *new_fdt_align; void *overlay_mem; int ret;
u32 size; struct overlay_changeset *ovcs;
*ret_ovcs_id = 0;
if (devicetree_corrupt()) {
pr_err("devicetree state suspect, refuse to apply overlay\n"); return -EBUSY;
}
/* * 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 = kmalloc(size + FDT_ALIGN_SIZE, GFP_KERNEL); if (!new_fdt) {
ret = -ENOMEM; goto err_free_ovcs;
}
ovcs->new_fdt = new_fdt;
overlay_mem = of_fdt_unflatten_tree(new_fdt_align, NULL,
&ovcs->overlay_root); if (!overlay_mem) {
pr_err("unable to unflatten overlay_fdt\n");
ret = -EINVAL; goto err_free_ovcs;
}
ovcs->overlay_mem = overlay_mem;
ret = of_overlay_apply(ovcs, base); /* * If of_overlay_apply() error, calling free_overlay_changeset() may * result in a memory leak if the apply partly succeeded, so do NOT * goto err_free_ovcs. Instead, the caller of of_overlay_fdt_apply() * can call of_overlay_remove();
*/
*ret_ovcs_id = ovcs->id; goto out_unlock;
/* * Find @np in @tree. * * Returns 1 if @np is @tree or is contained in @tree, else 0
*/ staticint find_node(conststruct device_node *tree, struct device_node *np)
{ if (tree == np) return 1;
for_each_child_of_node_scoped(tree, child) { if (find_node(child, np)) 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
*/ staticint 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 permitted.
*/ staticint 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. * * Return: 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;
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 err_unlock;
}
if (!overlay_removal_is_ok(ovcs)) {
ret = -EBUSY; goto err_unlock;
}
ret = overlay_notify(ovcs, OF_OVERLAY_PRE_REMOVE); if (ret) goto err_unlock;
ret_apply = 0;
ret = __of_changeset_revert_entries(&ovcs->cset, &ret_apply); if (ret) { if (ret_apply)
devicetree_state_flags |= DTSF_REVERT_FAIL; goto err_unlock;
}
ret = __of_changeset_revert_notify(&ovcs->cset); if (ret)
pr_err("overlay remove changeset entry notify error %d\n", ret); /* notify failure is not fatal, continue */
*ovcs_id = 0;
/* * Note that the overlay memory will be kfree()ed by * free_overlay_changeset() even if the notifier for * OF_OVERLAY_POST_REMOVE returns an error.
*/
ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_REMOVE); if (ret_tmp) if (!ret)
ret = ret_tmp;
free_overlay_changeset(ovcs);
err_unlock: /* * If jumped over free_overlay_changeset(), then did not kfree() * overlay related memory. This is a memory leak unless a subsequent * of_overlay_remove() of this overlay is successful.
*/
mutex_unlock(&of_mutex);
/** * of_overlay_remove_all() - Reverts and frees all overlay changesets * * Removes all overlays from the system in the correct order. * * Return: 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;
}
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