// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) /* * libfdt - Flat Device Tree manipulation * Copyright (C) 2016 Free Electrons * Copyright (C) 2016 NextThing Co. */ #include "libfdt_env.h" #include #include #include #include "libfdt_internal.h" /** * overlay_get_target_phandle - retrieves the target phandle of a fragment * @fdto: pointer to the device tree overlay blob * @fragment: node offset of the fragment in the overlay * * overlay_get_target_phandle() retrieves the target phandle of an * overlay fragment when that fragment uses a phandle (target * property) instead of a path (target-path property). * * returns: * the phandle pointed by the target property * 0, if the phandle was not found * -1, if the phandle was malformed */ static uint32_t overlay_get_target_phandle(const void *fdto, int fragment) { const fdt32_t *val; int len; val = fdt_getprop(fdto, fragment, "target", &len); if (!val) return 0; if ((len != sizeof(*val)) || (fdt32_to_cpu(*val) == (uint32_t)-1)) return (uint32_t)-1; return fdt32_to_cpu(*val); } int fdt_overlay_target_offset(const void *fdt, const void *fdto, int fragment_offset, char const **pathp) { uint32_t phandle; const char *path = NULL; int path_len = 0, ret; /* Try first to do a phandle based lookup */ phandle = overlay_get_target_phandle(fdto, fragment_offset); if (phandle == (uint32_t)-1) return -FDT_ERR_BADPHANDLE; /* no phandle, try path */ if (!phandle) { /* And then a path based lookup */ path = fdt_getprop(fdto, fragment_offset, "target-path", &path_len); if (path) ret = fdt_path_offset(fdt, path); else ret = path_len; } else ret = fdt_node_offset_by_phandle(fdt, phandle); /* * If we haven't found either a target or a * target-path property in a node that contains a * __overlay__ subnode (we wouldn't be called * otherwise), consider it a improperly written * overlay */ if (ret < 0 && path_len == -FDT_ERR_NOTFOUND) ret = -FDT_ERR_BADOVERLAY; /* return on error */ if (ret < 0) return ret; /* return pointer to path (if available) */ if (pathp) *pathp = path ? path : NULL; return ret; } /** * overlay_phandle_add_offset - Increases a phandle by an offset * @fdt: Base device tree blob * @node: Device tree overlay blob * @name: Name of the property to modify (phandle or linux,phandle) * @delta: offset to apply * * overlay_phandle_add_offset() increments a node phandle by a given * offset. * * returns: * 0 on success. * Negative error code on error */ static int overlay_phandle_add_offset(void *fdt, int node, const char *name, uint32_t delta) { const fdt32_t *val; uint32_t adj_val; int len; val = fdt_getprop(fdt, node, name, &len); if (!val) return len; if (len != sizeof(*val)) return -FDT_ERR_BADPHANDLE; adj_val = fdt32_to_cpu(*val); if ((adj_val + delta) < adj_val) return -FDT_ERR_NOPHANDLES; adj_val += delta; if (adj_val == (uint32_t)-1) return -FDT_ERR_NOPHANDLES; return fdt_setprop_inplace_u32(fdt, node, name, adj_val); } /** * overlay_adjust_node_phandles - Offsets the phandles of a node * @fdto: Device tree overlay blob * @node: Offset of the node we want to adjust * @delta: Offset to shift the phandles of * * overlay_adjust_node_phandles() adds a constant to all the phandles * of a given node. This is mainly use as part of the overlay * application process, when we want to update all the overlay * phandles to not conflict with the overlays of the base device tree. * * returns: * 0 on success * Negative error code on failure */ static int overlay_adjust_node_phandles(void *fdto, int node, uint32_t delta) { int child; int ret; ret = overlay_phandle_add_offset(fdto, node, "phandle", delta); if (ret && ret != -FDT_ERR_NOTFOUND) return ret; ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta); if (ret && ret != -FDT_ERR_NOTFOUND) return ret; fdt_for_each_subnode(child, fdto, node) { ret = overlay_adjust_node_phandles(fdto, child, delta); if (ret) return ret; } return 0; } /** * overlay_adjust_local_phandles - Adjust the phandles of a whole overlay * @fdto: Device tree overlay blob * @delta: Offset to shift the phandles of * * overlay_adjust_local_phandles() adds a constant to all the * phandles of an overlay. This is mainly use as part of the overlay * application process, when we want to update all the overlay * phandles to not conflict with the overlays of the base device tree. * * returns: * 0 on success * Negative error code on failure */ static int overlay_adjust_local_phandles(void *fdto, uint32_t delta) { /* * Start adjusting the phandles from the overlay root */ return overlay_adjust_node_phandles(fdto, 0, delta); } /** * overlay_update_local_node_references - Adjust the overlay references * @fdto: Device tree overlay blob * @tree_node: Node offset of the node to operate on * @fixup_node: Node offset of the matching local fixups node * @delta: Offset to shift the phandles of * * overlay_update_local_nodes_references() update the phandles * pointing to a node within the device tree overlay by adding a * constant delta. * * This is mainly used as part of a device tree application process, * where you want the device tree overlays phandles to not conflict * with the ones from the base device tree before merging them. * * returns: * 0 on success * Negative error code on failure */ static int overlay_update_local_node_references(void *fdto, int tree_node, int fixup_node, uint32_t delta) { int fixup_prop; int fixup_child; int ret; fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) { const fdt32_t *fixup_val; const char *tree_val; const char *name; int fixup_len; int tree_len; int i; fixup_val = fdt_getprop_by_offset(fdto, fixup_prop, &name, &fixup_len); if (!fixup_val) return fixup_len; if (fixup_len % sizeof(uint32_t)) return -FDT_ERR_BADOVERLAY; fixup_len /= sizeof(uint32_t); tree_val = fdt_getprop(fdto, tree_node, name, &tree_len); if (!tree_val) { if (tree_len == -FDT_ERR_NOTFOUND) return -FDT_ERR_BADOVERLAY; return tree_len; } for (i = 0; i < fixup_len; i++) { fdt32_t adj_val; uint32_t poffset; poffset = fdt32_to_cpu(fixup_val[i]); /* * phandles to fixup can be unaligned. * * Use a memcpy for the architectures that do * not support unaligned accesses. */ memcpy(&adj_val, tree_val + poffset, sizeof(adj_val)); adj_val = cpu_to_fdt32(fdt32_to_cpu(adj_val) + delta); ret = fdt_setprop_inplace_namelen_partial(fdto, tree_node, name, strlen(name), poffset, &adj_val, sizeof(adj_val)); if (ret == -FDT_ERR_NOSPACE) return -FDT_ERR_BADOVERLAY; if (ret) return ret; } } fdt_for_each_subnode(fixup_child, fdto, fixup_node) { const char *fixup_child_name = fdt_get_name(fdto, fixup_child, NULL); int tree_child; tree_child = fdt_subnode_offset(fdto, tree_node, fixup_child_name); if (tree_child == -FDT_ERR_NOTFOUND) return -FDT_ERR_BADOVERLAY; if (tree_child < 0) return tree_child; ret = overlay_update_local_node_references(fdto, tree_child, fixup_child, delta); if (ret) return ret; } return 0; } /** * overlay_update_local_references - Adjust the overlay references * @fdto: Device tree overlay blob * @delta: Offset to shift the phandles of * * overlay_update_local_references() update all the phandles pointing * to a node within the device tree overlay by adding a constant * delta to not conflict with the base overlay. * * This is mainly used as part of a device tree application process, * where you want the device tree overlays phandles to not conflict * with the ones from the base device tree before merging them. * * returns: * 0 on success * Negative error code on failure */ static int overlay_update_local_references(void *fdto, uint32_t delta) { int fixups; fixups = fdt_path_offset(fdto, "/__local_fixups__"); if (fixups < 0) { /* There's no local phandles to adjust, bail out */ if (fixups == -FDT_ERR_NOTFOUND) return 0; return fixups; } /* * Update our local references from the root of the tree */ return overlay_update_local_node_references(fdto, 0, fixups, delta); } /** * overlay_fixup_one_phandle - Set an overlay phandle to the base one * @fdt: Base Device Tree blob * @fdto: Device tree overlay blob * @symbols_off: Node offset of the symbols node in the base device tree * @path: Path to a node holding a phandle in the overlay * @path_len: number of path characters to consider * @name: Name of the property holding the phandle reference in the overlay * @name_len: number of name characters to consider * @poffset: Offset within the overlay property where the phandle is stored * @label: Label of the node referenced by the phandle * * overlay_fixup_one_phandle() resolves an overlay phandle pointing to * a node in the base device tree. * * This is part of the device tree overlay application process, when * you want all the phandles in the overlay to point to the actual * base dt nodes. * * returns: * 0 on success * Negative error code on failure */ static int overlay_fixup_one_phandle(void *fdt, void *fdto, int symbols_off, const char *path, uint32_t path_len, const char *name, uint32_t name_len, int poffset, const char *label) { const char *symbol_path; uint32_t phandle; fdt32_t phandle_prop; int symbol_off, fixup_off; int prop_len; if (symbols_off < 0) return symbols_off; symbol_path = fdt_getprop(fdt, symbols_off, label, &prop_len); if (!symbol_path) return prop_len; symbol_off = fdt_path_offset(fdt, symbol_path); if (symbol_off < 0) return symbol_off; phandle = fdt_get_phandle(fdt, symbol_off); if (!phandle) return -FDT_ERR_NOTFOUND; fixup_off = fdt_path_offset_namelen(fdto, path, path_len); if (fixup_off == -FDT_ERR_NOTFOUND) return -FDT_ERR_BADOVERLAY; if (fixup_off < 0) return fixup_off; phandle_prop = cpu_to_fdt32(phandle); return fdt_setprop_inplace_namelen_partial(fdto, fixup_off, name, name_len, poffset, &phandle_prop, sizeof(phandle_prop)); }; static int overlay_add_to_local_fixups(void *fdt, const char *value, int len) { const char *path, *fixup_end, *prop, *fixup_str; uint32_t clen; uint32_t fixup_len; char *sep, *endptr; const char *c; int poffset, nodeoffset, ret, localfixup_off; int pathlen, proplen; char propname[PATH_MAX]; localfixup_off = fdt_path_offset(fdt, "/__local_fixups__"); if (localfixup_off < 0 && localfixup_off == -FDT_ERR_NOTFOUND) localfixup_off = fdt_add_subnode(fdt, 0, "__local_fixups__"); if (localfixup_off < 0) return localfixup_off; while (len > 0) { fixup_str = value; /* Assumes null-terminated properties! */ fixup_end = memchr(value, '\0', len); if (!fixup_end) return -FDT_ERR_BADOVERLAY; fixup_len = fixup_end - fixup_str; len -= (fixup_len + 1); value += fixup_len + 1; c = path = fixup_str; sep = memchr(c, ':', fixup_len); if (!sep || *sep != ':') return -FDT_ERR_BADOVERLAY; pathlen = sep - path; if (pathlen == (fixup_len - 1)) return -FDT_ERR_BADOVERLAY; fixup_len -= (pathlen + 1); c = path + pathlen + 1; sep = memchr(c, ':', fixup_len); if (!sep || *sep != ':') return -FDT_ERR_BADOVERLAY; prop = c; proplen = sep - c; if (proplen >= PATH_MAX) return -FDT_ERR_BADOVERLAY; /* * Skip fixups that involves the special 'target' property found * in overlay fragments such as * /fragment@0:target:0 * * The check for one node in path below is to ensure that we * handle 'target' properties present otherwise in any other * node, for ex: * /fragment@0/__overlay__/xyz:target:0 */ /* Does path have exactly one node? */ c = path; clen = pathlen; if (*c == '/') { c++; clen -= 1; } sep = memchr(c, '/', clen); if (!sep && proplen >= 6 && !strncmp(prop, "target", 6)) continue; memcpy(propname, prop, proplen); propname[proplen] = 0; fixup_len -= (proplen + 1); c = prop + proplen + 1; poffset = strtoul(c, &endptr, 10); nodeoffset = localfixup_off; c = path; clen = pathlen; if (*c == '/') { c++; clen -= 1; } while (clen > 0) { char nodename[PATH_MAX]; int nodelen, childnode; sep = memchr(c, '/', clen); if (!sep) nodelen = clen; else nodelen = sep - c; if (nodelen + 1 >= PATH_MAX) return -FDT_ERR_BADSTRUCTURE; memcpy(nodename, c, nodelen); nodename[nodelen] = 0; childnode = fdt_add_subnode(fdt, nodeoffset, nodename); if (childnode == -FDT_ERR_EXISTS) childnode = fdt_subnode_offset(fdt, nodeoffset, nodename); nodeoffset = childnode; if (nodeoffset < 0) return nodeoffset; c += nodelen; clen -= nodelen; if (*c == '/') { c++; clen -= 1; } } ret = fdt_appendprop_u32(fdt, nodeoffset, propname, poffset); if (ret < 0) return ret; } return 0; } /** * overlay_fixup_phandle - Set an overlay phandle to the base one * @fdt: Base Device Tree blob * @fdto: Device tree overlay blob * @symbols_off: Node offset of the symbols node in the base device tree * @property: Property offset in the overlay holding the list of fixups * @fixups_off: Offset of __fixups__ node in @fdto * @merge: Both input blobs are overlay blobs that are being merged * * overlay_fixup_phandle() resolves all the overlay phandles pointed * to in a __fixups__ property, and updates them to match the phandles * in use in the base device tree. * * This is part of the device tree overlay application process, when * you want all the phandles in the overlay to point to the actual * base dt nodes. * * returns: * 0 on success * Negative error code on failure */ static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off, int property, int fixups_off, int merge) { const char *value, *total_value; const char *label; int len, total_len, ret = 0; total_value = value = fdt_getprop_by_offset(fdto, property, &label, &len); if (!value) { if (len == -FDT_ERR_NOTFOUND) return -FDT_ERR_INTERNAL; return len; } total_len = len; do { const char *path, *name, *fixup_end; const char *fixup_str = value; uint32_t path_len, name_len; uint32_t fixup_len; char *sep, *endptr; int poffset; fixup_end = memchr(value, '\0', len); if (!fixup_end) return -FDT_ERR_BADOVERLAY; fixup_len = fixup_end - fixup_str; len -= fixup_len + 1; value += fixup_len + 1; path = fixup_str; sep = memchr(fixup_str, ':', fixup_len); if (!sep || *sep != ':') return -FDT_ERR_BADOVERLAY; path_len = sep - path; if (path_len == (fixup_len - 1)) return -FDT_ERR_BADOVERLAY; fixup_len -= path_len + 1; name = sep + 1; sep = memchr(name, ':', fixup_len); if (!sep || *sep != ':') return -FDT_ERR_BADOVERLAY; name_len = sep - name; if (!name_len) return -FDT_ERR_BADOVERLAY; poffset = strtoul(sep + 1, &endptr, 10); if ((*endptr != '\0') || (endptr <= (sep + 1))) return -FDT_ERR_BADOVERLAY; ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off, path, path_len, name, name_len, poffset, label); if (ret) return ret; } while (len > 0); /* * Properties found in __fixups__ node are typically one of * these types: * * abc = "/fragment@2:target:0" (first type) * abc = "/fragment@2/__overlay__:xyz:0" (second type) * * Both types could also be present in some properties as well such as: * * abc = "/fragment@2:target:0", "/fragment@2/__overlay__:xyz:0" * * While merging two overlay blobs, a successfull overlay phandle fixup * of second type needs to be recorded in __local_fixups__ node of the * combined blob, so that the phandle value can be further updated via * overlay_update_local_references() when the combined overlay blob gets * overlaid on a different base blob. * * Further, since in the case of merging two overlay blobs, we will also * be merging contents of nodes such as __fixups__ from both overlay * blobs, delete this property in __fixup__ node, as it no longer * represents a external phandle reference that needs to be resolved * during a subsequent overlay of combined blob on a base blob. */ if (merge) { ret = overlay_add_to_local_fixups(fdt, total_value, total_len); if (!ret) ret = fdt_delprop(fdto, fixups_off, label); } return ret; } /** * overlay_fixup_phandles - Resolve the overlay phandles to the base * device tree * @fdt: Base Device Tree blob * @fdto: Device tree overlay blob * @merge: Both input blobs are overlay blobs that are being merged * * overlay_fixup_phandles() resolves all the overlay phandles pointing * to nodes in the base device tree. * * This is one of the steps of the device tree overlay application * process, when you want all the phandles in the overlay to point to * the actual base dt nodes. * * returns: * 0 on success * Negative error code on failure */ static int overlay_fixup_phandles(void *fdt, void *fdto, int merge) { int fixups_off, symbols_off; int property, ret = 0, next_property; /* We can have overlays without any fixups */ fixups_off = fdt_path_offset(fdto, "/__fixups__"); if (fixups_off == -FDT_ERR_NOTFOUND) return 0; /* nothing to do */ if (fixups_off < 0) return fixups_off; /* And base DTs without symbols */ symbols_off = fdt_path_offset(fdt, "/__symbols__"); if ((symbols_off < 0 && (symbols_off != -FDT_ERR_NOTFOUND))) return symbols_off; /* Safeguard against property being deleted in below loop */ property = fdt_first_property_offset(fdto, fixups_off); while (property >= 0) { next_property = fdt_next_property_offset(fdto, property); ret = overlay_fixup_phandle(fdt, fdto, symbols_off, property, fixups_off, merge); if (ret && (!merge || ret != -FDT_ERR_NOTFOUND)) return ret; if (merge && !ret) { /* Bail if this was the last property */ if (next_property < 0) break; /* * Property is deleted in this case. Next property is * available at the same offset, so loop back with * 'property' offset unmodified. Also since @fdt would * have been modified in this case, refresh the offset * of /__symbols__ node */ symbols_off = fdt_path_offset(fdt, "/__symbols__"); if (symbols_off < 0) return symbols_off; continue; } property = next_property; } if (merge && ret == -FDT_ERR_NOTFOUND) ret = 0; return ret; } /** * overlay_apply_node - Merges a node into the base device tree * @fdt: Base Device Tree blob * @target: Node offset in the base device tree to apply the fragment to * @fdto: Device tree overlay blob * @node: Node offset in the overlay holding the changes to merge * * overlay_apply_node() merges a node into a target base device tree * node pointed. * * This is part of the final step in the device tree overlay * application process, when all the phandles have been adjusted and * resolved and you just have to merge overlay into the base device * tree. * * returns: * 0 on success * Negative error code on failure */ static int overlay_apply_node(void *fdt, int target, void *fdto, int node) { int property; int subnode; fdt_for_each_property_offset(property, fdto, node) { const char *name; const void *prop; int prop_len; int ret; prop = fdt_getprop_by_offset(fdto, property, &name, &prop_len); if (prop_len == -FDT_ERR_NOTFOUND) return -FDT_ERR_INTERNAL; if (prop_len < 0) return prop_len; ret = fdt_setprop(fdt, target, name, prop, prop_len); if (ret) return ret; } fdt_for_each_subnode(subnode, fdto, node) { const char *name = fdt_get_name(fdto, subnode, NULL); int nnode; int ret; nnode = fdt_add_subnode(fdt, target, name); if (nnode == -FDT_ERR_EXISTS) { nnode = fdt_subnode_offset(fdt, target, name); if (nnode == -FDT_ERR_NOTFOUND) return -FDT_ERR_INTERNAL; } if (nnode < 0) return nnode; ret = overlay_apply_node(fdt, nnode, fdto, subnode); if (ret) return ret; } return 0; } /** * copy_node - copy a node hierarchically * @fdt - pointer to base device tree * @fdto - pointer to overlay device tree * @fdt_child - offset of node in overlay device tree which needs to be copied * @fdt_parent - offset of parent node in base tree under which @fdto_child * need to be copied * * This function copies a node in overlay tree along with its child-nodes and * their properties, under a given parent node in base tree. */ static int copy_node(void *fdt, void *fdto, int fdt_parent, int fdto_child) { const char *name, *value; int offset, len, ret, prop, child; void *p; name = fdt_get_name(fdto, fdto_child, &len); if (!name) return len; offset = fdt_subnode_offset(fdt, fdt_parent, name); if (offset < 0) { offset = fdt_add_subnode(fdt, fdt_parent, name); if (offset < 0) return offset; } fdt_for_each_subnode(child, fdto, fdto_child) { ret = copy_node(fdt, fdto, offset, child); if (ret < 0) return ret; } fdt_for_each_property_offset(prop, fdto, fdto_child) { int fdt_len = 0; value = fdt_getprop_by_offset(fdto, prop, &name, &len); if (fdt_getprop(fdt, offset, name, &fdt_len)) len += fdt_len; ret = fdt_setprop_placeholder(fdt, offset, name, len, &p); if (ret < 0) return ret; if (fdt_len > 0) { p = (char *)p + fdt_len; len -= fdt_len; } memcpy(p, value, len); } return 0; } /** * overlay_merge - Merge an overlay into its base device tree * @fdt: Base Device Tree blob * @fdto: Device tree overlay blob * @merge: Both input blobs are overlay blobs that are being merged * * overlay_merge() merges an overlay into its base device tree. * * This is the next to last step in the device tree overlay application * process, when all the phandles have been adjusted and resolved and * you just have to merge overlay into the base device tree. * * returns: * 0 on success * Negative error code on failure */ static int overlay_merge(void *fdt, void *fdto, int merge) { int fragment; fdt_for_each_subnode(fragment, fdto, 0) { int overlay; int target; int ret; /* * Each fragments will have an __overlay__ node. If * they don't, it's not supposed to be merged */ overlay = fdt_subnode_offset(fdto, fragment, "__overlay__"); if (overlay == -FDT_ERR_NOTFOUND) continue; if (overlay < 0) return overlay; target = fdt_overlay_target_offset(fdt, fdto, fragment, NULL); if (target < 0) { /* * No target found which is acceptable situation in case * of merging two overlay blobs. Copy this fragment to * base/combined blob, so that it can be considered for * overlay during a subsequent overlay operation of * combined blob on another base blob. */ if (target == -FDT_ERR_BADPHANDLE && merge) { target = copy_node(fdt, fdto, 0, fragment); if (!target) continue; } return target; } ret = overlay_apply_node(fdt, target, fdto, overlay); if (ret) return ret; } return 0; } static int get_path_len(const void *fdt, int nodeoffset) { int len = 0, namelen; const char *name; FDT_RO_PROBE(fdt); for (;;) { name = fdt_get_name(fdt, nodeoffset, &namelen); if (!name) return namelen; /* root? we're done */ if (namelen == 0) break; nodeoffset = fdt_parent_offset(fdt, nodeoffset); if (nodeoffset < 0) return nodeoffset; len += namelen + 1; } /* in case of root pretend it's "/" */ if (len == 0) len++; return len; } /** * overlay_symbol_update - Update the symbols of base tree after a merge * @fdt: Base Device Tree blob * @fdto: Device tree overlay blob * @merge: Both input blobs are overlay blobs that are being merged * * overlay_symbol_update() updates the symbols of the base tree with the * symbols of the applied overlay * * This is the last step in the device tree overlay application * process, allowing the reference of overlay symbols by subsequent * overlay operations. * * returns: * 0 on success * Negative error code on failure */ static int overlay_symbol_update(void *fdt, void *fdto, int merge) { int root_sym, ov_sym, prop, next_prop, path_len, fragment, target; int len, frag_name_len, ret, rel_path_len; const char *s, *e; const char *path; const char *name; const char *frag_name; const char *rel_path; const char *target_path; char *buf; void *p; ov_sym = fdt_subnode_offset(fdto, 0, "__symbols__"); /* if no overlay symbols exist no problem */ if (ov_sym < 0) return 0; root_sym = fdt_subnode_offset(fdt, 0, "__symbols__"); /* it no root symbols exist we should create them */ if (root_sym == -FDT_ERR_NOTFOUND) root_sym = fdt_add_subnode(fdt, 0, "__symbols__"); /* any error is fatal now */ if (root_sym < 0) return root_sym; /* iterate over each overlay symbol */ /* Safeguard against property being possibly deleted in this loop */ prop = fdt_first_property_offset(fdto, ov_sym); while (prop >= 0) { next_prop = fdt_next_property_offset(fdto, prop); path = fdt_getprop_by_offset(fdto, prop, &name, &path_len); if (!path) return path_len; /* verify it's a string property (terminated by a single \0) */ if (path_len < 1 || memchr(path, '\0', path_len) != &path[path_len - 1]) return -FDT_ERR_BADVALUE; /* keep end marker to avoid strlen() */ e = path + path_len; if (*path != '/') return -FDT_ERR_BADVALUE; /* get fragment name first */ s = strchr(path + 1, '/'); if (!s) { /* Symbol refers to something that won't end * up in the target tree */ continue; } frag_name = path + 1; frag_name_len = s - path - 1; /* verify format; safe since "s" lies in \0 terminated prop */ len = sizeof("/__overlay__/") - 1; if ((e - s) > len && (memcmp(s, "/__overlay__/", len) == 0)) { /* //__overlay__/ */ rel_path = s + len; rel_path_len = e - rel_path - 1; } else if ((e - s) == len && (memcmp(s, "/__overlay__", len - 1) == 0)) { /* //__overlay__ */ rel_path = ""; rel_path_len = 0; } else { /* Symbol refers to something that won't end * up in the target tree */ continue; } /* find the fragment index in which the symbol lies */ ret = fdt_subnode_offset_namelen(fdto, 0, frag_name, frag_name_len); /* not found? */ if (ret < 0) return -FDT_ERR_BADOVERLAY; fragment = ret; /* an __overlay__ subnode must exist */ ret = fdt_subnode_offset(fdto, fragment, "__overlay__"); if (ret < 0) return -FDT_ERR_BADOVERLAY; /* get the target of the fragment */ ret = fdt_overlay_target_offset(fdt, fdto, fragment, &target_path); if (ret < 0) { if (ret == -FDT_ERR_BADPHANDLE && merge) { prop = next_prop; continue; } return ret; } target = ret; /* if we have a target path use */ if (!target_path) { ret = get_path_len(fdt, target); if (ret < 0) return ret; len = ret; } else { len = strlen(target_path); } ret = fdt_setprop_placeholder(fdt, root_sym, name, len + (len > 1) + rel_path_len + 1, &p); if (ret < 0) return ret; if (!target_path) { /* again in case setprop_placeholder changed it */ ret = fdt_overlay_target_offset(fdt, fdto, fragment, &target_path); if (ret < 0) return ret; target = ret; } buf = p; if (len > 1) { /* target is not root */ if (!target_path) { ret = fdt_get_path(fdt, target, buf, len + 1); if (ret < 0) return ret; } else memcpy(buf, target_path, len + 1); } else len--; buf[len] = '/'; memcpy(buf + len + 1, rel_path, rel_path_len); buf[len + 1 + rel_path_len] = '\0'; /* * In case of merging two overlay blobs, we will be merging * contents of nodes such as __symbols__ from both overlay * blobs. Delete this property in __symbols__ node of second * overlay blob, as it has already been reflected in * first/combined blob's __symbols__ node. */ if (merge) { ret = fdt_delprop(fdto, ov_sym, name); if (ret < 0) return ret; /* Bail if this was the last property */ if (next_prop < 0) break; /* * Continue with same 'prop' offset, as the next * property is now available at the same offset */ continue; } prop = next_prop; } return 0; } int fdt_overlay_apply(void *fdt, void *fdto) { uint32_t delta; int ret; FDT_RO_PROBE(fdt); FDT_RO_PROBE(fdto); ret = fdt_find_max_phandle(fdt, &delta); if (ret) goto err; ret = overlay_adjust_local_phandles(fdto, delta); if (ret) goto err; ret = overlay_update_local_references(fdto, delta); if (ret) goto err; ret = overlay_fixup_phandles(fdt, fdto, 0); if (ret) goto err; ret = overlay_merge(fdt, fdto, 0); if (ret) goto err; ret = overlay_symbol_update(fdt, fdto, 0); if (ret) goto err; /* * The overlay has been damaged, erase its magic. */ fdt_set_magic(fdto, ~0); return 0; err: /* * The overlay might have been damaged, erase its magic. */ fdt_set_magic(fdto, ~0); /* * The base device tree might have been damaged, erase its * magic. */ fdt_set_magic(fdt, ~0); return ret; } /* * Property value could be in this format * fragment@M ...fragment@N....fragment@O.. * * This needs to be converted to * fragment@M+delta...fragment@N+delta....fragment@O+delta */ static int rename_fragments_in_property(void *fdto, int offset, int property, int delta) { char *start, *sep, *end, *stop, *value; int needed = 0, ret, len, found = 0, available, diff; unsigned long index, new_index; void *p = NULL; const char *label; value = (char *)(uintptr_t)fdt_getprop_by_offset(fdto, property, &label, &len); if (!value) return len; start = value; end = value + len; /* Find the required additional space */ while (start < end) { sep = memchr(start, '@', (end - start)); if (!sep) { needed += end - start; break; } /* Check if string "fragment" exists */ sep -= 8; if (sep < start || strncmp(sep, "fragment", 8)) { /* Start scan again after '@' */ sep = sep + 9; needed += (sep - start); start = sep; continue; } found = 1; sep += 9; needed += (sep - start); index = strtoul(sep, &stop, 10); if (ULONG_MAX - index < delta) return -FDT_ERR_BADVALUE; new_index = index + delta; needed += snprintf(NULL, 0, "%lu", new_index); start = stop; } if (!found) return 0; p = value; if (needed > len) { ret = fdt_setprop_placeholder(fdto, offset, label, needed, &p); if (ret < 0) return ret; } start = p; end = start + len; ret = 0; while (start < end) { sep = memchr(start, '@', (end - start)); if (!sep) break; /* Check if string "fragment" exists */ sep -= 8; if (sep < start || strncmp(sep, "fragment", 8)) { /* Start scan again after '@' */ start = sep + 9; continue; } sep += 9; index = strtoul(sep, &stop, 10); new_index = index + delta; needed = snprintf(NULL, 0, "%lu", new_index); available = stop - sep; if (available < needed) { diff = needed - available; memmove(stop + diff, stop, (end - stop)); end += diff; } { /* +1 for NULL char */ char buf[needed + 1]; snprintf(buf, needed + 1, "%lu", new_index); memcpy(sep, buf, needed); } start = sep + needed; } return 0; } /** * rename_fragments_in_node - Rename fragment@xyz instances in a node's * properties * * @fdto - pointer to a device-tree blob * @nodename - Node in whose properties fragments need to be renamed * @delta - Increment to be applied to fragment index */ static int rename_fragments_in_node(void *fdto, const char *nodename, unsigned long delta) { int offset, property; int ret; offset = fdt_path_offset(fdto, nodename); if (offset < 0) return offset; fdt_for_each_property_offset(property, fdto, offset) { ret = rename_fragments_in_property(fdto, offset, property, delta); if (ret < 0) return ret; } return 0; } /** * rename_nodes - Rename all fragement@xyz nodes * * @fdto - pointer to device-tree blob * @parent_node - node offset of parent whose child fragment nodes need to be * renamed * @delta - increment to be added to fragment number */ static int rename_nodes(void *fdto, int parent_node, unsigned long delta) { int offset = -1, ret, len, strsize; int child_len, child_offset; const char *name, *child_name, *idx; char *stop = NULL; unsigned long index, new_index; offset = fdt_first_subnode(fdto, parent_node); while (offset >= 0) { name = fdt_get_name(fdto, offset, &len); if (!name) return len; if (len < 9 || strncmp(name, "fragment@", 9)) goto next_node; child_offset = fdt_first_subnode(fdto, offset); if (child_offset < 0) return child_offset; child_name = fdt_get_name(fdto, child_offset, &child_len); if (!child_name) return child_len; /* Extra FDT_TAGSIZE bytes for expanded node name */ strsize = FDT_TAGALIGN(len+1+FDT_TAGSIZE); if (child_len >= 11 && !strncmp(child_name, "__overlay__", 11)) { char new_name[strsize]; idx = name + 9; stop = NULL; index = strtoul(idx, &stop, 10); if (ULONG_MAX - delta < index) return -FDT_ERR_BADVALUE; new_index = index + delta; ret = snprintf(new_name, sizeof(new_name), "fragment@%lu", new_index); if (ret >= sizeof(new_name)) return -FDT_ERR_BADVALUE; ret = fdt_set_name(fdto, offset, new_name); if (ret < 0) return ret; } next_node: offset = fdt_next_subnode(fdto, offset); } return 0; } /* Return maximum count of overlay fragments */ static int count_fragments(void *fdt, unsigned long *max_base_fragments) { int offset = -1, child_offset, child_len, len, found = 0; const char *name, *child_name, *idx; char *stop; unsigned long index, max = 0; offset = fdt_first_subnode(fdt, 0); while (offset >= 0) { name = fdt_get_name(fdt, offset, &len); if (!name) return len; if (len < 9 || strncmp(name, "fragment@", 9)) goto next_node; child_offset = fdt_first_subnode(fdt, offset); if (child_offset < 0) return child_offset; child_name = fdt_get_name(fdt, child_offset, &child_len); if (!child_name) return child_len; if (child_len < 11 || strncmp(child_name, "__overlay__", 11)) goto next_node; found = 1; idx = name + 9; index = strtoul(idx, &stop, 10); if (index > max) max = index; next_node: offset = fdt_next_subnode(fdt, offset); } if (!found) return -FDT_ERR_NOTFOUND; *max_base_fragments = max; return 0; } /* * Merging two overlay blobs involves copying some of the overlay fragment nodes * (named as fragment@xyz) from second overlay blob into first, which can lead * to naming conflicts (ex: two nodes of same name /fragment@0). To prevent such * naming conflicts, rename all occurences of fragment@xyz in second overlay * blob as fragment@xyz+delta, where delta is the maximum overlay fragments seen * in first overlay blob */ static int overlay_rename_fragments(void *fdt, void *fdto) { int ret, local_offset; unsigned long max_base_fragments = 0; ret = count_fragments(fdt, &max_base_fragments); /* no fragments in base dtb? then nothing to rename */ if (ret == -FDT_ERR_NOTFOUND) return 0; else if (ret < 0) return ret; max_base_fragments += 1; ret = rename_nodes(fdto, 0, max_base_fragments); if (ret < 0) return ret; ret = rename_fragments_in_node(fdto, "/__fixups__", max_base_fragments); if (ret < 0) return ret; ret = rename_fragments_in_node(fdto, "/__symbols__", max_base_fragments); if (ret < 0 && ret != -FDT_ERR_NOTFOUND) return ret; /* * renaming fragments in __local_fixups__ node's properties should be * covered by rename_nodes() */ local_offset = fdt_path_offset(fdto, "/__local_fixups__"); if (local_offset >= 0) ret = rename_nodes(fdto, local_offset, max_base_fragments); if (ret == -FDT_ERR_NOTFOUND) ret = 0; return ret; } /* merge a node's properties from fdto to fdt */ static int overlay_merge_node_properties(void *fdt, void *fdto, const char *nodename) { int fdto_offset, ret; fdto_offset = fdt_path_offset(fdto, nodename); if (fdto_offset < 0) return fdto_offset; ret = copy_node(fdt, fdto, 0, fdto_offset); return ret; } static int overlay_merge_local_fixups(void *fdt, void *fdto) { int fdto_local_fixups, ret; fdto_local_fixups = fdt_path_offset(fdto, "/__local_fixups__"); if (fdto_local_fixups < 0) return fdto_local_fixups; ret = copy_node(fdt, fdto, 0, fdto_local_fixups); return ret; } int fdt_overlay_merge(void *fdt, void *fdto, int *fdto_nospace) { uint32_t delta = fdt_get_max_phandle(fdt); int ret; fdt_check_header(fdt); fdt_check_header(fdto); *fdto_nospace = 0; ret = overlay_rename_fragments(fdt, fdto); if (ret) { if (ret == -FDT_ERR_NOSPACE) *fdto_nospace = 1; goto err; } ret = overlay_adjust_local_phandles(fdto, delta); if (ret) goto err; ret = overlay_update_local_references(fdto, delta); if (ret) goto err; ret = overlay_fixup_phandles(fdt, fdto, 1); if (ret) goto err; ret = overlay_merge(fdt, fdto, 1); if (ret) goto err; ret = overlay_symbol_update(fdt, fdto, 1); if (ret) goto err; /* Can't have an overlay without __fixups__ ? */ ret = overlay_merge_node_properties(fdt, fdto, "/__fixups__"); if (ret) goto err; /* __symbols__ node need not be present */ ret = overlay_merge_node_properties(fdt, fdto, "/__symbols__"); if (ret && ret != -FDT_ERR_NOTFOUND) goto err; /* __local_fixups__ node need not be present */ ret = overlay_merge_local_fixups(fdt, fdto); if (ret < 0 && ret != -FDT_ERR_NOTFOUND) goto err; /* * The overlay has been damaged, erase its magic. */ fdt_set_magic(fdto, ~0); return 0; err: /* * The overlay might have been damaged, erase its magic. */ fdt_set_magic(fdto, ~0); /* * The base device tree might have been damaged, erase its * magic. */ if (!*fdto_nospace) fdt_set_magic(fdt, ~0); return ret; }