Restore phandle references from __fixups__ node

The __fixups__ node contains information about labels. Parse its
properties to create phandle markers which improve the resulting dts
when decompiling a device tree blob.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Message-ID: <20250919092912.663304-14-u.kleine-koenig@baylibre.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

checks.c

@@ -340,6 +340,14 @@ static void check_node_name_format(struct check *c, struct dt_info *dti,
 }
 ERROR(node_name_format, check_node_name_format, NULL, &node_name_chars);
 
+static void check_node_name_not_empty(struct check *c, struct dt_info *dti,
+				      struct node *node)
+{
+	if (node->basenamelen == 0 && node->parent != NULL)
+		FAIL(c, dti, node, "Empty node name");
+}
+ERROR(node_name_not_empty, check_node_name_not_empty, NULL, &node_name_chars);
+
 static void check_node_name_vs_property_name(struct check *c,
 					     struct dt_info *dti,
 					     struct node *node)
@@ -718,11 +726,14 @@ static void check_alias_paths(struct check *c, struct dt_info *dti,
 			continue;
 		}
 
-		if (!prop->val.val || !get_node_by_path(dti->dt, prop->val.val)) {
+		/* This check does not work for overlays with external paths */
+		if (!(dti->dtsflags & DTSF_PLUGIN) &&
+		    (!prop->val.val || !get_node_by_path(dti->dt, prop->val.val))) {
 			FAIL_PROP(c, dti, node, prop, "aliases property is not a valid node (%s)",
 				  prop->val.val);
 			continue;
 		}
+
 		if (strspn(prop->name, LOWERCASE DIGITS "-") != strlen(prop->name))
 			FAIL(c, dti, node, "aliases property name must include only lowercase and '-'");
 	}
@@ -1894,34 +1905,9 @@ static void check_graph_endpoint(struct check *c, struct dt_info *dti,
 }
 WARNING(graph_endpoint, check_graph_endpoint, NULL, &graph_nodes);
 
-static void check_graph_child_address(struct check *c, struct dt_info *dti,
-				      struct node *node)
-{
-	int cnt = 0;
-	struct node *child;
-
-	if (node->bus != &graph_ports_bus && node->bus != &graph_port_bus)
-		return;
-
-	for_each_child(node, child) {
-		struct property *prop = get_property(child, "reg");
-
-		/* No error if we have any non-zero unit address */
-                if (prop && propval_cell(prop) != 0 )
-			return;
-
-		cnt++;
-	}
-
-	if (cnt == 1 && node->addr_cells != -1)
-		FAIL(c, dti, node, "graph node has single child node '%s', #address-cells/#size-cells are not necessary",
-		     node->children->name);
-}
-WARNING(graph_child_address, check_graph_child_address, NULL, &graph_nodes, &graph_port, &graph_endpoint);
-
 static struct check *check_table[] = {
 	&duplicate_node_names, &duplicate_property_names,
-	&node_name_chars, &node_name_format, &property_name_chars,
+	&node_name_chars, &node_name_format, &node_name_not_empty, &property_name_chars,
 	&name_is_string, &name_properties, &node_name_vs_property_name,
 
 	&duplicate_label,
@@ -2005,7 +1991,7 @@ static struct check *check_table[] = {
 
 	&alias_paths,
 
-	&graph_nodes, &graph_child_address, &graph_port, &graph_endpoint,
+	&graph_nodes, &graph_port, &graph_endpoint,
 
 	&always_fail,
 };

dtc.c

@@ -338,9 +338,14 @@ int main(int argc, char *argv[])
 	if (auto_label_aliases)
 		generate_label_tree(dti, "aliases", false);
 
+	generate_labels_from_tree(dti, "__symbols__");
+
 	if (generate_symbols)
 		generate_label_tree(dti, "__symbols__", true);
 
+	fixup_phandles(dti, "__fixups__");
+	local_fixup_phandles(dti, "__local_fixups__");
+
 	if (generate_fixups) {
 		generate_fixups_tree(dti, "__fixups__");
 		generate_local_fixups_tree(dti, "__local_fixups__");

dtc.h

@@ -339,9 +339,12 @@ struct dt_info *build_dt_info(unsigned int dtsflags,
 			      struct reserve_info *reservelist,
 			      struct node *tree, uint32_t boot_cpuid_phys);
 void sort_tree(struct dt_info *dti);
+void generate_labels_from_tree(struct dt_info *dti, const char *name);
 void generate_label_tree(struct dt_info *dti, const char *name, bool allocph);
 void generate_fixups_tree(struct dt_info *dti, const char *name);
+void fixup_phandles(struct dt_info *dti, const char *name);
 void generate_local_fixups_tree(struct dt_info *dti, const char *name);
+void local_fixup_phandles(struct dt_info *dti, const char *name);
 
 /* Checks */
 
@@ -357,6 +360,9 @@ struct dt_info *dt_from_blob(const char *fname);
 
 /* Tree source */
 
+void property_add_marker(struct property *prop,
+			 enum markertype type, unsigned int offset, char *ref);
+void add_phandle_marker(struct dt_info *dti, struct property *prop, unsigned int offset);
 void dt_to_source(FILE *f, struct dt_info *dti);
 struct dt_info *dt_from_source(const char *f);
 

fdtdump.c

@@ -129,23 +129,25 @@ static void dump_blob(void *blob, bool debug)
 			continue;
 		}
 
-		if (tag != FDT_PROP) {
+		if (tag == FDT_PROP) {
-			fprintf(stderr, "%*s ** Unknown tag 0x%08"PRIx32"\n", depth * shift, "", tag);
+			sz = fdt32_to_cpu(GET_CELL(p));
-			break;
+			s = p_strings + fdt32_to_cpu(GET_CELL(p));
+			if (version < 16 && sz >= 8)
+				p = PALIGN(p, 8);
+			t = p;
+
+			p = PALIGN(p + sz, 4);
+
+			dumpf("%04"PRIxPTR": string: %s\n", (uintptr_t)s - blob_off, s);
+			dumpf("%04"PRIxPTR": value\n", (uintptr_t)t - blob_off);
+			printf("%*s%s", depth * shift, "", s);
+			utilfdt_print_data(t, sz);
+			printf(";\n");
+			continue;
 		}
-		sz = fdt32_to_cpu(GET_CELL(p));
-		s = p_strings + fdt32_to_cpu(GET_CELL(p));
-		if (version < 16 && sz >= 8)
-			p = PALIGN(p, 8);
-		t = p;
 
-		p = PALIGN(p + sz, 4);
+		fprintf(stderr, "%*s ** Unknown tag 0x%08"PRIx32"\n", depth * shift, "", tag);
-
+		break;
-		dumpf("%04"PRIxPTR": string: %s\n", (uintptr_t)s - blob_off, s);
-		dumpf("%04"PRIxPTR": value\n", (uintptr_t)t - blob_off);
-		printf("%*s%s", depth * shift, "", s);
-		utilfdt_print_data(t, sz);
-		printf(";\n");
 	}
 }
 

fdtput.c

@@ -254,19 +254,21 @@ static int create_paths(char **blob, const char *in_path)
 static int create_node(char **blob, const char *node_name)
 {
 	int node = 0;
-	char *p;
+	const char *p;
+	char *path = NULL;
 
 	p = strrchr(node_name, '/');
 	if (!p) {
 		report_error(node_name, -1, -FDT_ERR_BADPATH);
 		return -1;
 	}
-	*p = '\0';
 
 	*blob = realloc_node(*blob, p + 1);
 
 	if (p > node_name) {
-		node = fdt_path_offset(*blob, node_name);
+		path = xstrndup(node_name, (size_t)(p - node_name));
+		node = fdt_path_offset(*blob, path);
+		free(path);
 		if (node < 0) {
 			report_error(node_name, -1, node);
 			return -1;

flattree.c

@@ -807,6 +807,7 @@ struct dt_info *dt_from_blob(const char *fname)
 	struct node *tree;
 	uint32_t val;
 	int flags = 0;
+	unsigned int dtsflags = DTSF_V1;
 
 	f = srcfile_relative_open(fname, NULL);
 
@@ -919,5 +920,8 @@ struct dt_info *dt_from_blob(const char *fname)
 
 	fclose(f);
 
-	return build_dt_info(DTSF_V1, reservelist, tree, boot_cpuid_phys);
+	if (get_subnode(tree, "__fixups__") || get_subnode(tree, "__local_fixups__"))
+		dtsflags |= DTSF_PLUGIN;
+
+	return build_dt_info(dtsflags, reservelist, tree, boot_cpuid_phys);
 }

libfdt/fdt_overlay.c

@@ -407,7 +407,8 @@ static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off,
 		const char *fixup_str = value;
 		uint32_t path_len, name_len;
 		uint32_t fixup_len;
-		char *sep, *endptr;
+		const char *sep;
+		char *endptr;
 		int poffset, ret;
 
 		fixup_end = memchr(value, '\0', len);

libfdt/fdt_ro.c

@@ -306,8 +306,8 @@ const char *fdt_get_name(const void *fdt, int nodeoffset, int *len)
 	const char *nameptr;
 	int err;
 
-	if (((err = fdt_ro_probe_(fdt)) < 0)
+	if (!can_assume(VALID_DTB) && (((err = fdt_ro_probe_(fdt)) < 0)
-	    || ((err = fdt_check_node_offset_(fdt, nodeoffset)) < 0))
+	    || ((err = fdt_check_node_offset_(fdt, nodeoffset)) < 0)))
 			goto fail;
 
 	nameptr = nh->name;

libfdt/libfdt_env.h

@@ -66,31 +66,4 @@ static inline fdt64_t cpu_to_fdt64(uint64_t x)
 #undef CPU_TO_FDT16
 #undef EXTRACT_BYTE
 
-#ifdef __APPLE__
-#include <AvailabilityMacros.h>
-
-/* strnlen() is not available on Mac OS < 10.7 */
-# if !defined(MAC_OS_X_VERSION_10_7) || (MAC_OS_X_VERSION_MAX_ALLOWED < \
-                                         MAC_OS_X_VERSION_10_7)
-
-#define strnlen fdt_strnlen
-
-/*
- * fdt_strnlen: returns the length of a string or max_count - which ever is
- * smallest.
- * Input 1 string: the string whose size is to be determined
- * Input 2 max_count: the maximum value returned by this function
- * Output: length of the string or max_count (the smallest of the two)
- */
-static inline size_t fdt_strnlen(const char *string, size_t max_count)
-{
-    const char *p = memchr(string, 0, max_count);
-    return p ? p - string : max_count;
-}
-
-#endif /* !defined(MAC_OS_X_VERSION_10_7) || (MAC_OS_X_VERSION_MAX_ALLOWED <
-          MAC_OS_X_VERSION_10_7) */
-
-#endif /* __APPLE__ */
-
 #endif /* LIBFDT_ENV_H */

libfdt/libfdt_internal.h

@@ -6,17 +6,18 @@
  * Copyright (C) 2006 David Gibson, IBM Corporation.
  */
 #include <fdt.h>
-#include <string.h>
 
 #define FDT_ALIGN(x, a)		(((x) + (a) - 1) & ~((a) - 1))
 #define FDT_TAGALIGN(x)		(FDT_ALIGN((x), FDT_TAGSIZE))
 
 int32_t fdt_ro_probe_(const void *fdt);
-#define FDT_RO_PROBE(fdt)					\
+#define FDT_RO_PROBE(fdt)						\
-	{							\
+	{								\
-		int32_t totalsize_;				\
+		if (!can_assume(VALID_DTB)) {				\
-		if ((totalsize_ = fdt_ro_probe_(fdt)) < 0)	\
+			int32_t totalsize_;				\
-			return totalsize_;			\
+			if ((totalsize_ = fdt_ro_probe_(fdt)) < 0)	\
+				return totalsize_;			\
+		}							\
 	}
 
 int fdt_check_node_offset_(const void *fdt, int offset);
@@ -93,7 +94,7 @@ static inline uint64_t fdt64_ld_(const fdt64_t *p)
  * signature or hash check before using libfdt.
  *
  * For situations where security is not a concern it may be safe to enable
- * ASSUME_SANE.
+ * ASSUME_PERFECT.
  */
 enum {
 	/*

livetree.c

@@ -340,20 +340,73 @@ void append_to_property(struct node *node,
 			char *name, const void *data, int len,
 			enum markertype type)
 {
-	struct data d;
+	struct property *p;
+
+	p = get_property(node, name);
+	if (!p) {
+		p = build_property(name, empty_data, NULL);
+		add_property(node, p);
+	}
+
+	p->val = data_add_marker(p->val, type, name);
+	p->val = data_append_data(p->val, data, len);
+}
+
+static int append_unique_str_to_property(struct node *node,
+					 char *name, const char *data, int len)
+{
 	struct property *p;
 
 	p = get_property(node, name);
 	if (p) {
-		d = data_add_marker(p->val, type, name);
+		const char *s;
-		d = data_append_data(d, data, len);
+
-		p->val = d;
+		if (p->val.len && p->val.val[p->val.len - 1] != '\0')
+			/* The current content doesn't look like a string */
+			return -1;
+
+		for (s = p->val.val; s < p->val.val + p->val.len; s = strchr(s, '\0') + 1) {
+			if (strcmp(data, s) == 0)
+				/* data already contained in node.name */
+				return 0;
+		}
 	} else {
-		d = data_add_marker(empty_data, type, name);
+		p = build_property(name, empty_data, NULL);
-		d = data_append_data(d, data, len);
-		p = build_property(name, d, NULL);
 		add_property(node, p);
 	}
+
+	p->val = data_add_marker(p->val, TYPE_STRING, name);
+	p->val = data_append_data(p->val, data, len);
+
+	return 0;
+}
+
+static int append_unique_u32_to_property(struct node *node, char *name, fdt32_t value)
+{
+	struct property *p;
+
+	p = get_property(node, name);
+	if (p) {
+		const fdt32_t *v, *val_end = (const fdt32_t *)p->val.val + p->val.len / 4;
+
+		if (p->val.len % 4 != 0)
+			/* The current content doesn't look like a u32 array */
+			return -1;
+
+		for (v = (const void *)p->val.val; v < val_end; v++) {
+			if (*v == value)
+				/* value already contained */
+				return 0;
+		}
+	} else {
+		p = build_property(name, empty_data, NULL);
+		add_property(node, p);
+	}
+
+	p->val = data_add_marker(p->val, TYPE_UINT32, name);
+	p->val = data_append_data(p->val, &value, 4);
+
+	return 0;
 }
 
 struct reserve_info *build_reserve_entry(uint64_t address, uint64_t size)
@@ -918,11 +971,12 @@ static bool any_fixup_tree(struct dt_info *dti, struct node *node)
 	return false;
 }
 
-static void add_fixup_entry(struct dt_info *dti, struct node *fn,
+static int add_fixup_entry(struct dt_info *dti, struct node *fn,
-			    struct node *node, struct property *prop,
+			   struct node *node, struct property *prop,
-			    struct marker *m)
+			   struct marker *m)
 {
 	char *entry;
+	int ret;
 
 	/* m->ref can only be a REF_PHANDLE, but check anyway */
 	assert(m->type == REF_PHANDLE);
@@ -939,32 +993,39 @@ static void add_fixup_entry(struct dt_info *dti, struct node *fn,
 
 	xasprintf(&entry, "%s:%s:%u",
 			node->fullpath, prop->name, m->offset);
-	append_to_property(fn, m->ref, entry, strlen(entry) + 1, TYPE_STRING);
+	ret = append_unique_str_to_property(fn, m->ref, entry, strlen(entry) + 1);
 
 	free(entry);
+
+	return ret;
 }
 
-static void generate_fixups_tree_internal(struct dt_info *dti,
+static int generate_fixups_tree_internal(struct dt_info *dti,
-					  struct node *fn,
+					 struct node *fn,
-					  struct node *node)
+					 struct node *node)
 {
 	struct node *dt = dti->dt;
 	struct node *c;
 	struct property *prop;
 	struct marker *m;
 	struct node *refnode;
+	int ret = 0;
 
 	for_each_property(node, prop) {
 		m = prop->val.markers;
 		for_each_marker_of_type(m, REF_PHANDLE) {
 			refnode = get_node_by_ref(dt, m->ref);
 			if (!refnode)
-				add_fixup_entry(dti, fn, node, prop, m);
+				if (add_fixup_entry(dti, fn, node, prop, m))
+					ret = -1;
 		}
 	}
 
 	for_each_child(node, c)
-		generate_fixups_tree_internal(dti, fn, c);
+		if (generate_fixups_tree_internal(dti, fn, c))
+			ret = -1;
+
+	return ret;
 }
 
 static bool any_local_fixup_tree(struct dt_info *dti, struct node *node)
@@ -989,7 +1050,7 @@ static bool any_local_fixup_tree(struct dt_info *dti, struct node *node)
 	return false;
 }
 
-static void add_local_fixup_entry(struct dt_info *dti,
+static int add_local_fixup_entry(struct dt_info *dti,
 		struct node *lfn, struct node *node,
 		struct property *prop, struct marker *m,
 		struct node *refnode)
@@ -1020,30 +1081,56 @@ static void add_local_fixup_entry(struct dt_info *dti,
 	free(compp);
 
 	value_32 = cpu_to_fdt32(m->offset);
-	append_to_property(wn, prop->name, &value_32, sizeof(value_32), TYPE_UINT32);
+	return append_unique_u32_to_property(wn, prop->name, value_32);
 }
 
-static void generate_local_fixups_tree_internal(struct dt_info *dti,
+static int generate_local_fixups_tree_internal(struct dt_info *dti,
-						struct node *lfn,
+					       struct node *lfn,
-						struct node *node)
+					       struct node *node)
 {
 	struct node *dt = dti->dt;
 	struct node *c;
 	struct property *prop;
 	struct marker *m;
 	struct node *refnode;
+	int ret = 0;
 
 	for_each_property(node, prop) {
 		m = prop->val.markers;
 		for_each_marker_of_type(m, REF_PHANDLE) {
 			refnode = get_node_by_ref(dt, m->ref);
 			if (refnode)
-				add_local_fixup_entry(dti, lfn, node, prop, m, refnode);
+				if (add_local_fixup_entry(dti, lfn, node, prop, m, refnode))
+					ret = -1;
 		}
 	}
 
 	for_each_child(node, c)
-		generate_local_fixups_tree_internal(dti, lfn, c);
+		if (generate_local_fixups_tree_internal(dti, lfn, c))
+			ret = -1;
+
+	return ret;
+}
+
+void generate_labels_from_tree(struct dt_info *dti, const char *name)
+{
+	struct node *an;
+	struct property *p;
+
+	an = get_subnode(dti->dt, name);
+	if (!an)
+		return;
+
+	for_each_property(an, p) {
+		struct node *labeled_node;
+
+		labeled_node = get_node_by_path(dti->dt, p->val.val);
+		if (labeled_node)
+			add_label(&labeled_node->labels, p->name);
+		else if (quiet < 1)
+			fprintf(stderr, "Warning: Path %s referenced in property %s/%s missing",
+				p->val.val, name, p->name);
+	}
 }
 
 void generate_label_tree(struct dt_info *dti, const char *name, bool allocph)
@@ -1056,29 +1143,173 @@ void generate_label_tree(struct dt_info *dti, const char *name, bool allocph)
 
 void generate_fixups_tree(struct dt_info *dti, const char *name)
 {
-	struct node *n = get_subnode(dti->dt, name);
-
-	/* Start with an empty __fixups__ node to not get duplicates */
-	if (n)
-		n->deleted = true;
-
 	if (!any_fixup_tree(dti, dti->dt))
 		return;
-	generate_fixups_tree_internal(dti,
+	if (generate_fixups_tree_internal(dti, build_root_node(dti->dt, name), dti->dt))
-				      build_and_name_child_node(dti->dt, name),
+		fprintf(stderr,
-				      dti->dt);
+			"Warning: Preexisting data in %s malformed, some content could not be added.\n",
+			name);
+}
+
+void fixup_phandles(struct dt_info *dti, const char *name)
+{
+	struct node *an;
+	struct property *fp;
+
+	an = get_subnode(dti->dt, name);
+	if (!an)
+		return;
+
+	for_each_property(an, fp) {
+		char *fnext = fp->val.val;
+		char *fv;
+		unsigned int fl;
+
+		while ((fl = fp->val.len - (fnext - fp->val.val))) {
+			char *propname, *soffset;
+			struct node *n;
+			struct property *p;
+			long offset;
+
+			fv = fnext;
+			fnext = memchr(fv, 0, fl);
+
+			if (!fnext) {
+				if (quiet < 1)
+					fprintf(stderr, "Warning: Malformed fixup entry for label %s\n",
+						fp->name);
+				break;
+			}
+			fnext += 1;
+
+			propname = memchr(fv, ':', fnext - 1 - fv);
+			if (!propname) {
+				if (quiet < 1)
+					fprintf(stderr, "Warning: Malformed fixup entry for label %s\n",
+						fp->name);
+				continue;
+			}
+			propname++;
+
+			soffset = memchr(propname, ':', fnext - 1 - propname);
+			if (!soffset) {
+				if (quiet < 1)
+					fprintf(stderr, "Warning: Malformed fixup entry for label %s\n",
+						fp->name);
+				continue;
+			}
+			soffset++;
+
+			/*
+			 * temporarily modify the property to not have to create
+			 * a copy for the node path.
+			 */
+			*(propname - 1) = '\0';
+
+			n = get_node_by_path(dti->dt, fv);
+			if (!n && quiet < 1)
+				fprintf(stderr, "Warning: Label %s references non-existing node %s\n",
+					fp->name, fv);
+
+			*(propname - 1) = ':';
+
+			if (!n)
+				continue;
+
+			/*
+			 * temporarily modify the property to not have to create
+			 * a copy for the property name.
+			 */
+			*(soffset - 1) = '\0';
+
+			p = get_property(n, propname);
+
+			if (!p && quiet < 1)
+				fprintf(stderr, "Warning: Label %s references non-existing property %s in node %s\n",
+					fp->name, n->fullpath, propname);
+
+			*(soffset - 1) = ':';
+
+			if (!p)
+				continue;
+
+			offset = strtol(soffset, NULL, 0);
+			if (offset < 0 || offset + 4 > p->val.len) {
+				if (quiet < 1)
+					fprintf(stderr,
+						"Warning: Label %s contains invalid offset for property %s in node %s\n",
+						fp->name, p->name, n->fullpath);
+				continue;
+			}
+
+			property_add_marker(p, REF_PHANDLE, offset, fp->name);
+		}
+	}
 }
 
 void generate_local_fixups_tree(struct dt_info *dti, const char *name)
 {
-	struct node *n = get_subnode(dti->dt, name);
-
-	/* Start with an empty __local_fixups__ node to not get duplicates */
-	if (n)
-		n->deleted = true;
 	if (!any_local_fixup_tree(dti, dti->dt))
 		return;
-	generate_local_fixups_tree_internal(dti,
+	if (generate_local_fixups_tree_internal(dti, build_root_node(dti->dt, name), dti->dt))
-					    build_and_name_child_node(dti->dt, name),
+		fprintf(stderr,
-					    dti->dt);
+			"Warning: Preexisting data in %s malformed, some content could not be added.\n",
+			name);
+}
+
+static void local_fixup_phandles_node(struct dt_info *dti, struct node *lf, struct node *n)
+{
+	struct property *lfp;
+	struct node *lfsubnode;
+
+	for_each_property(lf, lfp) {
+		struct property *p = get_property(n, lfp->name);
+		fdt32_t *offsets = (fdt32_t *)lfp->val.val;
+		size_t i;
+
+		if (!p) {
+			if (quiet < 1)
+				fprintf(stderr, "Warning: Property %s in %s referenced in __local_fixups__ missing\n",
+					lfp->name, n->fullpath);
+			continue;
+		}
+
+		/*
+		 * Each property in the __local_fixups__ tree is a concatenation
+		 * of offsets, so it must be a multiple of sizeof(fdt32_t).
+		 */
+		if (lfp->val.len % sizeof(fdt32_t)) {
+			if (quiet < 1)
+				fprintf(stderr, "Warning: property %s in /__local_fixups__%s malformed\n",
+					lfp->name, n->fullpath);
+			continue;
+		}
+
+		for (i = 0; i < lfp->val.len / sizeof(fdt32_t); i++)
+			add_phandle_marker(dti, p, dtb_ld32(offsets + i));
+	}
+
+	for_each_child(lf, lfsubnode) {
+		struct node *subnode = get_subnode(n, lfsubnode->name);
+
+		if (!subnode) {
+			if (quiet < 1)
+				fprintf(stderr, "Warning: node %s/%s referenced in __local_fixups__ missing\n",
+					lfsubnode->name, n->fullpath);
+			continue;
+		}
+
+		local_fixup_phandles_node(dti, lfsubnode, subnode);
+	}
+}
+
+void local_fixup_phandles(struct dt_info *dti, const char *name)
+{
+	struct node *an;
+
+	an = get_subnode(dti->dt, name);
+	if (!an)
+		return;
+
+	local_fixup_phandles_node(dti, an, dti->dt);
 }

meson.build

@@ -18,6 +18,7 @@ add_project_arguments(
     '-Wshadow',
     '-Wsuggest-attribute=format',
     '-Wwrite-strings',
+    '-Wdiscarded-qualifiers',
   ]),
   language: 'c'
 )

srcpos.c

@@ -88,6 +88,26 @@ static char *shorten_to_initial_path(char *fname)
 	return NULL;
 }
 
+/**
+ * Returns true if the given path is an absolute one.
+ *
+ * On Windows, it either needs to begin with a forward slash or with a drive
+ * letter (e.g. "C:").
+ * On all other operating systems, it must begin with a forward slash to be
+ * considered an absolute path.
+ */
+static bool is_absolute_path(const char *path)
+{
+#ifdef WIN32
+	return (
+		path[0] == '/' ||
+		(((path[0] >= 'A' && path[0] <= 'Z') || (path[0] >= 'a' && path[0] <= 'z')) && path[1] == ':')
+	);
+#else
+	return (path[0] == '/');
+#endif
+}
+
 /**
  * Try to open a file in a given directory.
  *
@@ -103,7 +123,7 @@ static char *try_open(const char *dirname, const char *fname, FILE **fp)
 {
 	char *fullname;
 
-	if (!dirname || fname[0] == '/')
+	if (!dirname || is_absolute_path(fname))
 		fullname = xstrdup(fname);
 	else
 		fullname = join_path(dirname, fname);

tests/retain-fixups.dts

@@ -0,0 +1,29 @@
+/dts-v1/;
+/plugin/;
+
+/ {
+	fixup-node {
+		property = <0xffffffff>;
+		property-with-fixup = <0xffffffff>;
+		property-with-label = <&somenode>;
+		property-with-label-and-fixup = <&somenode>;
+	};
+
+	label: local-fixup-node {
+		property = <0xffffffff>;
+		property-with-local-fixup = <0xffffffff>;
+		property-with-local-label = <&label>;
+		property-with-local-label-and-fixup = <&label>;
+	};
+
+	__fixups__ {
+		somenode = "/fixup-node:property-with-fixup:0", "/fixup-node:property-with-label-and-fixup:0";
+	};
+
+	__local_fixups__ {
+		local-fixup-node {
+			property-with-local-fixup = <0x00>;
+			property-with-local-label-and-fixup = <0x00>;
+		};
+	};
+};

tests/run_tests.sh

@@ -667,6 +667,11 @@ dtc_tests () {
         run_test dtbs_equal_ordered $tree.test.dtb $tree.test.dts.test.dtb
     done
 
+    # Check preservation of __fixups__ and __local_fixups__
+    run_dtc_test -I dts -O dtb -o retain-fixups.test.dtb "$SRCDIR/retain-fixups.dts"
+    run_fdtget_test "/fixup-node:property-with-fixup:0 /fixup-node:property-with-label-and-fixup:0 /fixup-node:property-with-label:0" retain-fixups.test.dtb /__fixups__ somenode
+    run_fdtget_test "property-with-local-fixup\nproperty-with-local-label-and-fixup\nproperty-with-local-label" -p retain-fixups.test.dtb /__local_fixups__/local-fixup-node
+
     # Check -Oyaml output
     if ! $no_yaml; then
             for tree in type-preservation; do
@@ -749,7 +754,6 @@ dtc_tests () {
     check_tests "$SRCDIR/bad-phandle-cells.dts" interrupts_extended_property
     check_tests "$SRCDIR/bad-gpio.dts" gpios_property
     check_tests "$SRCDIR/good-gpio.dts" -n gpios_property
-    check_tests "$SRCDIR/bad-graph.dts" graph_child_address
     check_tests "$SRCDIR/bad-graph.dts" graph_port
     check_tests "$SRCDIR/bad-graph.dts" graph_endpoint
     check_tests "$SRCDIR/bad-graph-root1.dts" graph_nodes
@@ -758,7 +762,6 @@ dtc_tests () {
     check_tests "$SRCDIR/bad-graph-root4.dts" graph_nodes
     check_tests "$SRCDIR/bad-graph-reg-cells.dts" graph_endpoint
     check_tests "$SRCDIR/bad-graph-reg-cells.dts" graph_port
-    check_tests "$SRCDIR/bad-graph-child-address.dts" graph_child_address
     run_sh_test "$SRCDIR/dtc-checkfails.sh" deprecated_gpio_property -- -Wdeprecated_gpio_property -I dts -O dtb "$SRCDIR/bad-gpio.dts"
     run_sh_test "$SRCDIR/dtc-checkfails.sh" -n deprecated_gpio_property -- -Wdeprecated_gpio_property -I dts -O dtb "$SRCDIR/good-gpio.dts"
     check_tests "$SRCDIR/bad-interrupt-cells.dts" interrupts_property

treesource.c

@@ -173,23 +173,59 @@ static struct marker **add_marker(struct marker **mi,
 	return &nm->next;
 }
 
-static void add_string_markers(struct property *prop)
+void property_add_marker(struct property *prop,
+			 enum markertype type, unsigned int offset, char *ref)
 {
-	int l, len = prop->val.len;
+	add_marker(&prop->val.markers, type, offset, ref);
-	const char *p = prop->val.val;
+}
+
+static void add_string_markers(struct property *prop, unsigned int offset, int len)
+{
+	int l;
+	const char *p = prop->val.val + offset;
 	struct marker **mi = &prop->val.markers;
 
 	for (l = strlen(p) + 1; l < len; l += strlen(p + l) + 1)
-		mi = add_marker(mi, TYPE_STRING, l, NULL);
+		mi = add_marker(mi, TYPE_STRING, offset + l, NULL);
 }
 
-static enum markertype guess_value_type(struct property *prop)
+void add_phandle_marker(struct dt_info *dti, struct property *prop, unsigned int offset)
 {
-	int len = prop->val.len;
+	cell_t phandle;
-	const char *p = prop->val.val;
+	struct node *refn;
-	struct marker *m = prop->val.markers;
+	char *ref;
+
+	if (prop->val.len < offset + 4) {
+		if (quiet < 1)
+			fprintf(stderr,
+				"Warning: property %s too short to contain a phandle at offset %u\n",
+				prop->name, offset);
+		return;
+	}
+
+	phandle = dtb_ld32(prop->val.val + offset);
+	refn = get_node_by_phandle(dti->dt, phandle);
+
+	if (!refn) {
+		if (quiet < 1)
+			fprintf(stderr,
+				"Warning: node referenced by phandle 0x%x in property %s not found\n",
+				phandle, prop->name);
+		return;
+	}
+
+	if (refn->labels)
+		ref = refn->labels->label;
+	else
+		ref = refn->fullpath;
+
+	add_marker(&prop->val.markers, REF_PHANDLE, offset, ref);
+}
+
+static enum markertype guess_value_type(struct property *prop, unsigned int offset, int len)
+{
+	const char *p = prop->val.val + offset;
 	int nnotstring = 0, nnul = 0;
-	int nnotstringlbl = 0, nnotcelllbl = 0;
 	int i;
 
 	for (i = 0; i < len; i++) {
@@ -199,30 +235,49 @@ static enum markertype guess_value_type(struct property *prop)
 			nnul++;
 	}
 
-	for_each_marker_of_type(m, LABEL) {
+	if ((p[len-1] == '\0') && (nnotstring == 0) && (nnul <= len - nnul)) {
-		if ((m->offset > 0) && (prop->val.val[m->offset - 1] != '\0'))
-			nnotstringlbl++;
-		if ((m->offset % sizeof(cell_t)) != 0)
-			nnotcelllbl++;
-	}
-
-	if ((p[len-1] == '\0') && (nnotstring == 0) && (nnul <= (len-nnul))
-	    && (nnotstringlbl == 0)) {
 		if (nnul > 1)
-			add_string_markers(prop);
+			add_string_markers(prop, offset, len);
 		return TYPE_STRING;
-	} else if (((len % sizeof(cell_t)) == 0) && (nnotcelllbl == 0)) {
+	} else if ((len % sizeof(cell_t)) == 0) {
 		return TYPE_UINT32;
 	}
 
 	return TYPE_UINT8;
 }
 
+static void guess_type_markers(struct property *prop)
+{
+	struct marker **m = &prop->val.markers;
+	unsigned int offset = 0;
+
+	for (m = &prop->val.markers; *m; m = &((*m)->next)) {
+		if (is_type_marker((*m)->type))
+			/* assume the whole property is already marked */
+			return;
+
+		if ((*m)->offset > offset) {
+			m = add_marker(m, guess_value_type(prop, offset, (*m)->offset - offset),
+				       offset, NULL);
+
+			offset = (*m)->offset;
+		}
+
+		if ((*m)->type == REF_PHANDLE) {
+			m = add_marker(m, TYPE_UINT32, offset, NULL);
+			offset += 4;
+		}
+	}
+
+	if (offset < prop->val.len)
+		add_marker(m, guess_value_type(prop, offset, prop->val.len - offset),
+			   offset, NULL);
+}
+
 static void write_propval(FILE *f, struct property *prop)
 {
 	size_t len = prop->val.len;
-	struct marker *m = prop->val.markers;
+	struct marker *m;
-	struct marker dummy_marker;
 	enum markertype emit_type = TYPE_NONE;
 	char *srcstr;
 
@@ -241,14 +296,8 @@ static void write_propval(FILE *f, struct property *prop)
 
 	fprintf(f, " =");
 
-	if (!next_type_marker(m)) {
+	guess_type_markers(prop);
-		/* data type information missing, need to guess */
+	m = prop->val.markers;
-		dummy_marker.type = guess_value_type(prop);
-		dummy_marker.next = prop->val.markers;
-		dummy_marker.offset = 0;
-		dummy_marker.ref = NULL;
-		m = &dummy_marker;
-	}
 
 	for_each_marker(m) {
 		size_t chunk_len = (m->next ? m->next->offset : len) - m->offset;
@@ -369,7 +418,10 @@ void dt_to_source(FILE *f, struct dt_info *dti)
 {
 	struct reserve_info *re;
 
-	fprintf(f, "/dts-v1/;\n\n");
+	fprintf(f, "/dts-v1/;\n");
+	if (dti->dtsflags & DTSF_PLUGIN)
+		fprintf(f, "/plugin/;\n");
+	fprintf(f, "\n");
 
 	for (re = dti->reservelist; re; re = re->next) {
 		struct label *l;